Consilience: The Unity of Knowledge

A c c l a i m f oEro w e n o O . W l r - s o N ' s

ffi //-\

.1 .

uonslllence "Edward O. Wilson is a hero . . . he has made landmark scientificdiscoveriesand has a writing styleto die for. . . . A complex and nuanced -TheBostonGlobe argument."

of sciencesince popularizers "One of the clearest andmostdedicated -Time T. H. Huxley. . . Mr. Wilsoncando the sciencecnd theprose-" "Exceptionallyinsigh$rl. . . . Looking beyond today'sspectacular . . . in readingthe molecularlycodedbook of life, Wilson advances will give us pointsto a fuhrrein which this biologicalunderstanding polarized much . . . He cutsthrough th" potu".to reshapeourselves. ,,orri.rrt. aboutnatureversusnurtureor genesversusculfure,showing howbothareasrelevantto usasto otheranimals."-ScientificAmerican to be "A workto be held in awe,to be readwith joy and attentiveness, ' act . . an celebratedandchallengedandreturnedto againand again of consummateintellecfual heroism."

-The BaltimoreSun

"An excellentbook. Wilson providessuperb overviewsof Western intellectualhistoryand the current stateof understandingin many -Slate disciplines." academic mind wide-ranging "TheRenaissance scholarstilllives.. . . A sensitive, is courage discoursingbeautifully.. . . Wilson'sbuoyantintellectual *SeattleWeeklY bracing." "Extraordinarilyclear,evocative. . . elegant' . . the sheerbreadthof his proiectand daringin its undertakingwin him the benefitof the -PublishersWeekly doubt....Atourdeforce."

EpwARD O. WTLSoN ,-t

.I.

uonslllence EowARD O. WILsoN wasborn in Birmingham,Alabaffia,in 1929. He received his B.S. and M.S. in biology from the University of Alabama and, in 1955,his Ph.D. in biol ogyfrom Harvard, where he has since taught, and where he has receivedboth of its college-wide teaching awards.He is currently Pellegrino University ResearchProfessor and Honorary Curator in Entomology of the Museum of Comparative Zoology at Harvard. He is the author of two Pulitzer Prize-winning books,On Human Nature (tqZ8) and The Ants (t99o, with Bert H
ALSO

BY EDWARD

O, WILSON

Naturalist TheDiversityof Life The Ants (withBertH\lldobler) Btophilia OnHumanNature Sociobiology: TheNewSynffiesis Thelntect Societies

Consilience

Enweno O. WrlsoN

Consilience THE UNITY OF KNOWLEDGE

Vtxt.lcn Boors A DIVISION OF RANDOM HOUSE' INC. NEW YORK

FIRST VTNTACE BOOKS EDITTON, ApRIL rggg

Co.pyright@ry98by EdwardO.Wilson All rightsreservedunderlnternationalandpan-American Copyright Conventions.Publishedin the UnitedStatesby VintageBooks, a divisionof RandomHouse,Inc.,Newyork,andsimultaneously in Canadaby RandomHouseof CanadaLimited,Toronto. Originallypublishedin hardcover in the UnitedStates by AlfredA. Knopf,Inc.,NewYork,in 1998. Owing to limitationsof space,all acknowledgmenb of permission to reprintpreviouslypublishedmaterialwill be foundfollowing the index. The Libraryof Congresshascatalogedthe Knopfeditionasfollows: Wilson,EdwardOsborne. Consilience: the unityof knowledge / EdwardO. Wilson.-rsted. P. cm. 'A Borzoibook." Includesindex. tsnNo-679_45o77_7 philosophyandscience. r. Philosophy.z. Order (Philosophy). 3. I. Tide. Y72.w54ry98 u.t-dczr g7-28t6 CIP

Vintage rssN:o-67g-76867-x Authorphotogtaph@I. D. Sloan Designedby Cassandral. Pappas www.randomhouse.com Printedin the United Statesof America ro9876

ThushaveI madeasit werea smallglobeof the intellectual world, as truly and faithfully as I coulddiscover. FRlNcrs BecoN (16o5)

CONTE NTS

C H A P T E RT

The IonianEnchantment

C H A P T E R2

of Learning The GreatBranches

cHAPTER 3

The Enlightenment

r5

cHAPTER 4

The NaturalSciences

49

CHAPTER5

fuiadne'sThread

C H A P T E R6

The Mind

72 ro5

cHAPTER 7

FromGenesto Culture

176

CHAPTER8

The Fitnessof HumanNature

r78

cHAPTER 9

The SocialSciences

t97

C H A P T E RT O

The futs andTheir InterPretation

229

C H A P T E RT T

EthicsandReligion

z6o

C H A P T E RT 2

To What End?

29L

Nofes

327

Acknowledgments

353

Index

357

3 8

Consilience

CHAPTER

T

THs IoNleN EUcHANTMENT

dream-ofuniI n n rvrn ras u n verywell the time I wascapturedby the came eighteen-I at fied learning.It wasin the early fall of ry47,when theUniat year io entermy sophomore up fro* Vtoiite to Tuscaloosa by adolescententhusibiologist,-fired A beginning ef"Uama' in natural "f "Jniry as* but shorton theory"andu[iorr, I-hadschooledmyself excursions solitary during satchel in a trir,orywith field guidei canied and along the freshwaterstreamsof my native into the woodlan-ds I still mean)the ,a",., f sawscience,by which I ireant (andin my heart outdoors' stay to way asa wonderful snakes, ri"if oft"r, togt, . ""a eighteenth' the My inteilectiralworld was framedby Linnaeus' classifica' centuryswedishnahrralistwho inventedmodernbiological by separating tion. The Linnaeansystemis deceptivelyeasy'You start sort species you Then species' into animals sp."irn.rs of planb and of such Examples g"n"t"' th" groups, into ,'"r.rniting on, "rroth", tTl.P::i"J you Next oaks' all the ;;";pt are"allthe crowsand }bd the rsn t**p.rt Latinized name, such asCorvus ossiftagustor iith crows" of species the crow,where Cornn standsfor the genus-all higherclasi^"a"ttifr"gs for the fish crow in particular'Then on to familiesinto i"*io", wtere similar generaaregroupedinto families' six orders,and so on up to-phylaand finally,at the very summif-the animals,fungi, protisb,monerans'and archaea'It ti"ga"it-planr, into islike the army:men lplus women,nowadap)into squads'squads

CoNsrrrnNcs platoons,platoonsinto companies,and in the final aggregate, the armedseruices headedby the joint chiefsof staff.It is,in ofr.i*orar, conceptualworldmadefor the mind of an eighteen_year_old. " I had reachedthe levelof the Carolu,LI.,.,".u, of ry35or, more accurately(sinceat that time I knew littre of the swedish #ast..), tr," Roger'ToryPeterson 9!Wl+, when the greatnaturalistpublishelthe first edition of A Fierd cuide to the Biids.My Linnaean period was nonetheless a goodstart for a scientificcareer. ih" firrt rt"p io *irdorr,, asthe Chinesesay,isgettingthingsby theirright names. Then I discovered. evolution.Suddenlyiglat is not too stronga word-I sawthe worldin a wholly .,.r, *"y. This epiphany f or""a-to my mentorRalphChermock,an intense,chairr_r.rrtkl.,g youngassistant professornewlyarrivedin the provinceswith a ph.d i., .r,t*orogy from cornell university.Aftei listeningto me natter for a whire aboutmy loftygoalof classifying all the aris of Alabama,he handec me a copy of ErnstMayr's Systematics and the Origin of Species. ry42 Readit,h.esaid,ifyou wantto becomea realbiologist. The thin volumein the plain blue cover*r, o'n. of the New synthesis the nineteenth-century Darwinian theory of .works,-uniting evolutionand moderngenetics.By givinga theoretical shuctureto nafuralhistory,it vastlyexpandedtheLinnaeanenterprise. A tumbler fell.somewherein my mind, and a door openedto a new world. I was enthralled,couldn'tstop thinking aboutthe imprications evolution has for classificationand for the iest of biorogy.i'd fo, philosophy. And for iust abouteverything.static patternslil'i'to nuid ito""rr.'rriy ,lo$ht,embryonicaliy tho"r.of a modernbiologist,traueled chain of causalevents,from mutationsthat altef genesto "i"";; euoluti?r, that multipliesspecies, to speciesthat assemble intJfaunasand floras. Scale expanded,and tu-rned-9o1tin_uous. By inwardly *r.,ip,rtJng timeand space,IfoundI could climb the stepsin biological;*;r: tion fr_ommicroscopicparticlesin cellsto thetoreststhafcrothe"mountain slopes.A new enthusiasm surgedthroughme. The animalsand plantsl-loved sodearlyreenteredtle stage t."d players t" ;il;; ", drama.Naturalhistorywasvalidated ,"e"1 science. ", " I had experiencedthe Ionian Enchantment. That recentlycoined expressionI bo'ow from the physicistand historianGerald Fiolton.It meansa beliefin the unity of the sciences-aconviction, far deeper than a mereworkingproposition,that the worldis orderly and b. ""n

The IonianEnchantment

5

to Thales explainedby a smallnumberof naturallaws'Its rootsgoback philoso' legendary of'Mil.trs,ln lonia, in the sixthcenturys.c. The founder the be pt., *", considereiby fuistotletwo cenhrrieslater to concretely of the physicalsciences.He is of courserememberedmore the Although water. of ultimately consists matter for his'beliefthat all Greekspecunotion is oftencitedasan exampleof howfar astrayearly it exmetaphysics the is significance lation could wander, its real nature' of unity the and world the basisof fr.rr.a aboutthe material hasdomiThe Enchantment,growingsteadilymoresophisticated' its focushas physics natedscientificthoughi.u", Ji"""' In modern stong' been the unification of all the forcesof nature-electroweak' as to tight so anJgr"uitation-the hoped-forconsolidationof theory i'perfect"sptem of thought' which by sheer turn the scienceinto a to revision.Butthe spell *"ighr"f *iaence andtoii" i, madere_sistant scienceaswell, and in of fieltls other to of the Enchanbnentexteids and still sciences, social the into the mindsof a few it reachesbeyond of the idea The humanities' further,asI will explainlater,to touchthe experiof baths acid in unity of scienceis not idle. It hasbeentested logic and enioyedrepeatedvindication'It hassufferedno *.r,t "nd by the very decisived.f."at. At leastnot yet,eventhoughat its center' vulnerable' natureof the scientificmethod,it mustbe thoughtalways course' in due expand I will also On thisweakness Ionian Einstein,the architectof grandunificationin physics'was e-arly In strength' greatest his to the core.That vision wa, ierhaps 1 a wonderful-feel"It is lefter to his friend Marcel Giorrrnarmhe said, to direct i"g il t."og"ize the unity of a complexof phenomenathat to his referring things'' He was to be quite ob"servatioriappear "p"'"tt physicsof capillarieswith the alignmentof the -icroscopic successful physicsof gravity'In laterlife he aimedto universe-wide macroscopic, with *.ia .".ty,fting else into a singlepaisimonioussystem'space He cosmology' and eiectromagnetism time and motion, gravity*ith not Einstein scientisb' All but nwer capturedthat-grail' approached to grasp .*iept.d, are children of Tantalus,frustratedby the failure thermothose by that which seemswithin reach' They are typified temperature havedrawnevercloserto the dynamicisbwho for decades ceaseall motion' In 1995'pushingdown atoms when zero, oi absolute created to within a fewbillionths of a degreeaboveabsolurezero'they the beyond matter of form fu-nd"*"ntal condensate, a Bose-Einstein "

6

6oNSrLrENcE

familiargases, Iiquids,andsolids,in whichmanyatomsactasa singie atom in one quantumstate.As temperaturedropsand pressure is Tn_ creased,a gascondenses into a liquid, then a solid;then appearsthe Bose-Einstein condensate. But absolute, entirelyabsolute,"ro, ton_ peraturethatexistsin imagination, hasstillnotbeenattained. " on a far moremodestscale,I foundit a wonderfur feelingnot iust to tastethe unificationmetaphysicsbut alsoto be released ?.o- th" confinementof fundamentalist rerigion.I hadbeenraiseda southem Baptist,laid backwardunder the wateron the sturdyarm of a pastor, been born again.I knew the healingpowerof redemption.'f,ritt,, hope,and charitywerein my bones,andwithmillionsof others I knew that my savior/esusChristwould grantme eternallife. More pious than the averageteenager,I readthe Bible coverto cover,h+,ice. But now at college,steroid-driven into moodsof adorescent rebelrion,I choseto doubt.I foundit hardto acceptthatour deepest beliefswere setin stoneby agriculfuralsocietiesof the easternMediterranean more thousandyearsago.r sufferedcognitivedissonance between fan -two the-cheerfullyreportedgenocidalwarsof ihere peopleand Christian civilizationin r94osAlabama.It seemedto methattheBookof Revelation might be blackmagichallucinatedby an ancientprimitive. And I thought,surelya lovingpersonalGod, ii He is payingattention, will not abandonthosewho rejectthe literal interpretationof the bibrical cosmology.It is only fair to awardpointsfor inteilectuar n.iter damnedwith PlatoandBacon,bheileysaid,thango to"our"g". heauZ.with Paleyand Malthus.But mostof all, Baptisttheorogyriude no provision for evolution The biblicalauthorshai missedthJmost i-po.t"rri r"uelationof alll could it bethattheywerenot reailyprivyto a. *rrrrgio of God?.Might the pastorsof my childhood, iood and loving rien though lhey were,be mistaken?It wasall too much,and freedol was eversosweet.I driftedawayfrom the church,not definitively agnostic or atheistic,iustBaptistno more. Still, I had no desireto purgereligiousfeelings. Theywerebredin me; they suffirsedthe wellspringtoi-y creativelife. i arsoretained a small measureof commonsense.To wi! peoplemustbelong to a tribe; they yearn to have a purposelarge, ti"rr themselves. d. ,r" obliged by the deepestdrivesof the huiran spirit to make ourselves morethan animateddust,andwe musthavea storyto tell about where we camefrom, and why we arehere.Could Holy Writ be iustthe firsi literateaftemptto explainthe universeand makeourrdu., slgrifi;i

The lonianEnchantment

7

within it? Perhapsscienceis a continuationon new and befter-tested groundto attainthe sameend. If so,then in that sensescienceis religionliberatedandwrit large Such, I believe,is the sourceof the Ionian Enchantment:Preferringa searchfor obiectiverealityoverrevelationis anotherwayof religioushunger.It is an endeavorafmostasold ascivilizasatisfuIng tion aniintei*in.d *iih tr"ditiotralreligion,but it followsa verydifferent course-a stoic'screed, an acquired taste, a guidebookto adventureplottedacrossroughterrain.It aimsto savethe spirit,not by surrenderLut by liberationof the human mind. Its centraltenet,as Einsteinknew,is the unificationof knowledge'When we haveunified enoughcertainknowledge,we will understandwho we are and why we arehere. If thosecommittedto the questfail, they will be forgiven.when lost,theywill find anotherway.The moral imperativeof humanismis or not, providedthe effort is the endeavoralone,whethersuccessful the honorableand failure memorable.The ancientGreeksexpressed with from crete ideain a mythof vaultingambition.Daedalusescapes and wax.Ignorfeathers from fashioned has he wings on his sonIcaius whereupon sun, the toward flies Icarus father, his ing the wamingsof of lcarus end is the That sea. the into falls hiiwings comeapartandhe boy?-Did foolish a he Was iust in the riyth. But we areleft to wonder: he payth. pricefor hubris,for pridein sightof the gods?I like to think a savinghuman grace'And t}t"i on the contraryhis daringrepresents so the great astropirysicistSubrahmanyanChandrasekharcould pay tributeio the spiritoihis mentor,Sirfuthur Eddington,by saying:Let us seehowhigh we can fly beforethe sun melb the waxin our wings'

CHAPTER

2

THe Gnrar BnaNcnps op LnenNrNG

You wrrl sEE at once why I believethat the Enlightenment thinkersof the seventeenth and eighteenthcenturiesgot it riostly right the first time. The assumptions th"y madeof a lawfui materialffi;, the inhinsic unity ofknowledge,and the potentialof indefinitehuman progressare the oneswe still take most readilyinto our hearb,suffer without, and find maximallyrewardingthroughintellechral "iu.".. The greatestenterpriseof the mind hasal*ays-been andalwap will be the attemptedlinkageof the sciencesand irumanities.The ongoing fragmentationof knowledgeand resurtingchaosin phirosophyar?noi reflectionsof the real world but artifacs of scholarship. rir. p.poJ tionsof the originalEnlightenmentare increasingly favoredUyoU;""_ tive evidence,especially from the naturalsciences. consilienceis the keyto unification.I preferthis wordover..coherence"becauseib rarityhaspreservedits precision,whereascoherence hasseveralpossiblemeanings,only one of which is consilience. william whewell, in his r84osynthesis ihe philosophy of thernductive Sciences, wasthe first to speakof consilience,literally a ..jumpingto_ gether" of knowledgeby the linking of facb and fact-baseatrrlo, acrossdisciplinesto createa common groundworkof explanation.He said,"The consilienceof Inductionstakesplacewhenan Induction,

The GreatBranchesof Learning

9

obtainedftom one classof facb, coincideswith an Induction, obtained from anotherdifferentclass.This Consilienceis a testof the huth of the Theoryin which it occurs." The only wayeitherto establishor to refuteconsilienceis by methodsdevelopedin the nahrralsciences-no! I hastento add,an effort or frozenin mathematicalabshaction,but ratherone led by scientists, allegiantto thehabin of thoughtthathaveworkedsowell in exploring the materialuniverse. The belief in the possibilityof consiliencebeyondscienceand acrossthe greatbranchesof learningis not yet science.It is a metaphysicalwJrld view,and a minority one at that, sharedby only a lew scientismand philosophers.It cannotbe provedwith logic from-first principlesol.gio,*ded in any definitivesetof empiricaltests,at least not by anyyeiconceived.Ib bestsupportis no morethan an extrapolaof the naturalsciences.lts suresttest pastsuccess tion of the consistent will be ib effectivenissin the socialsciencesand humanities.The shongestappealofconsilienceis in the prospectof intellectualadventure ind, ginatt.n"tt modestsuccess'the value of understandingthe humanconditionwith a higherdegreeof certainty' just Bearwith me while I cite an exampleto illustratethe claim made.Think of two intersectinglinesforminga cross,and picturethe four quadrantsthus created.l,abel one quadrantenvironmental policy,the nextethics,the nextbiology,andthe final one socialscience'

we alreadyintuitivelythink of thesefour domainsascloselyconnected,,o thai rationalinquiry in one informsreasoningin *re other three.Yetundeniablyeachstandsapartin the contemporaryacademic mind. Eachhasib own practitioners,language,modesof analpis,and of validation.The resultis confusion,and confusionwascorstandards rectly identified by FrancisBacon four centuriesago asthe most fatal

lo

CoNsll,tsNce

of errors, which "occurs wherever argument or inference passesfrom one world of experience to another." Next draw a series of concentric circles around the point of intersection.

environmental

As we crossthe circlesinward towardthe point at which the quadrantsmeet,we find ourselves in an increasingly unstableand disoiienting region.The ring closestto the intersection,wheremostreal-world problems exist,is the one in which fundamentalanalpis is most needed.Yetvirtually no mapsexist.Fewconceptsand wordsserveto guide us.Only in imaginationcanwe tavel clockwisefrom the recog_ nition of environmentalproblemsandthe needfor soundrybasedporicy; to the selectionof solutionsbasedon moral reasonir,g;to the biologicalfoundationsof that reasoning; to a graspof sociali'ititutions asthe producbof biology,environment,andhistory.And thenceback to environmentalpolicy. consider this example.Govemmenbeverywhere areat a lossasto the bestpolicyfor regulatingthe dwindlingforestreserves of the world. There are few establishedethical guidelinesfrom which agreement might be reached,and thosearebasedon an insufficientknoi,ledgeof ecology. -!_ve1if adequatescientificknowledgewere available,tf,ere would still be little basisfor the long-termval,t"tio'of forests.The ece nomicsof sustainable yield is still a primitiveart,and the psychological benefir of naturalecosyntems arealmostwhollyunexplored. The time hascometo achievethetour in reality.rt i, i, notan idle exercisefor the delectationof intellectuals.How wiselypolicy is che senwill dependon the easewith which the educatedp;blic;not iust intellectualsand political leaders,can think aroundtheseand similar circuib, startingat anypoint and movingin anydirection. To askif consiliencecan be gainedin the innermostdomainsof

of Learning The GreatBranches

1l

the circles,suchthat soundiudgmentwill flow easilyfrom one discipline to another,is equivalentto askingwhether,in the gatheringof disciplines,specialistscan everreachagreementon a common bodyof abstractprinciplesand evidentiaryproof. I think they can. Trust in consilienceis the foundationof the naturalsciences.For the material world at least,the momentum is overwhelminglytowardconceptual unity. Disciplinary boundarieswithin the nahrral sciencesare disap p."iing, to be replacedby shifting hybrid domains in which con,ili.rr"! is implicit. These domains reach acrossmany levels of complexity,from chemicalphpics and phpical chemistryto molecular genetics,chemicalecology,and ecologicalgenetics'None -of the is consideredmorethana focusof research.Eachis an new specialties industryoffreshideasand advancingtechnology. Given that human action comprisesevenb of physical causation, why shouldthe socialsciencesand humanitiesbe imperviousto conAnd how can they fail to benefit siliencewith the natural sciences? to saythat human actionis historienough It is not from that alliance? of cal, and that history is an unfolding unique evenb' Nothing fundathe courseof human history from the courseof mental separates phpical history,whetherin the starsor in organicdiversity'fubonomy, of primarily historical i"otogy, and evolutionarybiologyareexamples lit"ipiir,.t linked by consilienceto the rest of the nahrral sciences' History is todaya fundamentalbranch of learning in ib own right, down to the finest detail. But if ten thousandhumanoid histories could be bacedon ten thousandEadhlikeplanets,and ftom a comparativestudyof thosehistoriesempiricaltestsand principles_evolved, iristoriography-the explanationof historicaltrends- would already be a nafuralscience. The unification agendadoesnot sit well with a few professional The subiectI addresstheyconsidertheir own, to be exphilosophers. pressed-intheir language,their frameworkof formal thought' They will draw this indichnent: conflation, simplism,ontologicalreduction' ism, scientimt,and other sins made official by the hissing suffix' To which I pleadguilty,guilty,guilty.Now let us moveon, thus' Philoso' and it keepsus alive-to phy plap a vital role in intellectualsynthesis, if," io*o and continuity of thought through the centuries. It also p..r, irrto the future to give shapeto the unknown-and that hasalwaysbeenib vocationof choice.One of ib mostdistinguishedpractihasrecentlyarguedthat philosophyin tioners,AlexanderRosenberg,

rz

CoNsrr,rrNcs

fact addresses the questions that the sciences-physiiusttwo issues: cal,biological,andsocial-cannotanswer, andthe reasons for thatincapacity."Now of course,"he concludes,'.theremay not be any questions thatthe sciences cannotanswereventually, in the long run, when all the factsare in, but certainlytherearequestionsthat tte sciencescannotansweryef."This assessment is admirablyclearandhonestandconvincing. It neglects, however, theobviousfactthatscientists areequallyqualifiedto iudgewhatremainsto be discovered, andwhv. Therehasneverbeena bettertime for collaboration betweenscientists and philosophers, especially wherethey meetin the borderlands betweenbiology,the socialsciences,and the humanities.We are ap_ proachinga newageof synthesis, whenthetestingof consilience isthe greatestof all intellectualchallenges. Philosophy, the contemplation of the unknown,is a shrinkingdominion.We havethe commongoal of turningasmuchphilosophyaspossible into science.

Ir rgn woRLD reallyworksin a waysoasto encourage the con_ silienceof knowledge, I believethe enterprises of culturewill eventuallyfall out intoscience, by which I meanthenaturalsciences, andthe humanities,particularlythe creativearts,Thesedomainswiil be the two greatbranchesof learningin the twenty-firstcentury.The social sciences will continueto split within eachof its disciplines, a process alreadyrancorottslybegun, with one part folding into or becoming continuouswith biology,the other fusingwith the humanities.Its disciplines will continue to exist but in radicallyalteredform. In the processthe humanities,rangingfrom philosophyand historyto moral reasoning,comparativereligion, and interpretationof the arts,will drawcloserto the sciencesand partlyfusewith them. of theseseveral subiecbI will saymorein laterchapters. I admit that the confidenceof nafuralscientistsoften seemsoverweening.Scienceoffersthe boldestmetaphysics of the age.It is a thoroughly human construct,driven by the faith that if we dieam,pressto discover,explain,and dreamagain,therebyplungingrepeatedly into new terrain,the world will somehowcomeclearerand we wiil grasp the true strangeness of the universe.And the shangeness will all provl to be connectedandmakesense. In his r94r classicMan on His Nature,the British neurobiologist CharlesSherrin$onspokeof the brain asan enchantedloo*, p.ri.t-

of Learning The GreatBranches

r7

ually weavinga picture of the externalworld, tearing down and inventingotherworlds,creatinga miniatureuniverse.The reweaving, communalmind of literatesocieties-worldculture-is an immensely largerloom.Through scienceit hasgainedthe powerto map external realityfar beyondthe reachof a singlemind, and throughthe arb images,and rhythmsimmeasurably the meansto conshuctnarratives, products of any solitarygenius.The loom is the morediversethan the for scienceand for the arts,and there is a samefor both enterprises, generalexplanationof ib origin and natureand thenceof the human condition,proceedingfrom the deephistoryof geneticevolutionto modernculture. Consilienceof causalexplanationis the meansby which the singlemind cantravelmostswiftlyand surelyftom onepart of the communalmind to the other. In educationthe searchfor consilienceis the way to renewthe crumbling structureof the liberal arts.During the pastthirf years and Enlightthe idealof the unity of learning,which the Renaissance enment bequeathedus, has been largelyabandoned'With rare exceptionsAmerican universitiesand collegeshave dissolvedtheir courses' and specialized curriculuminto a slurryof minor disciplines coursesper institution While the averagenumber of undergraduate doubled,the percentageof mandatorycoursesin generaleducation in the same droppedby more than half- Sciencewas sequestered and colleges universities third of period;as I write, in ryg7,only a The requirestudentsto takeat leastonecoursein the naturalsciences. trend cannot be reversedby force-feedingstudentswith some-ofof learning.Win or lose,true the branches across thisandsome-of-that reformwill aim at the consilienceof sciencewith the socialsciences and humanitiesin scholarshipand teaching.Every collegestudent shouldbe ableto answerthe followingquestion:What is the relation betweenscienceand the humanities,and how is it importantfor humanwelfare? Everypublicintellectualandpoliticalleadershouldbe ableto answerthat questionaswell. Alreadyhalf the legislationcomingbefore the United StatesCongresscontainsimportantscientificand techno' thatvexhumanitydaily-ethMost of the issues logicalcomponents. abortion,environment, nic conflict,armsescalation,overPopulation, beforeus-cannot be endemicpoverty,to citeseveralmostpersistently naturalscienceswith from the knowledge solvedwithout integrating that of the socialsciencesand humanities.Onlv fluencyacrossthe

14

CoNsllrrNce

boundarieswill providea clearview of the world asit really is, not as seenthrough the lens of ideologiesand religiousdogmasor commandedby myopicresponse to immediateneed.Yetthe vastmajority of our politicalleadersare trainedexclusively in the socialsciences and humanities,and have little or no knowledgeof the natural sciences.The sameistrueof the public intellecfuals, the columnists, the media interrogators,and think-tankgurus.The bestof their analyses are carefuland responsible, and sometimes correct,but the substantive baseof their wisdomis fragmentedandlopsided. A balancedperspective cannotbe acquiredby studyingdisciplines in piecesbut throughpursuitof the consilience amongthem. Such unificationwill comehard.But I think it is inevitable.Intellectuallyit ringstrue,and it gratifiesimpulsesthatrisefromthe admirablesideof human nature.To the extentthat the gapsbetweenthe greatbranches of learningcanbe narrowed,diversityanddepthof knowledgewill increase.They will do so becauseof, not despite,the underlyingcohesion achieved.The enterpriseis importantfor yet anotherreason:It givesultimate purposeto intellect. It promisesthat order,not chaos, lies beyondthe horizon.I think it inevitablethatwe will acceptthe advenfure,go there,andfind out.

CHAPTER

J

THn ENTTcuTENMENT

Tnn onneM oF INTELLECTUALuNtrv firstcameto full an Icarianflight of the mind flowerin the originalEnlightenment, and eighteenthcenturies.A vision of that spannedthe seventeenth secularknowledgein the serviceof human rightsandhumanprogress, it wasthe West'sgeatestcontributionto civilization.It launchedthe Then it failed. modernerafor the wholeworld;we areall its legatees. periodcome historical When does such a futonishingly-it failed. the aftermath to an end?It dieswhen,for whateverreason,usuallyin of warand revolution,ib ideasno longerdominate.It is of surpassing importance,therefore,to understandthe essentialnatureof the Enthat brought it down. Both can be lightenmentand the weaknesses saidto be wrappedup in the life of the Marquisde Condorcet.In particular, no single eventbettermarksthe end of the Enlightenment weteexquisitely thanhis deathon March zg,r7g+.The circumstances l,aws of Progress. prophet of the ironic.Condorcethasbeencalledthe By virtue of his toweringintellect and visionarypolitical leadership, he seemeddestinedto emergefrom the Revolutionasthe ]efferson of France.But in late ryg3and early1794,as he wascomposingthe ultimate Enlightenmentblueprint,Sketchfor a Histoical Pictureof the Prcgresof the Human Mind, he was insteada fugitive from the of the causehe law, liable to sentenceof death by representatives perceivedto political: He was His had sofaithfully served. crime was

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be a Girondist, a member of a faction found too moderate-too reasonable-bythe radical|acobins.Worse,he hadcriticizedthe constitutiondrawnup by the facobindominatedNationalConvention. He died on the floor of a cell in the iail at Bourg-la-Reine, afterbeing mauledby villagerswho had capturedhim on the run. They would certainlyhave turned him over to the Parisauthoritiesfor hial. The causeof deathis unknown.Suicidewasruled out at tlre time. Poison, which he carriedwith him, is nevertheless possible; soaretraumaand heartattack.At leasthe wassparedthe guillotine. The French Revolutiondrew its intellectualstrengthfrom men and women like Condorcet.It wasreadiedby the growthof educational opportunityand then fired by the ideaof the universalrightsof man.Yetasthe Enlightenment seemed aboutto achieveby thismeans political fruition in Europe,somethingwent terriblywrong.What seemedat first to be minor inconsistencies widenedinto catastuophic failures.fean-facquesRousseau, in The SocialContracfthirty years earlier,had introducedthe idea that waslater to inspirethe rallying slogan"Liberty, Equality,Fraternip." But he had also inventedthe deadlyabshactionof the "generalwill" to achievethesegoals.The generalwill, he said,is the rule of justiceagreeduponby assemblies of freepeoplewhoseinterestis only to servethe welfareof the societyand of eachpersonin it. When achieved,it formsa sovereign conhactthat is "alwaysconstant,unalterable,and pure. . . . Eachof usputshis personand all his powerin commonunderthe supremedirectionof the generalwill, and in our corporatecapacity,we receiveeachmemberas an indivisiblepart of the whole."Thosewho do not conformto the generalwill, Rousseaucontinued,are deviantssubiectto necessary forceby the assembly. Thereis no otherwayto achievea huly egalitarian democracyand thus to break humanity out of the chainsthat everywhere bind it. Robespierre, leaderof the Reignof Terrorthat overtookthe Revo Iution in ryg7, graspedthis logic all too well. He and his fellow facobins acrossFrance implemented Rousseau's necessaryforce to include summarycondemnations and executionsfor all thosewho op posedthe new order.Some3oo,ooonobles,priesb,politicaldissidenb, and othertroublemakerswereimprisoned,and r7,ooodiedwithin the year.In Robespierre's universe,the goalsof the facobinswerenoble and pure.They were,ashe serenelywrotein February1794(shortlybe-

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fore he himselfwasguillotined), "the peacefulenioymentof libefly and equality,the rule of that eternaliusticewhoselawshavebeenengraved. . . upon the heartsof men, even upon the heart of the slave who knowsthem not and of the tyrantwho deniesthem." Thus took form the easycohabitationof egalitarianideologyand savagecoercionthat wasto plaguethe next two centuries.Betterto follows,thoseunwilling to makethe exilefrom the tribe,the reasoning commihnentto the perfectsocietythanto riskthe infection of dissent. The demagogue asksonly for unity of purposeon behalfof virtue:"My Volk),eggsmustbe bre' brothersandsisters, fellow citizens(comrades, ken to makean omelette.To achievethat nobleend, it may be necessaryto wagea war."After the Revolutionsubsided,the principle was administeredby Napoleonand the soldiersof the Revolution,who, into the grandearmde,were determinedto having metamorphosed Enlightenment by conquest.Instead,they gaveEuropeadspreadthe ofreason. ditionalcauseto doubtthe sovereignty The decline ofthe EnIn fact, reasonhad neverbeensovereign. lightenmentwashastenednot iust by tyranbwho usedit for iustification but by risingandoftenvalid intellectualopposition.Its dreamof a world madeorderlyand fulfilling by freeintellecthad seemedat first indestructible,the instinctivegoalof all men. Its creators,amongthe greatestscholarssince Plato and fuistotle,showedwhat the human hisIsaiahBerlin,oneof theirmostperceptive mind canaccomplish. "The honpower, intellectual torians,praisedthem fustlyasfollows: love of the huth of the most esty,lucidig, courage,and disinterested gifted thinkersof the eighteenthcenturyremain to this day without parallel.Their ageis one of the bestand mosthopefulepisodesin the life of mankind."But they reachedtoo far, and their besteffortswere not enoughto createthe sustainedefforttheirvisionforetold.

into thelife of the ill-fatedMarieTnrrn spIRIT wAs compressed Caritat,Marquisde Condorcet.He wasthe last fean-Antoine-Nicolas public philosophers the eighteenth-century of the Frenchphilosophes, who immersedthemselvesin the political and social issuesof their times. Voltaire, Montesquieu,d'Alembert,Diderot, Helv€tius,and Condorcet'smentor, the economistand statesmanAnne-Robertwas facquesTurgot,Baronde I Aulne-all thatremarkableassemblage

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gone by 1789.Condorcetwasthe only onein their rankswho lived to seethe Revolution. He embracedit totallyandlaboredin vainto conhol its demonicforce. Condorcetwasborn in ry47in Picardy,oneof the mostnortherly provincesof old France,a memberof an ancientnoble familythat originatedin Dauphin6, the southeastern provincefrom which the dauphin,eldestsonof theking,tookhistide.The Caritatswerehereditary membersof the noblesse d'6.pde, orderof the sword,haditionally devotedto militaryservice,and of highersocialstatusthan the noblesse derobe,or highcivil officials. To the disappointmentof his famrly,Condorcetchosenot to be a soldierlike hisfatherbut a mathematician. At theageof sixteen, while still a studentat the NavarreCollegein Paris,he publiclyreadhisfirst paperon the subject.But havingenteredthe onescientificprofession wheretalentcanbe confidentlysortedintolevelsby the ageof twenty, Condorcetturnedout not to be a mathematician of the firstrank,and certainly nowherenear the equal of his greatcontemporaries LeonhardEulerandPierreSimonde Laplace.Still,he achievedenoughto be elected, at the exceptionallyyoung age of hventy-five,to the Acad6miedesSciences,and at thirty-twobecameits permanentsecretary. In r78o,at age thirty-eight,he wasacceptedinto the august Acad6mieFrangaise,arbiter of the literarylanguageand pinnacleof intellectualrecognitionin his country. Condorcet'sprincipalscientificaccomplishment wasto pioneer the applicationof mathematicsto the socialsciences, an achievement he sharedwith Laplace.He wasinspiredby the idea,centralto the Enlightenmentagenda,that whathad beenaccomplishedin mathematics and physicscan be extendedto the collectiveactionsof men. His ry85 Essayon theApplication of Analysisto the Probabilityof Maiority Decisionsis a distant forerunner of presentdaydecisiontheory.As pure science,however,it is not impressive. While l,aplacedeveloped the calculusof probabilities and appliedit brilliantlyto physics,Condorcetmademinor advancesin mathematics and usedthe techniques he inventedwith little effectin the shrdyof politicalbehavior.Still, the conceptthat socialaction might be quantitativelyanalyzedand even predictedwasoriginal to Condorcet.It influencedthe later develop ment of the socialsciences, especiallytheworkof the earlysociologists AugusteComteandAdolpheQu6teletin the r8oos. Condorcethasbeen called the "noble philosopher,"referringnot

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just to his socialrank but to his characterand demeanor.Without irony his friendsdubbedhim "Le Bon Condorcet,"Condorcetthe who presidedoverhis favoritesalonon the Good.fulie de l,espinasse, rue de Belle Chasse,describedhim thus in a letter to a friend: "His phpiognomyis sweetand calm; simplicityand negligencemark his qualityof hissoul." bearing,"reflectingthe "absolute to others,includingeventhe He wasunfailinglykind andgenerous virulentlyjealousfean-PaulMarat,whoseown ambitionsin science wereunrewardedand who would gladlyhaveseenhim dead.He was committedto the ideal of socialiusticeand the welfare passionately of others,both individuallyand collectively.He opposed,at considerablepoliticalrisk,the colonialpoliciesof France.With l,afayetteand Mirabeau he founded the antislaveryorganizationSocietyof the Friendsof the Blacks.Even afterhe had goneinto hiding during the Terror,his argumentscontributedto the abolitionof slaveryby the NationalConvention. Liberal to the bone, a follower of the English philosopherfohn Locke,Condorcetbelievedin the naturaldghtsof men, and,like his ImmanuelKant,he soughtmoral imperativesthat lead contemporary rather than follow the passions.He ioined Tom Paine to createl-e Mpublicain, a Revolutionaryiournalthat promotedthe ideaof a progressive, egalitarianstate."The time will come,"he laterwrote,"when the sun will shineonly on free men who know no other masterthan theirreason." memory for Condorcetwasa polymathwith a near-photographic relentlessly to acquired and shared whomknowledgewasa heasure be infatuated,praisedthesequalitiesin particfreely.fulie de Lespinasse, ular: "Conversewith him, readwhathe haswritten;talk to him of philosophy,belleslethes,science,the arts,government,iurisprudence, andwhenyouhaveheardhim, youwill tellyourselfa hundredtimesa daythatthis is the mostastonishingmanyouhaveeverheard;he is ignorantof nothing,not eventhe thingsmostalien to his tastesand ocof the courtiers,the details cupations;he will know . . . the genealogies in facf nothing is names the in fashion; of hats of the policeand the beneathhis attention,and his memory is so prodigiousthat he has neverforgottenanything." Condorcet'scombinationof talent and personalitypropelledhim Parisiansocietyand quicklyto the highestlevelsof pre-Revolutionary His taste his reputationasthe youngestof the philosophes. established

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for synthesisled him to fit into a coherentwhole the principal ideas representing,if any suchcollectioncan legitimatelybe saidto do so, the positionof the late Enlightenment.On humannaturehe wasa nurturist:He believedthat the mind is moldedwhollyby its environment,sothat humansarefiee to makethemselves and societyasthey please.He wasconsequently a perfectibilist: The qualityof human Iife, he insisted,can be improvedindefinitely.He waspoliticallya completerevolutionaryboth anticlericaland republican,departing from Voltaireand otherswho would "destroythe altarbut preservethe throne."In socialscienceCondorcetwasa historicist, believingthat historycan be readto understand the presentand predictthe future. As an ethicist,he wascommittedto the ideaof the unity of the human race. And while egalitarian,he was not a multiculturalistin the presentdaysense,but ratherthoughtall societies would eventually evolvetowardthe high civilizationof Europe.Aboveall, he wasa humanitarianwho sawpoliticsaslessa sourceof powerthan a meansof implementinglofty moralprinciples. With the outbreakof the Revolutionin 1789,Condorcetabruptly turned from scholarship andthrewhimselfinto politics.He servedtwo yearsasan electedmemberof the Communeof Paris,and when the LegislativeAssemblywasformedin t7gr,hebecamea deputyfor Paris. Immensely popular among his fellow revolutionaries,he was ap pointedone of the fusemblysecretaries, then electedvice-president and finally president.When the Assemblywassucceededin September rygz by the National Convention,and the Republicestablished, Condorcet waselectedas representative for the Departmentof the Aisne,part of his nativeprovinceof Picardy. Throughouthis brief public career,Condorcettried to stayaloof from partisanpolitics. He had friends amongboth the moderate Girondistsand the leftist Montagnards(the latter so namedbecause their deputiessaton the higherbenches,or "Mountain," of the assembly). He wasidentifiedwith the Girondistsnonetheless, and the more sowhen the Montagnardsfell underthe spellof the radicalwing of the facobin Club of Paris.After the overthrowof the Girondistsduring the popular insurrectionsof ryg3,the Montagnardscontrolledthe ConventionandthentheCommitteeof PublicSafety, which ruledFrance during the yearJongTerror.It wasduringthisspasmof official murder that Condorcetfell fiom hero to criminal suspect,and his arrestwas orderedby the NationalConvention.

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When he leamedof the warrant,Condorcetfled to the boardinghouseof MadameVernet,on the rue Servandoniof old Paris,where he remainedin hiding for eightmonths.In April ry94 the refugewas discovered, and friendswarnedhim that his arrestwasimminent' He escapedonce again,and for severaldayswanderedabout homeless until detectedand throwninto the prisonat BourgJa-Reine. During his stayon the rue Sewandoni,Condorcetwrotehis masof the Human terwork, Sketchfor a Histoical Pictureof the Progress mind and will. Desof both achievement Mind.lt wasa remarkable memhis prodigious on only peratelyinsecure,with no books,relying The humanity. oty, he composedan intellectualand socialhistoryof optimisticin tone,containslittle mentionof the Revotext,relentlessly lution andnoneof his enemiesin the sheetsof Paris.Condorcetwrote asthoughsocialprogressis inevitable,and warsand revolutionswere justEurope'swayof sortingitselfout. arosefromthe convictionthatcultureis govHis sereneassurance ernedby lawsasexactasthoseof physics.We need only understand them,he wrote,to keephumanityon its predestinedcourseto a more perfectsocialorder ruled by scienceand secularphilosophy.These laws,he added,canbe adducedfrom a studyof pasthistory. hustingof Condorcet,howevermistakenin detailsand hopelessly humannature,madea maiorcontributionto thoughtthroughhis in"The solefoundasistencethathistoryis an evolvingmaterialProcess. "is theideathatthe he declared, natural sciences," in the tion for belief known or ununiverse, the of generallawsdirectingthe phenomena be any this principle Why should and constant. known,arenecessary of faculties lesstruefor the developmentof the intellectualand moral manthanfor otheroperationsof nature?" The ideawasalreadyin the air when thosewordswerepenned. Pascalhadcomparedthe humanraceto a man who neverdies,always while Leibnizspokeof the Presentbig with the gainingknowledge, Future.Turgof Condorcet'sfriendandsPonsor'had writtenfortyyears beforeCondorcet'sSftetchthat "all epochsare fastenedtogetherby a and effecb,linking the conditionof the worldto all of causes sequence "the the conditionswhich have gone beforeit'" In consequence, from ib firstbeginning,seemsin the eyesof the humanrace,observed to be onevastwhole,which,like eachindividualin it, has philosopher ib own infancyand iu own conditionsof growth." Kant, in 1784,expressed the germ of the sameconcept,observingin particularthat

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man's rational dispositionsare destined to expressthemselvesin the speciesas a whole, not in the individual. Inevitable progressis an idea that has survivedCondorcet and the Enlightenment. It hasexerted,at differenttimesand variouslyfor good and evil, a powerful influence to the present day. In the final chapter of the Sftefcft,'The Tenth Stage:The Future Progressof the Human Mind," Condorcet becomesgiddily optimistic about its prospect.He assuresthe reader that the glorious processis underway: All will be well. His vision for human progressmakeslittle concessionto the stubbornly negative qualities of human nature. When all humanity has attained a higher level of civilization, we are told, nationswill be equal, and within each nation citizenswill also be equal. Sciencewill fourish and lead the way. Art will be freed to grow in power and beauty. Crime, poverty, racism, and sexual discriminationwill decline. The human life span,through scientificallybasedmedicine,will lengthen indefinitely. With the shadowof the Terror deepeningwithout, Le Bon Condorcet concluded: How consoling for the philosopher who lamentsthe errors, the crimes,the injustices which still pollutethe earthandof whichhe is often the.victimis this view of the human race,emancipated fiom its shackles, released from the empireoffate and from that ofthe enemiesof its progress, advancingwith a firm andsurestepalongthe path of truth, virtue,andhappiness! It is the contemplationofthii proqpect that rewardshim for all his effortsto assistthe progress ofreasonand the defenseofliberty.

T H s E N L I c H T E N M E N T c A v E R r s E t o t h e m o d e r ni n t e l l e c t u a l tradition of the West and much of its culture. Yet, while reason was supposedlythe defining hait of the human speciesand needed only a Iitde more cultivation to flower universally, it fell short. Humanity was not paying attention. Humanity thought otherwise.The causesof the Enlightenment's decline, which persist to the present day, illuminate the labyrinthine wellspringsof human motivation. It is worth asking, particularly in the present winter of our cultural discontent, whethir the original spirit of the Enlightenment-confidence, optimism, eyes to the horizon-can be regained.And to ask in honest opposition, should it be regained, or did it possessin its first conception, as some

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a dark-angelicflaw? Might its idealism have conhave suggested, the horrendousdreamof hibuted to the Terror,which foreshadowed so might the the totalitarianstate?If knowledgecan be consolidated, "perfect"society be designed-oneculh:re,onescience-whetherfascist,communist,or theocratic. The Enlightenmentitself, however'was never a unified movement. It ,u", i"rt a determinedswift river than a laceworkof deltaic streamsworkingtheir wayalongtwistedchannels.By the time of the French Revolutionit wasvery old. It emergedfrom the Scientific centuryandattainedits greatRevolutionduringthe earlyseventeenth the eighteenthcentury' during academy European the in infuence est issues.Most engaged fundamental over often clashed Its originators suchaslookspeculations, and digressions from ti*. to time in absurd of the soul. seat the anatomical or for ing for hiddencodesin the Bible clearand and extensive Tf," ouerl"pof their opinionwasnevertheless well reasonedenough to bear this simple characterization:They shareda passionto demystifythe world andfreethe mind from the impersonalforcesthat imprisonit. Th.y were driven by the thrill of discovery.They agreedon the universeand power of scienceto revealan orderly,understandable thought They discourse. rational ftee for base iherebylay an enduring and astronomy by discovered that the perfectionof the celestialbodies in the believed They physicscouldserveasa modelfor human society. inlaw, and knowledge,individualhuman rights,natural of ""ity "U evenwhile They tried to avoidmetaphysics definitehuman progress. of their explanationsforced them to the flawsand incompleteness practiceit. They resistedorganizedreligion.They despisedrevelation and dogma.They endorsed,or at leasttolerated,the stateas a contrivancerequiredfor civil order. They believedthat educationand right reasonwould enormouslybenefit humanity.A fe1v,like CondJrcet,thoughthumanbeingsperfectibleand capableof achievinga politicalutopia. We havenot forgottenthem. In their front rankwerea disproportionatenumberof the tiny group of scientistsand philosophersrecognizableby a singlename:Bacon,Hobbes,Hume, Locke,and Newton around philosophes andthe eighteenth-century in England;Descartes in Holland; Grotius in Germany; Voltaiiein France;KantandLeibniz Galileoin ltaly.

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It hasbecomefashionable to speakof the Enlightenmentasan idiosyncraticconshuctionby Europeanmalesin a bygoneera, one wayof thinking amongmanydifferentconshuctionsgeneratedacross time by a legionof othermindsin othercultures,eachof which deservescarefuland respecfulattention.To which the only decentresponseis yes, of course-to a point. Creative thought is forever precious,and all knowledgehasvalue.But what countsmostin the longhaulof historyis seminality, not sentiment.If we askwhoseideas werethe seedsof the dominantethicandsharedhopesof contemporaryhumanity,whoseresultedin the mostmaterialadvancemenf in historywhosewerethe firstof theirkind andtodayenjoythemostemulation,then in that sensethe Enlightenment, despitethe erosionof itsoriginalvisionanddespitetheshakiness of someof itspremises, has beenthe principalinspirationnot iustof westernhigh culturebut,increasingly, of the entireworld.

Sc I r Nc s wAs the engineof theEnlightenment. The morescientificallydisposed of the Enlightenment authorsagreedthatthecosmos is an orderlymaterialexistencegovernedby exactlaws.It can be broken downinto entitiesthat can be measured and arrangedin hierarchies, suchassocieties,which are madeup of persons,whosebrainsconsist of newes,which in hrm are composedof atoms.In principle at leasf the atomscan be reassembled into nerves,the nervei into trains, and the personsinto societies,with the whole understoodas a systemof mechanisms andforces.If youstill insiston a divineintewention,continuedthe Enlightenmentphilosophers, think of the world asGodt machine.The conceptualconshainbthat cloud our visionof the physicalworld can be easedfor the bettermentof humanitvin everv sphere.Thus Condorcet,in an era still unburdenedby complicatin! fact,calledfor the illumination of the moral and political s"i.n"., b| the "torch of analysis." The grandarchitectof this dreamwasnot Condorcet.or anvof the otherphilosophes who expressed it sowell, but FrancisBacon.ilrnorrg the Enlightenmentfounders,hisspiritis theone that mostendures. Il informsusacrossfour cenfuriesthat we mustunderstandnafure,both aroundusand within ourselves, in orderto sethumanityon the course of self-improvement. We must do it knowing that destinyis in our handsand that denial of the dreamleadsback to barbarism.In his

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scholarshipBaconquestionedthe solidityofclassical"delicate"learning, thosemedievalformsbasedon ancienttextsand logical expatiacalling philosophy, tio-n.He spurnedrelianceon ordinaryscholastic tetms, own on their condition for a studyof natureand the human mental into insights without artifice. Drawingon his extraordinary that because"the mind, hastilyand without he observed processes, imbibes and treasuresup the first noticesof things, from "hoi"r, all the restproceed,errorsmust foreverprevail,and remain whence uncorrected."Thus knowledgeis not well constructedbut "resembles a magnificentshucturethathasno foundation."

.

of the Andwhilstmenagreeto admireandmagnifrthefalsepowers true,there thosethatmightberendered mind,andnegleciordeshoy to beginthe work is no othercourseleft but with befterassistance all humanknowland arts, sciences, the rebuild or anew,andraise edgefroma firmandsolidbasis.

By reflectingon all possiblemethodsof investigationavailableto he concludedthatthe bestamongthemil induction, his imagination, which i the gatheringof largenumbersof factsand the detectionof patterns.In oider to obtain maximum obfectivity,we must entertain Baconproclaimeda pyramidof only a minimum of Preconceptions. disciplines,with naturalhistoryforming the base,physicsabove-and subsumingit, and metaphysicsat the peak, explainingeverything below-though perhapsin powersandformsbeyondthe graspof man' He wasnot a giftedscientist("I can not thridd needlessowell") or but a brilliant thinker who foundedthe phihained in mathematics, man' he took, in his own famous losophyof science.A Renaissance pht"r., all knowledgeto be his province.Then he steppedforwardinto the Enlightenmentasthe first taxonomistand masterpuweyorof the scientificmethod.He wasbuccinatornovitempois,the trumpeter of new times who summonedmen "to make peacebetweenthemselves,and turning with united forcesagainstthe Natureof things,to and extendthe bounds stormand o""rpy h"r castlesand strongholds, of humanempire." Proud ani recklessphrasingthat, but appropriateto the age' Bacon,born in 156r,wasthe youngerson of Sir Nicholasand Lady deAnn Bacon,both of whom werewell educatedand extravagantly by votedto the arts.During his lifetime England,ruled successively

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ElizabethI andfamesI, passed tumultuouslyfrom a feudarsocietyto a nation-state andfledglingcolonialpower,with its ownnewryacquired religion and an increasingly powerfulmiddle class.By the year of Bacon'sdeath,1626,Jamestown wasan established colonywith the first representative governmentin North America,and the pirerims were-settledat Plymouth.Baconsawthe English languagecorie to first full flower.He ranksasone of its grandmasters,wen thoughhe regardedit as a crude parochiallanguageand prefe'ed to write in Latin.He livedin a goldenageof indushyandculture,surrounded by otherglobaloverachievers, including,mostfamously, Drake,Raleigh, andShakespeare. Baconenioyedthe privilegesof rankthrougheverystepof his life. He waseducated at TrinityCollegeat Cambridge, whichhadbeenenrichedsomedecadesearlierby land grantsfrom HenryVIII (and a centurylaterwasto serveashometo Newton).He wascalledto thebar in r58zand two yearsafterwardappointedto membershipin parliament.virtually from infancyhe wascloseto the throne.His fatherwas Lord Keeperof the seal,the highestjudicialofficerof theland.Elizabethtookearlynoticeof theboy,talkingwith him often.pleased byhis precociousknowledgeand gravityof manner,shefondlydubbedhim The l6ung Lord Keeper. He becamea confirmedcourtierfor life, tying his politicalbeliefs and fortunesto the crown.Under|amesI he rose,throughflatteryand wisecounsel,to the heightscommensurate to his ambition:Knishted in 16o3,the yearof fames'accession, he wasthen named,rc"rriiu.ly AttomeyGeneral,Lord Keeper,and,in 1618,Lord Chancellor.With the lastofficehe wascreatedfirstBaronof Verulamandsoonafterward ViscountSt.Alban. Then, havingfown too closetoo long to the royalflame,Baconat last sustainednear-fatalburns.He wastargetedby a circle of determinedpersonalenemieswhofound the wedgeto his destructionin his tangledfinances,and in 16zrsuccessfully engineeredhis impeach_ mentasLord Chancellor.The charge,to which he pleadedguilty,was acceptance of bribes-"gifts,"he said-while in high publicoffice.He washeavilyfined,escorted throughtheTraitor'sGate,andimprisoned in the Towerof London. Unbowed,he at once wrotethe Marquisof Buckingham:"Good my Lord: Procurethe warrantfor my discharge thisday. . . Howsoever I acknowledge the sentencejust,andfor refJr-

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mationsakefit, [I was]the iustestChancellorthathath beenin the five sinceSirNicholasBacon'stime'" changes H" hea been all tha! and more. He wasreleasedin three days' Shornat lastof the burdenof public ambition,he spenthis lastdaysto His deathin the earlyspring tally immersedin contentedscholarship. of an impromptu experiresult the condign, of i6z6 wassymbolically "As he wastaking the air in a ideas. favorite ment to testone of his High-gate," towards John Aubrey recoach with Dr. Witherborne it came into my and ported at the time, "snow lay on the ground, in i,ordt thoughts,why fleshmight not be preserved snow,asin salt' They wereiesolvedthey would try the experimentpresently'They alightedout of the coachand went into a Poorwoman'shouseat the boftomof High-gatehill, and boughta hen,and madethe womanexenterateit, andthenshrffedthe bodywith snow,and my Lord did help to do it himself.The snowso chilled him that he immediatelyfell so extremelyill, that he could not returnto his lodgings"""-He was takeninsteadto the Earl offuundel's housecloseby. His conditionremainedgrave,andhe died on April 9, mostlikely of pneumonia' The ache of disgracehad been subduedby the return to his true calling of visionaryscholar.As he wrotein one of his oftquoted "H-ethat diesin an earnestpursuitis like one that is wounded adages, in liot blood,who for the time scarcefeelsthe hurt." He sawhis life asa contestbetweentwo greatambitions,and towardthe end he regrettedhavinginvestedsomuch effortin public servicewith an equivain "My soul,"he mused,"hathbeena stranger Lnt lossof scholarship. lifet pilgrimage." His g""lus, while of a differentkind, matchedthat of Shakespeare' Some haue believed, erroneously,that he was Shakespeare'He of Leaming, meldedgreatliterarygifts,soevidentinThe Advancement at the dawnof needed most qualities two synthesis, for passion with a wasthat of knowledge to conhibution great His the Eniighter.n"ri. from-rote away scholarshiP in shift a learnedfututitt. He proposed entoward texts and classical learningand deductivereasoningftom is civilization's g"g"-*t with the world. In science,he proclaimed, future. Bacondehnedsciencebroadlyand differendyfrom todayt ordiof the social sciences nary conceptionto include a foreshadowing of knowledgeby repeated The humanities' the festing parts oi and

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experiment,he insisted,is the cutting edgeof learning. But to him ex_ periment meant not just conholled manipulationsin the manner of modern science.It was all the wayshumani$ brings change into the world through information, agriculture, and industry. He thought the great branchesoflearning to be open-endedand constantly evolving ("I do not promise you anything"), but he nonethelessfocused elJ quently on his belief in the underlying unity of knowledge. He rejected the sharp divisions among the disciplines prevailing since Aristotle. And fortunately, he was reticent in this enterprisJ when needed: He refrained from forecastinghow the great branches of learning would ultimately fall out. Bacon elaboratedon but did not inventthe method of induction as a counterpoint to classicaland medievaldeduction. still, he deserves the title Fatherof Induction, on which much of his fame restedin later centuries.The procedure he favoredwas much more than mere factual generalizations,such as-to usea modern example-,.ninety per_ cent of plant specieshaveflowersthat areyellow,red, or white, andare visited by insects."Rather,he said,startwith such an unbiaseddescrip tion of phenomena.collect their common traits into an intermediaie level of generality. Then proceed to higher levels of generality, such as: "Flowers have evolved colors and anatomy designed to-athact certain kinds of insects,and these are the creaturesthat exclusivelv pollinate them." Bacon'sreasoningwas an improvement over the haditional methods of description and classificationprevailing in the Renaissance,but it anticipated little of the methodi of concept formation, competing hypotheses,and theorythat form the core of modern science. It was in psychology,and particularly the nature of creativity, that Bacon cast his vision farthest ahead. Although he did not use the word-it wasnot coined until r653-he understoodthe critical importance of psychologyin scientific researchand all other forms of scirolHe had a deep intuitive feel for the mental processesof lrship. discovery. He understood the means by which the proceises are best systematizedand most persuasivelyhansmitted. "The human understanding,"he wrote, "is no dry light, but receivesan infusion from the will and affections;whence proceedscienceswhich may be called'sciencesas one would.' " He did not mean by this to distortperceptionof the-real world by intelposing a prism of emotion. Reality is ill to be embraced directly and reported without flinching. But lt is also best

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deliveredthe sameway it was discovered,retaininga comparable vividnessand play of the emotions.Nature and her secretsmust be as stimulatingto the imaginationas are poehyand fables'T.tlt" stories,fables, illushations, us to useaphorisms, end,Bacona-dvised to his readfiscoverer from the truth thatconveys ".r"iogies-"nything "is like a wax not pi"tut.. The mind, he argued, "t " youcannotwritethe newtill yourub out the old; on "r, "J"learly tablet.On a iablet the mind you cannotrub out the old exceptby writing in the new'" Through light shedon the mental Process'Baconwishedto reall thebranchesof learning'Beware,hesaid,of across form reasoning the idolsof tlle mind, the fallaciesinto which undisciplinedthinkers mosteasilyfall. They arethe real distortingprismsof human nature' Among them, idols of the tribe assumemore order than existsin of inchaotii nature;thoseof the imprisoningcave,theidiosyncrasies mere power of the dividual belief and passion;of the marketplace, wordsto induce belief in nonexistentthings;and of ihe theater,wquestioning acceptanceof philosophical beliefs and misleading d.*onrtralions. Siayclearof iheseidols,he urged,observethe world aroundyou asit truly is, and reflecton the bestmeansof transmitting it; put into it everyfiber ofyour being' realitya; you haveexperienced IdonotwishbyrankingFrancisBaconsohighlyinthisrespect-to porhayhim asa thoroughiymodern man' He wasfar ftom that' His yourrg., friend Willia*-Hr*.y, a physicianand a real scientistwho made"a fundamentaldiscoverythe circulation of the blood, noted drily that Baconwrotephilosophylike a Lord Chancellor'His phtases make splendidmarble inscriptionsand commencementflourishes. The,rnity of knowledgehe conceivedwasremotefrom the presentday linkage-of far from the deliberate,systematic conceptLf consilienc-e, upon the lay instead stress causeand effectacrossthe disciplines.His all the serve commonmeansof inductiveinquirythatmightoptimally convey best branchesof learning.He searchedfor the techniquesthat the knowledgegained,and to that end he arguedfor the full employincludingartandfiction,asthebestmeansfor mentof thehumanities, science.Science,ashe broadlydefinedit' developingand expressing poitry sci.ttce.That, at least,hasa pleasingly ,hould bJpoetry, and modernring. a disciplinedand unified learningasthetey to Bacone'nvisioned improvementof the human condition.Much of the veritablelibrary thai accumulatedbeneathhis pen still makesinterestingreading,from

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his often quoted essaysand maximsto Advancement of Leaming (16o5),Noyum Organum (The New Logic, 16zo),and New ktantis lattera utopianfableabouta science-based society. Mostof !6rZ),the hisphilosophical and fictionalwritingwasplannedto implementthe schemeof the unification of knowledge,which he ca[ed lnstauratio Magna,literallythe GreatInstauration, or the New Beginning. Hi: philosophyraisedthesightsof a smallbut influentialp"uti". tt _ helpedto prime the scientificrevolutionthatwasto blossomspectacularly in the decades ahead.To thisdayhisvisionremainsthe heartof the scientific-technological ethic.He wasa magnificentfigurestanding alone by necessityof circumstance,who achievedtha'taffecting combinationof humility and innocentarrogance presentonly in th! greatestscholars.Beneaththe title of Novum organum he irad the publisherprint theselines: FMNCIS OF VERULAM REASONED THUS WITH

HIMSELF

andjudgedit to befortheinterest ofthepresent andfuture generations thattheyshouldbemadeacquainted withhisthoughs.

AL r. Hr sr o Rr Es r n er live in our heartsarepeopledbyarchetypes in mythic narratives,and suchI believeis part of Fiancis'Bacon', "p pealand why his fame endures.In the tableauof the Enlighten*eni, Baconis the heraldof adventure.Thereis a new world *riing, h. "nnounced let us begin the long and difficult march into its uri*"pped terrain.Ren6Descartes,the founderof algebraicgeometryand modem philosophyand France'spreeminentscholaiof all time, is the mentorin the narrative.Like Bacortbeforehim, he summonedscholarsto the scientificenterprise,amongwhom wassoonto follow the youngIsaacNewton.Descartes showedhowto do sciencewith the aid of precisededuction,cuttingto the quickof eachphenomenon and skeletonizingit. The world is three-dimensional, hi explained,so let our perceptionof it be framedin threecoordinates-cartesiancoordinatestheyarecalledtoday.with them the length,breadth,andheight of any objectcan be exactlyspecifiedand suiiected to mathemati"cal operationsto exploreits essentialqualities.He accomplishedthis step in elementaryform by reformulatingalgebraicnotation so that it

The Enlightenment

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could be usedto solvecomplexproblemsof geometryand,further' to explore realmsof mathematicsbeyond the visual realm of threedimensionalspace. overarchingvisionwasoneof knowledgeasa systemof Descartes' interconnectedtruths that can be ultimatelyabshactedinto mathematics.It all cameto him, he said,througha seriesof dreamson a whensomehowin a flurryof symbols(thunderNovembernightin 1619, evil spirit,a deliciousmelon)he perceivedthat the claps,books,-an orrin.rr" is both rational and united throughout by causeand effect' He believedthat this conceptioncould be appliedfrom physicsto In this_remedicine-hencebiology-and evento moralreasoning. that learning of spect,he laid th" gto,tnJ.'orkfor the beliefin the unity eighteenth wasto influenceinlightenment thoughtprofoundlyin the century. Descartesinsistedupon systematicdoubt asthe first principle of wasto be laid out andtestedupon learning.By hislight all knowledge himself only one undeniable allowed the iroi fr"*. oi logic. He CogitgetFo s1:m:I thi$ phrase premise,capturedinihe celebrated which still thrivesin doubt, ih.r.for" I am. The systemof Cartesian aresystematpossible modernscience,is one in which all assumptions ically eliminatedso as to leaveonly one set of axiomsupon which rationalthoughtcan be logicallybased,and experimentscan be rigorouslydesigned. bescartesnonethelessmade a fundamentalconcessionto metaphysics.A lifelong Catholic, he believedin God as an absolutely being,manifestedby the powerof the idea of sucha beingin perfect 'hi, orunmin"d.That given,he went on to arguefor the completeseparationof mind and matter.The shatagemfreedhim to put spirit aside to concenhateon matterasPuremechanism'In workspublishedov-er introducedreductionism,the studyof the the years677-4g,Descartes parb that can be brokenapartand physical of *orid ", "r,1rr.*bl"g.i.d,r"iionit* and analyticmathematicalmodelanalyzedseparately. ing were destinedto becomethe most powerful intellectual instrumlnts of modem science.(The year 164zwas a signal one in the s' Meditationesde Pima Philosophia historyof ideas:with Descarte pincipia soonto follow, Galileodied Philosophide lustplblished and and Newtonwasborn.) fu Enlightenmenthistory unfolded,IsaacNewton came to rank with Galile-oas the most influential of the heroeswho answered

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Bacon'scall.A restless seekerof horizons,stunninglyresourcefur, he inventedcalculusbeforeGottried Leibniz,whosenotationwasneverthelessclearerand is the one usedtoday.calculusprovedto be, in companywith analyticgeometryoneof thetwocrucialmathematical te-chniques in physics and,later,in chemistrybiology,andeconomics. Newtonwasalsoan inventiveexperimentalist, oneoithe firstto recognize that the generallawsof sciencemight be discoveredby manipi_ lating-physical processes. while investigating prisms,he demonstraied the relationof the refrangibilityof lightio coioi andfrom thatthe compoundnatureof sunlight_and the originof rainbows. As in manygreat experiments of science,this one is simple;anyonecan quicklyre"peat It. With a prism bend a beam of sunlightso that its differentwave_ lengthsfall out into the colorsof the visibrespectrum.Now bend the colors.backtogetheragainto createthebeamof sunlight.Newtonapplied his findingsin the construction of thefirstrefleciingtelescope, a superiorinstrumentperfecteda centurylaterby the Britishastronomer William Herschel. In 1684NeMon formulatedthe massand distancelawsof gravity, and in 1687thethreelawsof motion.with thesemathematicdTor*ulationshe achievedthe firstgreatbreakthroughin modernscience.He showedthat the planetaryorbitspostulatedby copernicusand proved elliptical by Keplercan be predictedfrom ti,e fiist principre, of *"chanics.His lawswereexactand equallyapplicableto ali inanimate matter,from the solarsystemdown to grainsof sand,and of courseto the falling applethat had triggeredhisihinking on the subjecttwenty yearspreviously-apparentlya true story.The universe,he said,is noi just orderly but also intelligible. At leastpart of Godt grand design could be writtenwith a few lines on a pieceof paper.HiJtriumph elnshrinedCartesianreductionismin the conductof science. BecauseNewtonestablished orderwheremagicand chaoshad reigned before, his impact on the Enlightenmentwas enormous. AlexanderPopecelebratedhim with a fam-ous couplet: Nature and Nahrre's laws lay hid in night: God said, "LetNewton bet,, and all wai light.

Well-not all, not yel But the lawsof gravityand motion werea powerful beginning.And they startedEnlightenmentscholarsthinking: Why not a Newtoniansolution to the affairsof men?The idea greiv

l The Enhghtenment

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of the Enlightenmentagenda'Aslate-as1835' into oneof the mainstays AdolpheQu6teletwasproposing"socialphysics"asthe basisof the discipline soonto be namedsociology.AtrgusteComte, his contempo' ,"ry b.li.u.d a true socialscience'tobe inevitable."Men," he said, e"hoingCondorcet,"are not allowedto think fieely aboutchemistry a.d biiogy, sowhy shouldtheybe allowedto think freelyaboutpoliti cal philos"ofhy?"People,afterall, are iust extremelycomplicated-machines.why shouldn'ttheir behaviorand socialinstitutionsconform to certainstill-undefinednaturallaws? during the Reductionism,given its unbrokenshing of successes haveconto way best nextthreecenfuries,mayseemtodaythe obvious to grasp so easy not structedknowledgeof the physicalworld,but it was posThey at the dawnof science.Chinesescholarsneverachievedit. asevidenced the sameintellectualability aswesternscientists, sessed s-ci-entifi.c acquired they isolated, more far though Uyttt. f""t tttat,even knowlGreek all of had who Arabs, Iid th. informationasrapidly ", Betrveenthe first.andthirteenthcenturies edgeasa launching iamp. thJyl.d Europeby-awidemargin.But accordingtoJosephNeedham' their theprincipalW.ri"r' chroniclerof Chinesescientificendeavors, hierarchifocu, st"y.d on holisticpropertiesand on the harmonious' cal relatilnshipsof entities,from starsdownto mountainsand flowers and andsand.In this world viewthe entitiesof Natureareinseparable perpetuallychanging,not discreteand constantas perceivedUy tJr' bniigt t.r,*.nt tf,inlers. fu a resultthe Chineseneverhit upon the analyticresearchattainedby entripoint ofabshactionandbreak-apart century' Europeansciencein the seventeenth Why no Descartesor Newton under the Heavenlylvlandate? The reasonswerehistoricaland religious'The Chinesehad a distaste for abstractcodified law, stemmingfrom their unhappyexperience with the Legalists,rigid quantifiersof the law who ruled during the transitioi to- f.-,tdalismto bureaucracyin the Ch'in dynasty (rrr-*An.c.). L,egalism wasbasedon the beliefthat peoplearefundaand mustbe bent to lawsthat placethe security mentally "niiro"iil of the stateabovetheir personaldesires.of probablyevengreaterimthe ideaof a supremebeing portance,Chinese,"holatsabandoned ,uith ptrron"l and creativeproperties'No rationalAuthor of Nature existedin their universe;consequentlythe obiectsthey meticulously describeddid not follow univeisalprinciples,but insteadoperated *i6i" particularrulesfollowedby thoseentitiesin the cosmicorder.

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In the absenceof a compellingneedfor the notionof generallawsthoughtsin the mind of God,soto speak-littleor no r.fr"h wasmade for them. westernsciencetook the leadrargerybecauseit cultivatedreductionismand physicallaw to expandthe understanding of spaceand time beyondthat attainableby the unaidedsenses. Th""rduarrce.however,carriedhumanitybself-imageeverfurtherfrom its perceptionof the remainderof the universe, andasa consequence the furl realityof theuniverseseemedto growprogressively morealien.The rulingtalis_ mansof twentieth-century science,relativityand quantummech"anics, havebecomethe ultimatein shangeness io theiu-r' mind. Thev wereconceivedby AlbertEinstein,Max planck,andotherpio.reers of theoreticalphysicsduring a searchfor quantifiabletruthsih"t *orrla beknownto extraterrestria]s aswell asto our species, andhencecertifiablyindependentof the humanmind.The physicists succeeded mag_ nificently,but in so doing they revearedthe iir'itations of intuitioln unaidedby mathematics; an understanding of Nature,they discov_ ered,comesveryhard.Theoreticalphysicsand molecul,arbiologyare acquiredtastes. The costof scientificadvance is thehumbling..Jogni tion that realitywasnot constructedto be easilygraspedby th"ehurian mind- This is the cardinaltenet of scientificunderstandins: our speciesand-its waysof thinkingarea productof evolution,not tie pur, poseofevolution.

Wn Now pASs to the final archetype of the epictableau,the keep ersof the innermostroom. The more radicalEnlightenmentwriters, alert to the implicationsof scientificmaterialism,movedto reassess God Himselfl They inventeda creator obedientto His own natural laws,the belief known asdeism.They disputedthe theismof JudaeoChristianity,whosedivinity is both omniiotent and personallyi.t"r_ estedin human beings,and they reiectedthe nonmaterialworld of heavenand hell. At the sametime, few daredgo the wholeroute and embraceatheism,which seemedto imply cismic meaninglessness and.risked_ ouhagingthe pious.So by and largethey took a'middle position.God the Creator exists,they conceded,bui He is allowed only the entitiesand processes manifestin His own handiwork. Deisticbelief, by persistingin aftenuatedform to the presentday, . hasgivenscientistsa licenseto searchfor God. More precisely, it has

The Enlightenmenl

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(Her?It? orompteda small numberto makea partial sketchof Him in another material is He meditations. il..ri lio* their professional uniofalternative manager planebut not personal.He is,perhaps,the and laws physical ParaI.tt.t p"ppi"g out of blackhoies,Who adlusts faint haceof a see we Maybe outcome' the obs.*. to ordJ, meters'ir, dating Hit" it the patternof ripplesin cosmicbackgroundradiation' of our own universe'Alternatively'we may backto the first *o*.nt to reachHim billionsof yearsin the futureat an omega be predestined which the poi.,aof evolution-total unity, total knowledge-toward I mustsay converging' are forms life andextraterrestrial irurn"n species arecomthey though even and that I havereadmanysuchschemes, non-Enlightenment'-That I find them depressingly oosed ',ft. bv scientists, somehowbe revealedat will and universe this outside frves C*l* havebeentelling usall along' its end iswhatthe theologians Few scientistsand ihilosoph"tt, however, let alone religious of scientifictheologyvlV sefthinkers,takethe playf,ri,,,aunderings within the ourty.A'*ote coherentand interestingapproach'possibly question: following the to answer reac'hof theoreticalphysics,is to try one sPewith only possible Is a universeof discretematerialparticles does words' other In cific set of natural lawsand parametervalues? values' and human imagination,which can conceiveof other laws Any act of Creation maybe only a ,it;Jy .*".?a porribl. existence? Einsteinis resubsetof the universeswe can imagine'To this point momentof p"i.a to haveremarkedto his assisLntErnst Straus'in a God had is whether me interests "What really neodeisticreflection, can-be of reasoning line That anychoicein the creationof the world'" principle"' "anthropic the exiendedrather mysticallyto formulate least,had to be whi"h ,rote,that the lawsof natgre, in our universeat ableto ask seta certainprecisewaysoasto allowthe creationofbeings way? aboutthe lawsof naturl. Did So*.one decideto do it that can be theology and deism Enlightenment The disputebetween isrooted su*mari"ei asfollows.The traditionaltheismof Christianity knowlof sources conceivable two in both reasonand revelation,the in conbe cannot revelation edge.Accordingto this view,reasonand tfgher is given fict, becausein areasof opposition,revelation $e theyoffered role-as the Inquisitio.,,.*indtd Galileo in Romewhen grants him a choicebitween orthodoryand pain' In contrast'deism useof the edge,and insiststhattireistsiustifyrevelationwith the ;;; reason.

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Traditionaltheologiansof the eighteenthcentury,faced with the Enlightenmentchallenge, refusedto yield an inch of ground.christianfaith,theyarguedback,cannotsu6mititselfto theiebasing testof rationality.Deeptruthsexistthat are beyondthe grasp of th. u".raiied human mind, and God will revealthem to ou, Jnde.standing when andby whatevermeansHe chooses. Given the cenhalityof religionin everyday life, the standof the theistsagainstreasonseemed. . . welr,it seemed reasonable. Berievers in the eighteenthcenturysawno difficultyin conducting theirlivesby both ratiocinationandrevelation. The theologi"n,*on"th"l;";;. simplybecausetherewasno compellingreasonto adopt a ne,i meta_ physics.Forthe firsttime,the Enlightenment visiblystumbled. The fatal flaw in deismis thus not rationalat all, but emotional. Pure reasonis unappealingbecauseit is b]oodlesr. Ceremorie, strippedof_sacredmysterylose their emotionalforce, becausecele_ brantsneedto deferto a higherpowerin orderto consummate their instinctfor tribal loyalty.In timesof dangerandtragedy ,rn_ reasoningceremonyis everything.There is .ro ,ubstitrte"rp""i"lly, for r,rrrende, to an infallibleand benevorent being,the commitmentcalledsalvation. And no substitutefor formal iecognition of an immortar life force,the leapof faithcalledtransc.nd.ri"..It folrows th"t *ori p.ople would verymuchlike scienceto provethe existence of God but not to takethe measureof His capacity. Deismand sciencealsofairedto coronizeethics.The sparkring Enlightenmentpromiseof an objectivebasisfor moral reasoning Jould not be met. If an immutablesecularfield of ethicarpremises r*"irt, n. humanintellectduringtheEnlightenmentseemedioo weaka'a sr,ning to locateit. so theo-logians andphilosophersstuckto their original positions,either by deferring-torerigiousauthority or by articullting subjectivelyperceivednaturarrights.There wasno logicar artemativS open to them. The millennium_old rules sacralizled by religion seemedto work,moreor less,and in any casetherewas no ii-. to"ig_ ure it all out. You can deferreflectionon the cerestiarspheres indef,nitelybut not on dailymattersof life and death. Tnens wes andremainsanother,morepurelyrationalistobiection to the Enlightenmentprogram.Grant foi argument,s ,"k. ;h;;;;

The Enlightenment

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true' claimsof the Enlightenmentsupporters-proved mostextravagant to and future into the look to ," ar,"ait beJamepossiblefor scientists in us trap that Wouldn't seewhatcourseof actionis bestfor humanity' Enlightenm€nt' the of of logic and revealedfate?The thrust "the The " "rg. Creek humanismthat prefiguredit, was Promethean: like the above it lno*t"ag. it generatedwasto liberatemankindby lifting dimininqulV r"""g. *i*a."But the oppositemight occur'Ifscientific natural immutable prescribing Jhile liuirrity oi irfr"i n" conception Perpossessesit already freedom what lose laws,then humanitycan find will scientists o1d3r,^and "perfect" soc-ial frrpt ,ft"t" is only one the ii]o. *orr., falselyclaim to havefound it. Religiousauthority, of barbarians the and will be breached Hadrian'sW"U of "iuitization, Enlightenof side totalitarianideolorywill pour in' Such is the dark and ex*.r,t ,"",r1"r thoJght, unveiledin the French Revolution of "scientific"socialismand racialist fr.ur"a *or" ..".nily by theories fascism. risks And there is anotherconcem:that a sciencedrivensociety you if or' God by place in set world rpr.ii"g,h. naturalorderof the aumuch too given Science evolution' il.f*, oJybillions of yearsof cregodless impiety'The ihority risksconversioninto a selfdestroying ationsof scienceand technologyare in fact powerful.and,anesting monsterand kloltywooos imagesof modern culture. Frankenstein's FrankenT".iir,"tor, the latter an all-metaland microchipguided including the *irrt *onrter, wreak destructionon their creators' ruled by gt"i"tes in lab coatswho arrogantlyforecasta new age men""i". Nations life dies' spread' s"ie.r""e.Stormsrage,hostilemutants Winston Even technology' o.r. another ivith world-destroying """ afterthe atom Churchill, whosecountrywassavedby radar'worried "on the gleaming ;omLG of ;"p"n that the stoneage might return wingsof Science." Faustianrather Fo n r n o s s w Ho for solong thusfearedscienceas graqethreatto a posed program thanPromethean,the Enlightenment to such a answer the is What spiritual freedom,even to-life itself' individof primacy the threat?Revolt!Returnto naturalman, reassert to a escape Find-an u"1 i-"gitt"tion and confidencein immortality' r8o7 In ftigt.t t".A* through art, promotea RomanticRevolution'

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William Wordsworth,in-words $pical of the movementthen spread_ ing ovcr Europe,evokedthe auraof a moreprimaland sereneexistencebeyondReason's grasp: OurSoulshavesightofthatimmortal sea Whichbroughtushither, Canin a momenttravelthither, AndseetheChildren sportupontheshore, Andhearthemightywaters rollingevermore. with wordsworth's"breathingsfor incommunicabre powers,"the eyes close,the mind soars,the inversesquaredistancelar of grauityfilis away'The spirit entersanotherrealitybeyondthe reach *J measure'If the constraining "r?.igrlt universeof matterandenergy cainot be denied,at leastit can be ignoredwiih splendidcontemptl'Th... ir;; questionthat Wordsworthand his fellowEnglishRomantic poetsof the firsthalf of the ninetee,nthcenturyconlurJdworks of greaiu"r.,,y. They spokehuthsin anothertongue,and guidedthe arts"stilr furthe, fromthesciences. Romanticismalsofloweredin philosophy,whereit placed a pre_ mium on rebellion,spontaneity, intenseemotion,and heroicvisiorr. Searchingfor aspirationsavailableonry to the heart, in practitione* of man_aspart of boundless nature. Rousseau, while often ,dreamed listedasan Enlightenmentphilosophe, wasreallyinsteai A. fo"r,a., andmostextremevisionaryof the Iiomanticphirosophi""l ,,'ou"-.ni. For-him learningand socialorderare the enemiesof humanity.In r74g,(Discourseon the Sciences and the Ar*) to'r7iz LLkj ,fr:* \Emtle),he extolledthe "sleepof reason."His utopiais a minimalist statein which peopleabandonbooksand other accouterments of intellectin orderto cultivateenioymentof the senses and goodhearth. Humanity,Rousseau claimed,wasoriginailya raceof nobier"u"g", i., a peacefulstateof nature,who *... Lt , corruptedby civilization_ andby scholarship. Religion,marriage,law,ani government arede_ createdby the powerfulfor their o*., ,.li'rh ."ar. fh" ".f|:"r fri". paid by the common man for this highJevelchicanery i, ui".'"nJ unhappiness. Where Rousseauinventeda stunninglyinaccurateform of anthropologt,the Cerman Romantics,led by"Coethe, Hegel,Herder,and Schelling,setout to reinsertmetaphysics into sciencelndphilosophy.

The Enlightenment

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wasa hybrid-of sentiment'mysticism' The product,N aturphilosophie, q,r"ri-r"ientifichypothesis')ohann Wolfgangvon Goethe' pre"r,d wantedmostof all to be a greatscientist' eminentamongits expositors, an He placedthaiambitionaboveliterature,wherein fact he became approach an idea' His respectfor scienceasan immortalcontributor. unresewed,and he understoodits basictenets' was reality, to tangible h.liked to say,shouldbe altematedasnaturally LJy;'i, ""a,y"thesis, oul At the sametime he wascritical of breathing U*rnirrg in and ", matheriaticalabsgactionls of Newtonianscience,thinking physics the also far too ambitiousin its goal of explainingthe universe'He was experimenby employed of the "technicaltricks" oftencontemptuous tal scientisb.in fact,he tried to repeatNewton'soptical experimenb but with poorresults' Goethecan be easilyforgiven'After all, he had a noble PurPose' engine no lessthan the couplingof the soul of the humanitiesto the verdict: of science.He would hive grievedhad he foreseenhistory's lack of through his synthesis in failed H"e greatpoet, poor scientist. necesthe to mention Not instinct' itft"t it todi calledthe scientist's could he said it is and him, skills.Calculusbaffied ,"f t "hnl"rl spirprofoundly in a Nature ,roit.ll a larkfrom a sPalrow.But he loved pro' he her, for itual sense.One mustcultivatea close,deepfeeling spurs she claimed."Shelovesillusion.Sheshroudsman in mist,and she him towardthe light. Thosewho will not partakeof her illusions punishesas a ty'rantwould punish' Thosewtro accepther illusions her'" lh" pr.rr", to her heart-To love her is the only wayto approach lecsince long has Bacon I imagine In the philosophers'emPyrean patience lost have will turedioethe on the idoli of the mind. Newton immediately' FriedrichSchelling,leadingphilosopherof the German Romannot tics, attemptedto bin; the scientificPrometheusto immobility things' ;ih p..oi but with reason.He proposeda cosmicuni$ of all be never can themselves by Facts matt' of U.yondth! understanding the of fragments only are perceive we *or. tft"r, partialtruths.fhor" universalflux. Nature is alive, Schellingconcluded;she is a creative through greaterand rpitiarfr" unitesknowerand known, progressing stateof comeventual towardan fe"t., understandingand feeling pleteself-realization. wasmirroredin In America,GermanphilosophicalRomanticism whosemostcelebratedproponents New Englandtranscendentalism,

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wereRalphWaldoEmersonandHenryDavidThoreau.The hanscen_ dentalists wereradicalindividualists who reiectedthe overwhelming commercialism that cameto prevailin Americansocietyduringthe Iacksonianera. They envisioneda spiritualuniversebuirt entirelv within their personalethos.They nevertheless found ,"i"r,"" *or. congenialthan did their-European counterparts_wihress the many accuratenaturalhistoryobservations in Faith in a seed andotler writingsby Thoreau.Their ranksevenincludedone full-fledgedscientist: Louis Agassiz,directorof the Museumof ComparativeZoology at university,founding memberof the NationarAcaderii of llrvard Science,geologist,zoologist,and supremelygifted lecturer.,i,his greatman,in a metaphysical excursion parallelingthat of Schelling, conceivedthe universeas a visionin the mind oI God. The deitiJs of sciencein his universewereessentially the sameas thoseof the_ ology.In 1859,at the height of his career,Agassizwasscandalized by the appearance of Darwin,sOriginof Speciis,which advanced the th.1v of evolutionby naturalselectio' and sawthe diversityof life as self-assembling.-surely, hearguedbeforeraptaudiencetin "iti., "tong the Atlantic seaboard,God would not creaiethe living world by ranl dom variationandsurvivalof the fittest.our viewof lifJmust not beallowedto descend from cosmicgrandeurto thegrubbydetailsof pond, and woodlob.Even to think of th, hr-"r, in sucha man_ "o'dition ner,he argued,is intolerable.

Nerunel scrENTrsrs, chastened by suchrobustoLiections to the Enlightenmentagenda,mostly abandonedthe examination of humanmentallife,yieldingto phirosophers andpoetsanothercentury fr9eplay'In fact,the concessionturnedout to^be, he"rthyd."isioi 9f for the professionofscience,becauseit steeredresearchers t* "*"y the pifalls. of metaphysics.Throughoutthe nineteenth century, knowledgein the physicalandbiologicalsciences grewat an exponen_ tial rate. At the same time the sociarscienceslsociorogy, anthr* pology, economics,and political theory_newly risen li"ki upstart duchiesand earldoms,vied for territoryin the spacecreatedbetween the hardsciences and the-humanities. The greaibranchesof l."*ing emergedin their presentform-natural scie-nces, socialscienc.r,,ni the humanities-out of the unified Enlightenmentvision generated during the seventeenth and eighteenth ""ituri.r.

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The Enlightenment,defiantly secularin orientation while indebtedandattentiveto theology,hadbroughtthe Westernmind to the thresholdof a new freedom.It wavedasideeverything,everyform of religiousand civil authority,everyimaginablefear,to giveprecedence to the ethic of free inquiry.It pictureda universein which humani$ playsthe role of perpetualadventurer.For two centuriesGod seemed io sp."k in a new voice to humankind.That voice had been foreshado*edin 1486by Giovanni Pico della Mirandola, Renaissance forerunnerof the Enlightenmentthinkers,in this benediction: norof earlh,neithermortalnor Wehavemadetheeneitherof heaven of choiceandwithhonor,asthough immortal,sothatwithfreedom fashionthpelf in whatthoumayest themakerandmolderof thyself, thoushaltPrefer. evershape

Bv rsn EARLY r8oos, however,the splendidimagewasfading' Reasonfractured,intellechralslost faith in the leadershipof science, and the prospectof the unity of knowledgesharplydeclined.lt is true that the spirii of the Enlightenmentlived on in political idealismand new schools the hopesof individualthink"tt. In the ensuingdecades_ utilitarian the tree: shattered a base of from the shoots spranguplike Mam and of materialism historical the Mill, B.rrtham and "thi"r"of William Peirce, )ames,and |ohn Engels,the pragmatismof Charles The abandoned. D"iu.y. But the core agendaseemedi'etrievably two previous gand conceptionthat had rivetedthinkersduring the centurieslostmostof iu credibility. sciencetraveledits own way.It continuedto doubleeveryfifteen and technical iournals,as it had yearsin practitioners,discoveries, to leveloff only aroundr97o'Ir beginning finally sincethe earlyr7oos, to give credenceagainto the began continuouslyescalatingsuccess ideaof an oidered,intelligibleuniverse.This essentialEnlightenment premisegrewstrongerin the disciplinesof mathematics,phpics, and Yet Liology,ihere it had firstbeenconceivedby Baconand Descartes' perthe enormoussuccessof reductionism,ib key method,worked verselyagainstanyrecoveryof the Enlightenmentprogramasa whole. Preciselybecausescientificinformationwasgrowingat a geometric were not concernedwith unificapace,most individual researchers iion,'"nd evenlesswith philosophy'They thought,whatworks,works,

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and so what needis thereto refect moredeeplyon the matter?They wereevenslowerto address the tabooladenphysicalbasisof mind, a concepthailed in the late l7oosasthe gatewayfrom biologyto the so_ cial sciences. There wasanother,humblerreasonfor the lackof interestin the big picture:scientists simplydidn't havethe requisiteintellectualenergy. The vast majority of scientistshave never been more than journeymenprospectors. That is evenmore the casetodav.Thev are professionally focused;their educationdoesnot orientthem to the wide contoursof the world.They acquirethe trainingthey needto travelto the frontier and makediscoveries of their o*.r, asfastas "nd possible,becauselife at the growingedgeis expensive and chancy. The mostproductivescientists, installedin milliondollarlaboratories, haveno time to think aboutthe big pictureand seelittle profit in it. The rosetteof the united StatesNationalAcademyof sciences, which the two thousandelectedmemberswearon theirlapelsasa mark of achievement, containsa centerof scientificgold surroundedbv the purple of naturalphilosophy.The eyesof moslleadingscientists, alas, arefixedon the gold. It is thereforenot surprisingto find physicistswho do not know whata geneis, and biologists who guessthat stringtheoryhassomething to do with violins.Granb and honorsaregiveninsciencefor discoveries,not for scholarship and wisdom.And so has it everbeen. FrancisBacon, using the political skills that lofted him to the l,ord chancellorship, personallyimportuned the English monarchsfor fundsto carryforth his greatschemeof unifyingknowledge.He never got a penny.At the height of his fame Descartes wasceremoniously awardeda stipend by the French royal court. But the account re_ mainedunfunded,helpingto drivehim to the moregenerousswedish court in the "land of bearsbetweenrock and ice,"wherehe soondied of pneumonia. The sameprofessional atomizationaffiictsthe socialsciencesand humanities.The facultiesof highereducationaroundthe worrdarea congeriesof experts.To be an originalscholaris to be a highlyspecialized world authorityin a polyglotcalcutta of similarlyfocusedworld authorities.ln ryg7, when feffersontook the president'schair at the American Philosophicalsociety,all Americanscientistsof professionalcaliberand their colleagues in the humanitiescouldbe seated comfortablyin the lectureroom of PhilosophicalHail. Mostcould dis-

The Enlightenment

43

well on the entireworld of learning,which wasstill coursereasonably today,including small enough to be seenwhole. Their successors alone, engineering 41o,oooholden of the doctoratein scienceand scholarsin generalhave would overcrowdPhiladelphia.Professional little choice but to dice up researchexpertiseand researchagendas scholarmeansspendinga career To bea successful amongthemselves. the Romanticpoets,earlyAmericanhistory on membranebiophysics, or someothersuchconshictedareaof formal study. Fragmentationof expertisewasfurther mirrored in the twentieth centurybymodernismin the arts,includingarchitecture.The work of the masters-Braque,Picasso,Stravinsky,Eliot, foyce, Mad*raGraham,Gropius,FrankLlol Wright,and their Peers-wassonoveland discursiveas to thwart genericclassification,exceptperhapsfor this: The modernisb tried to achievethe new and provocativeat any cost.They identified the constrainingbonds of tradition and selfin order brokethem.Many reiectedrealismin expression consciously as a scienliterary stylist a much Freud,as to explorethe unconscious. Psyranks' in their tist, inspiredthem and can be iustifiablyincluded modernist choanalysiswas a force that shifted the attention of intellectualsand artistsfrom the socialand political to the privateand Subiectingeverytopicwithin their domainto the "ruthpsychological. lesscenkifugeof change,"in Carl Schorske'sphrase,they meantto proudly assertthe independenceof twentieth-centuryhigh culture from the past.They werenot nihilisb; rather,they soughtto createa newlevelof orderand meaning'They werecompleteexperimentalisb who wishedto participatein a centuryof radicaltechnologicaland political changeandto fashionpartof it entirelyon their own terms. by the Enlightenment,which disThus the freefight bequeathed engagedthe humanitiesduring the Romanticera,had by the middle of thi twentieth century all but erasedhope for the unification of knowledgewith the aid of science.The two culturesdescribedbyC. P' Snowin his 1959RedeLecture,the literaryand the scientific,wereno longeron speakingterms.

All uovsMENTs rEND to exhemes,which is approximately wherewe are today.The exuberantself-realizationthat ran from ro' manticismto modernismhasgivenrisenow to philosophicalpostmodemism (often called poststruchrralism,especiallyin its more political

+4

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and sociological expressions).Postmodernismis the ultimate polar antithesis of the Enlightenment. The difference between the two extremes can be expressedroughly as follows: Enlightenment thinkers believe we can know everything,and radical postmodernistsbelieve we can know nothing. The philosophical postmodernists,a rebel crew milling beneath the black flag of anarchy,challenge the very foundationsof science and traditional philosophy. Reality, they propose,is a stateconstructed by the mind, not perceivedby it. In the most exhavagantversion of this constructivism,there is no "real" reality,no objectivetruths externalto mental activity,only prevailingversionsdisseminatedby ruling social groups.Nor can ethicsbe firmly grounded,given that eachsocietycreatesits own codesfor the benefit of the same oppressiveforces. If thesepremisesare correct,it followsthat one culture is asgood as any other in the expressionof truth and morality, each in its own special way. Political multiculturalism is justified; each ethnic group and sexualpreferencein the community hasequalvalidity.And, more than mere tolerance, it deservescommunal support and mandatedrepresentation in educational agendas,not becauseit has general importance to the society but because it exists.That is-again-if the premisesare correct. And they must be correct, saytheir promoters,becauseto suggestotherwise is bigotry, which is a cardinal sin. Cardinal, that is, if we agree to waive in this one instance the postmodernistprohibition againstuniversal truth, and all agreeto agreefor the common good. Thus, Rousseauredivivus. Postmodernismis expressedmore explicitly still in deconshuction, a technique of literary criticism. Each author'smeaning is unique to himself, goes the underlying premise; nothing of his hue intention or anything else connected to obiective realig can be reliably assignedto it. His text is therefore open to fresh analysisand commentary issuing from the equally solipsisticworld in the head of the reviewer.But then the reviewer is in turn subiect to deconstruction, as well as the reviewer of the reviewer, and so on in infinite regress.That is what facquesDerrida, the creatorof deconstruction,meant when he stated the formula Il n'y a pasde hors-texfe(There is nothing outsidethe text). At least,that is what I think he meant, after readinghim, his defenders, and his critics with some care. If the radical postmodernistpremise is correct, we can never be sure that is what he meant. Conversely,if that

The Enlightenment

4,

is what he meant,it is not certainwe areobligedto considerhis argumentsfurther. This ptzzle, which I am inclined to set asideas the "Derridaparadox,"is similarto the Cretanparadox(a Cretansays"all Cretansare liars"). It awaitssolution,though one need not feel any greatsenseof urgencyin the matter. prosethat he Nor is it certainfrom Derrida'sornatelyobscurantist think his writing is himself knowswhat he means.Some observers meantasa ieu d' esprit,akind of ioke.His new"science"of grammatologyis the oppositeof science,renderedin fragmentswith the incoherIt is innocentof the enceof a dream,at oncebanaland fantastical. scienceof mind and languagedevelopedelsewherein the civilized world, rather like the pronouncemenbof a faith healerunawareof He seems,in the end,to be conscious the locationof the pancreas. of this omission,but contentshimselfwith the stanceof Rousseau, enemy of booksand writing, whosework Emile he self-professed quotes:". .. the dreamsof a bad night aregivento us asphilosophy. Youwill sayI too am a dreamer;I admit it, but I do whatothersfail to do, I give my dreamsas dreams,and leavethe readerto discover whetherthere is anythingin them which may proveusefulto those who areawake." Scientists,awakeand held responsiblefor what they say while posuseful.The postmodernist awake,havenot foundpostmodernism Thereappearsto be hrretowardsciencein returnis one of subversion. a provisionalacceptanceof gravity,the periodictable, astrophysics, and similarstanchionsof the externalworld,but in generalthe scientific culture is viewedasiustanotherwayof knowing,and,moreover, contrivedmostlyby EuropeanandAmericanwhitemales. to history'scuriositycabiIt is temptingto relegateposhnodernism idealism,but it has net alongsidetheosophyand transcendental andhumaniof thesocialsciences by nowinto themainstream seeped ties.It is viewedthereasa techniqueof metatheory(theoryabouttheo' analyzenot somuchthe subiectmatterof the ries),by which scholars reasons particuscientificdisciplineasthe culturaland psychological lar scientiststhink the way they do. The analystplacesemphasison "root metaphors,"thoseruling imagesin the thinker'smind by which he designstheory and experiments.Here, for example,is Kenneth Gergen explaining how modern psychologyis dominated by the metaphorof humanbeingsasmachines:

46

CoNsrr,rexce Regardless of the characterof the person'sbehavior,the mechanist theoristis virtually obligedto segmenthim from the environment,to viewthe environmentin termsof stimulusor input elements,to view the personas reactiveto and dependenton theseinput elements,to view the domain of the mentalasstrucfured(constifutedof interacting elements),to segmentbehaviorinto unitsthat canbe coordinated to the stimulusinputs,andsoon.

Put briefly, and to face the issue squarely,psychology is at risk of becoming a natural science. As a possibleremedy for those who wish to keep it otherwise, and there are many scholarswho do, Gergen cites other, perhaps lesspernicious root metaphors of mental life that might be considered,such asthe marketplace,dramatur5/, and rule-following. Psychology,if not allowed to be contaminated with too much biology, can accommodate endlessnumbers of theoreticiansin the future. fu the diversity of metaphors has been added to ethnic diversity and gender dualism to createnew workstationsin the postmodernist academic industry and then politicized, schoolsand ideologieshave mulfiplied explosively.Usuallyleftist in orientation,the more familiar modes of general postmodernist thought include Afrocentrism, conshuctivist social anthropology, "critical" (i.e., socialist) science, deep ecology,ecofeminism, Lacanian psychoanalysis, Latourian sociolog] of science, and neeMaxism. To which add all the bewildering varieties of deconstruction techniques and New Age holism swirling round about and through them. Their adherents fret upon the field of play, sometimesbrilliantly, usually not, jargon-prone and elusive. Each in his own way seemsto be drifting toward that mysteium tremendum abandoned in the seventeenth century by the Enlightenment. And not without the expression of considerable personal anguish. Of the late Michel Foucault, the great interpreter of political power in the history of ideas,poised"at the summit of Western intellectual life," George Scialabba has percep tively written, Foucaultwasgrapplingwith the deepest,mostinhactabledilemmas of modern identity.. . . For thosewho believethat neitherGod nor natural law nor transcendentReasonexists,and who recognizethe variedand subtlewaysin which materialinterest-power-has corrupted,evenconstifuted,everypreviousmoralfy,how isoneto live,to whatvaluescanone holdfast?

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How and what indeed?To solvethesedisturbingproblems,let us despair. beginbysimplywalkingawayfrom Foucault,and existentialist Considerthisrule of thumb:To the extentthatphilosophicalpositions both confuseand closedoorsto further inquiry, they are likely to be wrong. To FoucaultI would say,if I could (andwithout meaningto sound pahonizing),it'snot sobad.Oncewe getoverthe shockof discovering that the universewasnot madewith us in mind, all the meaningthe braincanmaster,and all the emotionsit can bear,and all the shared adventurewe might wish to enioy,can be found by decipheringthe that hasborneour speciesthroughgeological hereditaryorderliness time and stampedit with the residuesof deephistory.Reasonwill be advancedto new levels,and emotionsplayedin potentiallyinfinite patterns.The truewill be sortedfrom thefalse,and we will understand oneanotherverywell, the morequicklybecausewe areall of the same biologicallysimilarbrains. andpossess species And to othersconcernedaboutthe growingdissolutionand irelevanceof the intelligentsia,which is indeedalarming,I suggestthere havealwaysbeentwo kindsof originalthinkers,thosewho upon viewing disordertry to createorder, and thosewho uPon encountering The tensionbetweenthe two ordertry to protestit by creatingdisorder. is whatdriveslearningforward.It lifo usupwardthrougha zigzagg,ing And in the Darwiniancontestof ideas,orderaltrajectoryof progress. wayswins,because-simply-that is the waythe realworld works. Astoday'scelehereis a saluteto the poshnodernisb. Nevertheless, brantsof corybanticRomanticism,theyenrichculture.They sayto the rest of us: Maybe, iust maybe,you are wrong. Their ideasare like sparksfrom fireworkexplosionsthat havelawayin all directions,dedark. void of followingenergy,soonto wink out in the dimensionless Yeta fewwill endurelong enoughto castlight on unexpectedsubiecb. evenasit menaces That is onereasonto think well of postmodernism, who havechosen relief it those is the affords rationalthought.Another with a scientificeducation.Anotheristhe not to encumberthemselves small industryit has createdwithin philosophyand literary studies. Still another,the onethat countsthe most,is the unyieldingcritiqueof traditionalscholarshipit provides.We will alwaysneedpostmodernists or their rebelliousequivalenb.Forwhatbetterwayto strengthenorganized knowledgethan continuallyto defend it from hostile forces? fohn StuartMill correctlynoted that teacherand learner alike fall

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asleepat their postswhen thereis no enemyin the field.And if somehow,againstall the evidence,againstall reason,the linchpin fallsout and everythingis reducedto epistemological confusion,we will find the courageto admit that the postmodernists were right, and in the bestspiritof the Enlightenment, we will startoveragain.Because, as the greatmathematicianDavid Hilbert once said,capturingso well that part of the human spirit expressed throughthe Enlightenment, Wir miissenwissen.Wir werdenwissen. We mustknow.we will know.

cHAPTER

4

THs Neruner ScTENCES

Bv eNv REASoNABLEMEASuRs oF achievement,thefaithof thinkersin sciencewasiustified.Todaythegreatest theEnlightenment dividewithin humanityis not betweenraces,or religions,or even,as widelybelieved,betweenthe literateand illiterate.It is the chasmthat separates scientificfrom prescientificcultures.Without the instruknowledgeof the naturalsciences-physics, mentsand accumulated chemistry,and biology-humans are happedin a cognitiveprison. pool. WonderThey arelike intelligentfish born in a deep,shadowed longingto reachout, theythink aboutthe world outing and restless, speculations andmythsaboutthe originof side.Theyinventingenious the confiningwaters,of the sun and the skyand the starsabove,and the meaningof their ownexistence.But theyarewrong,alwayswrong, becausethe worldis too remotefrom ordinaryexperienceto be merely imagined. It is a combinaScienceis neithera philosophynor a beliefsystem. the habit of edthat hasbecomeincreasingly tion of mentaloperations ucatedpeoples,a cultureof illuminationshit uponby a fortunateturn of historythatyieldedthe mosteffectivewayof leamingaboutthe real world everconceived. With inshumentalsciencehumanity has escapedconfinement and prodigiouslyextendedits graspof physicalrealiry.Once we were

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nearly blind; now we can see-literally. Visible light, we havelearned, is not the sole illuminating energy of the universe, as prescientific common sensedecreed.It is insteadan infinitesimal sliver of electromagnetic radiation, comprising wavelengthsof 4oo to 7oo nanometers (billionths of a meter), within a spectrum that rangesfrom gamma wavestrillions of times shorterto radio wavestrillions of times longer. Radiation over most of this span, in wildly varying amounts, continually rains down on our bodies.But without instrumentswe were oblivious to its existence.Becausethe human retina is rigged to report only 4oo-7oo nanometers,the unaided brain concludes that only visible light exists. Many kinds of animals know better.They live in a different visual world, oblivious to part of the human visible spectrum, sensitiveto some wavelengthsoutside it. Below 4oo nanometers,butterfliesfind flowersand pinpoint pollen and nectar sourcesby the pattern of ultraviolet raysreflectedoffthe petals.Where we seea plain yellow or white blossom,they seespotsand concentric circles in light and dark. The patterns have evolved in plants to guide insect pollinators to the anthers and nectar pools. With the aid of appropriate inshuments we can now view the world with butterfly eyes. Scientisb have entered the visual world of animals and beyond becausethey understandthe electromagneticspectrum.They can hanslate any wavelen$h into visible light and audible sound, and generate most of the spectrum from diverseenergysources.By manipulating selected segmenb of the electromagnetic spechum they peer downward to the hajectories of subatomic particles and outward to star birth in distantgalaxieswhoseincoming light datesback to near the beginning of the universe.They (more accurately we, since scientific knowledge is universally available) can visualize matter acrossthirty-seven orders of magnitude. The largest galactic cluster is larger than the smallest known particle by a factor of the number one with about thirty-seven zeroesfollowing it. I mean no disrespectwhen I say that prescientific people, regardlessoftheir innate genius,could never guessthe nature ofphysical reality beyond the tiny sphere attainable by unaided common sense. Nothing else ever worked, no exercise from myth, revelation, art, trance, or any other conceivable means;and notwithstanding the emotional satisfaction it gives, mysticism, the strongestprescientific probe

The NaturalSciences

5r into the unknown,hasyieldedzero.No shaman's spellor fastupon a sacredmountaincansummonthe electromagnetic spectrum.pioph_ etsof thegreatreligionswerekeptunawareof its existence, not because ofa secretivegodbut because theylackedthe hard-wonknowredgeof *ti:?,, a paeanto the godof science? No-to humantng.r,uif,,to the capacityin all of us,freedat lastin the modernera.Andlo thefortunatecomprehensibility of the universe. The signature achievement of humanity has been to find its way without assistance through a worldthatprovedsulprisingly well ordered. All our othersenses havebeenexpanded by science. Oncewewere deaf;now we can hearevery,thing. The human auditoryrangeis zo to 2o,oooHz, or cyclesof air compression per second. Abovethat range, fying batsbroadcast ultrasonic pulsesinto the nightair and listenlor echoesto locatemothsand otherinsecbon the wing.Many of their potentialprey listen with earstuned to the samefrequenciesas the bais.when theyhearthetelltalepulses,theydip andwheelin evasive maneuvers or elsepower-dive to the ground.Beforethe r95os,zoologistswere unawareof this nocfurnal contest.Now, with receivers, transformers,and nighftime photographythey can follow every squeak andaerialroll-out. We haveevenuncovered basicsenses entirelyoutsidethe human repertory.Where humansdetectelechicity only indirectlyby a tingling of skin or flashof light, the electrichshesof Africaand South America,a medleyof freshwatereels,catfish,and elephant-nosed fishes,live in a galvanicworld.They generatechargedfieldsaround their bodieswith trunk muscletissuethat hasbeenmodifiedby evolution into organicbatteries. The poweris controlledby a neuralswiteh. Each time the switchturnson the field, individualfish sensethe resultingpowerwith electroreceptors dishibutedovertheir bodies.perturbations causedby nearbyobjects,which castelectricshadows over the receptors,allow them to iudgesize,shape,and movement.Thus continuously informed,the fishglide smoothlypastobstacles in dark water,escapefrom enemies,and targetprey.They alsocommunicate with oneanotherby meansof codedelectricalbursts.Zoologists, using generators and detectors,can ioin the conversation. They are able to talkasthrougha fish'sskin.

m

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Fnou rHEsE lND countlessother examplescan be drawnan informal rule of biological evolution important to the understanding of the human condition: If an organicsensorcan be imaginedthat picks up any signalfrom the environment,there existsa speciessomewhere it. The bountiful powers of life expressedin such diverthat possesses sity raisea questionabout the incapacityofthe unaided human senses: Why can't our species,the supposedsummumbonum of Creation,do as much as all the animals combined, and moreT Why were we brought into the world physicallyhandicapped? Evolutionary biology offersa simple answer.Natural selection,defined as the differential survival and reproduction of different genetic forms, prepares organismsonly for necessities.Biological capacity evolvesuntil it maximizes the fitness of organismsfor the niches they fill, and not a squigglemore. Every species,everykind of butterfly,bat, fish, and primate, including Homo sapiens,occupies a distinctive niche. It follows that each specieslives in its own sensoryworld. In shapingthat world, natural selectionis guided solelyby the conditions of past history and by eventsoccurring moment to moment then and now. Becausemoths are too small and indigestibleto be energetically efficient food for large primates, Homo sapiensnever evolved echolocation to catch them. And since we do not live in dark water,an elechical sensewasnever an option for our species. Natural selection, in short, does not anticipate future needs.But this principle, while explaining so much so well, presentsa difficulty. If the principle is universally true, how did natural selection prepare the mind for civilization before civilization existed?That is the great mystery of human evolution: how to account for calculus and Mozart. Later I will attempt an answerby expanding the evolutionary explanation to embrace culture and technological innovation. For the mo. ment, let me soften the problem somewhatby addressingthe peculiar nature of the natural sciencesas a product of history. Three preconditions, three strokesof luck in the evolutionary arena, led to the scientific revolution. The first wasthe boundlesscuriosity and creativedrive of the best minds. The secondwas the inborn power to abshactthe essential qualities of the universe.This ability was possessed by our Neo. lithic ancestors,but (again, here the primary puzzle) seemingly developedbeyond their survival needs.In just three centuries,from 16ooto r9oo, too short a time for improvement of the human brain by genetic evolution, humankind launched the technoscientificage.

The Natural Sciences

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The third enabling precondition is what the physicist Eugene Wigner once called the unreasonableeffectiveness of mathematicsin the natural sciences.For reasonsthat remain elusive to scientistsand philosophersalike, the corespondence of mathematical theory and experimentaldata in physicsin particular is uncannily close.It is so closeas to compel the belief that mathematicsis in some deep sense the natural language of science."The enormous usefulnessof mathematicsin the nafural sciences,"Wigner wrote, "is somethingbordering on the mysteriousand there is no rational explanation for it. It is not at 'laws all natural that of nahrre' exist, much lessthat man is able to discover them. The miracle of the appropriatenessof the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understandnor deserye." The laws of physics are in fact so accurate as to hanscend cultural differences.They boil down to mathematical formulae that cannot be given Chinese or Ethiopian or Mayan nuances.Nor do they cut any slack for masculinist or feminist variations. We may even reasonably supposethat any advanced extraterrestrialcivilizations, ifthey possess nuclear power and can launch spacecraft,have discoveredthe same laws,such that their physicscould be hanslatedisomoqphically,point to point, set to point, and point to set, into human notation. The greatestexactitudeof all hasbeen obtained in measurements of the electron. A single electron is almost unimaginably small. Abshacted into a probabilistic packet of wave energy, it is also nearly impossibleto visualize (as is the case generally for phenomena in quantum physics) within the conventional cognitive framework of obiectsmoving in threedimensionalspace.Yet we know with confidence that it has a negative charge of o.16 billion-billionth (-r.6 X lo-,e) coulomb and a rest massof o.9r billion-billion-billionth (9.r x ro-"; gram. From these and other verifiable quantities have been accurately deduced the properties of electric currents, the elechomagnetic spectrum, the photoelectriceffect,and chemical bonding. The theory that unitessuch basicphenomenais an interlocking set of graphical representationsand equations called quantum electrodynamics(Q.E.D.). Q.E.D.treatsthe positionand momentum of each elechon as both a wave function and a discrete particle in space.The electron is further envisionedin Q.E.D. as randomly emitting and reabsorbingphotons, the unique masslessparticles that carry the electromagnetic force. _-.tr..r

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In one property of the electron, its magneticmoment, theory and experiment have been matched to the most extreme degree ever achievedin the physicalsciences.The magneticmoment is a measure of the interaction betweenan electronand a magneticfield. More precisely,it is the maximum torque experiencedby the electron divided by the magnetic induction acting on it. The quantity of interestis the grromagnetic ratio, the magnetic moment divided in turn by the angular momentum. Theoretical physicistspredictedthe value of the gyromagnetic ratio with calculationsincorporating both specialrelativity and perturbationsfrom photon emissionand resorption,the two phenomena expected from Q.E.D. to cause small deviationsfrom the ratio previouslypredictedby classicalatomic physics. For their part, and independently, atomic scientistsdirectly measuredthe gyromagneticratio. In a technical tour de force,they trapped single electrons inside a magnetic-electricbottle and studied them for long periods of time. Their data matched the theoretical prediction to one part in a hundred billion. Together the theoretical and experimental physicistsaccomplishedthe equivalentof launching a needle due eastfrom San Franciscoand correctly calling in advance where it would strike (nearWashington,D.C.) to within the width of a human hair.

Tue orscENT ro minutissima,the searchfor ultimatesmallness in entitiessuch as electrons,is a driving impulse ofWesternnatural science. It is a kind of instinct. Human beingsare obsessed with building blocks, forever pulling them apart and putting them back together again.The impulse goesasfar back as4oo B.c. to the first protoscience, when Leucippus and his student Democrih-rsspeculated,correctly as it turned out, that matter is made of atoms.Reduction to microscopic units has been richly consummatedin modern science. The search for the ultimate has been aided through direct visual observation by steadyadvancesin the resolving power of microscopes. This technological enterprise satisfiesa second elemental craving: to see all the world with our own eyes.The most powerful of modern instruments, invented during the r98os, are the scanning-tunneling microscopeand atomic force microscope,which providean almostliteral view of atoms bonded into molecules.A DNA double helix can now

The NaturalSciences

,5

be viewedexactlyasit is, including everytwistand turn into which a particularmoleculefell asthe technicianpreparedit for study.Had suchvisualtechniquesexistedfifty yearsago,the infantscienceof mo. lecularbiologywouldhaveescalatedevenmoresharplythan it has.In science,asin whistandbridge,one peekis wortha hundredfinesses. AtomicJevelimagingis the end productof threecenturiesof technologicalinnovationin searchof the final peek.Microscopybegan with the primitive optical instrumentsof Anton van Leeuwenhoek, which in the late r6oosrevealedbacteriaand otherobiectsa hundred timessmallerthanthe resolutionof the humaneye.It hasarrivedat methodsfor showingobjectsa million timessmaller. The passionfor dissecting hasresultedin the inand reassembling ventionof nanotechnology, the manufactureof devicescomposedof a relativelysmallnumberof molecules.Amongthe moreimpressiverecentachievements are: . Etchingstainless steelpinswith ion beams,BruceLamartineand RogerStutzof the LosAlamosNationalLaboratoryhavecreatedhighdensityROMs ("read-only memories"),whoselines are cut so fine, down to r5o billionthsof a meter,asto allow the storageof two gigab1'tes of dataon a pin z5millimeterslongandr millimeterwide.Since the materialsare nonmagnetic,the informationthus storedis nearly indeshuctible.Yet there is still a long way to go. In theory at least, atomscanbe orderedto storeknowledge. . A fundamentalquestionin chemistrysincethe work of Lavoisier in the eighteenthcenturyhas been the following:How long doesit takea pair of moleculesto meetand bondwhendifferentreagents are mixed together?By confining solutionsto extremelysmall spaces, Mark Wightmanand his fellow researchers at the Universityof North Carolinaobservedflashesof light that mark the contactof oppositely chargedreagentmolecules,enabling the chemiststo time the reactionswith unprecedented accuracy. . Molecule-sized machinesthatassemble themselves underthedirectionof technicianshavefor manyyearsbeenconsidereda theoretiNow the ensembles calpossibility. arebeingrealizedin practice.One of the mostpromisingtechniques,engineeredby GeorgeM. Whitesidesof HarvardUniversityand other organicchemists,consistsin

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self-assembled monolayers.The SAMs (for short) consistof sausageshapedmolecules such as long hydrocarbonchains called alkanethiols. After synthesisin the laboratorythe substancesare paintedonto a gold surface.One end of each molecule has propertiesthat causeit to adhere to the gold; the other end, built of atoms with different properties,projectsoutwardinto space.Thus lined up like soldierson parade, molecules of the same kind create a single layer only one to two nanometersthick. Molecules of a different construction are next laid down to createa secondlayer on top of the first, and so on, compound by compound, to produce a stratified film of desired thicknessand chemical properties.SAMs sharesomeof the basicpropertiesof membranesof living cells.Their constructionsuggestsone possiblestepin the eventualassemblyof simple artificialorganisms.Although far from being alive, SAMs are simulacra of elemental pieces of life. Given enough such components assembledthe right way, chemists may somedayproduce a passableliving cell.

T H s r N ' r s L L E c r u A L T H R U S T o f m o d e r ns c i e n c ea n d i t ss i g n i f i cance for the consilient world view can be summarized as follows.In the ultimate senseour brain and sensorysystemevolvedasa biological apparatusto preserveand multiply human genes.But they enableus to navigate only through the tiny segment of the physical world whose masteryservesthat primal need. Instrumental science has removed the handicap. Still, sciencein its fullnessis much more than iust the haphazard expansionof sensorycapacityby instruments. The other elements in its creative mix are classificationof data and their interpretation by theory. Together they compose the rational processing of sensoryexperienceenhancedby inshumentation. Nothing in science-nothing in life, for that matter-makes sense without theory. It is our nature to put all knowledge into context in order to tell a story and to re-createthe world by this means. So let us visit the topic of theory for a moment. We are enchanted by the beauty of the natural world. Our eye is caught by the dazzling visual patterns of polar star hails, for example, and the choreography of chromosomes in dividing root tip cells of a plant. Both discloseprocessesthat are also vital to our lives. In unprocessedform, however, without the theoretical frameworks of heliocenhic astronomy and Mendelian heredity, they are no more than beautiful patternsof light.

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Theory:a word hobbledby multiple meanings.Takenalonewithotta or the,it resonates with erudition.Takenin everydaycontext,it is shotthroughwith corruptingambiguity.We often hearthat suchand suchan assertionis only a theory.Anyonecan havea theory;payyour moneyandtakeyour choiceamongthe theoriesthat competefor your attention.Voodoopriestssacrificingchickensto pleasespiritsof the deadareworkingwith a theory.So are millenariancultistswatching theIdahoskiesfor signsof theSecondComing.Because scientifictheoriescontainspeculation, theytoomayseemiustmoreguesswork, and thereforebuilt on sand.That, I suspect, is the usualposhnodernist conception:Everyone's theoryhasvalidityand is interesting.Scientific theories,however,are fundamentallydifferent.They are conshucted specificallyto be blown apartif provedwrong,and if so destined,the soonerthe better."Make your mistakesquickly" is a rule in the practice of science.I grantthat scientists often fall in love with their own constructions. I know;I have.They mayspenda lifetime vainlytrying to shorethemup. A fewsquandertheirprestigeand academicpolitical capitalin the effort.In that case-asthe economistPaulSamuelson oncequipped-funeralby funeral,theoryadvances. Quanhrm elechodynamics and evolution by natural selection are examplesof successfulbig theories,addressingimportant phenomena. The entitiesthey posit, such as photons,electrons,and genes,can be measured. Their statements are designed to be tested in the acid washesof skepticism,experiments,and the claims of rival theories. Without this vulnerability, they will not be accorded the statusof scientific theories.The besttheoriesare renderedlean by Occam'srazor, first expressedin the r3zosby William of Occam. He said, "What can be done with fewer assumptionsis done in vain with more." Parsimony is a criterion of good theory. With lean, tested theory we no longer need Phoebusin a chariot to guide the sun acrossthe sky,or dryadsto populate the boreal forests.The practice grants less license for New Age dreaming, I admit, but it getsthe world straight. Still, scientific theories are a product of imagination-informed imagination. They reach beyond their graspto predict the existenceof previously unsuspectedphenomena. They generate hypotheses,disciplined guessesabout unexplored topics whose parametersthe theories help to define. The best theoriesgeneratethe most frui$rl hypoiheses, which translatecleanly into questionsthat can be answeredby observation and experiment. Theories and their progeny hypothesescom-

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pete for the availabledata,which comprisethe limiting resourcein the ecologyof scientificknowledge.The survivorsin this tumultuous environment are the Darwinian victors,welcomed into the canon, settling in our minds, guiding us to further explorationof physicalreality,more surprises.And yes,more poetry. Science,to put its warrantasconciselyaspossible,is theorganized, systematicenterprisethat gathers knowledgeabout the world and condensesthe knowledgeinto testablelaws and principles. The diagnostic featuresof sciencethat distinguishit from pseudoscience are first, repeatability: The same phenomenon is sought again, preferably by independent investigation,and the interpretation given to it is confirmed or discarded by means of novel analysisand experimentation. Second, economy: Scientistsattempt to abstractthe information into the form that is both simplest and aestheticallymost pleasing-the combination called elegance-while yielding the largestamount of information with the least amount of effort. Third, mensuration: If something can be properly measured, using universally accepted scales,generalizationsabout it are rendered unambiguous. Fourth, heuristics: The best science stimulates further discovery,often in unpredictable new directions;and the new knowledgeprovidesan additional test of the original principles that led to its discovery.Fifth and finally, consilience: The explanationsof different phenomena most likely to surviveare thosethat can be connectedand provedconsistent with one another. fuhonomy, biomedicine, and physiologicalpsychologlrpossess all these criteria. Astrology, ufolory, creation science, and Christian Science, sadly,possess none. And it should not go unnoticed that the true natural scienceslock together in theory and evidence to form the ineradicabletechnical baseof modern civilization.The pseudosciences satis$rpersonalpsychologicalneeds,for reasonsI will explainlater,but lack the ideasor the meansto conhibute to the technicalbase.

THs currING Encs of science is reductionism,the breaking apart of nature into its natural constituents. The very word, it is true, has a sterile and invasivering, like scalpel or catheter.Critics of science sometimesportray reductionism as an obsessionaldisorder,declining toward a terminal stageone writer recently dubbed "reductive

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That characterization is an actionablemisdiagnosis. megalomania." Practicingscientists, whosebusinessis to makeverifiablediscoveries, viewreductionismin an entirelydifferentway:It is the searchshategy employedto find pointsof entryinto otherwiseimpenetrablycomplex in the end,not simplicsystems. Complexityis what interestsscientists ity. Reductionismis the wayto understandit. The love of complexity without reductionismmakesart; the love of complexitywith reductionismmakesscience. Here is how reductionismworksmostof the time, asit might appearin a user'smanual.Let yourmindtrayelaroundthesystem. Pose an interesting questionabout it. Breakthequestiondownand visualizethe elements andguestionsit implies.Thinkout altemativeconceivable anamountof evidencemakesa swers.Phrasethem so that a reasonable clear-cutchoicepossible.lftoomarryconcepfualdfficultiesareencountered,backoff. Searchfor anotherquestion.Whenyou finally hit a soft spot,searchfor the modelsystem-sdyd controlledemission in particle physicsor a fast-breedingorganismin genetics-on which decisive experimentscan be mosteasily conducted.Becomethoroughlyfamiliar-no, better,becomeobsessed-withthesystem.Lovethedetails,the feelof aII of them,for their ownsake.Designthe expeimentsothat no malterwhat the result,the answerto the questionwill be convincing. new systems. Usethe resultto presson to newquestions, Dependingon (and alwayskeepin howfar othershavealreadygonein thissequence mind,you mustgivethemcompletecredit),youmayenterit at anypoint alongtheway. Followedmore or lessalongtheselines,reductionismis the primaryand essential activityof science.But dissection and analysis are not all that scientistsdo. Also crucial are synthesisand integration, reflectionon significance andvalue.Even temperedby philosophical most focused researchers, including the narrowly thosedevotedto the searchfor elementalunits,still think all the time aboutcomplexity.To makeanyprogress theymustmeditateon the networksof causeandef fect acrossadjacentlevelsof organization*from subatomicparticles to atoms,say,or organismsto species-andtheymustthink on the hidden designand forcesof the networksof causation.Quantum physics thusblendsinto chemicalphysics,which explainsatomicbondingand chemicalreactions, which form the foundationof molecularbiology, which demystifies cell biology.

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Behind the mere smashingof aggregates into smaller pieceslies a deeper agenda that also takes the name of reductionism, to fold th. laws and principles of each level of organizationinto those at more general, hence more fundamental levels.Its strongform is total consilience, which holds that nature is organizedby simple universallaws of physicsto which all other laws and principlescan eventuailybe reduced. This transcendentalworld view is the light and way fo, .r,a.,y scientific materialists(l admit to being among them), but it could be wrong. At the least,it is surely an oversimplification.At each level of organization,especiallyat the living cell and above,phenomena exist that require new laws and principles, which still cannot be predicted from those at more generallevels.Perhapssome of them wiir remain forever beyond our grasp.Perhapsprediction of the most complex systems from more general levels is impossible.That would not be ail bad. I will confesswith pleasure:The challengeand the crackling of thin ice are what give scienceits metaphysicalexcitement.

S c r n rvc a , its imperfections notwithstanding,is the sword in the stone that humani$ finally pulled. The questionit poses,of universal and orderly materialism,is the most important that can be askedin philosophy and religion. Its proceduresare not easyto master,even to conceptualize; that is why it took so long to get started, and then mostly in one place, which happened to be westernEurope. The work is also hard and for long intervalsfrushating.you haveto te a bit compulsive to be a productive scientist.Keep in mind that new ideasare commonplace, and almost alwayswrong. Most flashesof insight lead nowhere; statistically, they have a half-life of hours or maybe davs. Most experiments to follow up the suwiving insights are tedious and consume large amountsof time, only to yield negativeor (worse!)ambiguous results.Over the yearsI have been presumptuousenough to counsel new Ph.D.'sin biology as follows:If you choosean acad-emic career you will need forty hours a week to perform teaching and ad_ minishative duties, another twenty hours on top of that to conduct respectableresearch,and still another twenty hours to accomplish really important research.This formula is not boot-camp rhetoric. More than half the Ph.D.'s in scienceare stillborn, dropping out of original researchafter at most one or two publications.percy Bridgm"rr, th.

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founder of high-pressurephysics-no pun intended-put the guideline another way: "The scientific method is doing your damnedest,no holds barred." Original discoveryis everything. Scientistsas a rule do not discover in order to know but rather, as the philosopher Alfred North Whitehead observed,they know in order to discover.They learn what they need to know, often remaining poorly informed about the rest of the world, including most of science for that matter, in order to move speedily to some part of the frontier of science where discoveriesare made.There they spreadout like foragerson a picket line, each alone or in small groups probing a carefully chosen,narrow sector.When two scientistsmeet for the first time the usual conversation entry is, "What do you work on?" They already know what generally bonds them. They are fellow prospectorspressingdeeper into an abstracted world, content most of the time to pick up an occasionalnugget but dreaming of the mother lode. They come to work each day thinking subconsciously,lt'sthere, l'm close,this could be the day. They know the first rule of the professionalgame book: Make an important discoveryand you are a successfulscientistin the true, elitist sensein a professionwhere elitism is practicedwithout shame.You go into the textbooks.Nothing can take that away; you may rest on your laurels for the rest of your life. But of courseyou won'! almost no one driven enough to make an important discoveryever rests.And any discoveryat all is thrilling. There is no feeling more pleasant,no drug more addictive, than setting foot on virgin soil. Fail to discover, and you are little or nothing in the culhrre of science, no matter how much you learn and write about science.Scholars in the humanitiesalso make discoveries,of course,but their most original and valuable scholarship is usually the interpretation and explanation of already existing knowledge. When a scientist begins to sort out knowledge in order to sift for meaning, and especiallywhen he carriesthat knowledgeoutsidethe circle ofdiscoverers,he is classified as a scholar in the humanities. Without scientific discoveriesof his own, he may be a veritablearchangel among intellectuals,his broad wings spreadabovescience,and still not be in the circle. The hue and final test of a scientific careeris how well the following declarative sentence can be completed:He (or she)discoyeredthat.. . Afundamental distinction thus exists in the natural sciences between process and

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product.The differenceexplains whysomanyaccomplished scientists arenarroq foolishpeople,andwhy somanywisescholars in the field areconsidered weakscientists. Yet,oddly,thereis verylittle scienceculture,at leastin the shict tribalsense. Fewritesareperformed to speakof.Thereisat mostonlya scattering of icons.one does,however,heara greatdealof bickering overterritoryand status.The socialorganization of sciencemostresembles a looseconfederation of pettyfiefdoms.In religiousbelief individualscientistsvaryfrom born-againchristians,ad-ittedly rare,to hard-core atheists, verycommon.Fewarephilosophers. Mostareintellectualiourneymen, exploringlocally,hopingfor a strike,livingfor the present.They arecontentto workat discovery, oftenteachingicience at the collegelevel,pleasedto be relativelywell-paidmembe-rs of one of the more contentiousbut overallleastconspiratorialof professions. In charactertheyare asvariableasthe populationat large.Thke any randomsampleof a thousandand you will find the near-full human rangeon everyaxisof measurement-generous to predatory well adjustedto psychopathic, casualto driven,graveto frivolous,gregariousto reclusive.Some are as stolid as tax accountantsin April, while a few areclinicallycertifiableasmanic-depressives (or bipoiars, to usetheambiguousnewterm). In motivationthey run from venalto noble.Einsteinclassifiedscientistsverywell during the celebrationof Max planck'ssixtiethbirthdayin r9:8. In the templeof science,he said,arethreekindsof people. Many taketo scienceout of a ioyfulsenseof theirsuperiorintelleciual power;for them, researchis a kind of sportthat satisfies personalambition.A secondclassofresearchers engages in scienceto achievepurely utilitarianends.But of the third: If "the angelof the Lord wereto c.omeand driveall the peoplebelongingto thesetwo categories out of t}e temple,a few peoplewould be Lft, including planckl and that is whywelovehim." scientific researchis an art form in this sense:It doesnot matter how you makea discoveryonly that your claim is true and convincingly validated.The idealscientistthinkslike a poetand workslike a bookkeeper,and I supposethat if gifted with a full quiver,he also writeslike a journalist.As a painterstandsbeforebarecanvasor a novelistrecyclespastemotionwith eyesclosed,he searches his imagination for subjectsasmuch asfor conclusions, for questions -u"h ", ", for answers. Even if his highestachievement is only to perceive the

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needfor a new instrumentor theory,that maybe enoughto openthe doorto a newindustryofresearch. This levelof creativityin science,asin art, dependsasmuch on the scientistmustbe self-imageason talent.To be highly successful confidentenoughto steerfor blue water,abandoningsightof land for a while. He valuesriskfor its own sake.He keepsin mind that the footarestrewnwith the namesof the giftedbut notesof forgottentreatises thevastmaiorityof hiscoltimid. If on theotherhandhe chooses,like what leagues,to hug the coast,he mustbe fortunateenoughto possess science: bright intelligence for normal optimum like to as I define enoughto seewhatneedsto be donebut not sobright asto sufferboredom doingit. The scientist's styleof investigationis the productof the discipline he choosgs,further narrowedby aptitudeand taste.If a naturalistat throughrealwoodsthick with at random,sometimes heart,he saunters cellsthick with molecules,in trees,or, more commonlynowadays, His instinctis that still unimagined. searchof obiectsandhappenings theo' is mathematical hand the scientist a hunter. If on the other of the poorly understood rist,he createsa mentalpictureof a knownbut still areits essentialeleit into what intuition suggests process, skeletonizes ments,and recastsit in diagramsand equations.He looksfor vindicaIf this is the way the process tion, by sayingto the experimentalists: works,evenif we cannotseeit directly,then here are the parameters for an indirectprobe,andthe languageby which we might cometo explain the results. the disciplinesareaccordDifferences in validationcriteriaacross ingly vast.Systematicbiologistsneedonly stumbleupon an unusual andrecognizeits novelty,to makean importantdiscovery. newspecies, In 1995two Danishzoologistserectedan entirelynew phylum of aniof tiny rotiferlikecreatures mals,the thirty-fifthknown,from a species found living on the mouthpartsof lobsters.In a wholly differentdoof main, and style,biochemistsregularlytracethe natural syntheses hormonesand otherbiologicallyimportantmoleculesby duplicating the stepswith enzymaticallymediatedreactionsin the laboratory.Exevenfurther removedthan chemistsfrom direct perimentalphysicists, perception,and hencethe most esotericamongthe scientificmultitude,deduce(to takea properlyesotericexample)the spatialdishibution of quarksfrom high-energycollisionsof electronswith protonsof atomicnuclei.

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Adviceto the novicescientist:Thereis no fixedwayto makeand establisha scientificdiscovery.Throw everythingyou can at the subiect,aslongasthe procedures can be duplicatedby others.consider repeated observations of a physicaleventundervaryingcircumstances, experimentsin different modes and styles,correlationof supposed causesand effects,statisticalanalysesto rejectnull hypother"r(thor. deliberately raisedto threatenthe conclusion), logicalargument,and attentionto detailandconsistency with theresultspublishedby others. All theseactions,singlyand in combination, arepartof the testedand true armamentariumof science.As the work comestogether,also think aboutthe audienceto whom it will be reported.pranto publish in a reputable,peer-reviewed ofihe sciiournal.one of the strictures entific ethosis that a discoverydoesnot existuntil it is safelyreviewed and in print.

ScInNrr'rc EvrDENcr rs accretionary, builtfromblocks ofevidenceioinedarfully by the blueprintsandmortarof theory.only very rarely,asin thetheoriesofnaturalselection andrelativity. doesan idea changeour conceptionof the world in one quantalleap.Eventhe revolutionof molecularbiologywasaccretionary buildingupon but not fundamentally alteringphysicsandchemishy. Fewclaimsin science,and particularlythoseentailingconcepts, areaccepted asfinal.Butasevidencepilesuponevidenceandtheoiies interlock more firmly, certain bodiesof knowledgedo gain universal acceptance. In seminarpatoisthey ascenda scali of credibilityfrom "interesting"to "suggestive" to "persuasive" and finally ,,compelling." And givenenoughtime thereafter,"obvious." No objectiveyardstickexistson which to markthesedegrees of acceptance;there is no body of extemalobiectivetruth by *hi"h th.v can be calibrated.There is only warrantedassertibility, to usewilliam within which particulardescriptions James'phrase, oirealitygrowever more congenialto scientistsuntil obiectionscease.A proof, as the mathematician Mark Kac once put it, is that which convincesa reasonableman; a rigorousproof is that which convincesan unreasonableman. It is occasionally possibleto encapsulate a methodof scienceasa recipe.The mostsatis$ingis that basedon multiplecompetinghy-

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potheses, alsoknown as stronginference.It worksonly on relatively and particularlyin under restrictedcircumstances simple processes physicsandchemistry,wherecontextandhistoryareunlikelyto affect the outcome.The phenomenonunderscrutinyis knownto occurbut cannotbeseendirectly,with the resultthatits exactnaturecanonly be guessed. Investigators think out everypossibleway the processmight deviseteststhatwill occur-the multiplecompetinghypotheses-and eliminateall but one. In a celebrated1958example,Matthew Meselsonand Franklin Stahl,then at the CaliforniaInstituteof Technolory,usedthe method to demonshatethe stepsby which DNA moleculesduplicatethemselves.I will first givetheir conclusion:The doublehelix splitslengtha wiseto createtwo singlehelices;eachsinglehelix then assembles new partnerto createanotherdouble helix. Alternativehypotheses, that the doublehelix duplicatesitselfin its entiretyor that the single by the duplicationprocess,mustbe helicesarebrokenand dispersed discarded. Nowthe proof,which despiteitstechnicalcontentis elegantlysimturnsout to havebeenthe right ple. Havingphrasedwhat in retrospect question,Meselsonand Stahl devisedthe right experimentto make a choice among the competingalternatives.They first let bacteria medium that had manufacturedDNA moleculesin a heavy-nitrogen The remedium. in normal-nitrogen a their multiplication continue them in a molecules and centrifuged searchersthen extractedthe DNA molecesiumchloridesolutionthatformeda gradientof density. culesbuilt by the bacteriawith hearynitrogensettleddeeperinto the cesiumchloride densitygradientthan did otherwiseidentical DNA moleculesbuilt by the samebacteriawith normal nihogen.When out into sharplydeequilibriumwasreached,the DNA had separated fined bandsin a patternthat exacdyfit the hypothesisof single-helix The patterneliminatedthe separation and double-helixregeneration. two competinghypothesesof whole-moleculeduplicationand fragmentationfollowedby dispersionof the fragments. Science,evenin the relativelytidy worldof moleculargenetics,is a patchworkof such argumentsand proofs.But perhapstherearecommon elementsin its methods.Can we devisea universallitmustestfor scientificstatemenband with it eventuallyattainthe grail of obiective truth?Currentopinion holdsthat we cannotand neverwill. Scientists

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and philosophers havelargelyabandoned the searchfor absoluteobjectivityand arecontentto ply their hadeelsewhere. I think otherwiseand will risk heresy:The answercould well be yes.criteria of objectivetruth might be attainable throughempirical investigation. The keyliesin clarifyingthestiflpoorryunderstoldop erationscomposingthe mind and in improvingthe piecemealap_ proachsciencehastakento itsmaterialproperties. i1 the argument.Outsideour headsthere is freestanding .Here_ reality.Only madmenand a scatteringof constructivistphilosophers doubt its existence.Inside our headsis a reconstitutionof reality basedon sensoryinput and the self-assembly of concepts. Input and self-assembly, ratherthan an independententity in the brain-the "ghost in the machine,"in the philosophercitbert Ryle's famous derogation-constitutethe mind. The alignmentof ouier existence with its inner representation hasbeendistortedby the idiosvncrasies of human evolution,asI notedearlier.That is,,,"iuralseleciionbuilt the brain to survivein the world and only incidentallyto understand it at a depth greaterthan is neededto survive.Thepropertaskof scien_ fisfsis fo diagnoseand conectthemisalignment.'fheeffortto do sohas only begun.No oneshouldsuppose that obiectivetruth is impossible to attain, even when the most committed philosophersurge us to a-ckn-owledge that incapacity.In particularit is too earlyfor sJientists, the foot soldiersof epistemology,to yierd ground so vital to their mission. Although seeminglychimericalat times,no intellectualvision is more importantanddauntingthan that of objectivekuth basedon scientific understanding.or more venerable.Arguedat length in Greek philosophy,it tookmodernform in the eighteenth-centu{, Enlighten_ ment hopethat sciencewouldfind the lawsgoverningall physica"l existence.Thus empowered,the savants believed,,. clearawaythe "ould debrisof millennia, includingall the mythsandfalse cosmologies that encumberhumanityt self-image. The Enlightenmentdreamfaded beforethe allure of Romanticism;but, .u.r, *or. important,science could not deliverin the domainmostcrucialto its promise,the physi_ cal basisof mind. The two failingsworkedtogetherin a devasiating combination:Peopleare innate romantics,ihey desperately neei myth and dogma,and scientistscould not e*plain ,hy peopiehave thisneed.

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As the nineteenthcenturyclosed,the dreamof obiectivehuth was The first,Europeanin origin,wasposirekindledby two philosophies. the only certainknowledgeis the exactdethat tivism,the conviction The second,American scriptionof whatwe perceivewith our senses. in origin, waspragmatism,the belief that truth is what consistently worksin humanaction.Fromthe outsetbothpositionsweresymbiotic advances with science.They drewmaiorstrengthfrom the spectacular them by the whichvindicated thenunderway, in thephysicalsciences variedactions-elechomagneticmotors,X-rays,reagentchemistrythatexact,practicalknowledgemadepossible. The dreamof obiectivehuth peakedsoonafterwardwith the formulationof logicalpositivism,a variationon generalpositivismthat attemptedto define the essenceof scientificstatementsby meansof logic and the analysisof language.Although many thinkers contributedto the movement,its driving forcewasthe Vienna Circle, a group of mostlyAustrianintellectualsfounded by the philosopher Moritz Schlickin 1924.Regularmeetingsof the Circle continueduntil of its members dispersion Schlick'sdeathin 1936andthe subsequent America as exiles to whom emigrated of some and correspondents, fromthe Naziregime. On September)j, 1939,many of the scholarssympatheticto logicalpositivismmet at HarvardUniversityto attendthe fifth lnternational Congressfor the Unity of Science.It wasa scintillatingassemblageof namesnowenshrinedin the historyof ideas:RudolfCarnap, Phillip Frank,SusanneLanger,Richardvon Mises,ErnestNagel, Willard van Quine, and GeorgeSarOtto Neurath,TalcottParsons, badly distractedby the invasion have been must ton. The conferees of Poland,which begantwo daysbeforethe meetingstarted.Where the Napoleoniccampaignsweakenedthe plausibilityof the original Enlightenment,now a savagewar of territorial conquestfired by a theoryof racialsuperioritythreatenedto makea still pseudoscientific greatermockeryof the powerof reason.The scholarspersisted,however,in exploringthe idea that rationallyacquiredknowledgeis the besthopeof humanity. How then, theyasked,to distill the scientificethos?The mov'ement createdby theViennaCircle had workedat two levelsoverthe years.First wasthe reaffirmationof the core Enlightenmentideal that the causeof the human speciesis bestservedby unblinking

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realism.Having"no protectorsor enemies,"in carnap's expressiorr, humanitymust find its way to transcendent existencesoreryby its own intelligenceand will. Scienceis simplythe besti.,st.u-ent at our disposal.As the vienna circre had ieclared a decade earlier "the scientificworld conceptionserveslife and in turn is t"f.." ,p by life." The secondlevel,requisiteto thefirst,wasthe searchforpure stan_ dardsagainstwhich scientific can be fu.ry ,1rn_ iudged. _knowledge bol, the logicalpositivists concruded, shouldd*oir sJmething ,"i.t, shouldbe consistent with the total struchrreof established fa'ctsand theories,with no revelations or free-flightgeneralizing alrowed. Theory rnustfollow in lockstepwith facts.Finally,the infJrmational content of languageis to be carefullydistinguished from its emotional content'To thesevariousendsverificationis ail important-indeed, the meaningof a statementis its methodof verification.If the -v1v guidelinesareprogressively refinedandfollowed,we will in timeclose in on obiectivetruth. whire this happens,ignorance-based metaphysicswill back awaystepby step,likl a u"-pire before the lifted cross. The logical positivistswho met in Cambridgeknew that pure mathematicswas on the road to the grail but not the prize iLeF. Mathematics,for all its unchallengeable power in framingtheory is tautological.That is, everyconclusionfoilowscompletelyfr"om itsown premises,which may or may not haveanythingio do with the real world' Mathematicians inventand provelemmasand theoremsthat leadto otherlemmasand theorems, andonwardwith """J;;igh;. Some fit data from the material world, some do not. fn. gr."i.rt mathematiciansare intellectualathletesof dazzlingskill. sorietimes they hit upon conceptsthat open new domainsoiabstract thought. Complex numbers,linear transformations, and harmonic functilns areamong thosethat haveprovedmostinterestingmathematicaily as well asusefulto science. Puremathematics is the scienceof all conceivable worlds,a logi_ cally closedsystemyet infinite in all directionsallowed Uy ,t"rtiig premises.With it we might, if given unlimited time and tional capacity,describeeveryimaginableuniverse.But mathematics "o_p.,t"l alonecannotinform us of the veryspecialworld in which we live. only observation candisclose theperiodictable,the Hubbleconstant.

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and all the other certainties of our existence,which may be different or nonexistent in other universes.Becausephysics,chemistry, and biology are conshained by the parametersof this universe, the one we see from inside the Milky Way, they compose the science of all possible phenomenatangible to us. Still, becauseof its effectivenessin the natural sciences,mathemat' ics seemsto point arrowlike toward the ultimate goal of obiective huth. The logical positivistswere especiallyimpressedby the tight meshing of observationwith abstractmathematical theory in quantum and relativistic physics. This greatestof twentieth-century triumphs inspired new confidence in the inborn power of the human brain. Think of it. Here is Homo sapiens,a primate speciesbarely out of its stone-agevillages,correctly divining phenomena almost unimaginably beyond ordinary experience. Surely, the theorists reasoned, we are close to a generalformula for obiective truth. Yet the grail eluded them. Logical positivism stumbled and halted. Today its analyses,while favoredby a few, are more commonly studied in philosophy, as dinosaur fossilsare studied in paleontolog, laboratories, to understand the causesof extinction. Its last stand may have been a seldom-read 1956monograph by Carnap inMinnesota Studies in the Philosophyof Science.The fatal flaw was in the semantic linchpin of the whole sptem: The founders and their followers could not agreeon the basic distinctions between fact and concept, between empirical generalization and mathematical truth, between theory and speculation, and from a collation of all these fog-shrouded dichotomies, the differences behveen scientific and nonscientific statements. Logical positivism was the most valiant concerted effort ever mounted by modern philosophers.Its failure, or put more generously, its shortcoming, was causedby ignorance of how the brain works. That in my opinion is the whole story. No one, philosopher or scientist, could explain the physical acts of observation and reasoning in other than highly subiective terms. Not much has improved in the past fifty years. The mindscape is now under active exploration but still laryely unmapped. Scientific discourse,the focus of logical positivism, comprisesthe most complex of mental operations, and the brain is a messyplace at best even when handling the most elementary of ideas. Scientiststhemselvesdo not think in straight lines. They contrive concepts,evidence, relevance,connections, and analysisasthey go along,

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parsing-it allinto fragments andin no particularorder.Herbertsimon, a Nobelistwho hasdevotedpartof hiscareerto thesubject,says of the complexityof conceptformation:"what chieflycharacierize, .r.",iu" thinking from more mundaneforms are (i) willingnersto acc.pt vaguelydefinedproblemstatements and graduailyltructure them, (ii)-continuingpreoccupation with problerisovera considerable periodof time,and (iii) extensive background knowledge in relevantand potentiallyrelevantareas." To put that in a nutshell:knowledge, obsession, daring.The creative processis an opaquemix. perhapsonly openlyclnfessiona, memoirs,still rareto nonexistent, might disclose how scientists actually find their wayto a publishabre coicrusion.In onesensescientific articlesare deliberately misleading. fust asa novelis betterthan the novelist'a scientificreportis betterthan the scientist, havingbeen strippedof all the confusions and ignobrethoughtthatled to iti composition.Yetsuchvoluminousandincomprehensible chaff,soonto be forgotten,containsmostof thesecrets of scientificsuccess. The canonicaldefinitionof obiectivescientificknowledge avidry soughtby the logicalpositivists is not a philosophicalprobl...,"no. it be attained,astheyhoped,by logicaiandsemanticanalysis. ""r, It is an empiricalquestionthatcanbe answered onlyby a continuingprobeof the physicalbasisof the thoughtprocessitserf.The mostfruif,rt p-".dureswill almostcertainlyincludethe useof artificialirt.rrii.""., aidedin time by the still embryonicfieldof artificiaremotion,tJri*,rlatecomplexmentaloperations. This modelingsystem will be joined to an alreadyswiftlymaturingneurobiology of tf,ebrain,includingthe high-resolutionscanningof computationli networksactivein vaiious formsof thought.Importantadvances will alsocomefrom the molecuIar biolog;rof the learningprocess. If the exactbiologicalprocesses of conceptformationcan be dehned,we might devisesuperiormethodsof inquiry into both the brain and the worldoutsideit. As a consequence we'couldexpectto tigh;; the connectedness betweenthe eventsandlawsof nature th."phfrical basisof human thoughtprocesses. ".,d Might it be possible thin'to take th_e6nal stepand devisean unassailab"le definition of obiective huth? Perhapsnot. The veryideais risky.It smellsof absolutism, the dangerous Medusaof scienceandthe humanitiesalike.Itspr.-raur. acceptance is likely to be moreparalyzing than its denial.riut should -Better we then be preparedto give up? Neverl to steerby a lodestar

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sea.I think we will knowif we come thanto drift acrossa meaningless evenif unattainable.Itsglow will closeto the goalof our predecessors, beauty and powerofour sharedideas and in the elegance be caught the wisdomof our pragmatism, philosophical and,in the bestspirit of conduct.

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Antaoxe's THREAD

Wlrn rHE ArD of the scientificmethod,we havegainedan €ncompassing viewof thephysicalworldfarbeyondthedrJamsof earlier generations. The greatadvenfureis now beginningto turn inward,to_ wardourselves. In the lastseveraldecadesthe natuialsciences haveexpandedto reachthe bordersof the socialsciences and humanities. There the principle of consilientexplanationguidingthe advance must undergoits severest test.The physicalsciencesh-avebeen relatively easy;the socialsciences and humanitieswill be the ultimate challenge.This uncertainconiunctionof the disciplines hasmythic elemenbthat would havepleasedthe ancientGreeks:treacherous road,heroic journey,secretinstructionsthat lead us home.The ele_ mentshavebeen assembledinto many narrativesoverthe centuries. Amongthem is the storyof the cretan labyrinth,which canalsoserve asa metaphorof consilience. lnto the heart of the cretan labyrinth walksTheseus, Heracres-rike championof Athens.Througheachcorridor,pastuncountedtwistsand tums, he unrayelsa ball of threadgiven him by ,\riadne, Iovestruck daughterof Crete'sKing Minos.Somewhere in tie hidden passages he meetsthe Minotaur, the cannibalhalf man, half buil to whoiseven youthsand maidensaresacificedeachyearas Athens'tributeto crete. Theseuskills the Minotaur with his bare hands.Then, folrowing Al.adne'sthread,he retraceshis steps throughand outof thelabyintt.

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The labyrinth,its likely origin a prehistoricconfict betweenCrete andAttica,is a fitting mythicimageof the unchartedmaterialworld in which humanity wasborn and which it forevershugglesto understand.Consilienceamongthe branchesof learningis the Ariadne's threadneededto traverseit. Theseusis humanity,the Minotaur our own dangerousirrationality.Nearthe entranceof the labyrinth of empirical knowledgeis physics,comprising one gallery, then a few branchinggalleriesthat all searchers undertakingthe journeymust follow.In the deepinterioris a nebulaof pathways throughthe social sciences,humanities,art, and religion. If the thread of connecting causalexplanationshas been well laid, it is nonethelesspossibleto follow any pathwayquickly in reverse,back through the behavioral sciencesto biolory,chemistry,and finally physics. With time, we discoverthat the labyrinthhasa troublingpeculiarity that makesits completemasteryimpossible.While there is an enhance,more or less,thereis no center,only an immensenumber of end points deep within the maze.In trackingthe thread backward, from effectto cause,assumingwe haveenoughknowledgeto do so, we can beginwith only one end point.The labyrinthof the real world is thus a Borgesianmazeof almostinfinite possibility.We can never map it all, neverdiscoverand explaineverything.But we can hope to havel through the known partsswiftly,from the specificback to the general,and-in resonance with thehumanspirit-we cango on tracing pathwaysforever.We canconnectthreadsinto broadeningwebsof explanation,becausewe havebeen given the torch and the ball of thread. Thereisanotherdefiningcharacter of consilience: It is far easierto go backwardthroughthe branchingcorridorsthanto go forward.After segmentsof explanationhavebeenlaid one at a time, one level of organizationto the next,to manyend points(say,geologicalformations or speciesofbutterflies)we can chooseanythreadand reasonablyexpectto follow it throughthe branchingpointsof causationall the way backto the lawsof physics.But the oppositeiourney,from physicsto end points, is exhemelyproblematic.As the distanceaway from physicsincreases, the optionsallowedby the antecedentdisciplinesincreaseexponentially. Eachbranchingpoint of causalexplanationmultiplies the forward-boundthreads.Biology is almost unimaginably more complexthan physics,and the artsequivalentlymore complex than biologl'. To stayon courseall the way seemsimpossible.And

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worse, we cannot know before departure whether the complete journey we have imagined even exists. The accelerating growth of forward-bound complexi$,, from entrance to end points, is illustrated with textbook clarity by cell biology. Researchershave used the reductionist principles of physics and chemistry to explain cellular structure and activity in admirably brilliant detail, with no discernibleroom left for rival approaches.They expect in time to explain everythingabout any particular kind of cell chosen for study, reducing it organelle by organelle and finally reassemblingit holistically,thus travelingtowardthe labyrinth entrance and simplicity. But they nourish faint hope of predicting-as opposed to explaining and reconstructingretrodictively-the characterof any complete cell from physics and chemistry, hence traveling awayfrom the labyrinth entrance toward rising complexity. To recite one of the manhasof science,the explanationsof the physicalsciencesare necessary but not sufficient. There is too much idiosyncrasyin the arrangement of a particular cell's nucleus and other organellesas well as the molecules composing them, and too much complexity in the cell's constantly shifting chemical exchangeswith the environmen! to accomplish such a conceptual haverse.And beyond theseparticularities awaitsthe still-hidden history of the prescriptive DNA, stretchedacross countlessgenerations, Put briefly, the questions of interestare how the cell is put together and what was the evolutionary history that led to its prescription. In order to proceed,biologistsare compelledfirst to describecomplexity in the cell, then break it down. To go the other way is conceivable,but the biologistsall agree it will be forbiddingly difficult. To dissecta phenomenon into its elements, in this case cell into organellesand molecules, is consilienceby reduction. To reconstitute it and especially to predict with knowledge gained by reduction how nature assembledit in the first place, is consilienceby synthesis. That is the two-step procedure by which natural scientistsgenerally work: top down acrosstwo or three levels of organization at a time by analysis,then bottom up acrossthe sameleveli by synthesis. The procedure can be simply illustrated with a modest example from my own research.Ants alert one another to danger at a distance. When a worker ant is jostled, pinned to the ground, or otherwise threatened, nestmates up to several inches away somehow senseher disbessand rush to her aid. ("Her," I say, because all workers are fe-

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male.)Alarmcanbe communicated bysightbut onlyrarely,sinceconfrontationsusuallyoccur in the dark and in any casemanykinds of antsareblind. The signalcan alsobe transmittedby sound.Agitated workersmakesqueakingnoisesby rubbingtheir waistsagainsta rear segmentof their bodies,or elserepeatedlypump their bodiesup and down to strikethe ground. But again,sound is used only by some species, andthenonlyon specialoccasions. Knowingthesefactsin the r95os,asa beginningentomologist,I speculated thatthe keyalarmsignalsarechemical.The substances are whatresearchers in thosedayscalledchemicalreleasers andtodayare knownaspheromones. To testmy idea,I collectedcoloniesof red harvesterantsand a few other specieswhosenaturalhistoryI knewwell. Then I installedthem in artificial nestsnot much differentfrom a child's ant farm.With the aid of a dissectingmicroscopeand watchmaker'sforcepsI dissectedfreshlykilled worliersto obtain organsthat might containalarmpheromones.I crushedeachone of thesebarely visiblewhite gobbetsof tissueonto the sharpenedtips of applicator sticksand presentedthem in tum to restinggroupsof workers.In that wayI learnedthatat leasttwo of the glandsareactive.One opensat the baseof the mandiblesand the other nextto the anus.The antswere galvanizedby the substancesreleasedfrom the glands.They raced backandfo*h in whirligig loopsaroundthe applicatorsticks,pausing only occasionally to examineand snapat the crushedtissue. I had pinpointedthe origin of the pheromones.But what were they?I enlistedthe help of Fred Regnier,a chemistof like age just startinghis own career.He wasexpertin the skillsmostneededat that time to advancethe study of ant communication,the analysisof exhemelysmallorganicsamples.Usingthe Iatesttechniquesof the day, gaschromatography and massspechometry,Regnieridentified the activesubstances as a medley of simple compoundscalled alkanes and terpenoids.He then obtainedsamplesof identical compounds that hadbeensynthesized in the laboratoryguaranteeingtheir purity. Presenting minutequantitiesto the ant colonies,we obtainedthe same responses I had observedin my first experiments, and confirmedthat the glandularcomponentsRegnierhad identified were the alarm pheromones. This informationwasthe first stepto the understandingof broader and more basicphenomena.I next enlistedthe help of William Bossert,a young mathematician.(We wereall young in thosedays;

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young scientistshave the best ideas and, more important, the most time.) Inhigued by the novelty of the problem, as well as by the small stipend I offered him, he agreedto constructphysical models of the diffusion of the pheromones.we knew that chemicalsevaporatefrom the gland openings.The molecules closestto the openingsare dense enough to be smelled by the ants. The three-dimensionaldomain within which this occurs we called the activespace.The geometrical form ofthe activespacecan be predictedfrom knowledgeofthe physical propertiesof the moleculesand confirmed by the time requiredfor the expandingcloud of molecules to alert the ants.We used both the models and experimentsto measure the rate of spread of the molecules and the sensitivityof the ants to them, and establishedwith reasonablecertaintythat workersreleaseevaporatedpheromonesin order to communicate. The stepsin reasoningwe followed are universalin scientific research.They follow from the consilienceof the disciplinesestablished by generationsof earlierscientists.Tb solvethe problem of alarm communication in ants, we employed reduction, working our way down from one level of specific organization, namely the organism, to a more general level, the molecule. We tried to explain a phenomenon in biology with physicsand chemistry.Luckily, our ideassucceeded, this time. The same approach to pheromone researchcontinued to be rewarded in the decadesto follow. Scoresof biologistsworking independently established that ants organize their colonies with many chemical systemslike those used to hansmit alarm. Their bodies, we discovered, are walking batteries of glands filled with semiotic compounds. When ants dispensetheir pheromones,singly or in combination and in varying amounts, they say to other ants, in effect:danger, come quickly; or danger,disperse;or food, follow me; or there is a better nest site, follow me; or I am a nestmate,not an alien; or I am a lana; and on through a repertoire of ten to twenty messages,with the number differing accordingto caste(such assoldieror minor worker) and species.So pervasiveand powerful are thesecodesof taste and smell that all together they bind ant colonies into a single operational unit. As a result each colony can be viewed asa superorganism,a congeries of conventional organismsacting like a single and much large, organism' The colony is a primitive semiotic web that crudely.eiembles a nerve net, a hundred-mouthed hydra writ large. Touch one ant, one

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77 strand of the net, and the displacementspreadsout to engagethe communal intelligence. We had crossedfour levels-superorganism,to organism,to glands and senseorgans,to molecules.Was it possiblethen to turn around and travel in the opposite direction, predicting the outcome without advanceknowledge of the biology of the ants?yes, at least in the form of a few broad principles.From the theory of natural selection,moleculesservingaspheromonescan be expectedto possess certain properties that allow efficient manufacture and transmission. Adding in principlesof organicchemishy,we concluded that the molecules will likely contain 5 to zo carbon atoms and have molecular weights between 8o and 3oo. Molecules acting as alarm pheromonesin particular will usually be on the light side. They will be produced in comparativelylargequantities,for examplemillionths rather than billionths of a gram in each ant, and the responding workers will be less sensitiveto them than to mostother kinds of pheromones.This combination of traits allows quick transmissionfollowed by a rapid fade-out of the signalafterthe dangerpasses. In contrast,trail substances, which are followed by the ants from nestto food and back, can be predicted to consistof moleculeswith the oppositequalities.Their traitsallow long duration of the signal, as well as insuring privacy of transmission.This privacy prevents predators from locking onto the signals and hunting down the senders.In war-and Nature is a battlefield. make no mistake-one needssecretcodes. These predictions, or educated guessesif you prefer, qualify as consilience by synthesis.With some puzzling exceptions, they have been confirmed. But biologistscannot predict from physicsand chemistry alone the exact structure of the pheromone molecules or the identity of the glands that manufacture them. For that matter, in advance of experiments,they cannot stipulatewhether a given signal is usedor not usedby a particularspeciesofant. To attain that levei ofaccuracy, to travel all the way from physics and chemistry near the entranceofthe labyrinth to an end point in the sociallife of ants,we need detailed collateral knowledge of the evolutionary history of the species and of the environment in which it lives.

PRelrcrrvE s y N r H E S r s , i n s h o r t ,i s f o r m i d a b l y d i f E c u lO t .n t h e other hand, I believe that explanation in the opposite direction, by

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reduction, can in some instancesbe achievedacrossall levelsof organization and hence all branchesof learning.As a demonshation,I will now attempt to trace a magician'sdream all the way down to an atom. Serpents are in the magician's dream, transfigured from real-life snakes.I have not placed them there capriciously.They belong as the wild creatures most frequently coniured around the world in dreams and drug-induced hallucinations. Coming with ease to Zulu and Manhattanite alike, serpents are powerful images of human fantasy, flesh-and-blood snakes transformed into flickerin g imagesof the subconsciousmind. There, dependingon the culh:re and experienceof the individual dreamer,they are conjured variouslyaspredators,menacing demons,guardiansof a hidden world, oracles,spiritsof the dead, and gods.The slithering bodiesand lethal strikesof real snakesmake them ideal for magic. Their imagesevokeblends of emotion that fall on a triangular gradient defined by the three points of fear, revulsion, and reverential awe. Where the real snakefrightens, the dream serpent hansfixes.In the dreamer'sparalytic stateof sleepthe serpentcannot be escaped. Snakesare abundant and diversein the rain forestsof westernAmazonia. Serpents,their dream equivalents,figure prominently in the cultures of the Amerindian and mestizoinhabitants.Shamanspreside over the taking of hallucinogenic drugs and interpret the meaning of the serpentsand other apparitionsthat subsequentlyemerge.The Ji varo of Ecuador use maikua, the juice from the green bark of a member of the nighbhade family, Datura arborea. Warriors drink it to summon arutams, ancestorsliving in the spirit world. If the seekeris fortunate, a spirit emerges from the depths of the forest, often in the form of two giant anacondas,which in real life is the speciesEunectes murinus, heaviest of the world's snakes,big enough to kill a human being. The dream serpents roll toward him, entwined in combat. When they come within twenty or thirty feet the )ivaro must run forward and touch them. Otherwise they will explode "like dynamite," and disappear. After receiving his vision the fivaro must tell no one, or else the spell will end. That night he sleepson the bank of the nearestriver, and as he dreams the arutam returns to him as an old man. It says,"I am your ancestor. fust as I have lived a long time, so will you. fust as I have killed many times, so will you." The apparition then disappears,

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79 andasit doesits soulentersthe bodyof the dreamer.The |ivarorisesat dawnwith an enhancedfeelingof braveryand gracein bearing.His new demeanoris notedby othersin the scatteredhouseholdsof the locallivaro community.If he wishes,he candon the bird-boneshoulder ornamentthat symbolizes arutamsoul power.In the old dayshe would havebeen consideredfit to seryeasa warrioron headhunting expeditions. Five hundred miles southeastin AmazonianPeru lives pablo Amaringo,mestizoshamanandartist.Drawingon the traditionsof his Amerindianforebears,the Cocamaand Quechuaspeakersof AmazonasandCajamarca, Amaringoconiuresvisionsanddepictsthem in paintings.His drug of choice,widelyusedin communitiesof the Rfo Ucayaliregion,is ayahuasca, extractedfrom the junglevine Banisteiopsls.His dreamsarepopulatedwith selpentsin mostof their Amazonian cultural roles:mountsof gods,forestspirits,ambushpredatorsof animalsand people,impregnators of women,Iandlordsof lakesand forests,and sometimesthe sinuous ayahuascavine itself transmuted into animalform. In the rich local Shipibotradition followedby Amaringo in his paintings,the serpents,aswell asother real and supernaturalbeings, aredecorated with inhicategeometricdesigns in primarycolors.The paintingsalsosharethe Shipibohorrorvacui:Everyavailablespaceis crowdedwith detail. The stylefits the Amazonregion,which teems with life of stupendous variety. Amaringo's subjects arelooselyeclectic.Spiritsandconjurersand fantasticalanimalsfrom ancientAmerindian myths are thrown togetherwith contemporary Peruvians and industrialartifacts.Shipsand airplanespassby; even flying saucershover abovethe rain forest canopy.The images,surrealanddisturbing,freedfrom normalsensory input, areincarnateemotionsin searchof theaterand narrative.Their crazinessillushatesthe principle that during trancesand dreaming, anymetaphorseryesandanyfragmentof memoryableto slip into the unguardedmind becomespartof the story. The sacredplants,which havebeen analyzedby chemists,are no longer mysterious.Their juices are laced with neuromodulators that in large oraldosesproducea stateof excitation,delirium, and vision.The primaryeffecbareoftenfollowedby narcosisand dreaming of similarkind. In the fivaros'Dafuratheyarethe structurally similar

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alkaloids ahopine and scopolamine. In Banisteriopsisof the mestizos they include beta-carbolines,to which the shamansusually add dimethyltryptamine from another plant species.The substancesare psychotropic, stimulating a flurry of images intense enough to break through the conholled processes of ordinaryconsciousthought. They alter the brain in the same manner as the natural neuromodulator moleculesthat regulatenormal dreaming.The differenceis that under their influence people enter a semicomatosetrance in which dreaming, uncontrolled and often vivid and urgent, is no longer confined to sleep. It is tempting to patronizethe spiritual searchesof the Amazonian vegetalistas,just as it is easyto dismissthe counterculture'sinnocent faith in drug-soaked gurus and sorcerersduring the r96os and rg7os. Outside of a few cults, few people today believe in the late drug guru Timothy Leary, or even remember Carlos Castafledaand his oncefamousThe Teachingsof Don luan.Yetit would be a mistaketo underestimate the importance of such visions. They tell us something important about biology and human nature. For millennia the use of hallucinogens to enhance inner awarenesshas been widespread through the cultures of the world. Natural sleep and drug-induced dreamshave long been viewed in Westerncivilization asa portal to the divine. They appear at pivotal moments in both the Old and New Testaments. We learn from Matthew l:2o, for example, that as|oseph pondered Mary's pregnancy, the conception of fesus,"behold, an angel of the Lord appeared to him in a dream" to reveal the Holy Spirit as progenitor. foseph's witness establishedone of the two essentialpillars of Christian belief, the other being the disciples'accountof the Resurrection, alsodreamlike. Emanuel Swedenborg, the eighteenth-century scientist and theologian whose followers founded the Church of the New |erusalem, believed that dreams contain secretsof the divine. God does not restrict his word to Holy Scriphrre. If the sacred code cannot be found under the microscope (as the Swedish savant discovered to his disappointment), it might yet be forthcoming in the scenarios of the dreamworld. Swedenborg recommended irregular hours and sleep deprivation as a means of inducing shaqperand more frequent images. At least he had his physiology right; I suspectthat he would have enioyed a stiffdose of ayahuasca.

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m CoNsrosn rHEN the dreamsof a magician,a sorcerer,a shaman. They are more than just unique productions of a single mind; they exhibit qualitiesgeneralto the human species.The art of pablo Amaringo is worthy of analysisin the manner of the natural sciences.His paintingsarea testcaseof consilience,an arrestingfragmentof curture that might be explained and thereby given added meaning at the next, biological level down in complexity from artistic inspiration. It is the habit of scientiststo look for elementsavailableas entry points for such analysis.To this end I have chosen two elements from Amaringot paintings that present themselvesfor convenient explanation: the dreamscapeas a whole, and the serpentsthat conspicuously populateit. Mysticism and science meet in dreams. Freud, aware of the coniunction, composeda hypothesisto explain their meaning. He said that our dreamsare disguisesfor unconsciouswishes.When we sleep, the ego releasesits grip on the id, which is the embodiment of instinct, and our most primitive fears and desires then escape into the conscious mind. They are not, however, experienced in raw form. Like charactersin a bad victorian novel, they are altered by the mind's censor into symbolsso as not to disrupt sleep.The averageperson cannot expect to read their meaning accuratelyupon awakening.He must hrrn, Freud argued, to a psychoanalyst,who will guide him through free associationin order to decipher the codes.As the translations are made, the connectionsof the symbols to childhood experiencebecome clear. If the revelation unfolds correctly,the patient enioys an easing of neuroses and other psychological disturbances that stem from his repressedmemories. Freud'sconception of the unconscious,by focusing attention on hidden irrational processes of the brain, wasa fundame"ntalcontribution to culture. It becamea wellspring of ideasflowing from psycholo, gy into the humanities. But it is mostly wrong. Freud's fatal error was his abiding reluctance to test his own theories-to stand them up againstcompeting explanations-then revisethem to accommodate conhoverting facts.He also suffered from the luck of the draw. The acton of his drama-id, ego,and superego-and the rolesthey playedin suppressionand transference might have evolved smoothly into the

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elements of a modern scientific theory had he guessedtheir basic nature correctly. Darwin's theory of natural selection prosperedthat way, even though the great naturalist had no idea of particulate heredity carried by genes.Only later did modern geneticsverify his insight concerning the evolutionaryprocess.In dreamsFreud wasfaced with a far more complex and intractablesetof elementsthan genes,and-to put it askindly aspossible-he guessedwrong. The competingand more modern hypothesisof the basicnatureof dreaming is the activation-synthesis model of biology.As createdduring the past two decadesby J. Allan Hobson of Harvard Medical School and other researchers, it piecestogetherour deepeningknowledge of the actual cellular and molecular eventsthat occur in the brain during dreaming. In brief, dreamingis a kind of insanity,a rush of visions,largelyunconnectedto reality,emotion-chargedand symbol-drenched,arbitrary in content, and potentially infinite in variety.Dreaming is very likely a side effect of the reorganization and editing of information in the memory banksof the brain. It is not, as Freud envisioned,the resultof savageemotionsand hidden memoriesthat slip pastthe brain'scensor. The facts behind the activation-synthesishypothesis can be interpreted as follows. During sleep, when almost all sensoryinput ceases, the consciousbrain is activatedinternally by impulses originating in the brain stem. It scramblesto perform its usual function, which is to create images that move through coherent narratives. But lacking moment-by-moment input of sensoryinformation, including stimuli generated by body motion, it remains unconnected to external reality. Therefore, it does the best it can: It creates fantasy. The conscious brain, regaining control upon awakening,and with all its sensoryand motor inputs restored,reviews the fantasyand hies to give it a rational explanation. The explanation fails, and as a result dream interpretation itself becomes a kind of fantasy.That is the reasonpsychoanalytic theories relating to dreaming, as well as parallel supernatural intelpretations arising in myth and religion, are at one and the same time emotionally convincing and factually incorrect. The molecular basis of dreaming is understood in part. Sleep descends upon the brain when chemical nerve cell transmitters of a certain kind, amines such as norepinephrine and serotonin, decline in amount. Simultaneouslya transmitterof a secondkind, acetylcholine, risesin amount. Both wash the junctions of nerve cells specializedto

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be sensitiveto them. The two kinds of neurotransmittersexist in a dynamic balance.The amineswakenthe brain and mediateits control of the sensorysystemsand voluntary muscles.Acetylcholine shuts these organs down. fu acetylcholine gains ascendancy,the activities of the consciousbrain are reduced.so are other functionsofthe body except for circulation, respiration,digestion,and- remarkably- movement of the eyeballs.The voluntary muscles of the body are paralyzed during sleep.Temperatureregulation is also diminished. (That is whv it can be dangerousto fall asleepwhile the body is cold.) In a normal noctumal cycle, sleep is at first deep and dreamless. Then at intervals,consuming overall about z5 percent of the total sleep period,it turns shallow.During the shallowperiodsthe sleeperis more easilyawakened.His eyesmove erraticallyin their sockets,the condition called rapid eye movement, or REM. The consciousbrain stirs and dreamsbut remainssealedofffrom externalstimuli. Dreaming is triggeredwhen acetylcholinenervecells in the brain stembegin to fre wildly, initiating what are called PGO waves.The electrical membrane activity, still mediated by acetylcholine at the nerve iunctions, movesfrom the pons (the P of PGo), a bulbous massof nerve centers located at the top of the brain stem, upward to the lower center of the brain mass,where it entersthe geniculatenuclei (G) of the thalamus, which are maior switching centersin the visual neuronal pathways. The PGO wavesthen passon to the occipital cortex (O), at the rear of the brain, where integrationof visual information takesplace. Becausethe ponsis alsoa principal control stationfor motor activity when the brain is awake,the signals it passesthrough the pGO sptem falselyreport to the cortex that the body is in motion. But of course the body is immobile-in lact it is paralyzed.what the visuar brain doesthen is to hallucinate.It pulls imagesand storiesout of the memory banks and integratesthem in responseto the wavesarriving from the pons. Unconstrained by information from the outside *orl"d, d.prived of context and continuity in real space and time, the brain hastily conshucts images that are often phantasmagoric and engaged in eventsthat are impossible.We fly through the air, swim in the diep sea,-walk on a distantplanet,conversewith a longdead parent.people, wild animals,and namelessapparitionscome and go. Some constitute the materialization of our emotions triggered by ihe pGO surges,so that from dream to dream our mood is variously calm, fearJtruck, angry erotic, maudlin, humorous, lyrical, but most of the time iust

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anxious.There seemsto be no limit to the combinatorialpower of the dreaming brain. And whateverwe seewe believe,at leastwhile sleeping; it rarely occurs to us to doubt even the most bizarre events into which we havebeen involuntarily thrust. Someonehasdefinedinsanity as an inability to chooseamong falsealternatives.In dreamswe are insane.We wander acrossour limitlessdreamscapes asmadmen. Strongstimuli can breakthrough the sensorybarrier.If they do not wake us, they are fitted into the dream story.Let real thunder roll into our bedroom from lightning a mile away.To take one of endlesspossible responses,our dream switchesto a bank robbery,a gun is fired, we are shot. No, another personis shot, has fallen, but no again-we realize it is us, displaced to someone else'sbody. Oddly, we feel no pain. Then the scenechanges.We are walking down a long corridor, lost, anxious to get home, another shot is fired. This time we come awake,tense,to lie still in the real world and listen to real thunder roll in from the approachingstorm outside. In dreamswe seldom experiencethe physical discomfortsof pain, nausea,thirst, or hunger. A few people suffer apnea,a temporaryhalt in breathing, which may be turned into visions of suffocation or drowning. There is no smell or tastein dreams;the channelsof these sensorycircuits are shut down by the acetylcholinewashof the sleeping brain. Unless we wake soon afterward, we remember no details of any kind. Ninety-five to 99 percent of dreamsare forgotten completely. A small minority of persons believe, erroneously, that they do not dream at all. This amazingamnesia is apparently due to the low concentration of amine hansmitters, which are needed to convert shortterm memories into longer ones.

Wuer ls the function of dreaming?Biologistshave tentativelyconcluded from detailed studiesof animals and humans that the information learned while the brain is awake is sorted and consolidatedwhile it is asleep.There is further evidence that at least some of this processing, particularly the sharpening of cognitive skills by repetition, is limited to periods of REM sleeping,and therefore to dreamtime. The flow of acetylcholine itself may be a crucial part of the process.The fact that dreaming activatessuch intense inward motor and emotional activity has led some researchersto suggestthat REM sleep has an even more

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profound, Darwinian function. When we dream, we deepen moods and improve responsesbasicto survival and sexualactivity. The findings from neurobiology and experimental psychology neverthelesssaynothing about the content of the dreams.Are the fantasiesa// temporary insanity,the sum of quickly forgotten epiphenomena during the consolidationof learning?Or can we search in some neo-Freudianmanner for deep meaning in the symbolsfrom which dreamsare composed?Becausedreamsare not entirely random, the truth must lie somewherein between.The compositionmay be irrational, but the details comprise fragments of information appropriate to the emotions activated by the PGO waves.It is quite possible that the brain is genetically predisposedto fabricate certain images and episodesmore than others.These fragmentsmay correspond in a loose way to Freud's instinctual drives and to the archefpes of )ungian psychoanalysis. Both theoriescan perhapsbe made more concreteand verifiableby neurobiology. Genetic predispositionand evolution lead to the second element I have chosen from the Amaringo paintings: seqpents.The form of our understanding of these creaturesof the night is the exact opposite of that concerning the nature of dreams in general.fu I have just explained, biologistsnow understandin very generalterms how dreams happen-they have puzzled through many of the key cellular and molecular eventsof dreaming.They are much lesssure of the good that dreams do mind and body. In the case of the prevalence of serpents, the situation is reversed. Biologists have a sound working hypothesis on the function of the images but as yet no idea of their molecular and cellular basisbeyond the generalcontrol of dreaming. The mystery as to the exact mechanism is due to our ignorance of the cellular processesby which specific memories such as those of serpentsare assembledand coloredby emotion. What we know about serpentsas dream images can be expressed by the two key modes of analysis used in biology. The first mode exposesproximate causes,the entities and physiological processes that create the phenomenon. Proximate explanationsanswer the question of how biological phenomena work, usually at the cellular and molecular levels.The secondmode of explanationaddresses why they work-their ultimate causes,which are the advantagesthe organism enjoysas a result of evolution that createdthe mechanismsin the first

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place. Biologistsaim for both proximateand ultimate explanations.To put the study of dreaming in a nutshell, we understanda good deal about the proximate causesof dreaming in general, but very little about its ultimate causes,while the reverseis true for the presenceof serpentsin dreams. The account I will now give of the ultimate causeof the bond between snakeand man has been pieced togetherfrom accountsof animal and human behavior by many researchers, and most fully by the American anthropologist and art historian Balaji Mundkur. Fear of snakesis deep and primordial among the Old World primates,the phylogenetic group to which Homo sapiensbelongs.When vervetsand other guenons,common long-tailed arborealmonkeysof Africa, encounter certain kinds of snakes,they emit a unique chuttering call. They are evidently good instinctive herpetologists,becausethe response,which appearsto be inborn, is limited to the poisonouscobras, mambas, and puff adders. The responseis not made to harmless snakes.Others of the monkey group come to the side of the caller,and together they watch the intruder until it leaves the neighborhood. They are also ready with an inborn eaglecall, causing all the troop members to scramble down from the treesand out of danger, and an inborn leopard call, triggering a rush in the oppositedirection to parts ofthe canopythat big catscannot reach. Common chimpanzees,a speciesbelievedto sharea cemmon ancestorwith prehumansas recentlyasfive million yearsago,are unusually apprehensivein the presenceofsnakes,even ifihey have had no previousexperience.They back offto a safedistanceand follow the intruder with a fixed stare while alerting companions with a Wahl warning call. The responsegraduallyintensifiesduring adolescence. Human beingsalso possess an innate aversionto snakes,and, as in the chimpanzee,it growsstrongerduring adolescence.The reactionis not a hard-wired instinct. It is a bias in developmentof the kind psychologistscall preparedlearning. Children simply learn fear of snakes more easilythan they remain indifferent or learn affectionfor snakes. Before the age of five they feel no special anxie$. Later they grow increasingly wary. Then just one or two bad experiences-a snake writhing nearby through the grassor a frightening story-can make them deeply and permanently afraid. The propensity is deep-set. Other common fears-of the dark, shangers,loud noises-start to

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wane after sevenyearsof age.In contrast,the tendency to avoid snakes growsshonger with time. It is possibleto turn in the oppositedirection, learning to handle snakeswithout fear or even to like them in some specialway. I did, as a boy, and once thought seriouslyof becoming a professionalherpetologist. But the adaptation was for me forced and self-conscious. People'sspecialsensitivi$ can just as easilyturn into full-blown ophidiophobia, the pathological extreme in which the close proximity of a snake brings on panic, cold sweat,and wavesof nausea. The neural pathwaysof snakeaversionhave not been explored. We do not know the proximate causeof the phenomenon exceptto classify it as "prepared learning." In contrast,the probable ultimate cause,the survival value of the aversion,is well understood.Throughout human history a few kinds of snakeshave been a maior causeof sicknessand death.Every continent exceptAntarctica has poisonoussnakes.Over most of Africa and Asia the known death rate from snakebite is 5 personsper roo,ooo each year. The local record is held by a province in Burma (latelycalled Myanmar),with 36.8deathsper loo,oooin a year. Australia has an exceptional abundance of deadly snakes,most of whose speciesare evolutionary relativesof the cobras. Unless you are an expert, it is wise to stay clear of every snake in Aushalia, just as it is wise to avoid wild mushrooms anywhere in the world. In South and Central America live deadly snakeswell known to the fivaro andvegetalista shamans,including the bushmaster,fer-deJance, and iaracara, which are among the largestand most aggressiveof the pit vipers. Possessingskins patterned and colored like fallen leaves,and fangs long enough to passthrough a human hand, they wait in ambush on the floor of the tropical forest for small birds and mammals and are quick to deliver defensiveshikesat passinghumans. Snakesand dream serpentsprovide an example ofhow agentsof nature can be translated into the symbols of culture. For hundreds of thousandsof years, time enough for genetic changes in the brain to program the algorithms of prepared learning, poisonous snakeshave been a significantsourceof injury and death to human beings.The responseto the threat is not simply to avoid it, in the way that certain berriesare recognized aspoisonousthrough painful hial and error, but to feel the kind of apprehension and morbid fascination displayed in the presenceof snakesby the nonhuman primates.The snakeimage also athacts many extraneousdetails that are purely learned, and as a

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result the intense emotion it evokes enriches cultures around the world. The tendency of the serpentto appearsuddenlyin trancesand dreams,its sinuousform, and its power and mysteryare logical ingredientsof myth and religion. Amaringoan imagesstretch back through the millennia. prior to the pharaonic dynasties the kings of Lower Egypt were crowned at Buto by the cobra goddessWadjet. In Greece there was Ouroboros, the serpent that continuously devoured itself tail-first while regenerating from the inside. For gnosticsand alchemistsof later centuriesthis self-cannibalcame to symbolizethe eternal cycle of destructionand re-creationof the world. One day in 1865,while dozing by a fire, the German chemist Friedrich August Kekuie von Stradonitz dreamed of Ouroboros and thereby conceived of the benzene molecule as a circle of six carbon atoms,each bonded to a hydrogenatom. Becauseof that inspiration some of the most puzzling data of nineteenth-centuryorganic chemistry fell into place. In the Aztec pantheon,Quetzalcoatl, the plumed serpentwith a human head, ruled asthe god of the morning and evening star,and thus of death and resurrection.He was the inventor of the calendar and patron of learning and the priesthood. Tlaloc, god of rain and lightning, was another serpentinechimera, with humanoid upper lips formed from two rattlesnakeheads. Such apparitionscould havebeen born only in dreamsand trances.

IN urttp AND culTunn the serpenttranscendsthe snake.An understanding of its hansformation from an earthly reptile can be viewed as one of many pathwaysthrough the borderlandsthat separate science from the humanities. Having followed the seqpenta considerable distance in our iourney from magician to atom, we next enter the interior of the biological sciences.Here better maps are available, and progressconsiderablyeasier.Scoresof Nobel prizes,the fruit of millions of hours of labor and billions of dollarsallocatedto biomedical research,point the way on down through the sciencesfrom body and organ through cell to molecule and atom. The general structure of the human nerve cell has now been charted in considerabledetail. Its elechic discharge and synaptic chemistry are partly understood and can be expressedin formulasobedient to the principlesof physicsand chemistry. The stage has been set to attack the master unsolved prob-

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lem of biology: how the hundred billion nerve cells of the brain work togetherto createconsciousness. I say the master problem, because the most complex systems known to exist in the universe are biological, and by far the most complex of all biological phenomena is the human mind. If brain and mind are at basebiological phenomena, it follows that the biological sciencesare essentialto achievingcoherenceamong all the branches of learning, from the humanities on down to the physical sciences. The task is made somewhat easierby the fact that disciplines within biology itself are now generally consilient and growing more so each year.I would like to explain how this hasbeen accomplished. Consilienceamong the biologicalsciencesis basedon a thorough understandingof scalein time and space.Passingfrom one level to the next, saymolecule to cell or organ to organism,requires the correct orchestration of changesin time and space.To make the point, I will return for a last time to Pablo Amaringo, magician, artist, and fellow organism. Imagine that we can speedor slow the time we spend with him, while expandingor shrinking the spacewe seein and around his person. So we enter his house, we shake his hand, and Amaringo showsus a painting. The actions consume secondsor minutes. An obvious fact, so why mention it? The question makes more sensewhen put in another form: Why did these familiar actions not consume millionths of seconds,or months, instead?The answeris that human beings are constructed of billions of cells that communicate across merribranesby chemical surgesand electrical impulses. To see and speak with Amaringo entails a sequenceof these units covering seconds to minutes, not microsecondsor months. We think of that spanof time as normal and somehow standardfor the world in which we live. It is not. Becauseit involvesAmaringo and us, all of whom are organic machines,it is only organismictime. And becausethe full apparatusof our communication takesup from millimeters to meters of surfaceand volume, not nanometersor kilometers,our unaided minds dwell entirely in organismic space. Imagine now that with the bestof our instruments(and his permission!) we can look into the brain of PabloAmaringo. By magnifying the image, his smallestneryescome into view. Then we seethe constituent cells, and finally the molecules and atoms. We watch as a nerve cell discharges:Along the length of its membrane, the voltage

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drops as sodium ions flow inward. At each point on the shaft of the nerve cell, the eventsconsume only severalthousandthsof a second, while the electrical signal they create-the drop in voltage-speeds along the shaftat ten meters a second,as fastas an Olympic ,piirrt.r. With our field of vision now brought to a space only one tenthousandth that of our original field, the eventsoccur too swiftly to be seen.An electricdischargeof the cell membranecrosses the field of vision faster than a rifle bullet. To see it-remember, as human observerswe are still in organismictime*we must record and slow the action down enough to witnesseventsthat originally occurred in a few thousandthsof a secondor less.We are now in biochemicaltime, a necessityif we are to observeeventsin biochemicalspace. In the midst of this magic Amaringo keepstalking, but is scarcely aware of the changesthat occurred as our own actionsaccelerateda thousandfold. Only enough of his time has elapsedfor one or two words to be spoken.We turn the dials in the oppositedirection, shift time and space until his full image reappearsand his words flow through our minds at an audible pace. We turn the dials further. Amaringo shrinksin proportionatesize and speed-walksjerkily out of the room, like an actor in an early silent film. perhapshe does so in frustration becausewe are now frozen in position like marble statues. Our vision continuesto expand. Let us rise in the air to gather more space.Our view growsto encompassthe town of Pucallpa and then a large stretch of the Rio Ucayali valley. Housesdisappear,new onespop up. Day blendswith night into continuoustwilightas the flicker-fusion frequency of our organismic-time vision is exceeded.Amaringo grows old, he dies.His children grow old, they die. Nearby the rainfoiest is changing. Clearingsappear as great treesfall, saplingsspring up, the gapsclose.We are now in ecologicaltime. We turn the dialsagain,and space-time expandsstill more. Individual personsand other organisms are no longer distinguishable,only blured populations-of anacondas,ayahuasccvines, the people of cenhal Peru-and these can be seen acrossthe passageof generations.A century of their time collapsesinto a minute of ours. Some of theirgenes are changing,in both kind and relative frequency. Detached from other human beings and shorn of their emotions,godlike at last,we witnessthe world in evolutionary time and space. This conception of scaleis the meansby which the biological scienceshave become consilient during the pastfifty years.According to

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the magnitude of time and spaceadopted for analysis,the basic divisionsof biology are from top to boftom asfollows: evolutionary biology, ecology, organismic biology, cellular biology, molecular biology, and biochemistry. That sequence is also the basis of the organization of professionalsocietiesand ofthe curricula ofcolleges and universities. The degreeof consilience can be measuredby the degreeto which the principlesof each division can be telescopedinto those of the others.

Tsn tNrnnLoc KING of the biologicaldisciplines,a tidy concept, is still compromised in execution by the dilemma of the labyrinth with which I beganthis chapter.Consilienceamong the disciplinesgrows more smoothly from the top down as more links are laid in place, from the most specific of the entities, such as the brain of Amaringo, all the way to the most general,his atomsand molecules.But to establish consilience the other way, from general to more specific, is vastly more difficult. In short, it is far easierto analyzeAmaringo than to synthesizehim. The greatest obstacle to consilience by synthesis, the approach often loosely called holism, is the exponential increase in complexity encountered during the upward progressthrough levels of organization. I have already describedhow an entire cell cannot yet be predicted from a knowledge of its scrambled molecules and organelles alone. Let me now indicate how bad the problem really is. It is not even possible to predict the three-dimensional structure of a protein from a complete knowledge of its constituent atoms. The composition of amino acidscan be determined,and the exactposition of eachatom can be mapped precisely with the aid of X-ray crystallography. We know,to chooseone of the simplestproteins,that the insulin molecule is a spherecontaining fifty-one amino acids. Such reconstructionis one of the many triumphs of reductionist biolory. But this knowledge of the sequenceof all the amino acids and of the atoms composing them is not enough to predict the shape of the sphere or its internal structure as revealedby X-ray crystallography. In principle the prediction of the form of proteins is possible.Synthesisat the level of macromoleculesis a technical, not a conceptual, problem. The effort to solve it is in fact an important industry in biochemistry. To have such knowledge would be a major breakthrough in medicine. Synthetic proteins, some perhaps more effective than

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the natural molecules, could be created upon demand to combat disease-causing organismsand remedy .nry*" deficiencies.In practice, however, the difficulties seem almost insurmountable.Making the prediction requiresa summation of all the energy relationships among nearby atoms. That alone is daunting. But then the inter_ actions of more distantly separatedatoms in the molecule must be added.The forcesshapingthe molecule comprisean immenselycom_ plex web of thousandsof energ, contributions,all of which .rr,rrib" i.rtegratedsimultaneouslyin order to form the whole. Somebiochemists believethat to achievethat final step,eachenergycontribution in turn must be calculatedwith an accuracystill beyondthe graspof the physical sciences. Even greaterdifficulties exist in the environmentalsciences.The paramount challenge to ecology for the foreseeablefuture is the cracking apart and resynthesisof the assemblages of organismsthat occupy ecosystems,particularly the most complex ecosystems such as estuaries and rain forests.Most studiesin ecologyfocus on only one or two speciesof organismsat a time, out of the thousandsoccupyinga \pical habitat. The researchers, forced into reductionismby practical n.".rsity, start with small fragments of the whole ecosystem.yet thev are awarethat the fate of each speciesis determined by the diverse ""tior,, of scoresor hundreds of other speciesthat variouslyphotosynthesize, browse,graze,decompose,hunt, fall prey,and turn soil around the target species.The ecologistsknow this principle very well, but they still can do little about predictingits precisemanifestationin any particular case. Even more than biochemists manipulating atoms in a large molecule,-the ecologistsface immensurable dynamic relationshiis among still largely unknown combinationsof species. Consider this example of the complexity they face. When Gatun Lake wascreatedduring the constructionof the panamacanal in r9rz, the rising waters cut off a piece of elevatedland. The new isolate, covered by tropical evergreen forest, was named Barro colorado Island and made into a biologicalresearchstation.In the following decadesit became the most closely studied ecosystemof its kind in the world. The size of the island, seventeensquarekilometers,was too small to sustain iaguarsand pumas. The prey of the great cats had consisted partly_of agoutis and pacas,outsized rodents that vaguely resemble jackrabbitsand small deer.These animals,freedfrom, *"jo, cause of mortality, multiplied to ten times their original numbers.Thev over-

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exploited their own food, which consistsmostly of large seedsthat fall from the forestcanopy,which causeda reduction in the reproduction and abundanceofthe tree speciesthat produce the seeds.The effect rippled outward. Olher hee specieswhose seedsare too small to be of interest to the agoutis and pacasbenefited from the reduced competition. Their seedsset more abundantlyand their seedlingsflourished, and a larger number of the young hees reached full height and reproductive age.It was inevitable then that the animal speciesspecialized to feed on small-seedtrees also prospered,that the predators depending on theseanimals increased,that the fungi and bacteria parasitizing the small-seedtrees and associatedanimals spread, ihat the microscopic animals feeding on the fungi and bacteria grew denser,that the predatorsof these creafuresincreasedin turn, and so on acrossthe food web and back again as the ecosystemreverberated from the restrictionof its areaand consequentlossof its top carnivores.

Tue cnrerEsr c H A L L E N G E t o d a yn , o t j u s t i n c e l l b i o l o g ya n d ecologybut in all of science,is the accurateand complete description of complex systems.Scientistshave broken down many kinds of systems. They think they know most of the elements and forces.The next task is to reassemblethem, at leastin mathematical models that capture the key propertiesof the entire ensembles.Successin this enterprise will be measuredby the power researchersacquire to predict emergent phenomena when passingfrom general to more specific levels of organization.That in simplesttermsis the great challengeof scientific holism. Physicists, whosesubjectmatter is the simplestin science,havealreadysucceededin part. By heating individual particlessuch as nihogen atoms as random agents, they have deduced the patterns that emergewhen the particles act together in large assemblages.Statistical mechanics, originated in the nineteenth century by fames Clerk Maxwell (who also pioneered the theory of electromagnetic radiation) and Ludwig Boltzmann, accurately predicted the behavior of gasesat different temperaturesby the application of classical mechanics to the large numbers of freely moving molecules that compose the gases. Other researchers,by moving back and forth between the same two levels of organization,in other words between molecules and gases, were further able to define viscosity,heat conduction, phasetransition,

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and other macroscopicpropertiesas expressions of the forcesbetween the molecules.At the next level down, quantum theoristsin the early lgoos connected the collective behavior of electronsand other subatomic particles to the classical physics of atoms and molecules. Through many such advancesduring the past cenfury physics has been welded into the most exactof the sciences. At higher, more specific levels of organization, beyond the tradi_ tional realm of physics,the difficulties of synthesisare almost inconceivably more difficult. Entities such as organismsand species,unlike electrons and atoms,are indefinitely variable.worse, each particular one changesduring developmentand evolution.consider tiris example: Among the vastarrayof molecules that an organismcan manufac_ ture to serve its needs are simple hydrocarbonsof the methane series, composed entirely of carbon and hydrogen atoms.With one carbon atom, only a singlekind of molecule is possible.with ro carbon atoms the number is 75,with zo it is 3663ry,and with 4o it is 6z trillion. Add oxygenatomshere and there on the hydrocarbonchainsto produce al_ cohols, aldehydes,and ketones, and the number rises even more rapidly with molecular size. Now selectvarioussubsetsand imagine multiple ways they can be derived by enzyme-mediatedma'ufactlrr.e, and you have potential complexity beyond the powers of present_day imagination. Biologists,it has been said, suffer from physicsenvy. They build physicslike models that lead from the microscopic to the macroscopic, but find it difficult to match them with the messysystemsthey e*perience in the real world. Theoretical biologishare nevertheless easifyseduced' (I confessto being one, and having been responsiblefor more than my share of failures.) Armed with iophisticated mathematical concepb and high+peed computers, they can generate unlimited numbers of predictions about proteins, rain forests,and other complex systems.with the passageto each higher level of organization, ihey need to conhive new algorithms, which are sets of exactry defirred mathematical operations pointed to the solution of given problems. And so with aflfirlly chosen procedures they can create virtual worlds that evolve into more organized systems.Wandering through lighly the Cretan labyrinth of cyberspace they inevitably ,n"our,"t , gence, the appearanceof complex phenomena not predictable"-!rfrom the basic elementsand processesalone, and not initiallv conceivable

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from the algorithms. And behold! Some of the productions actually look like emergentphenomenafound in the real world. Their hopes soar. They report the results at conferences of likeminded theoreticians. After a bit of questioning and probing, heads 'Yes, nod in approval: original, exciting, and important-if true." If true . . . if lr:ue.Folie de grandeur is their foible, the big picture their illusion. They are on the edge of a breakthrough! But how do they know that nature'salgorithms are the sameastheir own, or even close?Many proceduresmay be false and yet produce an approximately correct answer. The biologistsare at special risk of committing the fallacy of affirming the consequent:It is wrong to assumethat becausea correct result was obtained by means of theory the stepsused to obtain it are necessarilythe sameasthose that exist in the real world. To seethis point clearly,think of a blossomin a painting rendered photographic in detail and as beautiful aslife. In our minds the macroscopic entity hastruth becauseit matches real flowers sprung from the soil. From a distancewe might easily confuse the image with the real thing. But the algorithms that created it are radically different. Its microscopic elements are flakes of paint instead of chromosomes and cells. Its developmental pathways exist in the brain of the artist, not in prescription by DNA of the unfolding of tissues.How do theoreticians know that their computer simulations are not just the paintings of flowers? These and other difficulties endemic to higher systemshave not gone unnoticed. Researchersfrom severalscientific disciplines have ioined to take the measure of the problems, forming a loose enterprise variously designatedas complexi$, complexity studies, or complexity theory. Complexity theory (the best expression,in my opinion) can be defined as the searchfor algorithms used in nature that display common featuresacrossmany levels of organization. At the very least, according to the proponents of complexity theory, the commonalities can be expectedto provide an explorer'sguide for quicker movement when passingfrom simple to more complex systemsthrough the realworld labyrinth. The commonalities will assistin pruning all the algorithms that can be conceived down to the ones that nature has chosen. At their best, they might lead to deep new laws that account for the and minds. emergenceof such phenomenaas cells,ecosystems, By and large, the theoreticians have focused their attention on

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biology,and that makessense.Organisms and their assemblages are the most complexsystemsknown.They are arsoself-assembriig and adaptive.Living systems in general,by constructing themselves"from molecule to cell to organismto ecosystem, ,,rrel/ displaywhatever deeplawsof complexityandemergence lie within orrrr.""h. Complexitytheorywasborn in the r97os,gatheredmomentumin the early rg8os,and wasenvelopedin controversyby the mid_r99os. The issuesof contentionarealmostastangledasthe systems the theoristshopedto unravel.I think it possible to cut to the heartof the matter, as follows.The greatmaiorityof scientists, their mindsfocused narrowlyon well-definedphenomena, do not careaboutcomplexity theory.Many havenot yet heardof it. They,the uninvolved, U. ij_ ""n nored,lestall of contemporary sciencebethoughtof asa boiling ca.,.idron of argument.Thosewho carecan be dividedinto three """-pr. The first comprises a heterogeneous scattering of skeptics. They believe that brainsand rain forestsaretoo complica=ted everto be reiucedto elementary processes, let alonereconstituted in a mannerthatpredicts the whole.Someof the skepticsdoubtthe existence of deeplawsof complexity, at leastanythatcanbegrasped by thehumanmind. In the secondcamparethe ferventadvocates, a bandof audacious complexitytheorists,exemplifiedby stuart Kauftnan (authorof The Oigins of Order)and ChristopherLangton,who work at the SanteFe Institute in New Mexico, unofficial hiadquartersof the comprexity movement.They believenot only that deeplawsexistbut that their discovery is on the nearhorizon.Someof the essential elementsof the laws,they say,are aheadyemergingfrom mathematicaltheoriesthat use-exoticconceptionssuch as chaos,self_criticality, and adaptive landscapes. Theseabstractions bring into vivid fo"u, ti,e w"y co*pl"* systemsmight build themselves up, persistfor a while, and then disir,_ tegrate.Their architecb-computer-oriented,abshaction-absorbed, light on nafural history hear,yon nonlinearhansformations-think they smell success. They believethat massivecomputer-aidedsimulations,exploringmanypossibleworlds,will revealthe methodsand principlesneededto leapfrogconventional science,includingmost of contemporarybiology,to-achievea comprehensive understfnding of the-higherproductionsof the materialworrd.Their grairis a seto? hoped-formasteralgorithmsthat will speedpassage frorn"atomto brain and ecosystem,consistentwith reality bui requiring far lessfactual knowledgethanwouldbe neededwithouttheaieorithms.

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of which I am a reluctantmember, The third groupof scientists, hassetdedalongpositionsstrungbetweenthe two extremesof reiection and unbridledsupport.I sayreluctant,becauseI would like to be and 6lanof a true believer:I reallyam impressedby the sophistication the complexitytheorists,and my heart is with them. But my mind is not, at leastnot yet.I believewith manyothercenhiststhat theyareon the right hack-but only moreor less,maybe,andstill far shortof suchavebrokenout even on importantissues cess.Doubt anddissension within their ownranks.The basicdifficulty,to put the matterplainly,is an insufficiencyof facts.The complexitytheoristsdo not yet have The poshrenoughinformationto carrywith them into cyberspace. thus Their conclusions latestheystartwith clearlyneedmoredetail. far aretoo vagueandgeneralto be morethan rallyingmetaphors,and their abshactconclusionstell usverylittle that is reallynew. Thke the "edgeof chaos,"one of the mostfrequentlycited parathat in a sysdigmsof complexitytheory.It startswith the observation tem containingperfectinternal order,suchasa crystal,there can be no furtherchange.At the oppositeextreme,in a chaoticsystemsuchas boiling liquid, thereis verylittle orderto change.The systemthat will evolvethe mostrapidlymustfall between,and morepreciselyon the orderbut with the partsconnectedloosely edgeof chaos,possessing enoughto be easilyalteredeithersinglyor in smallgroups. Kauffmanappliedthe conceptto the evolutionof life in his NK model.N is the numberof partsin an organism,suchasthe numberof genesor of amino acids,that contributeto its survivaland reproducK is the numberof in future generations. tion, henceitsrepresentation (genes in same the organismthat afpartsof suchkind or aminoacids) fectthe contributionof anyone of the parts.A gene,for example,does not act aloneto guide the developmentof a cell. It actswith other genes,typicallyin a complicatedfashion.Kauffmanpointedout that if geneswerecompletelyinterconnectedin their effects,with K equaling N, therecouldbe little or no evolutionin a populationof organisms, cannotbe changed becauseonething in the heredityof the organisms opposite case,where everything. In the extreme without changing that K equalszero,the thereare no connectionsamongthe genes,so populationis in evolutionarychaos.If each geneis on its own, the population of organismsevolvesrandomly acrossa near-infinityof time, never neverstablein evolutionary possiblegenecombinations, settlingon one adaptivetype. When connectionsexistbut are very

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few-the edgeof chaos-evolvingpopulations can settleon adaptive peaksbut are still capableof evolvingwith rerativeeaseto other, nearbyadaptive peaks.A species of bird,for example,mightshiftfrom eatingseeds to eatinginsects; a savanna plantmightacquiretheability to growin the desert.Beingon the edgeof chaos,Kauffman,."ror.j, perhaps providesthegreatest evolvability. species adiustthenumberof connections soasto remainin thismostfluid of adaptive zones. Kauffmanhasspreadthe NK modelsto touch on a wide arravof topicsin molecularand evolutionarybiologr.His argument iike , thoseof otherleadingcomplexitytheorists, arJoriginalJ,rddir.ctedat importantproblems.First time around,they soundgood.But asan evolutionary biologistfamiliarwith genetics, I haveleirnedlittle from them. While wadingthrough Kauffman'sequationsand peculiarly fustianprose,I realizedthat I alreadyknew most of the resultsin a differentcontext.They areessentially a reinventionof thewheel,a re_ creationin a difficultnew languageof principlesalreadyoutlinedin the mainstream literatureof biology.Unlikethe importanttheoriesof physics, theNK formulations do notshiftthefoundaiions of thoughtor offerpredictions in measurable quantities. Sofar theycontainnJthi'g to takeinto the field or laboratory. This personaland possiblyunfair reactionto a singleexampleis not to belitdethe ultimateprospects of the comprexitytf,eorists.iome of the elementaryconceptsthey haveadvancea, *ort notablvchaos and fractalgeomehy,haveassisted in understanding broad,."to^ of the physicalworld. In ecology,for example,the Brtish biologistand mathematicianRobertMay hasusedrealisticdifferenceequiions to derivepatternsof populationfluctuationof the kindsactuallvobserved in plantsand animals.As the rateofpopulationgrowthincreases, o. as the environmentrelaxesits conhol of populationgrowth,the number of individualspassesfrom a nearlysteadystateto a smoothupanddown cycle.Ther, asgrowthrateand environmentalcontrol.'h"rg. further,the numberof individualsshifisto complexcycreswith muliiple peaksin time. Finally, the numberslidesinto a chaoticregime, zigzaggingup and down in no discerniblepattern.The mostinf,rest_ ing featureof chaosin populationsis thatit can be producedby exactly defined propertiesof real organisms.conhary to previous beliei, chaotic patternsare not necessarilythe produci of randomlyacting forcesof the environmentthat rock the populationup and dor"n.Ii this caseand in many other complexphysicalphenomena,chaos

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theory providesan authenticallydeep principle ofnature. It saysthat extremely complicated, outwardly indecipherable patterns can be determined by small, measurablechangeswithin the system. But, again, which systems,which changes?That is the nub of the problem. None of the elementsof complexity theory has anything like the generality and the fidelity to factual detail we wish from theory. None has triggered an equivalent cascadeof theoretical innovations and practical applications.What does complexity theory need to be successfulin biolog,?

THEoRY NEEDS more empiricalinformation. Couplnxtry Biolory can supply it. Three hundred years in the making, having recently been wedded to physicsand chemistry biolory is now a mature may not require a body of specialtheory to science.But its researchers mastercomplexity. They have refined reductionism into a high art and begun to achieve partial synthesesat the level of the molecule and organelle.Even if complete cells and organismsare still beyond them, they know they can reconstructsome of the elements one at a time. They foreseeno need for overarchinggrand explanationsas a Prerequisitefor creatingartificial life. An organismis a machine, and the laws of physicsand chemishy, most believe, are enough to do the job, given sufficient time and researchfunding. Putting a living cell together will be a moon shot, not an Einsteinian revolution of spaceand time. Complexity in real organismsis being taken apart swiftly enough to enliven the pages of Nature and Scienceeach week and drain awaythe need for conceptual revolution. A greatvaulting revolution may occur, and suddenly, but the busy and well-fed massesof researchersare not awaiting it in desperatesusPense' The machine the biologisb have opened up is a creation of riveting beauty.At its heart are the nucleic acid codes,which in a typical vertebrateanimal may comprise about 5o,ooo to too,ooo genes.Each gene is a string of z,ooo to l,ooo basepairs (genetic letters).Among the basepairs composing active genes,each triplet (set of three) translates into an amino acid. The final molecular productsof the genes,astranscribed outward through the cell by scores of perfectly orcheshated of amino acidsfolded into giant prochemicalreactions,are sequences tein molecules. There are about loo,ooo kinds of protein in a vertebrate animal. Where the nucleic acids are the codes, the proteins are

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the substanceof life, making up half the animal's dry weight. They give form to the body, hold it together by collagensinews,move it by muscle, catalyzeall its animating chemical reactions,transportoxygen to all its parts,arm the immune system,and carrythe signalsby which the brain scansthe environmentand mediatesbehavior. The role a protein molecule playsis determinednot iust by its primary structure, not just by the sequenceof amino acidswithin it, but also by its shape.The amino acid string of each kind is folded upon itself in a precise manner, coiled about like twine and crumpled together like a piece of waddedpaper.The total molecule bearsresemblance to forms asvariableasclouds in the sky.Looking at theseforms, we readily imagine lumpy spheres,donuts, dumbbells, rams' heads, angelswith wings spread,and corkscrews. The resulting contours of the surfaceare particularly critical for the function of enzymes,the proteins that catalyzethe body'schemistry. Somewhereon the surfaceis the active site, a pocket or groove consistingof a few of the amino acids,held in placeby the architecture of the remaining amino acids.Only substratemoleculesof a very specific form can fit the activesite and submit to catalysis.As soonas one docksin the correctalignments,its activesitealtersshapeslightly.The two molecules bind more closely, like hands clasped in greeting. Within an instant the substratemolecule is changedchemically and released.In the embraceof the enzyme sucrase,for example,sucrose is cleaved into fructose and glucose. fust as swiftly the active site of the enzyme molecule returns to its original shape,with its chemical structure unchanged.The productivity of most typesof enzymemolecules, snappingin and out of the activestate,is prodigious.A singleone can processa thousandsubshatemoleculeseverysecond. How to put all thesenanometercomponenb and millisecondreactions together into a coherentpicture? Biologistsare determinedto do it from the ground up, molecule by molecule, and metabolic pathway by metabolic pathway.They have begun to assemblethe data and mathematical tools needed to model an entire cell. When they succeed, they will also have reachedthe level of entire simple organisms, the single-cell bacteria, archaea,and protists. Most biologistsfavor middlelevel models in their theory of cell integration-neither primarily mathematical nor purely descriptive but insteadfrontJoadedwith large amounts of empirical information

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and conceived as genetic networks. The flavor of this state-of-the-art approach has been nicely captured by two of the researchers,William Loomis and Paul Sternberg,asfollows: The nodesofsuch networksaregenesor their RNA andproteinproducts. The connectionsare the regulatoryand physicalinteractions of each DNA sequences amongthe RNfu, proteins,andcis-regulatory gene.Modem moleculargenetictechniqueshavegreadyincreased the rate at which genesare being recognizedand their primary sequencesdetermined.The challengeis to link the genesand their circuits,and networks.Analysesof productsinto functionalpathways, (such those involvingsignaltransductionand networks as regulatory kanscriptionalregulationcascades)illushate combinatorialaction that implements,for example,digital logic, analogdigitalconverand insulation,and signalintegration.Although the sions,cross-talk by network elementshas been suggested existenceof sophisticated shrdies,what is new is the scaleand detailbedecades ofphysiological comingavailablefor the components.Much of currentmolecularbidefiningthe regulatory ologyfocuseson identif ing new comPonents, inputsand outputsofeach node,and delineatingthe physiologically relevantpathways. The complexity conceived in this single paragraphexceedsthat in supercomputers,million-part spacevehicles,and all the other artifacts of human technology. Can scientistsmanageto explain it, and in a microscopic systemto boot? The answer is undoubtedly yes.Yes, for social reasonsif no other. Scientistshave been charged with conquering cancer, genetic disease,and viral infection, all of which are cellular disorders,and they are massivelyfunded to accomplish these tasks' They know roughly the way to reach the goals demanded by the public, and they will not fail. Science, like art, and as alwaysthrough history follows patronage. Rapidly improving instrumentation already allows biologists to probe the interior of living cells and inspect the molecular architecture directly. They are discovering some of the simplicities by which adaptive systemsorganize themselves.Among the most notable simplicities are the rules used to fold the flexuous shings of amino acids into serviceableshapesof protein molecules, and the powered filtering devicesby which membranesadmit selectedsubstancesin and out of the cell and organelles.Scientistsare alsoacquiringthe computational

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capacityneededto simulatetheseand evenmore comprexprocesses. In 1995an Americanteamusingtwo linkedIntel paragoncomputers seta world speedrecordof z8r billion calculations p.", ,r"orrd.Th" US. federalhigh-performance programhasuppedthegoalto a hillion calculations per secondby the end of the century.ey tne year2a2a, petacrunchers, capableof reachinga thousandLittion caicurations pe.rsecond, be possible, althoughnewtechnologies andprogram_ 1ay ming methodswill be neededto reachthatlevel.nt thispoint frruteforcesimulationof cell mechanics, trackingeveryactivemoleculeand its webof interactions, shouldbeattainable-evenwithoutthesimplifyingprinciplesenvisioned in complexity theory. scientistsalsoforeseeearlysolutionsto the self-assembly of finishedcellsinto tissues and wholemulticeilurarorganisms. In i994the editon of science,celebratingthe inauguratioriof developmentar biologyby Wilhelm Rouxa centuryearliJr,askedone hundied con_ temporaryresearchers in the fieldto identifywhattheyconsidered the crucialrnansweredquestionsin the discipline.Their responses, in rankorderof attributedimportance, were: r. The molecularmechanisms of tissueandorgandevelopment. z. The connectionbetweendevelopmentand geneticevolution. l. T. stepsby which cellsbecomecommittedto a particular fate. signalingin tissuedevelopment. 4. The roleof cellrto-cell The self-assembly oftissue patternsin the earlyembryo. 5. 6. The mannerin which nervecellsestablish theirspecificcon_ nectionsto createthe nervecordandbrain. 7. The meansby which cels chooseto divideandto diein the sculptingoftissuesandorgans. 8. The stepsby which the processes controllingtranscription (the transmission of DNA informationwithin the cell) affectthe differentiation of tissues andorgans. Remarkably,the biologistsconsideredresearchon all of these top_ icsto be in a stateof rapidadvance,with partiarsuccess in at reastsome of them closeat hand.

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m Lnr us supposE that early in the next centurythe hopesof the molecular and cellular biologistsare fully realized. Supposefurther succeedin breakinga human cell down into all its that the researchers component parts,track the processes,and accurately model the whole systemfrom the molecules up. And supposefinally that the developmental biologists,whose focus is on tissuesand organs,enjoy similar success.The stagewill then be setfor the final assaulton the still more complex systemsof mind and behavior. They are, after all, products of the selfsamekinds of molecules,tissues,and organs. Let us seehow such explanatory power might be acquired. With a close approximation of organic processesin a few speciescompleted, it will be possibleto infer how life is reproducedand maintained in an indefinite number of other species.With such an expansion of comparative holistic biolory, a picture could be drawn of life as it is today, asit alsowasin the earlieststagesof its evolution,and as it might be on other planetswith differentbut habitableenvironments.In visualizing habitable environments,we will need to be liberal, keeping in mind that algae grow within rocks in Antarctica and microorganisms thrive in the boiling water of deep-seathermal vents. At some point deep and powerful principles of complexity may well emerge from the large ensemble of simulations. They will reveal the algorithms conservedacrossmany levels of organization up to the most complex sptems conceivable. These systemswill be self-assembled, sustainable,and constantlychangingyet perfectly reproducing. In other words,they will be living organisms. At this time, if it comes,and I believe it will come, we will have a true theory of biologr, as opposedto thick descriptionsof particular living processes that now constitutethe science.Its principles will accelerate inquiry into mind, behavior, and ecosystems,which are products of organisms and, by virtue of their extreme complexity, the ultimate challenge. So the important questions are, first, do general organizing principles exist that allow a living organism to be reconstituted in full without recourseto brute force simulation of all its molecules and atoms? Second,will the sameprinciples apply to mind, behavior,and ecosystems?Third, is there a body of mathematics that will serveas a natural

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for biology,parallelto the onethatworkssowell for physics? fnguage Fourth, evenif the correctprinciplesare discovered, how deiailed mustfactualinformationbe in orderto usethoseprinciplesin the desired models?In all thesematterswe seetodayas thiough a glass, darkly.In time, to completethe biblicalailusion,we wilr comefa"ce to facewith it-all-and perhapsseeit clearly.In anycase,the search for answers will testthefull powersof thehumanintellect.

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THn MrNo

BsI,tnF IN rHE intrinsicunityof knowledge-therealityof the labyrinth-rides ultimately on the hypothesisthat every mental process hasa physicalgroundingandis consistentwith the naturalsciences.The mind is supremelyimportantto the consilienceprogram for a reasonboth elementaryand disturbinglyprofound:Everything thatweknowand caneverknowaboutexistenceis createdthere. The loftier formsof suchreflectionand belief may seemat first to be the properdomain of philosophy,not science.But historyshows that logic launchedfrom inhospectionalone lacksthrust,can travel only sofar,and usuallyheadsin the wrongdirection.Much of the history of modernphilosophy,from Descartes and Kant forward,consisb of failed modelsof the brain.The shortcomingis not the fault of the philosophers, who havedoggedlypushedtheir methodsto the limit, but a straighforwardconsequence of the biological evolutionof the brain.All thathasbeenlearnedempiricallyaboutevolutionin general and mentalprocessin particularsuggests that the brain is a machine assembled not to understanditself,but to survive.Becausethesetwo endsare basicallydifferent,the mind unaidedby factualknowledge from scienceseesthe worldonly in litde pieces.It throwsa spotlighton thoseportionsof the world it mustknowin orderto live to the nextday, and surrenders the restto darkness. For thousandsof generations peo' ple livedand reproducedwith no needto know how the machineryof

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the brain works.Myth and self-deception, tribal identityand rituar, morethan objectivetruth, gavethem the adaptiveedge. That is whyeventodaypeopleknowmoreabouttheirautomobiles thantheydo abouttheirownminds-and whythefundamental explanationof mind is an empiricalratherthan a philosophicalor religious quest.It requiresa iourneyinto the brain'sinteriordarkness with preconceptions left behind.The shipsthat broughtushereareto be left scutdedandburningat theshore.

THB snerN rs a helmet-shaped massofgrayandwhitetissueabout the size of a grapefruit,one to hvo quartsin volume,and on averageweighingthreepounds(Einstein'sbrain,for example,was2.75 pounds).Its surfaceis wrinkledlike that of a cleaningsponge, u"d ii, consistency is custardlike, firm enoughto keepfrom puddlingon the floor of the brain case,softenoughto be scoopedout with rpoo.r. " The brain'strue meaningis hidden in its microscopic detail.Its flufr, rnassis an intricatelywired systemof abouta hundredbillion nervecells,eacha few millionths of a meter wide and connectedto other nervecellsby hundredsor thousands of endings.If we could shrinkourselves to the sizeof a bacteriumand explorethe brain'sinterior on foot, as philosophers since Leibniz in ry4 haveimagined doing,we mighteventually succeedin mappingall thenervecellsand hackingall the electricalcircuits.But we couldnevertherebyunderstandthe whole. Far more information is needed.We needto know whatthe electricpatternsmean,aswell ashowthe circuitswereput togetherand,mostpuzzlingofall, for whatpurpose. What we know of the heredityand developmentof the brainshows them to be almostunimaginablycomplicated. The humangenome databaseaccumulatedto 1995revealsthat the brain'sstructureis prescribedby at least1,195distinctivegenes,5o percentmore tharr for any other organ or tissue(the total number of genesin the entire human genomeis estimatedto be 5o,oooto roo,ooo).The molecular processes that guide the growth of neuronsto their assignedplaces haveonly begun to be deciphered.Overall, the human brain is the mostcomplexobiectknown in the universe-known,that is, to itself. It roseby evolutionto itspresentform swiftly,evenby the standards of the generallyhurriedpaceof mammalianphylogenyevidentin the fossilrecord.Acrossthreemillion years,from the anceshalman-apes

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of Africato the earliestanatomicallymodernHomo sapiens, who lived about zoo,oooyearsago,the brain increasedin volume four times over.Much of the growthoccurredin the neocortex,the seatof the higher functions of mind, including, especially,languageand its symbol-based product,culture. The resultwasthe capacityto take possession of the planet.Advancedhumans,their big sphericalskullsteeteringprecariously on fragilestemsof compactedcervicalvertebrae,walked,paddled,and sailedout of Africa throughEuropeand Asiaand thenceto all the remaining continentsand great archipelagoesexcept uninhabitable Antarctica.By roooe.o. theyreachedthe outermostislandsof the Pacific and Indian Oceans.Only a handful of remotemid-Atlanticislands,includingSt.HelenaandtheAzores,remainedpristinefor a few centurieslonger. It is,I mustacknowledge, unfashionablein academiccirclesnowadaysto speakofevolutionaryprogress.All the morereasonfo do so.In fact,the dilemmathat hasconsumedso much ink can be evaporated with a simplesemanticdistinction.If we meanby progress the advance towarda presetgoal,suchasthat composedby intentionin the human mind,then evolutionby naturalselection,which hasno presetgoals,is not progress. But if we meanthe productionthroughtime of increasingly complexandcontrollingorganismsandsocieties, in at leastsome linesof descent,with regression alwaysa possibility,then evolutionary progress is an obviousreality.In this secondsense,the human attainment of high intelligenceandculture ranksasthe lastof the four great stepsin the overallhistoryof life. They followedone upon the otherat roughlyone-billion-year intervals.The firstwasthe beginningof life itself,in the form of simplebacteriumlikeorganisms.Then came the origin of the complexeukaryoticcell throughthe assemblyof the nucleus and other membrane-enclosed organellesinto a tightly organized unit. With the eukaryoticbuilding block available,the next advancewasthe origin of large,multicellular animalssuch as crustaceansand mollusks,whosemovementswereguidedby senseorgans and cenhal neryoussystems. Finally, to the grief of most preexisting life forms,camehumanity.

Vlnruelty ell contemporary and philosophers scientists expert on the subiectagreethat the mind, which comprisesconsciousness

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and rationalprocess,is the brain at work. They have reiectedthe mindbrain dualism of Ren6 Descartes,who in Meditationes (1642)concluded that "by ihe divine power the mind can existwithout the body, and the body without the mind." According to the great philosopher, the noncorporeal mind and hence the immortal soul reposesomewhere in the corporeal and mortal body. Its location, he suggested, might be the pineal gland, a tiny organlocatedat the baseof the brain. In this early neurobiological model, the brain receivesinformation where from all over the body and feedsit into the pineal headquarters, it is hanslatedsomehow into consciousthought. Dualism was congenial to the philosophy and scienceof Descartes'time, appealingas it did to the materialistic explanationof the universe while remaining safelypious. In one form or other, it has persistedinto the late twentieth century. The brain and its satellite glands have now been probed to the point where no particular siteremainsthat can reasonablybe supposed to harbor a nonphysical mind. The pineal gland, for example, is known to secretethe hormone melatonin and to assistin regulating the body'sbiological clock and daily rhythms. But even as mindbody dualism is being completelyabandonedat long last,in the r99os, scientistsremain unsure about the precise material basis of mind. Some are convinced that consciousexperiencehas unique physical and biological properties that remain to be discovered.A few among them, archly called the mysteriansby their colleagues,believe that conscious experience is too alien, too complex, or both, ever to be comprehended. No doubt, the hanscendent difficulby of the subiect inspires this kind of denial. fu late as r97o most scientiststhought the concept of mind a topic best left to philosophers.Now the issuehasbeen ioined where it belongs, at the iuncture of biology and psychology.With the aid of powerful new techniques, researchershave shifted the frame of discourse to a new way of thinking, expressedin the language of newe cells, neurotransmitters,hormone surges,and recurrent neural networks. The cutting edge of the endeavor is cognitive neuroscience, also and more popularly known as the brain sciences,an alliance formed by neurobiologists,cognitive psychologists,and a new school of empirically minded philosopherssometimesreferred to as neurophilosophers. Their researchreports are dispatched weekly to premier

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scientific journals,and their theoriesand impassioneddisagreements fill the pagesof such open-commentary periodi calsas Behayioral and Brain Science,s. Many of the popular booksand articles they write rank among the bestin contemporaryscienceexposition. Such traits are the hallmark of the heroic period, or romantic period as it is often called, experiencedby every successfulscientific discipline during its youth. For a relatively brief interval.,usually a decade or two, rarely more than half a century, researchersare intoxicated with a mix of the newly discoveredand the imaginable unknown. For the first time the really important questionsare asked in a form that can be answered,thus: Wftaf are the cellular eventsthat composethe mind?Not createthe mind-too vague,that expression-but compose the mind. The pioneers are paradigm hunters. They are risk takers, who compete with rival theorists for big stakesand are willing to endure painful shake-outs.They bear comparison with explorers of the sixteenthcentury who, having discovereda new coastline,worked rivers up to the fall line, drew crude maps,and commuted home to beg for more expeditionary funds. And governmental and private patrons of the brain scientists,like royal geographiccommissionsof past centuries,are generous.They know that history can be made by a single sightingof coastland,where inland lies virgin land and the future lineamentsof empire. Call the impulse Westernif you wish, call it androcentric,and by all meansdismissit as colonialistif you feel you must. I think it instead basic to human nature. Whatever its source, the impulse drives maior scientificadvance.During my careerI havebeen privilegedto witness closeat hand the heroic periodsof molecular biology, plate tectonics in geology,and the modern synthesisof evolutionary biology. Now it is the turn of the brain sciences.

T n e s A , n r - y c R o u N D w o R K f o r t h e r e v o l u t i o nw a s l a i d i n t h e nineteenthcentury by physicians,who noticed that injuries to certain parts of the brain result in special kinds of disability. perhapsthe most famous casewasthat of Phineas P. Gage, who in 1848wasa young construction foreman in charge of a crew laying railroad track acrossVermont. Part of the job wasto blast awayoutcrops of hard rock in order to shaighten out turns in the advancing path. fu Gage pressedpowder into a newly drilled hole, a premature explosion fired the iron tamping

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bar like a missiletowardhis head.It enteredhis left cheekand exited the top of his skull,carryingwith it a goodpartof the prefrontallobe of his cerebralcortex,thenarcedawaymorethana hundredfeetbefore still alive.To comingto earth.Gagefell to the ground,miraculously up and even sit to minutes the amazementof all, he wasablewithin "Wonderful acciHe neverlost consciousness. walk with assistance. time his exterdent"wasthe laterheadlineintheVermontMercury.In nal iniurieshealed,and he retainedthe abilityto speakand reason. he had Wherepreviously had changeddrastically. But his personality of employee a valued and well-mannered, responsible, cheerful, been unreliliar, habitual he was a now Railroad, Burlington the Rutland& Studieson behavior. self-destructive ableatwork,andgivento vagrant, many over the brain of other patientswith iniuries to the samepart by yearshaveconfirmedthe generalconclusionsuggested Gage'smisfortune:The prefrontallobe housescentersimportantfor initiative andemotionalbalance. For two centuriesthe medicalarchiveshavefilled with suchanecdoteson the effectsof localizedbrain damage.The datahavemadeit to piece togethera maP of functionsperpossiblefor neurologists parts of the brain. The iniuries,which occur formed by different tumors,infecthroughoutthe brain,includephysicalhaumas,strokes, pindetectable tions, and poisonirrg.They vary in extentfrom barely brain. points to deletions and transectionsof large parts of the Dependingon locationand magnitude,theyhavemultifariouseffects on thought and behavior. recentcaseis thatof KarenAnn Quinlan.On The mostcelebrated young New )erseywoman,while dosedwith the the r4, 1975, April drug Darvon,madethe mistakeof painkiller and tranquilizerValium drinking gin and tonic. Although the combinationdoesnot sound dangerous,it essentiallykilled Karen Ann Quinlan. She fell into a coma that lasteduntil her death from massiveinfectionsten years later.An autopsyrevealedthat her brain waslargelyintact,which explainswhy her bodysurvivedand evencontinuedits dailycycleof wakin the arranged, ing andsleep.It livedon evenwhenQuinlan'sparents The auremoved. her have ventilator to of national controversy, midst severe: local but very was damage brain topsyrevealedthat Quinlan's The thalamushad beenobliteratedasthoughburnedout with a laser. Why that particularcenterdeterioratedis unknown.A brain iniured by a heavy blow or certain forms of poisoningusually respondsby

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widespreadswelling. If the reaction is intense, it presseson centers that conhol heartbeatand respiration,shutting down blood circulation and soon ending in death of the whole body. The result of thalamusexcisionalone is brain death,or, more precisely put, mind death. The thalamus comprises twin egg-shaped massesof nerve cells near the center of the brain. It functions as a relay center through which all sensoryinformation other than smell is transmitted to the cerebral cortex, and therefore to the conscious mind. Even dreams are triggered by impulses that passthrough thalamic circuits. Quinlan's drug accident was the equivalent of blowing up a power station: All her lights downline went out, and she entered a sleep from which she had no chance of wakening. Her cerebral cortex lived on, waiting to be activated. But consciousness,even in dreams, wasno longer possible. Such researchon brain damage,while enormously informative, is neverthelessdependenton chance occurrence.Over the yearsit has been greatly enhanced by experimental brain surgery.Neurosurgeons routinely keep patients conscious to test their responseto electrical stimulation of the cortex, in order to locate healthy tissueand avoid excising it. The procedureis not uncomfortable:Brain tissue,while processingimpulses from all over the body, has no receptorsof its own. Instead of pain, the roving probes evoke a medley of sensationsand muscular contractions. When certain siteson the surfaceof the cortex are stimulated, patients experience images, melodies, incoherent sounds,and a gamut of other impressions.Sometimesthey involuntarily move fingers and other body parts. Beginning with experiments in brain surgery by Wilder penfield and other pioneersin the rgzosand r93os,researchershave mapped sensoryand motor functions over all parts of the cerebral cortex. The method is neverthelesslimited in two important respects.It is not easily extended beneath the cortex into the dark nether regions of the brain, and it cannot be used to observe neural activity through time. To reach those objectives-to create motion pictures of the whole brain in action-scientists haveadopteda broad rangeof sophisticated techniques borrowed from physics and chemistry. Since its inception in the r97os,brain imaging, as the methods are collectively called, has followed a trajectory similar to that of microscopy, toward ever finer resolution in snapshotsseparatedby shrinking intervals of time. The scientistshope eventually to monitor the activity of entire networks of

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individual nerve cells, both continuouslyand throughoutthe living brain.

G n e N t E o , the brain'smachineryremainsforbiddinglyalien and scientists have haced only a minute fraction of its circuitry. Still, the major anatomical featuresof the brain are known, and a great deal has been learned of their various functions. Before addressingthe nature of mind as a product of these operations,I wish to provide a quick look at the physical groundwork. The surestway to graspcomplexityin the brain, asin any other biological system,is to think of it asan engineeringproblem.What arethe broad principles needed to create a brain from scratch?Whether conhived by advanceplanning or by blind natural selection,the key features of architecture can be expected to be very broadly predictable. Researchersin biomechanicshave discoveredtime and again that organic structures evolved by natural selection conform to high levels of efficiencywhen iudged by engineeringcriteria.And at a more microscopic level, biochemists marvel at the exactitudeand power of the enzyme molecules conholling the actions of the cells. Like the mills of God, the processesof evolution grind slowly-yet, as the poet said, they grind exceeding fine. So let us spreadthe specificationsheetsout and considerthe brain as a solution to a set of physical problems. It is best to start with simple geometry. Because a huge amount of circuitry is required, and the wiring elements must be built from living cells, a relatively huge mass of new tissueneedsto be manufacfuredand housedin the brain case. The ideal brain casewill be sphericalor close to it. One compelling reason is that a sphere has the smallest surface relative to volume of any geometric form and hence provides the least accessto ib vulnerable interior. Another reason is that a sphere allows more circuits to be placed close together. The averagelen$h of circuits can thus be minimized, raising the speedof hansmissionwhile lowering the energycost for their construction and maintenance. Because the basic units of the brain-machine must be made of cells, it is best to stretch these elements out into string-shapedforms that sewe simultaneously as receiving stationsand coaxial cables.The dual-purpose cells created by evolution are in fact the neurons, also called nerve cells or nerve fibers. It is further practical to design the

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neurons so that their main bodies serve as the receiving sites for impulses from other cells. The neurons can send their own signars out along axons,cablelikeextensionsofthe cell bodies. For speed,make the hansmissionan electric dischargeby depolari_ zation of the cell membrane.The neuronsare then said to "fire." For accuracy during neuron firing, surround the axons with insulating sheaths.These in fact exist as white faw myelin membranes that tJ gethergive the brain its light color. To achieve a higher level of integration, the brain must be very inhicately and preciselywired. Given again that its elements are living cells, the number of neuron connections are best multiplied by gro*l ing threadlike extensionsfrom the tips of the *hi"h reacf, out "*or,r, and hansmit individually to the bodies of many other celrs. The discharge of the axon havels to these multiple terminal extensionsall the way to their tips, which then make contact with the receptor cells. The receptor cells accept some of the tips of the terminal axon branches on the surfaceof their main cell bodies.They acceptother tips on their dendrites, which are threadlike receptor branches growing out from the cell bodies. Now visualize the entire nerve cell as a miniahrre squid. From its body sprouts a cluster of tentacles (the dendrites). one tentacle (the axon) is much longer than the others, and from its tip it sprouts more tentacles. The messageis received on the body and short tentacles of the squid and travels along the long tentacle to other squids. The brain comprises the equivalent of one hundred billion squids linked together. The cell-to-cell connections-more precisely,the points of connection and the ulhamicroscopicspacesseparatingthem-are called synapses.when an electric dischargereachesa synapse,it induces the tip of the terminal branch to releasea neurotransmitter, a chemical that either excitesan elechic dischargein the receiving cell or prevents one from occurring.Each nervecell sendssignalsto hundredsor thousandsof other cells through its synapsesat the end of its axon, and it receives input from a similar myriad of synapseson its main cell body and dendrites.In eachinstanta nervecell either firesan impulse along its axon to other cells or falls silent. Which of the two ,.rpor,r., it makes depends on the summation of the neurohansmissionsreceived from all the cells that feed stimuli into it. The activity of the brain as a whole, hence the wakefulness and

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moods experiencedby the consciousmind, is profoundly affectedby the levels of the neurotransmitters that wash its trillions of synapses. Among the most important of the neurotransmittersare acetylcholine and the amines norepinephrine, serotonin,and dopamine' Others include the amino acid GABA (gammaaminobutyricacid) and, surprisingly, the elementary gasnitrous oxide. Some neurotransmittersexcite the reuron, they contact, while othersinhibit them. Still otherscan exert either effect depending on the location of the circuit within the neryous system. During development of the nervoussystemin the fetus and infant, the .r"uror-t,extend their axonsand dendrites into the cellular environment-like growing tentaclesof squids.The connectionsthey make are preciselyprogrammed and guided to their destinationsby chemical cues.Once in place each neuron is poisedto play a special role in signal transmission.Its axon may stretchonly a few millionths of a meter or thousandsof times longer. Its dendrites and terminal axon branchescan take any of a number of forms,coming to resemble, say,the leaflesscrown of a tree in winter or a dense, feltlike mat' Possessingthe aestheticinherent to pure function, and riveting to behold, they invite us to imagine their Powers.Concerning them, Santiago Ram6n y Caial, the great Spanish histologist, wrote of his own experience, after receiving the 19o6Nobel Prize for his researchon the subject: "Like the entomologist in pursuit of brightly colored butterflies, my attention hunted, in the flower garden of the gray matter, cells with delicate and elegant forms, the mysteriousbutterflies of the soul, the beatingsof whose wings may some day-who knows?-clarify the secret of mental life." The meaning of the neuron shape,which so pleasesthe biologist, is this: Neuron systemsare directed networks,receiving and broadcasting signals.They cross-talk with other complexes to form systemsof tytt.*t, in placesforming a circle, like a snakecatching its own tail, to createreveiberatingcircuits. Each neuron is touched by the terminal axon branchesof many other neurons,establishedby a kind of democratic vote whether it is to be activeor silent.Using a Morselikecodeof staccatofiring, the cell sends its own messagesoutward to others.The number of connections made by the cell, their pattern of spread,and the code they use determine the role the cell plays in the overall activity of the brain. Now to complete the engineeringmetaphor.When you're setting

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out to design a hominid brain, it is important to observeanother optimum design principle: Information hansfer is improved when n.,rro' circuitsfilling specializedfunctionsare placedtogetherin clusters.Examples of such agregates in the real brain are the sensoryrelay sta_ tions, integrativecenters,memory modules, and emotional control centers identified thus far by neurobiologists. Nerve cell bodies are gatheredin flat assemblages calledlayersand rounded onescalled nuclei' Most are placedat or nearthe surfaceof the brain. They are interconnected both by their own axons and by intervening neurons that coursethrough the deeperbrain tissues.one result is ttre grayor lightbrown color of the surfacedue to the massing of the celr bodies-*the "graymatter" of the brain-and a white color from the myelin sheaths of axonsin the interior of the brain. Human beingsmay possess the most voluminous brain in propor_ fion to body size of any largeanimal speciesthat has ever liveJ. For a primate speciesthe human brain is evidentlyat or closeto its physical limit. If it were much larger in the newborn, the passageof its protecting skull through the birth canal woirld be dangerousto both mother and child. Even the adult brain sizeis mechanicallyrisky:The head is a fragrle,internally liquescent globe balanced on a delicate bone-andmusclestem,within which the brain is vulnerable and the mind easilv stunned and disabled. Human beings are innately disposedto avoid violent physicalcontact. Becauseour evolving ancestorstraded brute shengthfor intelligence,we no longer need to seizeand rip enemies with fanged jaws. Given this intrinsic limit in brain volume, some wav must be found to fit in the memory banks and higher-order integrating systems neededto generateconsciousthought. The only *.".,i availabieis to increasesurface area: spread the cells out into a broad sheet and crumple it up into a ball. The human cerebral cortex is such a sheet about one thousandsquareinchesin area,packedwith millions of cell bodiesper squareinch, folded and wadded preciselylike an origami into many winding ridges and fissures,neatly stuffed in turn into the quart-sizedcranial cavity.

Wser MoRE clN be saidof brain structure?If a Divine Engineer designedit, unconstrainedby humanity'sbiological history HeLigtrt have chosen mortal but angelic beings cast in His own image. Tf,ey

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would presumablybe rational, far-seeing,wise, benevolent,unrebellious, silfless,and guilt-free,and, as such, ready-madestewardsof the beautiful planet bequeathedthem. But we are nothing like that' We have original sin, which makes us better than angels.Whatever good we possesswe have earned,during a l
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. The hindbrain comprisesin turn the pons,medulla, and cerebellum. Togetherthey regulatebreathing,heartbeat,and coordinationof body movements.The midbrain controls sleep and arousal.It also partly regulatesauditory reflexesand perception. . A maior part of the forebrainis composedof the limbic system, the mastertraffic-conhol complex that regulatesemotional responseas well as the integration and hansfer of sensoryinformation. Its key centers are the amygdala (emotion), hippocampus (memory, especially short-term memory), hypothalamus (memory temperature control, sexualdrive, hunger, and thirst),and thalamus(awareness of temperature and all other sensesexcept smell, awarenessof pain, and the mediationof some processes of memory). . The forebrain alsoincludesthe cerebralcortex,which hasgrown and expandedduring evolution to cover the rest of the brain. As the primary seatof consciousness, it storesand collatesinformation from the senses. It alsodirectsvoluntarymotor activityand integrateshigher functions,including speechand motivation. . The key functions of the three successivedivisions-hind- plus midbrain, limbic system,and cerebralcortex-can be neatly summarized in this sequence:heartbeat,heartstings, heartless. . No singlepart of the forebrainis the siteof consciousexperience. Higher levelsof mental activitysweepthrough circuits that embracea largepart of the forebrain.When we seeand speakof color, for example, visual information passesfrom the cones and interneurons of the retina through the thalamus to the visual cortex at the rear of the brain. After the information is codified and integrated anew at each step, through patternsofneuron firing, it then spreadsforwardto the speech centers of the lateral cortex. As a result, we first see red and then say "red." Thinking about the phenomenon consistsof adding more and more connectionsof pattern and meaning, and thus activatingadditional areasof the brain. The more novel and complicatedthe connections, the greater the amount of this spreading activation. The better the connections are learned by such experience,the more they are put on autopilot. When the samestimulus is applied later, new activation is diminished and the circuits are more predictable. The procedure becomesa "habit." In one such inferred pathwayof memory formation, sensoryinformation is conveyedfrom the cerebral cortex to

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the amygdalaand hippocampus,then to the thalamus,then to the prefrontal cortex (iust behind the brow), and back to the original sensory regionsof the cortex for storage.Along the way codesare interpreted and alteredaccordingto inputs from other partsofthe brain. . Becauseof the microscopicsizeof the nervecells,a largeamount of circuitry can be packedinto a very small space.The hypothalamus, a maior relay and control center at the baseof the brain, is about the sizeof a lima bean. (The nervoussystemsof animalsareevenmore impressivelyminiaturized. The entire brainsof gnatsand other extremely small insects,which carry instructionsfor a seriesof complex instinctive acts,from flight to mating, are barelyvisibleto the nakedeye.) . Disturbance of particular circuits of the human brain often produce bizarre results.Iniuries to certain sitesof the undersurfaceof the parietal and occipital lobes, which occupy the side and rear of the The pacerebralcortex,causethe rare condition calledprosopagnosia. but he can faces, their by persons recognize other tient can no longer the ability he retains as oddly, still remember them by their voices.|ust to recognizeobiectsother than facesby sightalone. . There may be centersin the brain that are especiallyactivein the organization and perception of free will. One aPPearsto be located within or at leastcloseto the anteriorcingulatesulcus,on the inside of a fold of the cerebral cortex. Patients who have sustained damage to the region lose initiative and concern for their own welfare.From one moment to the next they focuson nothing in particular,yet remain cawhen pressed. pable of reasonedresponses . Other complex mental operations,while engagingregionsover large parts of the brain, are vulnerable to localized perturbation. Patients with temporal Iobe epilepsy often develop hyperreligiosity, the tendency to charge all events,large and small, with cosmic significance. They are also prone to hypergraphia,a compulsion to express their visionsin an undisciplinedsheam of poems,letters,or stories. . The neural pathwaysused in sensoryintegrationare also highly specialized.When subiects name pictures of animals during PET (positron emission tomography) imaging, a method that revealspatterns of nerve-cellfiring, their visual corticeslight up in the samepattern seen when they sort out subtle differencesin the appearanceof obiects.When, on the other hand, they silently name picturesof tools,

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neural activity shifts to parts of the cortex concerned with hand movementsand action words,such as "write" for pencil.

I Hnvs spoKEN so far about the physical processesthat produce the mind. Now, to come to the heart of the matter, what is the mind? Brain scientists understandably dance around this question. Wisely, they rarely commit themselvesto a simple declarativedefinition. Most believe that the fundamental properties of the elements responsible for mind-neurons, neurotransmitters,and hormones-are reasonably well known. What is lacking is a sufficient graspof the emergent, holistic properties of the neuron circuits, and of cognition, the way the circuits processinformation to create perception and knowledge.Although dispatchesfrom the researchfront grow yearly in number and sophistication, it is hard to iudge how much we know in comparison with what we need to know in order to create a powerful and enduring theory of mind production by the brain. The grand synthesiscould come quickly, or it could come with painful slownessover a period of decades. Still, the expertscannotresistspeculationon the essentialnature of mind. While it is very risky to speakof consensus,and while I have no great trust in my own biasesas interpreter, I believe I have been able to piece together enough of their overlapping opinions to forecast a probable outline of the eventual theory as follows. Mind is a sheamof consciousand subconsciousexperience.It is at root the coded representationof sensoryimpressionsand the memory and imagination of sensoryimpressions.The information composing it is most likely sorted and retrieved by vector coding, which denotes direction and magnitude. For example, a particular taste might be partly classified by the combined activity of nerve cells responding to different degreesof sweetness,saltiness,and sourness.If the brain were designed to distinguish ten increments in each of these taste dimensions,the coding could discriminatero X ro X to, or l,ooo substances. Consciousnessconsistsof the parallel processingof vast numbers of such coding networks. Many are linked by the synchronized firing of the nerve cells at forty cyclesper second, allowing the simultaneous internal mapping of multiple sensoryimpressions.Some of the impressionsare real, fed by ongoing stimulation from outside the nervous system,while othersare recalled from the memory banksof the cortex.

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All together they create scenariosthat flow realistically back and forth through time. The scenariosare a virtual reality. They can either closely match pieces of the external world or depart indefinitely far from it. They re-create the past and cast up alternative futures that seryeas choices for future thought and bodily action. The scenarios comprisedenseand finely differentiatedpatternsin the brain circuits. When fully open to input from the outside, they correspond well to all the parts of the environment, including activity of the body parts, monitored by the senseorgans. Who or what within the brain monitors all this activity?No one. Nothing. The scenariosare not seenby some other part of the brain. is the virtual world composedby the sceThey just are. Consciousness narios.There is not even a Cartesiantheater,to use Daniel Dennett's dismissivephrase,no single locus of the brain where the scenariosare played out in coherent form. Instead,there are interlacingpatternsof neural activity within and among particular sitesthroughout the forebrain, from cerebral cortex to other specialized centers of cognition such asthe thalamus,amygdala,and hippocampus.There is no single in which all information is brought together stream of consciousness by an executive ego. There are instead multiple streamsof activity, some of which contribute momentarily to conscious thought and of then phase out. Consciousnessis the massivecoupled aggregates such participating circuits. The mind is a self-organizing republic of scenariosthat individually germinater grow, evolve, disappear,and occasionallylinger to spawnadditionalthought and physicalactivity. The neural circuits do not turn on and offlike partsof an electrical grid. In many sectorsof the forebrain at least,they are arrangedin parallel relays stepping from one neuron level to the next, integrating more and more coded information with each step.The energ/ of light shiking the retina, to expand the example I gave earlier, is transduced into patterns of neuron firing. The patterns are relayed through a sequence of intermediate neuron systems out of the retinal fields through the lateral geniculate nuclei of the thalamus back to the primary visual cortex at the rear of the brain. Cells in the visual cortex fed by the integrated stimuli sum up the information from different parts of the retina. They recognize and by their own pattern of firing specifi spotsor lines. Further systemsof these higher-order cells integrate the information from multiple feeder cells to map the shapeand movement of obiects.In ways still not understood,this pattern is coupled

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with simultaneous input from otherpartsof the brain to createthe full scenarios of consciousness. The biologistS. ). Singerhas drily expressed the matterthus:I link, thereforeI am. Because consciousness requiresan astronomically iustto generate Iargepopulationof cells,the brain is shaqplylimited in its capacityto createand hold complexmoving imagery.A key measureof that capacityliesin the distinctionmadeby psychologists betweenshort-term and long-termmemory.Short-termmemoryis the readystateof the conscious mind.It composes all of the currentandremembered parts of the virtualscenarios. It can handleonly aboutsevenwordsor other symbolssimultaneously. The brain takesabout one secondto scan thesesymbolsfully, and it forgetsmostof the informationwithin thirg seconds. Long-termmemorytakesmuchlongerto acquire,but it has an almostunlimitedcapacity,and a largefractionof it is retained for life. By spreading activation,the consciousmind summonsinformationfrom the storeof long'termmemoryand holds it for a brief intervalin short-termmemory.During this time it processes the information,at a rateof aboutone symbolper z5 milliseconds, while scenariosarisingfromthe informationcompetefor dominance. Long-termmemory recallsspecificeventsby drawingparticular persons, objects,and actionsinto the conscious mind througha time sequence. For example,it easilyre-creates an Olympic moment:the lightingof the torch,a runningathlete,the cheeringof the crowd.It alsore-creates not just moving imagesand soundbut meaningin the form of linked conceptssimultaneouslyexperienced.Fire is connectedto hot, red,dangerous, cooked,the passion ofsex,and the creative act, and on out through multitudinous hypertext pathways selected by context,sometimes buildingnew associations in memory for future recall.The conceptsare the nodesor referencepointsin long-termmemory.Many arelabeledby wordsin ordinarylanguage, but othersarenot. Recallof imagesfrom the long-termbankswith lif tle or no linkageis iustmemory.Recallwith linkages,and especially whentingedby the resonance of emotionalcircuits,is remembrance. The capacityfor remembranceby the manipulationof symbolsis a transcendent for an organicmachine.It hasauihoredall achievement of culture.But it still fallsfar shortof the demandsplacedby the body on the nervoussystem.Hundredsof organsmustberegulatedcontinuouslyand precisely; anyseriousperturbationis followedby illnessor death.-A heartforgefulfor ten seconds candropyou like a stone.The

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proper functioning of the organs is under the control of hard-wired autopilots in the brain and spinal cord, whoseneuron circuits are our inheritance from hundreds of millions of yearsof vertebrateevolution prior to the origin of human consciousness. The autopilot circuits are shorter and simpler than those of the higher cerebralcentersand only marginally communicatewith them. Only by intensemeditativetraining can they occasionallybe brought under consciouscontrol. Under automatic control, and specificallythrough balanceof the antagonisticelementsof the autonomic nervoussystem,pupils of the eye constrict or dilate, saliva pours out or is contained, the stomach churns or quietens,the heart pounds or calms,and so on through alternative statesin all the organs.The sympathetic nerves of the autonomic neryoussystempump the body up for action. They arisefrom the middle sectionsof the spinal cord, and typically regulate target organs by releaseof the neurotransmitternorepinephrine. The parasympatheticnervesrelax the body as a whole while intensifying the processesof digestion.They rise from the brain stem and lowermost segment of the spinal cord, and the neurotransmitterthey releaseto the targetorgansis acetylcholine-also the agentof sleep. Reflexesare swift automatic responses mediatedby short circuitsof neurons through the spinal cord and lower brain. The most complex is the startleresponse,which preparesthe body for an imminent blow or collision. Imagine that you are surprisedby a loud noise close by-a car horn blasts,someoneshouts,a dog chargesin a fury of barking.You react without thinking. Your eyesclose,your head sags,your mouth opens, your kneesbuckle slightly. AII are reactionsthat prepare you for the violent contact that might follow an instant later. The startle responseoccurs in a split second, fasterthan the conscious mind can follow, faster than can be imitated by conscious effort even with long practice. Automatic responses,true to their primal role, are relatively impervious to the consciouswill. This principle of archaismextendsevento the facial expressions that communicate emotion. A spontaneousand genuine smile, which originatesin the limbic systemand is emotiondliven, is unmistakableto the practicedobserver.A contrived smile is cohstructedfrom the consciousprocesses ofthe cerebrum and is behayed by telltale nuances: a slightly different configuration of facial muscle conhaction and a tendencytowardlopsidednessof the upward cuwing mouth. A natural smile can be closely imitated by an experi-

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enced actor. It can also be evokedby artificially inducing the appropriate emotion-the basictechniqueof method acting.In ordinary usage it is modified deliberately in accordance with local culture, to convey irony (the pursedsmile), restrainedpoliteness(the thin smile), threat (the wolfish smile),and other refined presentationsof self. Much of the input to the brain does not come from the outside world but from internal body sensorsthat monitor the state of respiration, heartbeat,digestion,and other physiologicalactivities.The flood of "gut feeling" that resultsis blended with rational thought, feeding it, and being fed by it through reflexes of internal organs and neurohormonal loops. As the scenarios of consciousnessfly by, driven by stimuli and drawing upon memories of prior scenarios,they are weighted and modified by emotion. What is emotion?It is the modification of neural activity that animatesand focusesmental activity. It is created by physiological activity that selectscertain streamsof information over others, shifting the body and mind to higher or lower degreesof activity, agitating the circuits that createscenarios,and selectingones that end in certain ways.The winning scenariosare thosethat match goalspreprogrammed by instinct and the satisfactions of prior experience.Current experience and memory continually perturb the states of mind and body. By thought and action the statesare then moved backward to the original condition or forward to conditions conceivedin new scenarios. The dynamism of the processprovokeslabeling by words that denote the basic categoriesof emotion-anger, disgust,fear, pleasure, sulprise.It breaksthe categoriesinto many degreesand joins them to createmyriad subtlecompounds.Thus we experieqcefeelingsthat are variously weak, strong, mixed, and new. Without the stimulus and guidance of emotion, rational thought slowsand disintegrates.The rational mind does not float above the irrational; it cannot free itself to engagein pure reason.There are pure theorems in mathematics but no pure thoughts that discover them. In the brain-in-the-vat fantasyof neurobiological theory and science fiction, the organ in its nutrient bath has been detached from the impediments of the body and liberated to explore the inner universe of the mind. But that is not what would ensue in reality.All the evidence from the brain sciencespoints in the opposite direction, to a waiting coffin-bound hell of the wakened dead, where the remembered and imagined world decaysuntil chaosmercifully grantsoblivion.

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Consciousnesssatisfiesemotion by the physical actions it selectsin the midst of turbulent sensation.It is the specializedpart of the mind that createsand sorts scenarios,the means by which the future is guessedand coursesof action chosen.Consciousness is not a remote command center but part of the system,intimately wired to all the neural and hormonal circuits regulating physiology.Consciousness actsand reactsto achieve a dynamic steadystate.It perturbsthe body in precisewayswith each changingcircumstance,as requiredfor wellbeing and responseto opportunity,and helps return it to the original condition when challengeand opportunityhavebeen met. The reciprocityof mind and body can be visualizedin the following scenario,which I have adaptedfrom an account by the neurologist Antonio R. Damasio. Imagine that you are strolling along a deserted city streetat night. Your reverie is interrupted by quick footstepsdrawing closebehind. Your brain focusesinstantlyand churns out alternative scenarios-ignore, freeze,turn and confront, or escape.The last scenario prevails and you act. You run toward a lighted storefront further down the street. In the spaceof a few seconds,the conscious responsetriggers automatic changes in your physiology.The catecholamine hormonesepinephrine ("adrenaline")and norepinephrine pour into the bloodstreamfrom the adrenalmedulla and travel to all parts of the body, increasing the basal metabolic rate, breaking down glycogenin the liver and skeletalmusclesto glucosefor a quick energy feed. The heart races.The bronchioles of the lungs dilate to admit more air. Digestion slows.The bladder and colon prepare to void their contents,disencumbering the body to preparefor violent action and possibleiniury. A few seconds more pass.Time slows in the crisis: The event span seemslike minutes. Signalsarising from all the changesare relayed back to the brain by more nerve fibersand the rise of hormone titers in the bloodstream. As further secondstick away,the body and brain shift together in precisely programmed ways.Emotional circuits of the limbic systemkick in-the new scenariosflooding the mind are charged with fright, then anger that sharply focusesthe attention of the cerebral cortex, closing out all other thought not relevantto immediate survival. The storefront is reached, the race won. People are inside, the pursueris gone.Was the follower really in pursuit?No matter.The re-

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public of bodilysystems, informedby reassuring signalsfrom the consciousbrain,beginsits slowstand-down to the originalcalm state. has Damasio,in depictingthe mind holisticallyin suchepisodes, The the broad of emotion. first, suggested existenceof two categories primaryemotion,comprisesthe responses ordinarilycalledinborn or instinctive.Primaryemotion requireslittle consciousactivitybeyond the recognitionof certainelementarystimuli,the kind that studentsof instinctivebehaviorin animalscall releasers-theyare saidto "release"the preprogrammed behavior.For human beingssuchstimuli of includesexualenticement,loud noises,the suddenappearance objects, largeshapes, the writhingmovements of snakes or serpentine andthe particularconfigurations with heartaftacks of painassociated or brokenbones.The primaryemotionshavebeenpassed downwith little changefrom the vertebrateforebears of the human line. Theyare activatedby circuitsof the limbic system,amongwhich the amygdala appears to be the masterintegratingandrelaycenter. eventsof life.To meet Secondary emotionsarisefrompersonalized an old friend,fall in love,win a promotion,or sufferan insultis to fire thelimbic circuitsof primaryemotion,but only afterthe highestintegrativeprocesses of the cerebralcortexhavebeen engaged.We must knowwho isfriendor enemy,andwhytheyarebehavinga certainway. By this interpretation,the emperor'srageand poetk raptureare cultural elaborations retrofittedto the samemachinerythat drivesthe pre"with its tinkerishknack humanprimates. Nafure,Damasioobserves, for economy,did not selectindependent for expressing mechanisms primaryand secondaryemotions.It simply allowedsecondaryemoby the samechannelalreadypreparedto convey tionsto be expressed primaryemotions." of Ordinarywords used to denoteemotion and other processes mentalactivitymakeonly a crudefit to the modelsusedby the brain scientistsin their attemptsat rigorousexplanation.But the ordinary and conventionalconceptions-what some philosopherscall folk psychology-are necessary if we areto makebettersenseof thousands of yearsof literatehistory andtherebyjoin the culturesof the pastwith thoseof the future. To that end I offer the following neuroscienceof menaccented definitionsof several of the mostimportantconcepts tal activig. What we call meaningis the linkageamongthe neural networks

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createdby the spreadingexcitation that enlargesimageryand engages emotion. The competitiveselection among scenariosis what we call decisionmaking. The outcome, in terms of the match of the winning scenarioto instinctiveor learned favorablestates,setsthe kind and intensity of subsequentemotion. The persistentform and intensity of emotions is calledmood.The ability of the brain to generatenovel scenarios and settle on the most effective among them is called creativity. The persistent production of scenarioslacking reality and survival value is called insanity. The explicit material constructionsI have put upon mental life will be disputedby some brain scientists,and reckonedinadequateby others. That is the unavoidablefate of synthesis.In choosing certain hypothesesover others,I havetried to serveasan honestbroker searching for the gravitationalcenter of opinion, where by and large the supporting data are most persuasiveand mutually consistent.To include all models and hypothesesdeservingrespectin this tumultuous discipline, and then to clarify the distinctionsamongthem, would require a full-dress textbook. Undoubtedly events will prove that in places I chose badly. For that eventuality I apologizenow to the slighted scientists, a concessionI comfortably make, knowing that the recognition they deserveand will inevitably receivecannot be blunted by premature omissionon the part of any one observer.

Tnn suoJncr thus qualified,I will next describethe deeperproblems that must be resolved before the physical basis of mind can be said to be truly solved.The one universallyiudged to be the most difficult of all is the nature of subiective experience.The Aushalian philosopher David Chalmers recently put the matter in perspectiveby contrasting the "easy problems" of general consciousnesswith the "hard problem" of subiective experience.In the first group (easy,I suppose, in the sensethat Mont Blanc is more readily climbed in beachwearthan Everest)are the classicalproblemsof mind research: how the brain respondsto sensorystimuli, how it incorporates information into patterns, and how it converts the patterns into words. Each of these steps of cognition is the subiect of vigorous contemporary research. The hard problem is more elusive:how physical processesin the brain addressedin the easyproblems give rise to subiectivefeeling.

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What exactly does it mean when we saywe expeience a color such as red or blue? Or experience,in Chalmers'words,"the ineffable sound ofa distantoboe,the agonyofan intensepain, the sparkleofhappiness or the meditative quality of a moment lost in thought. All are part of It is thesephenomena that compose what I am calling consciousness. the real mysteryof the mind." An imaginary experiment proposed by the philosopher Frank Jacksonin 1983illushatesthe supposedunattainability of subiective thought by the natural sciences.Consider a neurobiologist two centuries hence who understandsall the physics of color and all the brain's circuitry giving rise to color vision. But the scientist (call her Mary) hasneverexperiencedcolor; shehasbeen cloisteredall her life in a black-and-white room. She does not know what it is like for another person to see red or blue; she cannot imagine how they feel about color. According to fackson and Chalmers, it follows that ihere are qualities of conscious experience that cannot be deduced from knowledge of the physical functioning of the brain. Although it is the nature of philosophersto imagine impassesand expatiate upon them at book length with schoolmasterishdedication, the hard problem is conceptually easyto solve.What material description might explain subiective experience?The answer must begin by concedingthat Mary cannot know what it feels like to seecolor. The chromatic nuancesof a westeringsun are not hers to enioy. And for the same reason she and all her fellow human beings a fortiori cannot know how a honeybeefeelswhen it sensesmagnetismor what an electric fish thinks as it orients by an electric field. We can translate the energiesof magnetismand elechicity into sight and sound, the sensory modalities we biologically possess.We can read the active neural circuits of beesand fish by scanningtheir senseorgansand brains.But we cannot feel as they do-ever. Even the most imaginative and expert observerscannot think as animals, however they may wish or deceive themselvesotherwise. But incapacityis not the point. The distinction that illuminates subiectiveexperiencelies elsewhere,in the respectiveroles ofscience and art. Scienceperceiveswho can feel blue and other sensationsand who cannot feel them, and explains why that difference exists.Art in contrast transmits feelings among persons of the same capacity. In other words, science explains feeling, while art hansmits it. The majority of human beings, unlike Mary, seea full color spechum, and

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they feel its productions in reverberating pathwaysthrough the forebrain. The basic patterns are demonstrablysimilar acrossall colorsighted human beings.Variations exist,owing to remembrancesthat arisefrom the personalmemories and cultural biasesof different people. But in theory these variations can also be read in the patterns of their brain activity. The physical explanations derived from the patterns would be understandableto Mary the confined scientist.She might say,"Yes,that is the wavelength spanclassifiedby others asblue, and there is the pattern of neural activityby which it is recognizedand named." The explanationswould be equally clear to bee and fish scientistsif their speciescould somehowbe raisedto human levelsof intelligence. Art is the means by which people of similar cognition reach out to others in order to transmit feeling. But how can we know for sure that art communicatesthis way with accuracy,that people really,truly feel the same in the presence of art? We know it intuitively by the sheer weight of our cumulative responses through the many media of art. We know it by detailed verbal descriptionsof emotion, by critical analyses,and in fact through data from all the vast, nuanced, and interlocking armamentaria of the humanities.That vital role in the sharing of culture is what the humanities are all about. Nevertheless, fundamental new information will come from science by studying the dynamic patterns of the sensoryand brain systemsduring episodeswhen commonly shared feelings are evoked and experienced through art. But surely,skepticswill say,that is impossible.Scientific fact and art can never be hanslated one into the other. Such a responseis indeed the conventionalwisdom. But I believeit is wrong. The crucial link exists:The common property of scienceand art is the transmission of information, and in one sensethe respectivemodes of hansmission in science and art can be made logically equivalent. Imagine the following experiment: A team of scholars-led perhaps by colorchallenged Mary-has constructedan iconic languagefrom the visual patterns of brain activity. The result resemblesa stream of Chinese ideograms, each one representing an entity, process,or concept. The new writing-call it "mind script"-is translatedinto other languages. As the fluency of its readersincreases,the mind script can be read directly by brain imaging. In the silent recessesof the mind, volunteer subiects recount

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recitepoems,solveequations, in dreams, summonadvenfure episodes, recall melodies,and while they are doingthis the fiery play of their neuronalcircuitryis madevisibleby the techniquesof neurobiologr. The observer readsthe scriptunfoldingnot asink on paperbut aselectric patternsin live tissue.At leastsomeof the thinker'ssubjective The observerreflects,he experience-hisfeeling-is transferred. patterns he is ableto hansmit mind And from his own Iaughsor weeps. linked by perception the subiective responses back.The twobrainsare ofbrainactivity. Whetherseatedacrossfrom one anotherat a table,or alonein roomsor evenin separatecities,the communicantscan perseparate perception(ESP).But only suform featsthat resembleextrasensory perficially.The firstthinker glancesat a playingcardhe holdscupped in hishand.With no clueotherthantheneuralimageryto guidehim, the secondthinkerreadsthe faceof the card.The first thinker readsa novel;the secondthinkerfollowsthe narrative. of the mind scriptdependsasmuch asconAccuratetransmission ventionallanguagedoeson the commonalityof the users'culture. When the overlapis slight,the scriptmay be limited in useto a hundredcharacters; whenextensive,the lexiconcanexpandto thousands' At its most efficient,the script transmitsthe tonesand flourishesindigenous to particularculturesandindividualminds. Mind script would resembleChinesecalligraphy,not only a medium employedfor the communicationof factualand conceptual information,but alsoone of the greatart formsof Easterncivilization. The ideograms containsubtlevariationswith aestheticand othersubmeanings of their own sharedby writer and reader.Of this iective propertythe SinologistSimon Leyshaswritten,"The silk or paP€r usedfor calligraphyhasan absorbentquality:the lightesttouch of the at once- irretrievablyand inbrush,the slightestdrop of ink, registers of the mind, answering delibly. The brush acts like a seismograph everypressure, everyturn of the wrist.Like painting,Chinesecalligraphy addresses the eyeand is an art of space;like music, it unfoldsin pulof movements, a dynamicsequence time; Iike dance,it develops satingin rhythm."

If themindisboundbythe remains: Ar.r oln rMpAssEnonetheless lawsof physics,and if it can conceivablybe readlike calligraphy,how

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can there be free will? I do not mean free will in the trivial sense,the ability to chooseone's thoughts and behavior free of the will of others and the restof the world all around. I mean,instead,freedom from the constraintsimposed by the physiochemicalstatesof one's own body and mind. In the naturalisticview, free will in this deepersenseis the outcome of competition among the scenariosthat composethe consciousmind. The dominant scenariosare thosethat rousethe emotion circuits and engagethem to greatesteffect during reverie. They energize and focus the mind as a whole and direct the body in particular courses of action. The self is the entity that seems to make such choices.But what is the self? The self is not an ineffable being living apart within the brain. Rather, it is the key dramatic characterof the scenarios.It must exist, and play on center stage,becausethe sensesare located in the body and the body createsthe mind to representthe governanceof all consciousactions.The self and body are thereforeinseparablyfused:The self, despitethe illusion of its independencecreatedin the scenarios, cannot exist apart from the body, and the body cannot survive for long without the self.So closeis this union that it is almostimpossibleto envision soulsin heavenand hell without at leastthe fantasticalequivalent of corporealexistence.Even Christ, we havebeen inshucted,and Mary soon afterward, ascended to heaven in bodies-supernal in quality, but bodies nonetheless.If the nahrralistic view of mind is correct, as all the empirical evidencesuggests, and if there is also such a thing as the soul, theology has a new Mystery to solve. The soul is immaterial, this Mystery goes, it exists apart from the mind, yet it cannot be separatedfrom the body. The self an actor in a perpetually changing drama, lacks full command of its own actions. It does not make decisions solely by conscious,purely rational choice. Much of the computation in decision making is unconscious-strings dancing the puppet ego. Circuits and determining molecular processesexist outside conscious thought. They consolidatecertain memories and delete others, bias connections and analogies,and reinforce the neurohormonal loops that regulate subsequent emotional response.Before the curtain is drawn and the play unfolds,the stagehas alreadybeen partly set and much of the script written. The hidden preparation of mental activity givesthe illusion of free will. We make decisionsfor reasonswe often senseonly vaguely,and

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seldom if everunderstandfully. Ignoranceof this kind is conceivedby the consciousmind as uncertainty to be resolved;hence freedom of choice is ensured.An omniscientmind with total commitment to pure reasonand fixed goals would lack free will. Even the gods, who grant when they choosefoolishly, that freedomto men and showdispleasure avoid assumingsuch nightmarish power. Free will as a side product of illusion would seem to be free will enough to drive human progressand offer happiness. Shall we leave it at that?No, we cannot. The philosopherswon't let us. They will say: Supposethat with the aid of sciencewe knew all the hidden processes in detail. Would it then be correct to claim that the mind of a particular individual is predictable, and therefore truly, fundamentally determined and lacking in free willZ We must concede that much in principle, but only in the following, very peculiar sense.If within the interval of a microsecond the active networks composing the thought were known down to every neuron, molecule, and ion, their exactstate in the next microsecondmight be predicted.But to pursuethis line of reasoning into the ordinary realm of conscious thought is futile in pragmatic terms, for this reason:If the operations of a brain are to be seizedand mastered,they must alsobe altered.In addition, the principles of mathematicalchaoshold. The body and brain comprisenoisy legions of cells, shifting microscopicallyin discordant patternsthat cannot even begin to imagine. The cells are unaided consciousness bombarded every instant by outside stimuli unknowable by human intelligencein advance.Any one ofthe eventscan entrain a cascadeof microscopicepisodesleading to new neural patterns.The computer would have to be of stupendousProneededto track the consequences portions,with operationsconceivablyfar more complex than thoseof the thinking brain itself. Furthermore, scenariosof the mind are all but infinite in detail, their content evolving in accordance with the unique history and physiology of the individual. How are we to feed that into a computer? So there can be no simple determinismof human thought, at least not in obedienceto causationin the way physical laws describethe motion of bodiesand the atomic assemblyof molecules. Becausethe individual mind cannot be fully known and predicted, the self can go on passionatelybelieving in its own free will. And that is a fortunate circumstance.Confidence in free will is biologically adaptive.Without it the mind, imprisoned by fatalism,would slow and deteriorate.

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Thus in organismictime and space,in everyoperationalsensethat applies to the knowable self, the mind doeshave free will.

FINAT-Ly, given that consciousexperienceis a physicaland not a supernaturalphenomenon, might it be possibleto createan artificial human mind? I believe the answer to this philosophicallytroubling question to be yes in principle, but no in practice, at least not as a prospect for many decadesor even centuries to come. Descartes,in first conceivingthe questionoverthree centuriesago, declared artificial human intelligence to be impossible. Two absolutelycertain criteria,he said,would alwaysdistinguishthe machine from a real mind. It could never "modify its phrasesto reply to the senseof whateverwassaidin its presence,aseventhe most stupid men can do," and it could never"behavein all the occurrencesoflife asour reasonmakes us behave."The test was recastin operationalterms by the English mathematicianAlan Turing in r95o.In the Turing test,as it is now generally called, a human interpreteris invited to ask any questionof a hidden computer.All he is told is that either anotherperson or a computer will answer.If, after a respectableperiod of time, the questioneris unable to tell whether the interlocutor is human or machine, he losesthe game;and the mind of the machine is accorded human status.Mortimer Adler, the American philosopherand educator, proposedessentiallythe same criterion in order to challenge not iust the feasibilityof humanoids but also the entire philosophyof materialism. We cannot accept a thoroughly material basisfor human existence, he said, until such an artificial being is created. Turing thought the humanoid could be built within a few years.Adler, a devout Christian, arrivedat the same conclusion as Descartes:No such machine will everbe possible. Scientists,when told something is impossible, as a habit set out to do it. It is not, however, their purpose to searchfor the ultimate meaning of existencein their experiments.Their responseto cosmic inquiry is most likely to be: "What you suggestis not a productive question." Their occupation is instead exploration of the universe in concrete steps,one at a time. Their greatestreward is occasionallyto reach the summit of some improbablepeak and from there,like Keats'Cortezat Darien, look in "wild surmise" upon the vastnessbeyond. In their ethosit is better to havebegun a great iourney than to have finished it,

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better to make a seminal discoverythan to put the final touches on a theory. The scientific field of artificial intelligence, AI for short, was inaugurated in the r95os hard upon the invention of the first electronic computers.It is defined by its practitionersasthe study of computation needed for intelligent behavior and the attempt to duplicate that behavior using computers. A half century of work has yielded some impressiveresults. Programs are availablethat recognize obiects and faces from a few select feahrres and at different angles, drawing on rules of geometric symmetry in the manner of human cognition. Others can translate languages,albeit crudely, or generalize and classify novel obiects on the basisof cumulative experience-much in the manner of the human mind. Someprogramscan scanand chooseoptionsfor particularcourses of action according to preselectedgoals.In 1996 Deep Blue, an advanced chess-playing computer, earned grand master status by narrowly losing a six-gamematch to Gary Kasparov,the reigning human world champion. Deep Blue works by brute force, using thirty-two to examinetwo hundred million chesspositionseach microprocessors second. It finally lost because it lacked Kasparov'sability to assessan opponent'sweaknessand plan long-term strategybased in part on deception. ln t997 a reprogrammed and improved Deep Blue narrowly defeated Kasparov: the first game to Kasparov, the second to Deep Blue, then three ties and the final game to Deep Blue. The search is on for quantum advancesin the simulation of all domains of human thought. In evolutionary computation, AI programmers have incorporated an organismlike procedure in the evolution of design.They provide the computers with a rungeof options in solving problems, then let them select and modify the available procedures to be followed. By this means the machines have come to resemble bacteria and other simple one-celled organisms.A truly Darwinian twist can be added by placing elements in the machines that mutate at random to change the available procedures.The programs then compete to solve problems, such as gaining accessto food and space.Which mutated programs will be born and which among the neonates will succeedare not alwayspredictable,so the "species"of machines as a whole can evolve in ways not anticipated by the human designer.It is within the reach of computer scientiststo create mutable robots that travel about the laboratory,learn and classifyreal resources,and thwart

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other robots in attaining their goals.At this level their programswould be close to the instinctive repertoriesnot of bacteria but of simple multicellular animals such as flatworms and snails.In fiftv vearsthe -will havetraversedthe equivalent computer scientists- if successful of hundreds of millions of yearsof organicevolution. But for all that advance,no AI enthusiastclaimsto havea road map from fatworm instinct to the human mind. How might such an immense gap be closed?There are two schoolsof thought. One, representedby Rodney Brooksof the Massachusetts InstituteofTechnology, takesa bottom-up approach.In this version,the designerswould follow the Darwinian robot model to higher and higher levels,gaining new insights and elaboratingtechnology along the way. It is possible that in time, humanoid capabiliq,might emerge.The other approach is top-down. Favored by Marvin Minsky, a founding father of AI and colleague of Brooks at MII it concentratesdirectly on the highestorder phenomena of learning and intelligence as they might be conceived and built into a machine without intervening evolutionary steps. In the teeth of all pessimisticassessments of human limitation likely to be raised,human geniusis unpredictableand capableof stunning advances.In the near future a capacityfor at leasta crude simulation of the human mind might be attained,comprisinga level of brain sciencessophisticatedenough to understandthe basic operationsof the mind fully, with computer technology advancedenough to imitate it. We might wake up one morning to find such a triumph announced in the New YorkTimes,perhapsalong with a genericcure for canceror the discovery of living organisms on Mars. But I seriously doubt that any such event will ever occur, and I believe a great maiority of AI expertsare inclined to agree.There are two reasons,which can be called respectivelythe functional obstacleand the evolutionaryobstacle. The functional obstacle is the overwhelming complexity of inputs of information to and through the human mind. Rational thought emergesfrom continuous exchangesbetween body and brain through nerve dischargesand blood-borne flow of hormones, influenced in turn by emotional controls that regulate mental set, attention, and the selectionof goals.In order to duplicate the mind in a machine, it will not be nearly enough to perfect the brain sciencesand AI technolory, becausethe simulation pioneers must also invent and install an entirely new form of computation-artificial emotion, or AE.

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The second,or evolutionary,obstacleto the creation of a humanoidmind is the uniquegenetichistoryof the human species. Generichumannature-the psychicunityof mankind-is the product of millions of yearsof evolutionin environmentsnow mostlyforgotten. Without detailed attention to the hereditary blueprint of humannature,the simulatedmind mightbe awesomein power,but it wouldbe morenearlythat of somealienvisitor,not of a human. And evenif the blueprintwereknown,and evenif it could be followed,it would serveonly asa beginning.To be human, the artificial mind mustimitatethat of an individualperson,with its memorybanks filled by a lifetime'sexperience-visual,auditory,chemoreceptive, tactile,andkinesthetic,all freightedwith nuancesof emotion.And social: There mustbe intellectualand emotionalexposureto countless human contacts.And with thesememories,there must be meaning, connectionsmadeto eachandeverywordandbit of senthe expansive sory informationgiven the programs.Without all thesetaskscompleted,the artificialmind is fatedto fail Turing'stest.Any human iury couldtearawaythe pretenseof the machinein minutes.Eitherthat,or certifiablycommit it to a psychiatricinstitution.

cHAPTER

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Fn o u G B N s sr o C u r r u n e

THn NeruRAL scrENcn,s haveconstructedawebworkof causal explanationthat runs all the way from quantumphysicsto the brain sciences and evolutionary biology.Therearegapsin thisfabricof unknownbreadth,andmanyof thestrandscomposing it areasdelicateas spider'ssilk.Predictive syntheses, the ultimategoalof science, arestill in an earlystage,and especiallyso in biology.YetI think it fair to say thatenoughisknownto justifyconfidencein theprincipleof universal rationalconsilience across all the naturalsciences. The explanatorynetworknow touchesthe edgeof cultureitself.It hasreachedthe boundarythat separates the naturalscienceson one sidefrom the humanitiesandhumanisticsocialsciences on the other. Granted,for mostscholars the two domains,commonlycalledthe scientific and literarycultures,still have a look of permanence about them. From Apollonianlaw to Dionysianspirit, proseto poetry Ieft corticalhemisphereto right, the line betweenthe two domainscanbe easilycrossedbackand forth, but no one knowshow to translatethe tongueof one into that of the other. Shouldwe eventry?I believeso, and for the bestof reasons: The goalis both importantandattainable. The time hascometo reassess the boundary. Evenif that perceptionis disputed-andit will be-few candeny that the divisionbetweenthe two culturesis a perennialsourceof misunderstanding and conflict."This polarisation is sheerlossto us all,"

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wroteC. P. Snowin his defining1959essay TheTwoCulturesand the ScientificRevolution."To us aspeople,and to our society.It is at the sametime practicaland intellectualand creativeloss." The polarizationpromotes,for one thing, the perpetualrecycling of the nature-nurturecontroversy, spinningoff mostlysteriledebates ethnicity,andhuman nafureitself.The o.ngender,sexualpreferences, root causeofthe problemis asobvioustodayasit waswhen Snowruminatedon it at ChristCollegehigh table:the overspecialization of the educatedelite.Publicintellectuals,andtrailing closebehindthem havebeentrainedalmostwithout exception the mediaprofessionals, Theyconsiderhumannatureto in thesocialsciences andhumanities. be their provinceand havedifficulty conceivingthe relevanceof the natural sciencesto social behaviorand policy. Natural scientists, with little connecwhoseexpertiseis dicedinto narrowcompartments prepared tion to human affairs,areindeedill to engagethe samesubiects.What doesa biochemistknow of legal theory and the China trade?It is not enoughto repeatthe old nostrumthat all scholars,natand humanistsalike,areanimatedby a comural and socialscientists mon creativespirit.They areindeedcreativesiblings,but they lack a commonlanguage. There is only one wayto unite the greatbranchesof learningand end the culture wars.It is to viewthe boundarybetweenthe scientific and literaryculturesnot asa territorialline but asa broadand mostly unexploredterrain awaitingcooperativeentry from both sides.The misunderstandings arisefrom ignoranceof the terrain, not from a fundamentaldif[erencein mentality.The two culturessharethe following challenge.We know that virtually all of human behavioris hansmittedby culture. We alsoknow that biolog, hasan important The questionreeffecton the origin of culture and its transmission. in particularhow how biolory and culture interact, and maining is they interactacrossall societiesto createthe commonalitiesof human nafure.What, in final analysis, ioinsthe deep,mostlygenetichistory of the speciesasa whole to the more recentcultural historiesof its far-flungsocieties? That, in my opinion, is the nub of the relationship behveenthe two cultures.It can be statedas a problem to be solved,the centralproblemof the socialsciencesand the humanities, andsimultaneously oneof the greatremainingproblemsof the nahrral sciences. At the presenttime no one hasa solution.But in the sensethat no

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one in r84zknewthe truecauseofevolutionand inrg5zno oneknew the nature of the geneticcode,the wayto solvethe problemmay lie within ou( grasp.A few researchers, and I am one of them,eventhink they know the approximateform the answerwill take.From diverse vantagepoints in biology,psychology,and anthropology,they have conceiveda processcalledgene-culture coevolution.ln essence,the conceptionobsewes, first,thatto geneticevolutionthehumanlineage hasaddedthe paralleltrackofculturalevolution,and,second, thatthe twoformsof evolutionarelinked.I believethemaiorityof contributors to the theoryduring the pasttwentyyearswould agreeto the following outlineof itsprinciples: Culture is createdby thecommunalmind,and eachmind in tum is the productof the geneticallystructuredhumanbrain.Genesand culturearethereforeinseverably linked.But the linkageis flexible,to a degree still mostly unmeasured.The linkage is also tortuous:Cenes prescibeepigeneticruIes,whicharethe neuralpathwaysand regulaitiesin cogniti,tte development by whichtheindividualmindassembles itself. The mind growsfrom birth to death by absorbingparts of the existingcultureavailableto it, with selections guidedthroughepigenetic rulesinheited by the individualbrain. To visualizegene-culture coevolutionmore concretely, consider the exampleof snakesand dreamserpents, which I usedearlierto arguethe plausibilityof completeconsilience. The innatetendencyto react with both fear and fascinationtowardsnakesis the epigenetic rule. The culture draws on that fear and fascinationto create metaphorsand narratives. The processis thus: As part of gene-culture coevolution,culture is reconstructed each generationcollectivelyin the mindsof individuals.Whenoral tradition is supplemented by witing and art, culturecan growinilefinitelylarge and it canevenskipgenerations. But thefundamentalbiasinginfluence of theepigeneticrules,beinggeneticand ineradicable, staysconstant. Hencethe prominenceof dreamserpents in thelegends andart of the Amazonianshamansenrichestheir culture acrossgenerations underthe guidanceof the serpentine epigenetic rule. Someindividuak inherit epigeneticruIesenablingthem to sunive and reproducebetterin the sunoundingenvironment and culturethan individualswho lack thoserules,or at leastpossess themin weakervaIence.By this means,oyermanygenerations, the moresuccessful epigeneticruleshavespreadthroughthepopulationalongwiththegenesthat

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prescribe the rules.As a consequence the humanspecieshaserclvedgeneticallyby naturalselectionin behavior,iustas it hasin the anatonry andphysiology of thebrain. Poisonous snakes havebeenan importantsourceof mortalityin almost all societiesthroughouthuman evolution.Close attention to them, enhancedby dreamserpentsand the symbolsof culture, undoubtedlyimprovesthe chancesof survival. The natureof the geneticleashand the roleof culturecan now be betterunderstood, asfollows.Certainculturalnormsako suryiveand reproducebetterthan competingnorms,causingcultureto evolvein a hack parallel to and usuallymuch fasterthan geneticevolution.The quickerthepaceof culturalevolution,theloosertheconnectionbetween genesand culture,althoughthe connectionis nevereompletely broken. Culture allows a rapid adiustmentto changesin the environment throughfinelytunedadaptationsinventedand transmittedwithoutcorprecisegeneticpresciption.ln thisrespecthuman beings respondingly dffir fundamentallyfromall otheranimalspecies. Finally,to completethe exampleof gene-culturecoevolution,the frequencywith which dreamseqpents and serpentsymbolsinhabit a culture is seento be adjustedto the abundanceof real poisonous snakesin the environment.But owingto the powerof fearand fascination giventhem by the epigeneticrule, they easilyacquireadditional mythic meaning;they servein differentculturesvariouslyas healers, messengers, demons,andgods. Gene-culturecoevolutionis a specialextensionof the more general processof evolution by natural selection.Biologistsgenerally agreethat the primaryforcebehindevolutionin humanbeingsand all otherorganismsis naturalselection.That is what createdHonto sapiensduring the five or six million yearsafter the ancestralhominid speciessplit off from a primitive chimpanzeelikestock.Evolution by naturalselectionis not an idle hypothesis.The geneticvariationon which selectionactsis well understoodin principle all the way down to the molecularlevel. "Evolution watchers"among field biologists havemonitoredevolutionby naturalselection,generationby generation, in naturalpopulationsof animalsandplants.The resultcanoften be reproducedin the laboratory even up to the creation of new species,for exampleby hybridizationand the breedingof reproductively isolatedshains.The mannerin which traitsof anatomy,physiology,and behavioradaptorganismsto their environmenthas been

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massivelydocumented. The fossilhominid record, from man-apesto modern humans, while still lacking many details,is solid in main outline, with a well establishedchronologr. In simplestterms, evolution by natural selectionproceeds,as the French biologistfacquesMonod once put it (rephrasingDemocritus), by chance and necessity.Different forms of the same gene,called alleles, originate by mutations,which are random changesin the long sequencesof DNA (deoxyribonucleicacid) that composethe gene.In addition to such point-by-pointscramblingof the DNA, new mixesof alleles are created each generationby the recombining processesof sexualreproduction.The allelesthat enhance survivaland reproduction of the carrier organismsspread through the population, while thosethat do not, disappear.Chance mutationsare the raw materialof evolution. Environmental challenge, deciding which mutants and their combinations will survive,is the necessitythat molds us further from this proteangenetic clay. If given enough generations,mutations and recombination can generatea nearly infinite amount of hereditaryvariation among individuals in a population. For example,if even a mere thousandgenes out of the fifty thousandto a hundred thousandin the human genome were to exist in two forms in the population, the number of genetic combinationsconceivableis rot-, more than all the atomsin ihe visible universe.So except for identical siblings the probability that any two human beings share identical genes,or have ever sharedthem throughout the history of the hominid line, is vanishinglysmall. With each generation the chromosomes and genes of the parents are scrambled to produce new mixes. But this perpehral shearing and reconfigurationdoesnot of itselfcauseevolution.The consistentguiding force is natural selection. Genes that confer higher survival and reproductive successon the organismsbearing them, through the prescribed traits of anatomy, physiolory, and behavior, increase in the population from one generation to the next. Those that do not, decrease.Similarly, populations or even entire specieswith higher survival and reproductivesuccessprevail over competing populationsor species,to the samegeneralend in evolution. Such is the impersonal force that evidently made us what we are today. All of biology, from molecular to evolutionary points that way. At the risk of seeming defensive, I am obliged to acknowledge that many people, some very well educated,prefer special creation as an

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explanation for the origin of life. According to a poll conducted by the National Opinion ResearchCenter in rgg4,z3 percent of Americans reject the idea of human evolution, and a third more are undecided. This pattern is unlikely to change radically in the years immediately ahead.BecauseI was raisedin a predominantly antievolutionistculhrre in the Protestantsouthern United States,I am inclined to be empaihetic to these feelings, and conciliatory. Anything is possible,it can be said, if you believe in miracles.PerhapsGod did createall organisms, including human beings,in finished form, in one shoke, and maybe it all happenedseveralthousandyearsago. But if that is true, He alsosaltedthe earthwith falseevidencein such endlessand exquisite detail, and so thoroughly from pole to pole, as to make us conclude first that life evolved,and secondthat the processtook billions ofyears. Surely Scripture tells us He would not do that. The Prime Mover of the Old and New Testamentsis variouslyloving, magisterial,denying, thunderously angry, and mysterious,but never tricky. Virtually all biologists closely familiar with the details find the evidencefor human evolutioncompelling, and give natural selectionthe commandingrole. There is at leastone other force,however,that must be mentioned in any accountof evolution.By chancealone,the biologistsagree, substitutions are occurring through long shetches of time in someof the DNA lettersand the proteinsthey encode.The continuity of change is often smooth enough to measure the age of different evolvinglines of organisms.But this genetic drift, as it is called, adds very little to evolution at the level of cells, organisms,and societies. The reasonis that the mutantsinvolved in drift-haveproven to be neuhal, or nearly so: They have little or no effect on the higher levels of biologicalorganizationmanifestin cells and organisms.

To cnNrrrc E V o L U T To N , p u t t i n gt h e m a t t e ra sc o n c i s e l ay sp o s sible, natural selectionhas added the parallel track of cultural evolution, and the iwo forms of evolution are somehow linked. We are trapped, we sometimesthink, for ultimate good or evil, not just by our genesbut also by our culture. What preciselyis this superorganism, this shangecreature called culture7 To anthropologists,who have analyzed thousandsof examples,should go the privilege of response.For them, a culture is the total way of life of a discretesociety-.its religion, myths, art, technology, sports,and all the other systematicknowledge

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transmifted across generations. In r95z Alfred Kroeber and Clyde Kluckhohn melded 164prior definitionspertainingto all culturesinto one, as follows: "Culture is a product; is historical; includes ideas,patterns,and values;is selective;is learned;is basedupon symbols;and is an abstractionfrom behavior and the productsofbehavior." As Kroeber had earlier declared,it is also holistic, "an accommodationof discrete parts, largely inflowing parts, into a more or less workable fit." Among the parts are artifacts,but thesephysical obiectshave no significance exceptwhen addressedas conceptsin living minds. In the exheme nurturist view, which has prevailed in social theory for most of the twentieth cenfury, culture has departedfrom the genes a life of its own, growing like and become a thing unto itself. Possessing wildfire ignited by the strike of a match, it has acquired emergent propertiesno longer connectedto the geneticand psychologicalprocesses that initiated it. Hence, omnis cultura ex cultura. All culture comes from culture. Whether that metaphor is accepted or not, the undeniable huth is that each society createsculture and is created by it. Through constant grooming, decorating,exchangeof gifts,sharingof food and fermented beverages,music, and story"telling,the symbolic communal life of the mind takes form, unifying the group into a dreamworld that masters the external reality into which the group has been thrust, whether in forest, grassland,desert, ice field, or city, spinning from it the webs of moral consensusand ritual that bind each tribal member to the common fate. Culture is constructed with languagethat is productive, comprising arbitrary words and symbols invented purely to convey information. In this respect Homo sapiens is unique. Animals have communication systemsthat are sometimes impressivelysophisticated,but they neither invent them nor teach them to others. With a few exceptions, such as bird song dialecb, they are instinctive, hence unchanging across generations.The waggle dance of the honeybee and the odor trails of ants contain symbolic elemenb, but the performancesand meanings are tightly prescribed by genesand cannot be altered by learning. Among animals true linguistic capaci$ is most closelyapproached by the greatapes.Chimpanzeesand gorillascan learn the meaningsof arbitrary symbols when trained to use signaling keyboards. Their champion is Kanzi, a bonobo, or pygmy chimpanzee (Pan paniscus), arguably the smadest animal ever observedin captivity. I met this pri-

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mate genius when he was a precocious youngster at the yerkes Regional Primate Center of Emory Universityin Atlanta. He had been studied intensively since birth by Sue Savage-Rumbaughand her colleagues.As I played gamesand shareda cup of grapejuice with him, I was more than a bit disorientedby his general demeanor, which I found uncannily close to that of a human twoyear-old. More than a decade later, as I write, the adult Kanzi has acquired a large vocabuIary with which he signalshis wishesand intentions on a picturesymbol keyboard. He constructs sentencesthat are lexically if not grammatically correct. On one occasion, for example, lce water go ("Bring me some ice water")got him the drink. He has .u"n *"rr"g"d to pick up about r5o spoken English words spontaneously,listening to conversationamong humans, without the kind of haining neededby border collies and other smart breedsof dogsto go through their many tricks. On another occasion Savage-Rumbaugh,pointing to a companion chimpanzee nearby, said,"Kanzi, if you give Austin your mask, I'll let you have some of Austin's cereal." Kanzi promptly gaveAustin the mask and pointed to the cereal box. He has acted upon words in a fo. cusedand specificmanner too frequentlyfor the connection to be due to chancealone.Even so,Kanzi usesonly wordsand symbolssupplied him by human beings. His linguistic powers have not yet risen to the level of earlyhuman childhood. Bonobosand other greatapespossess high levelsofintelligence by animal standardsbut lack the singular human capacity to invent rather than merely to use symbolic language.It is further hue that common chimpanzeesare humanlike in guile and deception, the animal masters of "Machiavellian intelligence."As Frans de Waal and his fellow primatologistshave observedin the Afiican wild and the funhem zoo in the Netherlands, they form and break coalitions, manipulate friends,and outwit enemies.Their intentions are conveyedby voiced signals and posfures, body movements, facial expressions,and the bristling of fur. But in spite of the great advantage a productive, humanlike language would bestow, chimpanzees never create anything resembling it, or any other form of free-ranging symbolic language. In fact, the great apesare completely silent most of the time. The primatologistAllen Gardner describedhis experiencein Thnzaniaas follows: "A group of ten wild chimpanzees of assortedagesand sexes feeding peacefully in a fig tree at Gombe may make so little sound that

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an inexperiencedobserverpassingbelow can altogetherfail to detect them." Homo sapiens,by contrast, can righffirlly be called the babbling ape. Humans communicatevocally all the time; it is far easierto start them ialking than to shut them up. They begin in infancy during exchanges with adults, who urge them on with the slow, vowel-healy, emotionally exaggeratedsingsongcalled motherese.Left alone, they continue with "crib speech,"composedof squeaks,coos,and nonsense monosyllables,which evolveover a few months into a complex play of wordsand phrases.These earlyverbal repertories,conforming more or less to adult vocabularies,are repeatedad ndusedm,modified, and combined in experimental mixtures. By the age of four the average child has masteredsyntax.By six, in the United Statesat least,he hasa vocabularyofabout fourteenthousandwords.In conhast,young bonobos play and experimentfreelywith movementsand soundsand sometimes with symbols,bui so far progresstoward the Kanzi level depends on the rich linguistic environment providedby human trainers. Even if the greatapeslack true language,is it possiblethey possess culture? From evidencein the field it apPearsthey do, and many expert observershave so concluded. Wild chimps regularly invent and use tools. And the particular kinds of artifacb they invent, iust as in human culture, are often limited to local populations. Where one group breaks nuts open with a rock, another cracks them against tree trunks. Where some groups use twigs to fish ants and termites from the nests for food, others do not. Among those that fish, a minority first peel the bark offthe twigs. One chimp group has been obsewedusing long hooked branchesto pull down branchesof fig hees to obtain fruit. It is natural to conclude from such observationsthat chimpanzees have the rudiments of culture, and to suPPosethat their capability differs from human culture by degree alone. But that perception needsto be acceptedwith caution: Chimpanzee inventionsmay not be culture in any sense.The still scanty evidence on the subiect suggeststhat while chimps pick up the use of a tool more quickly when they seeothers using one, they seldom imitate the precise movements employed or show any clear sign of understanding the purpose of the activity. Some observershave gone so far asto claim that they are merely stirred into greater activity by watching others. This kind of response,which zoologistscall social facilitation, is common in many kinds of social animals,from antsto birds and mammals.Although the evidenceis in-

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conclusive, social facilitation alone, combined with trial-and-error manipulation of materialsconvenientlyat hand, might guide the chimps to tool-using behavior in the free-rangingAfrican populations. Human infants,on the other hand, do engagein preciseimitation and with astonishingprecocity. As early as forty minutes after birth, to cite the ultimate example, they stick out their tongues and move their heads from side to side in close concert with adults. Bv twelve davs they imitate complex facial erpressions and hand gestures. By two yearsthey can be verballyinshucted in the useof simple tools. In summary, the language instinct consists of precise mimicry compulsive loquacity, near-automatic masteryof syntax, and the swift acquisition of a large vocabulary. The instinct is a diagnostic and evidently unique human hait, based upon a mental power beyond the reach of any animal species,and it is the preconditionfor true culhrre. To learn how languageoriginated during evolution would be a discovery of surpassingimportance. Unfortunately, the evidencesof behavior rarelyfossilize.AII the millennia of campsitechatteringand gesticulation, and with them all the linguistic stepsup from our chimplike ancestors,havevanishedwithout hace. What paleontologistshave instead are fossil bones, which tell of the downward migration and lengthening of the voice box, as well as possiblechangesin the linguistic regionsof the brain impressedupon the inner cranial case.They also have steadilyimproving evidenceof the evolution of artifacts,from the controlled use of fire 4jo,ooo years ago, presumably by the ancestral speciesHomo erectu.s,to the construction of well-wrought tools by ear\ Homo sapiens25o,ooo years ago in Kenya, then elaborate spearheadsand daggers16o,ooo years later in the Congo, and finally elaboratepainting and the accouterments of ritual 3o,oooand zo,ooo yea:s again southem Europe. This pace in the evolution of artifactual culture is intriguing. We know that the modern Homo sapiens brain was anatomicaly ruUy formed by no later than roo,ooo years before the present. From that time forward the material culture at first evolved slowly, later expanded, and then exploded. It passedfrom a handful of stone and bone tools at the beginning of the interval to agricultural fields and villages at the 9o percent mark, and then-in a virtual eyeblink*to prodigiouslyelaboratetechnologies(example:five million patentsso far in the united Statesalone). In essence,cultural evolution has followed an exponential hajectory. It leavesus with a mystery:When did

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symbolic language arise, and exactly how did it ignite the exponentiation of cultural evolution?

To o o e o , but this great ptzzle of human paleontology seemsinsoluble, at leastfor the time being.To pick up the hail of gene-culhrrecoevolution, it is better to defer reconstructionof the prehistoricrecord and proceedto the production of culture by the contemporaryhuman brain. The next bestapproach,I believe,is to searchfor the basicunit of culture. Although no such element hasyet been identified, at least to the general satisfactionof experts,its existenceand some of its characteristicscan be reasonablyinferred. Such a focus may seem at first contrived and artificial, but it has many worthy precedents.The greatsuccessof the natural scienceshas been achieved substantiallyby the reduction of each physical phenomenon to its constituent elements,followed by the use of the elements to reconstitute the holistic properties of the phenomenon. Advancesin the chemistryof macromolecules,for example,led to the exact characterizationof genes,and the study of population biology basedon geneshasrefined our understandingofbiological species. What then, if anything, is the basic unit of culture? Why should it be supposedeven to exist?Consider first the distinction made by the Canadian neuroscientist Endel Tulving in t97z between episodic and semantic memory. Episodic memory recalls the direct perception of people and other concreteentitiesthrough time, like imagesseenin a motion pichrre. Semantic memory, on the other hand, tecalls meaningby the connection of obiectsand ideasto other obiectsand ideas, either directly by their images held in episodic memory or by the symbols denoting the images.Of course,semanticmemory originatesin episodesand almost invariably causesthe brain to recall other episodes. But the brain has a strong tendency to condense repeated episodesof a kind into concepts, which are then representedby ty*bols.Thus, "Proceedto the airport this way" yields to a silhouetteof an airplane and arrow,and "This substanceis poisonous"becomesa skull and crossboneson the side of a container. With the two forms of memory distinguished, the next step in the search for the unit of culture is to envision concepts as "nodes," or reference points, in semantic memory that ultimately can be associated with neural activity in the brain. Concepts and their symbols ate usu-

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ally labeled by words. Complex information is thus organized,and, transmitted by language composed of words. Nodes are almost always Iinked to other nodes,so that to recall one node is to summon otheis. This linkage, with all the emotional coloring pulled up with it, is the essenceof what we referto as meaning.The linkage of nodesis assembled as a hierarchy to organize information with more and more meaning. "Hound," "hare" and "chasing"are nodes,each symbolizing collectivelya classof more or lesssimilar images.A hound chasinga hare is called a proposition,the next order of complexity in information. The higher order above the proposition is the schema. A rypical schema is Ovid's telling of Apollo's courtshipof Daphne, like an unstoppable hound in pursuit of an unattainable hare, wherein the dilemma is resolvedwhen Daphne, the hare and a concept, turns into alaureltree,anotherconceptreachedbyaproposition. I havefaith that the unstoppableneuroscientists will encounter no such dilemma. In due course they will capture the physical basisof mental concepts through the mapping of neural activity patterns. They alreadyhave direct evidenceof "spreadingactivation',of aitr rent partsof the brain during memory search.In the prevailing view of the researchers, new information is classifiedand stored in a similar manner.When new episodesand conceptsare addedto memory they are processedby a spreading search through the limbic and cortical systems,which establisheslinks with previouslycreated nodes. The nodesare not spatiallyisolatedcentersconnectedto other isolatedcenters.They are typically complex circuits of large numbers of nerve ceils deployedoverwide, overlappingareasofthe brain. Suppose,for example,you are handedan unfamiliar piece of fruit. You automaticallyclassifyit by ib phpical appearance,smell, taste, and the circumstancesunder which it is given.A large amount of information is activatedwithin seconds,not iust the comparison of the fruit in hand with other kinds but alsothe emotional feelings,recollections of previousdiscoveriesof similar nature,and memories of dietary customsthat seemappropriate.The fruit-all its characteristicscompounded- is given a name. Considerthe durian of SoutheastAsia.regarded by aficionadosas the greatestofall tropical fruits. It looks like a spiny grapefruit, tastes sweet with a transient custardlike nuance, and when held awayfrom the mouth smellslike a sewer.The experience of a single piece establishes,I assureyou, the concept ,,durian" for a lifetime.

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The natural elementsof culture can be reasonablysupposedto be the hierarchically arranged components of semantic memory, encoded by discreteneural circuits awaitingidentification.The notion of a culture unit, the most basic element of all, has been around for over thirty years, and has been dubbed by different authors variously as mnemotype, idea, idene, meme, sociogene,concept, culturgen, and culture type.The one label that hascaughton the most,and for which I now vote to be winner, is meme, introduced by Richard Dawkins in his infuential work The Selfish Cene in ry76. more focusedand The definition of meme I suggestis nevertheless somewhat different from that of Dawkins. It is the one posed by the theoreticalbiologistCharles f . Lumsden and myself in r98r, when we outlined the first full theory of gene-culhrre coevolution. We recommended that the unit of culture-now called meme-be the sameas the node of semanticmemory and its correlatesin brain activity.The level of the node, whether concept (the simplestrecognizableunit), proposition,or schema,determinesthe complexityof the idea,behavior, or artifact that it helps to sustain in the culture at large. I realize that with advances in the neurosciencesand psychology the notion of node-as-meme, and perhaps even the distinction between episodic and semantic memory are likely to give way to more sophisticated and complex taxonomies. I tealize also that the assignment of the unit of culture to neurosciencemight seem at first an attempt to short-circuit semiotics, the formal study of all forms of communication. That objection would be uniustified.My purposein this exposition is the opposite, to establish the plausibility of the central program of consilience, in this instance the causal connectionsbetween semioticsand biology. If the connectionscan be established empirically, then future discoveriesconcerning the nodes of semantic memory will correspondinglysharpenthe definition of memes.Such an advancewill enrich, not replace,semiotics. {'genes to culture," as the conthat the very expression I coNcnns ceptual keystone of the bridge between science and the humanities, has an ethereal feel to it. How can anyone Presumeto speakof a gene that prescribesculture?The answeris that no seriousscientisteverhas. The web of causaleventscomprising gene-culfure coevolution is more complicated-and immensely more interesting.Thousandsof genes

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prescribe the brain, the sensorysystem,and all the other physiological processesthat interact with the physical and social environment to produce the holistic propertiesof mind and culture. Through natural selection, the environment ultimately selectswhich geneswill do the prescribing. For its implicationsthroughout biology and the socialsciences,no subject is intellectually more important. All biologists speak of the interaction between heredity and environment. They do not, except in laboratoryshorthand,speakofa gene "causing"a particular behavior, and they never mean it literally. That would make no more sensethan its converse,the idea of behavior arising from culture without the intervention of brain activity. The accepted explanation of causation from genesto culture, asfrom genesto any other product of life, is not heredity alone. It is not environment alone. It is interaction between the two. Of course it is interaction.But we need more information about interactionin order to encompassgene-culturecoevolution.The cenhal clarifying concept of interactionism is the norm of reaction. -fhe idea is easilygraspedasfollows. Choose a speciesof organism, whether animal, plant, or microorganism.Selecteither one gene or a group of genesthat act together to affect a particular trait. Then list all the environments in which the species can survive. The different environments may or may not cause variation in the trait prescribed by the selectedgene or group of genes. The total variation in the trait in all the survivable environments is the norm of reaction of that gene or group ofgenes in that species. The textbook caseof a norm of reaction is leaf shape in the arrowleaf, an amphibious plant. When an individual of the speciesgrowson the land, its leaves resemble arrowheads. When it grows in shallow water, the leavesat the surfaceare shapedlike lily pads;and when submerged in deeper water, the leavesdevelop as eelgrasslikeribbons that swayback and forth in the surrounding current. No known genetic differences among the plants underlie this extraordinary variation. The three basic types are variations in the expressionof the same group of genes caused by different environments. Together they compose the norm of reactionof the genesprescribingleaf form. They embrace,in other words, the full variation in expressionof the genesin all known survivable environments. When some of the variation within a speciesis due to differences

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in genespossessed by separatemembersof the species,and not just different environments,norms of reaction can still in principle be defined for each of the genes or set of genesin turn. The relation of variationin a trait to variation in genesand their norms of reactionis illustrated by human body weight. There is abundant evidencethat body form is influenced by heredity.A persongeneticallypredisposed to obesityby heredity can diet to moderateslimness,although he is prone to slide back when offthe diet.A hereditarilyslenderpetson,on the other hand, is likely to staythat way,and only persistentovereating or endocrineimbalancecan push him into obesity.The relevantgenes of the two individualshave different norms of reaction.They produce different results when both individuals occupy identical environments, including diet and exercise.The more familiar way to express the matter is in reverse,noting that hereditarilydistinct individualsrequire different environments,in particular different dietsand regimes of exercise,in order to produce the sameresult. The same kind of interaction between genes and environment occurs in every category of human biology, including social behavior. In his important 1996 work Bom to Rebel,the American social historian Frank f. Sullowayhas demonstratedthat people respondpowerfully during personalitydevelopmentto the order in which they were born and thus the roles they assumein family dynamics.Later-borns, who identify leasi wiih the roles and beliefs of the parents,tend to become more innovativeand acceptingof political and scientificrevolutions than do first-borns.fu a result they have, on average,conhibuted more than first-borns have to cultural change throughout history. They do it by gravitatingtoward independent, often rebelliousroles, first within the family and then within society at large. Becausefirstand later-bornsdo not differ genetically in any way correlatedwith their birth order, the genes influencing development can be said to spread their effects among various niches available in the environment. The birth-order effect documented by Sulloway is their norm of reaction. In some categoriesof biology,such asthe most elementarymolecular processesand propertiesof grossanatomy, almost everyonehas the samegenesaffectingtraits in thesecategoriesand hence the same norms of reaction.Long ago in geologicaltime, when the truly universal traits were evolving, there probably was variation in the prescribing genes,but natural selectionhassince narrowedthe variationalmostto

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zero.All primates,for example,have ten fingersand ten toes, and thereis virtuallyno variationdueto environment;sothe norm of reaction is exactlythe singlestate,of ten fingersand ten toes.In mostcategories,however,peoplediffer geneticallyto a considerabledegree, evenin traitsconsistentenoughto be regardedascultural universals. In orderto makethe mostof the variation,to cultivatehealthand talent andrealizehumanpotential,it is necessary to understandthe roles of both heredityand environment. By environmentI do not mean merely the immediatecircumstances in which peoplefind themselves. A snapshot will not suffice. The requiredmeaningis that usedby developmentalbiologistsand psychologists. It is nothinglessthan the myriadinfluencesthat shape bodyand mind stepby stepthroughouteverystageof life. Becausehuman beings cannot be bred and reared under controlled conditions like animals, information about the interaction of genesand environment comes hard. Relatively few genesaffecting behavior (someof which I will describelater) havebeen locatedon chromosomes,and the exactpathwaysof development they influence have seldom been traced. In the interim the preferred measure of interaclionis heitability,the percentageof variation in the trait due to heredity. Heritability does not apply to individuals; it is used only for populations. It is incongruous to say,"This marathoner'sathletic ability is zo percentdue to his genesand 8o percentto his environment." It is correct to make a statement such as, to use an imaginary example, "Twenty percent of the variation in performance of Kenyan marathoners is due to their heredity and 8o percent to their environment." For the reader who would like more precise definitions of heritability and variance,the measureof variation used by statisticiansand geneticists, I will add them here: Heritability,minusmathematicalrefinements,is estimatedasfollows. In a sampleof individualsfrom the population,measurethe trait in a standardized way,sayaerobicperformanceon a treadmillto represent endurance.Takethe variationin the measureamongthe individuals in the sample,andestimatethe amountof the variationdue to heredi ty. That fraction is the heritability.The measureof variationusedis the variance.To getit, firsttakethe averagescoreobtainedfrom individualsin the sample.Subtracteach individual'sscorein turn from the averageand squarethe difierence.The varianceis the averageof all the squareddifferences.

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The principal method of estimating the fraction of variation due to the genes-the heritability-is by studies of twins. Identical twins, which have exactlythe samegenes,are comparedwith fraternaltwins, which on averageshareonly the samenumber of genesasthe number sharedby siblings born at different times. Fraternaltwins are consistently lessalike than identical twins, and the differencebetweenpairs of fraternal twins and pairs of identical twins seryesas an approximate measureof the contribution of heredityto the overallvariationin the trait. The method can be considerablyenhanced by studiesof those special pairs of identical twins who were separatedin infancy and adopted by different families, thus possessingthe same heredity but reared in different environments.It is further improved by multiple correlation studies, in which the key environmental influences are identified and their contributions to the overall variation individually assessed. Heritability has been a standard measure for decadesin plant and animal breeding. It has gained recent controversialattention for its human applications through The BeIl Curve, the 1994 book by Richard J. Herrnstein and Charles Murray, and other popular works on the heredity of intelligence and personality.The measurehas considerable merit, and in fact is the backbone of human behavioral genetics.But it contains odditiesthat deservecloseattentionwith reference to the consilience between geneticsand the social sciences. The first is the peculiar twist called "geno$pe-environment correlation," which servesto increasehuman diversitybeyondthe ambit of its immediate biological origins. The twistworks asfollows. Peopledo not merely select roles suited to their native talents and personalities.They also gravitate to environments that reward their hereditary inclinations. Their parents, who possesssimilar inborn traits, are also likely to create a family atmosphere nurturing development in the same direction. The genes, in other words, help to create a particular environment in which they will find greater expressionthan would otherwise occur. The overall result is a greater divergence of roles within societiesdue to the interaction of genesand environment.For example,a musicallygifted child, receivingencouragementfrom adults,may take up an instrument early and spend long hours practicing. His classmate, innately thrill-seeking, persistently impulsive and aggressive,is drawn to fast cars. The first child grows up to be a professionalmusi-

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cian, the second (if he staysout of houble) a successfulracing-car driver. The hereditary differences in talent and personality between the classmatesmay be small, but their effectshave been amplified by the diverging pathwaysinto which they were guided by the differences. To put genotype-environment correlation in a phrase, heritability measured at the level of biology reacts with the environment to increaseheritability measuredat the level of behavior. Understanding genotype-environment correlation clarifies a second principle of the relation of genesto culture. There is no gene for playing the piano well, or even a particular "Rubinstein gene" for playing it exhemelywell. There is insteada largeensembleof geneswhose effectsenhance manual dexterity, creativity,emotive expression,focus, attention span, and control of pitch, rhythm, and timbre. All of these together compose the special human ability that the American psychologist Howard Gardner calls musical intelligence. The combination also inclines the gifted child to seizethe right opportunity at the right time. He hies a musical instrument,likely provided by musically gifted parents, is then reinforced by deservedpraise, repeats, is reinforced again,and soon embraceswhat is to be the central preoccupation of his life. Another important peculiarity of heritability is its flexibility. By simply changing the environment, the percentageof variation due to heredity can be increasedor decreased.Scoresfor heritability in IQ and measurablepersonalitytraits in white Americans, a segmentof population typically chosen for convenienceand in order to increase statistical reliability by making the sample more uniform, mostly fall around the 5o percent mark, at least closer to it than to zero or roo percent. Do we wish to change these numbers?I think not, at least not as a primary goal. Imagine the result if a societybecame huly egalitarian, so that all children were raisedin nearly identical circumstancesand encouragedto enter any occupation they chosewithin reach of their abilities.Variation in environment would thus be drasticallyreduced, while the original innate abilities and personalitytraits endured.Heritability in such a societywould increase.Any socioeconomicclassdivisions that persistedwould come to reflect heredity as never before. Supposeinstead that all children were testedfor ability at an early age and put on educational tracks that reflected their scores,with the

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aim of directing them to occupationsmost appropriateto their giffs. Environmental variation in this Brave New World would rise and innate ability would staythe same.If the scoresand hence environments reflected the genes,heritability would increase.Finally, imagine a society with the reversepolicy: uniformity of outcome is valued aboveall else.Gifted children are discouragedand slow children provided with intensive personal training in an effort to bring everyone to the same level in abilities and achievement.Becausea wide range of tailored environmentsis requiredto approachthis goal, heritability would fall. These idealizedsocietiesare posednot to recommend any one of them - all havea totalitarianstench- but to clarify the socialmeaning of this important phase of genetic research.Heritability is a sound measure of the influence of genes on variation in existing environments. It is invaluablein establishingthe presenceof the genesin the first place. Until the r96os,for example,schizophreniawas thought to be a result of what parents,especiallymothers,do to their children in the first three years of their lives. Until the r97os autism was also thought to be an environmental disorder.Now, thanks to heritability studies,we know that in both disabilitiesgenesplay a significantrole. In the reversedirection, alcoholism was once assumedto be largely inherited, so much so that careful heritability studieswere not conducted until the r99os.Now we know that alcoholism is only moderately heritable in malesand scarcelyat all in females. Still, except for the rare behavioral conditions approaching total genetic determination,heritabilities are at bestrisky predictorsof personal capacity in existing and future environments.The examplesI have cited also illustratethe danger of using them as measuresof the worth of either individuals or societies.The messagefrom geneticists to intellectualsand policy-makersis this: Choosethe societyyou want to promote, then prepare to live with its heritabilities. Never favor the reverse,of promoting social policies just to change heritabilities. For best results,cultivateindividuals,not groups.

I H ev n p u r these ideasfrom genetics in play so as to clarifl' the vexing differences between nurfurists and hereditarians, and to try to establisha common ground betweenthem. Until that much is accomplished, the searchfor consilience risksbeing sidetrackedby endless ideological bickering,with adversaries who promote different political

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and social agendas talking past one another. Nurturists traditionally emphasizethe contributions of the environment to behavior,while hereditariansemphasizethe genes.(Nurturists are sometimescalled environmentalists,but that label hasbeen preemptedby protectorsof the environment;and hereditarianscannot be called naturists,unless they hold their conferencesin the nude.) Redefined with the more preciseconceptsofgenetics,nurturistscan now be seento believethat human behavioral genes have very broad norms of reaction, while hereditarians think the norms are relatively narrow. In this sensethe differencebetweenthe two opinionsis thus one of degree,not of kind. It becomesa matter that can be settled and agreed upon empirically, should the adversaries agreeto take an objectiveapproach. Nurturists have also traditionally thought that the heritability of intelligenceand personalitytraits is low, while hereditarianshave consideredit to be high. That disagreementhas been largelyresolved.In contemporaryCaucasiansof Europe and the United Statesat least, heritability is usually in mid-range, with its exact value varying from one hait to another. Nurturists think that culture is held on a very long genetic leash, if held at all, so that the cultures of different societies can diverge from one anotherindefinitely.Hereditariansbelieve the leashis short,causing cultures to evolve major featuresin common. This problem is technicallylesstractablethan the first two, but it is also empirical in nature, and in principle can be solved. I will take it up again shortly, and give severalexamplesthat illustrate how a resolution can in fact be reached. There is alreadyat leastsomecommon ground to build upon. Nurturists and hereditarians generally agreethat almost all the differences between cultures are likely to be the product of history and environment. While individuals within a particular society vary greatly in behavioral genes, the differences mostly wash out statistically bebveen societies.The culture of the lGlahari huntergatherers is very distinct from that of Parisians,but the differencesbetween them are primarily a resultof divergencein historyand environment, and are not genetic in origin.

Tnn ct.lnrFrcATroN oF normsofreactionand heritability,while admittedly a bit technical and dry, is the crucial first step toward

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unbraiding the rolesof heredityand environment in human behavior, and hence important for the attainment of consilienceof biolog, with the social sciences.The logical next step is the location of the genes that affect behavior.Once geneshave been mappedon chromosomes and their pathwaysof expressionidentified, their interactionwith the environment can be more preciselytraced. When many such interactionshave been defined,the whole can be braidedback again to attempt a more completepicture of mental development. The stateof the art in human behavioralgenetics,including its still formidable difficulties in gene mapping, is illustratedby the study of schizophrenia.This most common of psychosesaffiicts just under r percent of people in populationsaround the world. The symptomsof schizophrenia are highly variable from person to person. But they shareone diagnostictrait: mental activity that consistentlybreakswith reality.In some casesthe patient believeshe is a greatpersonage(the Messiah is a popular choice) or the target of a clever and pervasive conspiracy.In others,he hallucinatesvoicesor visions,often bizarre,as in a dream while fully awake. In 1995 independent groups of scientistsachieved three breakthroughs while probing the physical origins of schizophrenia.Neurobiologists at the University of California in Irvine discoveredthat during fetal developmentsome nerve cells in the prefrontal cortex of future schizophrenics fail to communicate with other cells required for normal exchangeswith the restof the brain. In particular,the cells are unable to manufacturemessengerRNA moleculesthat guide synthesis of the neurotransmitter GABA, or gamma aminobutyric acid. With GABA missing, the nerve cells cannot function, even though they look normal. In somemanner still unknown, the impairmentpromotes internal mental constructions with no connection to external stimuli or ordinary rational thought. The brain createsa world of its own, asthough closedoffin sleep. In the same year a second team from Cornell University and two medical research centers in England reported the first direct observation of brain activity in hallucinating schizophrenicpatients.Using positron emissiontomography(PET) imaging, the investigators monitored activesitesin the cortexand limbic systemsof patientsduring periods of both normal and psychotic activity. In one case,they watched a male patient'sbrain light up while (accordingto his testimony)disembodied headsrolled through his mind barking orders.The region

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responsiblefor the most abnormal eventsis the anterior cingulate cortex, a region thought to regulate other portions ofthe cerebral cortex. Its malfunction evidently diminishes the integration of external information and provokeserratic,dreamlikeconfabulationby the wakened brain. What is the ultimate causeof schizophrenia?For yearsdata from twin and family-history studies have suggestedthat the malfunction has at least a partially genetic origin. Early attempts to locate the responsiblegenes misfired; particular chromosomeswere tentatively identified as sites of schizophreniagenes, but then further studies failed to duplicate the results.In 1995,four independent research groups,using advancedchromosome mapping techniqueson large samplesof subjects,placed at least one gene responsiblefor schizophrenia on the short arm of chromosome6. (Humans havezz pairs of chromosomesin addition to the sexchromosomesX and I each of the pairs of chromosomesis arbitrarily assigneda different number for easy reference.)Two other groupsfailed to confirm the result, but as I write two yearslater the weight of evidencefrom the four combined positive testshasled to wide acceptanceof their conclusion as to the probable placementof at leastone of the schizophreniagenes. These recent advancesand others have cleared the way toward an eventual understanding, not merely of one of the most important mental diseasesbut of a complex piece of human behavior. Although the behavior can in no way be called normal, it affectsthe evolution of culture. From the delusionsand visionsof madmen have come some of the world's despotisms,religious cults, and great works of art. The codified responsesof societies to extreme strangenesshave furthermore been part of the culture of the many societiesthat regard schizophrenics aseither blessedby godsor inhabited by demons. But surely,you may respond,culture is still basedmainly on normal responses,not insanity. Why has so little progressbeen made on love, altruism, competitiveness, and other elementsof everydaysocial behavior?The answerlies in the pragmatic bias of genetic research. Geneticistswho study inheritance and developmentfirst look for big effectscausedby single mutations, those easyto detect and analyze. In the classicalperiod of Mendelian genetics,for example,they began with instantly recognizable haits, such as vestigial wings in drosophila fruit fliesand wrinkled seedcoatsin gardenpeas.It so happensthat big mutations are also harmful mutations, for the same reason that large

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random changes in an automobile engine are more likely to stall it than small random changes.Big mutations almost alwaysreduce survival ratesand reproductivecapacity.Much of pioneeringhuman genetics has therefore been medical genetics,as exemplified by the studiesof schizophrenia. The practical value of the approach is beyond question.The use of large effectshas been parlayedmany times into important advancesin medical research.Over r,zoophysicaland psychologicaldisordershave been tied to single genes.They range (alphabetically) from AarskogScott syndrometo Zellwegersyndrome.The resultis the OGOD principle: One Gene, One Disease.So successfulis the OGOD approach that researchersjoke about the Diseaseof the Month reported in scientific journalsand mainstreammedia.Considerthis diversesetof examples:color blindness,cysticfibrosis,hemophilia, Huntington'schorea, hypercholesterolemia,Lesch-Nyhan syndrome, retinoblastoma,sicklecell anemia.And so pervasiveis the evidenceof the origin of pathologies in single and multiple gene deviations-even cigarettesmoking has a discernibleheritabilig-that biomedical scientistslike to quote the maxim that "all diseaseis genetic." Researchersand practicing physiciansare especiallypleasedwith the OGOD discoveries,becausea singlegene mutation invariablyhas a biochemical signahrrethat can be used to simplify diagnosis.Becausethe signatureis a defectsomewherein the sequenceof molecular events entrained by transcription offthe affectedgene, it can often be disclosedwith a simple biochemical test. Hope also risesthat genetic diseasecan be corrected with magic-bullet therapy,by which one elegant and noninvasiveprocedure corrects the biochemical defect and erasesthe symptoms of the disease. For all its early success,however,the OGOD principle can be profoundly misleading when applied to human behavior. While it is hue that a mutation in a single gene often causesa significantchangein a trait, it does not at all follow that the gene determinesthe organ or processaffected. Typically, many genes conhibute to the prescription of each complex biological phenomenon.How many?For that kind of information it is necessaryto hrrn from human beingsto the house mouse,which, being a prime laboratoryanimal with a short life span, is genetically the best known of all the mammals. Even here knowledge is sketchy. In the mouse, genesconhibuting to the texture of the hairs and skin are known from no fewer than seventy-twochromosome

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sites.At least forty-one other geneshave variants that cause defectsin the organ of balance in the inner ear, resulting in abnormal head shaking and circling behavior. The complexity of mouse heredity is a clue to the difficulties still facing human genetics.Whole organsand processes,as well as narrowly defined featureswithin them, are commonly prescribed by ensemblesof genes,each of which occupiesa different arrayof positions on the chromosomes.The difference in skin pigmentation between people of African and European ancesbyis believed to be determined by three to six such "polygenes."The estimatesfor this and other such systemsmay be on the low side. In addition to the more potent genes, which are easierto detect, there can be many others that contribute small portions of the variation observedand thus remain undiscovered. It follows that a mutation in any one of the polygenes might produce a large, overriding OGOD effect, or it may prescribe a much smaller quantitativedeviation from the averuge.The common occurrence of mutations of the second type is one reason that genes predisposingthe development of chronic depression,manic-depressive syndrome,and other disordershaveprovenso elusive.Clinical depression in Ireland, for example, may have at least a partially different gene-basedpredispositionfrom clinical depressionin Denmark. In such a case,careful researchin one laboratorythat locatesa gene site on one chromosome will fail to find confirmation by equally careful researchconductedin a secondlaboratory. Subde differences in environment can also distort the classic patterns of Mendelian inheritance. One common effect is the condition called incompletepenetrance.The trait appearsin one personbut not another, even though both possessthe same enabling genes. When one identical hvin developsschizophrenia,for example, the chance that the other twin will follow suit is only 5o percent, despite the fact that exactlythe samegenesare found in both. Another consequenceis variable expressivity.Those who develop schizophrenia have it in greatly varying form and intensity. To summarize,human behavioralgeneticsprovidesone of the crucial links in the track from genesto culture. The discipline is still in its infancy, and hampered by formidable theoretical and technical difficulties. Its principal methods are classicaltwin studies and family-tree analysis,gene mapping, and, most recently, DNA sequenceidentification. These approacheshave so far been but crudely ioined. fu their

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synthesisproceedsand is supplementedby studiesof psychologicaldevelopment, a clearerpicture of the foundationsof human nature will emerge.

MseNwHIre , what we know or (to be completelyforthright)what we think we know, about the hereditarybasisof human nature can be expressedby linking togetherthree determininglevelsof biological organization. I will presentthem from the top down, in a sequencethat begins with the universalsof culture, proceedsto epigenetic rules of social behavior,and endsin a secondlook at behavioralgenetics. In a classic 1945 compendium, the American anthropologist George P. Murdock listed the universalsof culture, which he defined as the social behaviorsand institutionsrecordedin the Human Relations Area Files for every one of the hundredsof societiesstudied to that time. There are sixty-sevenuniversalsin the list: age-grading,athletic sports,bodily adornment, calendar,cleanlinesstraining, community organization, cooking, cooperative labor, cosmology, courtship, dancing, decorativeart, divination, division of labor, dream interpretation, education, eschatology,ethics, ethno.botany,etiquette, faith healing, family feasting, fire-making, folklore, food taboos, funeral rites, games, gestures,gift-giving, government, greetings, hair styles, hospitality, housing, hygiene, incest taboos, inheritance rules, ioking, kin groups,kinship nomenclature, language,law, luck superstitions, magic, marriage,mealtimes, medicine, obstetrics,penal sanctions, personal names, population policy, postnatal care, pregnancy usages, proper$ rights, propitiation of supernatural beings, puberty customs, religious rifual, residence rules, sexual restrictions, soul concepts, stafus differentiation, surgery, tool-making, trade, visiting, weather conhol, and weaving. It is tempting to dismiss these haits as not huly diagnostic for human beings,not really genetic, but inevitable in the evolution of an7 speciesthat attains complex societiesbasedon high intelligence and complex language,regardlessof their hereditarypredispositions. But that interpretation is easily refuted. Imagine a termite speciesthat evolved a civilization from the social level of a living species.Take for the purpose the mound-building termites Macrotermes bellicosusof Africa, whose citylike nestsbeneath the soil each contain millions of

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inhabitants.Elevatethe basicqualitiesof their socialorganizationin their presentdayinsectileconditionto a culture that is guided,as in epigeneticrules.The "termitenahuman culture, by heredity-based ture" at the foundation of this hexapodcivilization would include celibacyand nonreproductionby the workers,the exchangeof symbiotic bacteriaby the eatingof one another'sfeces,the useof chemical secretions(pheromones)to communicate,and the routine cannibalism of shedskinsand deador iniured family members.I havecomspeechfor a termiteleaderto posedthe following state-of-the-colony deliverto the multitude,in her attemptto reinforcethe supertermite ethicalcode: the mauotermitinetermites,achievedtenEversinceour ancestors, kilogramweightand largerbrainsduingtheir rapid evolutionthrough the late TertiaryPeriod,and leamedto write with pheromonalscript, termiticscholarshiphaselevatedand refinedethical philosophy.lt is of moral behaviorwith precithe imperatives now possibleto express areself+videntand universal.Theyarethe very sion.Theseimperatives of termitity.Theyincludethe loveof darknessand of the deep, essence penetraliaof the soil; the centrality of saprophytic,basidiomycetic colonylife amidstthe ichnessof warand tradewith othercolonies;the the evil of personalrights(the castesystem; sanctityof the physiological royal the siblingsallowedto reprois N,L!); our love deep colony for duce;the ioy of chemicolsong;the aestheticpleasureand deepsocial of eatingfecesfrom nestmates'anusesafter the shedding satisfaction of cannibalismand surrenderof our own of our skins;and the ecstasy bodieswhenwe dre sickor iniured(it is moreblessedto be eatenthan to eat).

isthedualori Funtsnn EvIDENcE of humanculturaluniversals gin of civilizationin the Old andNewWorlds,evolvedin mutualisolain broaddetail. The secondpart of tion yet remarkablyconvergent "the grand experiment"begantwelvethousandor more yearsago, when the New World wasinvadedby nomadic tribesfrom Siberia. The colonistswereat that time Paleolithichuntergathererswho most likely lived in groupsof a hundredor fewer.In the centuriesto follow theyspreadsouththroughthe lengthof the New World,from the fuctic tundra to the icy forestsof Tierra del Fuego ten thousandmiles

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distant, splitting as they went into local tribes that adapted to each of the land environments they encountered. Along the way, here and there,some of the societiesevolvedinto chiefdomsand imperial states remarkablysimilar in their basic structure to thosein the Old World. In r94o the American archaeologistAlfred V. Kidder, a pioneer student of early North American settlements and Mayan cities, summarized the independent histories of civilization in the Old and New Worlds to make the casefor a hereditary human nature. In both hemispheres,he said,peoplestartedfrom the samebaseasstone-ageprimitives. First they brought wild plants under cultivation, allowing their populations to increaseand form villages.While this was happening they elaboratedsocialgroupingsand evolvedsophisticatedartsand religions, with priestsand rulers receiving specialpowersfrom the gods. They invented pottery and wove plant fibers and wool into cloth. They domesticated local wild animals for food and transport. They worked metal into tools and ornaments, first gold and copper, then bronze, the harder alloy of copper and tin. They inventedwriting and used it to record their myths, wars, and noble lineages.They created hereditary classesfor their nobles, priests, warriors, craftsmen, and peasants.And, Kidder pointed out, "In the New World aswell as in the Old, priesthoods grew and, allying themselveswith temporal powers, or becoming rulers in their own right, reared to their godsvasttemples adorned with painting and sculpture. The priesb and chiefsprovided for themselveselaboratetombs richly stockedfor the future life. In poIitical history it is the same.In both hemispheresgroup joined group to form tribes; coalitions and conquestsbrought preeminence;empires grew and assumedthe paraphernalia of glory."

Iupnusslvu es the universals may be, it is still riskyto usethem as evidence of the linkage between genes and culture. While the categories listed occur too consistentlyto be due to chance alone, their finer details differ widely among societies within and between the hemispheres.The hallmarksof civilization are moreovertoo scattered and recent in origin to have been genetically evolvedand somehow carried around the world by huntergatherers. It would be absurd to speakof particular genesthat prescribe agriculture, writing, the priesthood, and monumental tombs. In my own writings, from On Human Nature in 1978 forward, I

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havearguedthat the etiologyof culturewendsits waytortuouslyfrom to learningandsocialbehavior. thegenesthroughthebrainandsenses What we inherit are neurobiologicaltraits that causeus to seethe in preference worldin a particularwayandto learncertainbehaviors inheritedtraitsarenot memes,not The genetically to otherbehaviors. unitsof culture, but ratherthe propensityto invent and transmitcerto others. of memoryin preference tainkindsof theseelements had fu early as LgTzMartin Seligmanand other psychologists They calledit "prepared precisely. definedthe biasin development By thisconcepttheymeantthatanimalsandhumansareinlearning." natelypreparedto learn certain behaviors,while being counterto avoid-others.The many preparedagainst-that is, predisposed of epigelearning form a subclass prepared examples of documented the full rules comprise in biology,epigenetic neticrules.As recognized rangeof inheritedregularitiesof developmentin anatomy,physiology, cognition,and behavior.They arethe algorithmsof growthand differentiationthat createa fully functioningorganism. A secondproductiveinsight,contributedby sociobiology,is that ofepigenesis, like all otherclasses learningofsocialbehavior, prepared is usuallyadaptive:It confersDarwinianfitnesson organismsby imof the epigeprovingtheir survivalandreproduction.The adaptiveness result of either exclusive netic rulesof human behavioris not the of both.One of fromsubtlemanifestations biologyor culture.It arises the mostefficient waysto studythe epigeneticrulesof human social behavioris by methodsof conventionalpsycholory,informedby the conprocess. For this reasonthe scientists principlesof evolutionary evolutionarypsycholocenhatingon the subiectoftencall themselves drawnfrom bothsociobiology-the gists.Theirsis a hybriddiscipline, of socialbehaviorin all kindsof the basis studyof biological systematic organisms,including humans-and psychology,the systematicstudy of the basisof human behavior.Given our growingunderstandingof gene-culturecoevolution,however,and in the interestof simplicity, couragein thefaceof ideologclarity,and-on occasion-intellectual ical hostility,evolutionarypsychologyis bestregardedas identical to humansociobiologr.

altruismwasthe in my earlysyntheses, IN rnn t97os, asI stressed cenhal problem of sociobiologyin both animalsand humans.That

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challenge has now been largely met by successfultheory and empirical research.In the r99os attention is beginning to shift in human sociobiology to gene-culture coevolution. In this new phase of research,the definition of epigeneticrules is the bestmeansto make important advancesin the understandingof human nature. Such an emphasisseemslogically inescapable.The linkagebetweengenesand culture is to be found in the senseorgansand programsof the brain. Until this processis betterknown and taken into account,mathematical models of genetic evolution and cultural evolution will have very limited value. The epigeneticrules,I believe,operate,like emotion,at two levels. Primary epigeneticrules are the automatic processes that extendfrom the filtering and coding of stimuli in the senseorgansall the way to perception of the stimuli by the brain. The entire sequenceis influenced by previous experienceonly to a minor degree,if at all. Secondary epigenetic rules are regularities in the integration of large amounh of information. Drawing from selected fragments of percep tion, memory, and emotional coloring, secondaryepigenetic rules lead the mind to predisposeddecisionsthrough the choice of certain memes and overt responsesover others. The division between the two classes of epigeneticrulesis subjective,made for convenienceonly. Intermediatelevels of complexity exist,becausemore complex primary rulesgradeinto simpler secondaryrules. All of the sensesimposeprimary epigeneticrules.Among the most basic propertiesof such rules is the breaking of otherwisecontinuous sensationsinto discreteunits. From birth, for example,the cones of the retina and the neuronsof the lateralgeniculatenuclei of the thalamus classifi,visible light of differing wavelengthsinto four basic colors. In similar manner, the hearing apparatusof both children and adults automatically divides continuous speechsoundsinto phonemes.Series of sounds that run smoothly ftom ba to ga arenot heard as a continuum but either as bd or ga; the same is true of the transition from vtos. An infant begins life with other built-in acoustic responsesthat shape later communication and social existence.The newborn can distinguish innately between noise and tone. By four months the infant prefers harmonious tones,sometimes reacting to out-of-tune notes with a facial expressionof disgust,the same,it turns out, aselicited by a drop of lemon juice on the tongue.The newborn'sresponseto a loud

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soundis the Moro reflex:If on its back,the infantfirst extendsits arms forward,bringsthem slowlytogetheras though in embrace,emits a cry and then graduallyrelaxes.In four to sixweeksthe Moro reflexis earlier,is the which, asI described replacedby the startleresponse, and lastsfor the remainderof life. Within mostcomplexof the reflexes loud noiseis heard,the eyes a fractionofa secondafteran unexpected the shouldersand armssag, the head drops, close,the mouth opens, is positionedasthough body the kneesbuckleslightly.Altogether,the to absorba comingblow. in chemicaltastealsobegin at or shordyafter Somepreferences bi*h. Newbornsprefersugarsolutionsoverplain waterand in the folTheyreiectsubglucose. lactose, fructose, lowingfixedorder:sucrose, stancesthat are acid, salty,or bitter, respondingto each with the theywill usefor the restof their lives. distinctivefacialexpressions The primary epigeneticrules gear the human sensorysystemto process mostlyaudiovisualinformation.The predilectionis in contrast which dependmostlyon to that of the vastmaiorityof animal species, smelland taste.The humanaudiovisualbiasis reflectedby the disproportionateweightingof vocabulary.In languagesaround the world, from English and fapaneseto Zulu and Teton Lakota,two-thirdsto three-fourthsof all the wordsdescribingsensoryimpressionsrefer to hearingand vision.The remainingminority of wordsare divided includingsmell,taste,and touch,aswell as amongthe othersenses, humidity,and electricalfields. sensitivityto temperature, Audiovisualbiasalsomarksthe primaryepigeneticrulesthat estabhave lish socialbondsin infancyand earlychildhood'Experiments shownthat within ten minutesafter birth, infantsfixatemore on normal facial designsdrawnon postersthan on abnormaldesigns.After two days,they preferto gazeat their mother ratherthan other, unknownwomen.Other experimentshaverevealedan equallyremarkable ability to distinguishtheir mother'svoice from voicesof other women.For theirpar! mothersneedonly a brief contactto distinguish the cry of their newborns,aswell astheir personalbodyodor. The faceis the chiefarenaof visualnonlinguisticcommunication epigeneticrulesthat biastheir psychologicaldeveland the secondary have invariantmeaningthroughout opment.A few facialexpressions the human species,eventhough they are modified in different cultures to expressparticularnuances.In a classicexperimentto test the universalityof the phenomenon,PaulEkmanof the Universityof

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California at San FranciscophotographedAmericansasthey actedout fear, loathing, anger, surprise, and happiness. He also photographed New Guinea highland tribesmenfrom recently contactedvillagesas they told storiesin which similar feelingswere evoked.When individuals were then shown the portraitsfrom the other culture, they interpretedthe facial expressions with an accuracygreaterthan 8o percent. Within the face the mouth is the principal instrument of visual communication.The smile in particularis a rich siteof secondaryepigenetic rules. Psychologistsand anthropologistshave discoveredsubstantial degreesof similar programmed development in the usesof smiling acrosscultures.The expressionis first displayedby infantsbetween the agesof two and four months. It invariably attractsan abundance of affection from attending adults. Environment has little influence on the maturation of smiling. The infants of the lKung, a hunter-gathererpeople of South Africa'sKalahari desert,are nurtured under very different conditions from those in America and Europe. They are delivered by their motherswithout assistanceor anesthetic, kept in almost constant physical contact with adults, nursedseveral times an hour, and trained rigorouslyat the earliestpossibleageto sit, stand,and walk. Yet their smile is identical in form to that of American and European infants, appearsat the sametime, and servesthe same social function. Smiling also appearson schedule in deaf-blindchildren and even in thalidomidedeformed children who are not only deaf and blind but also crippled so badly they cannot touch their own faces. Throughout life smiling is usedprimarily to signalfriendlinessand approval,and beyondthat to indicatea generalsenseofpleasure.Each culhrre molds its meaning into nuances determined by the exact form and the context in which it is displayed.Smiling can be turned into irony and light mockery or to conceal embarrassment.But even in such casesits messagesspan only a tiny fraction of those transmittedby all facial expressions taken together. At the highest levels of mental activity complex secondaryepigenetic rules are followed in the processcalled reification: the telescoping of ideas and complex phenomena into simpler concepts,which are then compared with familiar obiectsand activities.The Dusun of Borneo-to take one of countlessexamplesfrom the archivesof anthropolory-reif' each house into a "body" possessing arms,a head, a belly, legs, and other parts. It is believed to "stand" properly only if

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alignedin a certaindirection;it is thoughtto be "upsidedown" if built asfat the houseis classified on the slopeof a hill. In otherdimensions or skinny,young or old and worn-out.All its interior detailsare investedwith intensemeaning.Everyroomandpieceof furnitureis connectedto calendricritualsandmagicalandsocialbeliefs. Reificationis the quick and easymental algorithm that creates orderin a world otherwiseoverwhelmingin flux and detail. One of its to usetwo.partclasisthe dyadicinstinct,theproneness manifestations everywhere Societies sificationsin treatingsociallyimportantarrays. breakpeopleinto in-groupversusout-group,child versusadult, kin versusnonkin,marriedversussingle,andactivitiesinto sacredandprofane,goodand evil. They fortify the boundariesof eachdivisionwith tabooand ritual.To changefrom onedivisionto the otherrequiresiniordinations,and otherritesof weddings,blessings, tiation ceremonies, passage that markeveryculture. and other writers The FrenchanthropologistClaudeL6vi-Strauss "structuralist" that the schoolhe helpedfound havesuggested of the binary instinct is governedby the interactionof inborn rules.They and posit oppositionssuch as man:woman,endogamy:exogamy, ascontradictionsin the mind that must be met and reearth:heaven solved,oftenby my"thicnarrative.Thus the conceptof life necessitates the conceptof death,which is resolvedby the myth of deathservingas the gatewayto eternallife. Binaryoppositions,in the full-dressstructuralistversion,are linked still further into complexcombinationsby into integratedwholes. which culturesareassembled The struchrralistapproachis potentiallyconsistentwith the picture of mind and culture emergingfrom naturalsciencesand biologi within but it hasbeen weakenedby disagreements cal anthropology, concerningthe bestmethods themselves the ranksof the structuralists Theirproblemis notthebasicconception,insofarasI have of analysis. beenableto understandthe massiveand diffuseliterature,but its lack of a realisticconnectionto biolog' and cognitivepsychology.That mayyetbe achieved,with potentiallyfruiffirl resulb.

N ow ro tHs nextstepin the searchfor humannature,the genetic basisof the epigeneticrules.What is that basis,and how much variaAsa cautionarypreludeto an antion istherein theprescribinggenes? swer,let me again shessthe limitations of the geneticsof human

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behavior as a whole. Human behavior geneticsis an infant field of study and still vulnerable to ideologueswho would be unkind to it in pursuit of their personal agendas.In only one level of analysis,the estimation of heritability, can it be said to be an advancedscientific discipline. With sophisticatedstatisticaltechniques,geneticistshave calculatedthe proportionatecontributionsofgenesacrossa large array of traits in sensoryphysiologr, brain function, personality, and intelligence. They have arrived at this important conclusion: Variation in virtually everyaspectof human behavioris heritable to some degree, and thus in some manner influenced by differencesin genesamong people.The finding should come asno surprise.It is equallytrue of behavior in all animal speciesthat have beenstudiedto date. But the measurementof heritability does not identift particular genes.Nor doesit provide us with a hint of the intricate pathwaysof physiologicaldevelopment leading from the genesto the epigenetic rules. The principal weaknessof contemporaryhuman behavioralgenetics and human sociobiologyis that only a small number of the relevant genesand epigenetic rules have been identified. This is not to deny that many othersexist-quite the contrary-only that they have not yet been identified and pinpointed in geneticmaps.The reasonis that human behavioral genetics is technically very difficult at this level. The paucity of exampleshas another, heightened consequence. Becauseboth the genesaffecting epigenetic rules and the rules themselvesare usually searchedout independently by different teams of researchers,matches between genes and epigenetic rules are even rarer. They come to light mostly by sheer luck. Suppose,at a guess,that r percent of the relevant genes and ro percent of the epigenetic rules have been discoveredup to the present time. The number of matches would be asfew asthe multiple of the two percentages,in this caseone tenth of r percent. The scarcity of matches is less a failing, however, than an opportunig for scientific discoverywaiting to be seized. It is precisely in this domain, on the frontier between biology and the social sciences,that some of the most significantprogressin studiesof human behaviorcan be expectedto occur. Among the known gene mutations affecting complex behavior is one that causesdyslexia,a reading disorderproduced by impairment of the ability to interpret spatial relationships. Another reduces performance on three psychological tests of spatial ability but not on three

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otherteststhat measureverbalskill, speedat perception,and memory. Genesaffectingpersonalityhavealsobeendiscovered. A mutationinducing outburstsof aggressive behavior,still known only in a single Dutch family,has been locatedon the X chromosome.It evidendy causesa deficiencyin the enzpe monoamineoxidase,neededto breakdownneurotransmitters that regulatethe fight-or-flightresponse. Because the neurotransmitters accumulateasa resultof this deviation, the brainremainskeyedup, preparedto respondviolentlyto low levels of shess.A more normal variantof personalityis broughtaboutby a "novelty-seeking gene,"which altersthe brain'sresponseto the neuro. transmitterdopamine.Personspossessing the genewhen given standardtestsarefound to be more impulsive,curiosity-prone, and fickle. The moleculesof the geneand the proteinreceptorit helpsprescribe are longerin molecularlength than the unmutatedforms.They are alsowidespread, havingbeendetectedin differentethnic groupsboth in Israeland in the United States(but not in a Finnish group).A varietyof othergenevariantshavebeendiscovered that changethe metab olism and activityof neurotransmitters, but their effectson behavior awaitinvestigation. I do not mean to suggestby citing theseexamplesthat it is only necessary to discoverand list genesoneby one in orderto establishthe geneticbasisof human behavior.The mappingof genesis justthe beginning.Most traits,including eventhe simplestelementsof intelligenceandcognition,areinfluencedby polygenes, which aremultiple genesspreadacrossdifferentchromosomesitesand actingin concert. In somecasespolygenes simplyaddtheir effects,sothat moregenesof a certainarraymeansmore of the product-more of a transmifter,say, or a higherconcentrationof skinpigment.Suchadditiveinheritance, asit is called,typicallyproducesa bell-shaped curvein the dishibution of the trait in the populationasa whole.Other polygenesaddup until they reach a certain threshold number, at which point the trait emergesfor the firsttime. Diabetesand somemental disordersappear to belongto this class.Finally, polygenescan interact epistatically: The presenceof a geneat one chromosomesitesuppresses the action of a geneat anotherchromosomesite.Brainwavepatternsasrevealed (EEGs) are an exampleof a neurological in elechoencephalograms phenomenoninheritedin this manner. Finally,to complicatemattersfurther,thereis pleiohopy,the prescriptionof multipleeffectsby a singlegene.A classichuman example

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of pleiotropyis providedby the mutantgenethat causesphenylkeof which includean excess of the aminoacid tonuria,the symptoms phenylalanine, a deficiencyof tyrosine,abnormalmetabolicproducts of the urine,lighteningof hair color,toxic of phenylalanine, darkening damageto the cenhalneryoussystem, and-mental retardation. The pathways from the genesto the traitstheyprescribemay seem A largepart convoluted. Still,theycanbedeciphered. overwhelmingly of future human biologywill consistof tracingthe developmentof bodyand mind theyinfluence.In the firsttwo decades of the coming stayson track,wewill seethe completesecentury if currentresearch quencingof the humangenomeand a mappingof mostof the genes. Furthermore,the modesof inheritancearescientifically manageable. traitsis fiThe numberof polygenes controllingindividualbehavioral nite,with thoseresponsible for mostof thevariationoftenbeingfewer than ten. The multiple effectsof singlegenesare alsofinite. They will be definedmorefully asmolecularbiologists tracethe cascades of chemical reactionsentrainedby groupsof genes,and as neuroscientistsmap the patternsof brain activitythat are amongthe final productsof thesereactions. For the immediatefuture the geneticsof human behaviorwill travel behind two spearheads. The first is researchon the heredityof mentaldisorders, andthe secondis research on genderdifference and sexualpreference.Both classesare favoredby shongpublic interest and have the further advantageof entailing processes that are well marked,hencerelativelyeasilyisolatedandmeasured. They fit a cardinal principlein theconductof scientificresearch: Find a paradigmfor which you canraisemoneyand attackwith everymethodof analysisat your disposal. Gender differencesare an especiallyproductiveparadigm,even though politically controversial.They arealreadyrichly describedin the psychologicaland anthropologicalliterature. Their biological foundationsarepartlyknown,havingbeendocumentedin the corpus callosum and other brain structures;in patternsof brain activity; in smell, taste,and other senses;in spatialand verbalability; and in innate play behaviorduring childhood.The hormonesthat mediate the divergenceof the sexes,resulting in statisticaldifferenceswith overlap in thesevarioushaits, are relativelywell understood.The major gene that higgerstheir ultimate manufactureduring fetal and childhooddevelopment hasbeenlocatedon theY chromosome. It is

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calledSry,for sex-determining regionofY. In its absence, when the individualhastwo X chromosomes ratherthan an X and I the fetal go. nadsdevelopinto ovaries,with all the consequences that follow in endocrineandpsychophysiological development. Thesefactsmaynot satisfi,everyone'sideologicalyearning,but they illushate in yet anotherwaythat,whetherwe like it or not, Homosapiensis a biological species.

To rnls porNr I havehacedmostof the stepsof gene-culture coevolution,circlingfrom genesto culture and backaroundto genes,as evidenceallows.Thesestepscanbe summedup verybrieflyasfollows: CenesprescibeepigeneticruIes,which arethe regularitiesof sensory perceptionand mentaldevelopment that animateand channelthe acquisitionof culture. Culture helpsto determinewhich of the prescibinggenessumive and multiplyfromonegeneration to thenext. Successful newgenesaltertheepigeneticrulesof populations. Thealteredepigenetic ruleschangethedirectionand ffictivenessof thechannelsof culturalacquisition. The final stepin this seriesis the mostcrucialand contentious.It is embodiedin the problem of the geneticleash.Throughout prehistory particularlyup to a hundred thousandyearsago, by which time the modernHomosapiensbrain had evolved,geneticand culhrral evolutionwere closelycoupled.With the adventof Neolithic societies,and especiallythe rise of civilizations,cultural evolution sprintedaheadat a pacethat left geneticevolutionstandingstill by comparison.So, in this lastexponentialphase,how far apartdid the epigeneticrulesallowdifferentculturesto diverge?How tight wasthe geneticleash?That is the keyquestion,and it is possibleto giveonly a partialanswer. In general,the epigeneticrulesarestrongenoughto be visiblyconstraining.They haveleft an indelible stampon the behaviorof people in eventhe mostsophisticated societies.But to a degreethat mayprove discomfitingto a diehardhereditarian,cultureshavedispersedwidely in their evolutionunderthe epigeneticrulessofar studied.Particular featuresof culturehavesometimesemergedthat reduceDarwinianfitness,at leastfor a time. Culture can indeedrun wild for a while. and evendestroythe individualsthat fosterit.

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TH s s s sr wAy to expressour still very imperfect knowledgeof the transitionfrom the epigeneticrules to cultural diversityis to describe real cases.I will offer two such examples,one relativelysimple, the other complex. The simple first. If all verbal communication were strippedaway, we would still be left with a rich paralanguagethat communicates most of our basic needs: body odors,blushing and other telltale repostures,gesticulations,and nonverbalvocalflexes,facial expressions, izations. all of which. in various combinations and often without consciousintent, composea veritable dictionary of mood and intention. They are our primate heritage,having likely persistedwith little change since before the origin of language.Although the signalsdiffer in detail from one culture to the next, they contain invariantelements that revealtheir ancient geneticorigin. For example: . Anstrostenolis a male pheromone concentratedin perspiration and freshurine. Perceivedvariouslyasmusk or sandalwood,it changes sexualattractionand warmth of mood during socialcontacts. . To touch another is a form of greeting regulated by the following innate rules: Touch strangersof the same sexon the arms only, spreading to other parts of the body as familiarity increases,the more so for intimates of the opposite sex. . Dilation of the pupils is a positive responseto others,and one especiallyprominent in women. . Pushing the tongue out and spitting are aggressivedisplaysof rejection; ficking the tongue around the lips is a social invitation, used most commonly during flirtation. . Closing the eyesand wrinkling the noseis another universalsign of rejection. . Opening the mouth while pulling down the corners of the mouth to exposethe lower teeth is to threaten with contempt. These and other nonverbal signals are ideal subiects for understandingthe coevolution of genesand culture. A great deal is already known of their anatomy and physiology;and their geneticprescription

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and controlling brain activity are likely to prove simple in comparison with verbal communication.The variation in meaning of each signal in turn caused by cultural evolution can be observedby its multiple usesacrossmany societies.Each signal has its own amount of such variation, its own flexibility and resulting scatter of nuance acrossthe cultures of the world. Put another way, each set of genes prescribing the basic structure of particular signalshas its own norm of reaction. The culture of nonverbal signals awaitsshrdy from this comparative viewpoint. An instinctive caseof moderatedispersionis that of eyebrow flashing, one of many examplesprovided by the pioneering German ethologistlrendusEibl-Eibesfeldt.when a person'sattention is caught, he opens his eyes widely to improve vision. When he is surprised, he opens his eyes very widely, while lifting the eyebrows conspicuously.Eyebrow lifting has been universallyritualized, presumably by genetic prescription,into eyebrowflashing, a signal that invites social contact. By ritualization is meant the evolution of a movementwith a function in one context,in this caseeye opening and eyebrowlifting, into a conspicuous,stereotypedform, in this caseeyebrow flashingusedfor communication.That is the genetic part of the gene-culturecoevolution.Eyebrowflashinghasalsobeen subiectedto moderatedispersionof meaning acrosssocietiesby the cultural part of gene-culture coevolution. In different societiesand contexts it is combined with other forms of body languageto signal greeting, flirtation, approval, requestfor confirmation, thanking, or emphasis of a verbal message.In Polynesiait is usedasa factual"yes." The secondcaseof gene-culturecoevolutionI wish to present,because it is the most thoroughly researchedof the more complex examples to date, is color vocabulary. Scientistshave traced it all the way from the genesthat prescribe color perception to the final expression ofcolor perceptionin language. Color doesnot existin nafure.At least,it doesnot existin nature in the form we think we see.Visible light consistsof continuously varying wavelength,with no intrinsic color in it. Color vision is imposed on this variation by the photosensitivecone cells of the retina and the connecting nerve cells of the brain. It begins when light energy is absorbed by three different pigments in the cone cells, which biologists have labeled blue, green, or red cells according to the photor.rrritiu. pigments they contain. The molecular reaction triggered by the light energy is transduced into electrical signals that are relayed to the

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retinalganglioncellsformingthe opticnerve.Herethe wavelen$hinformationis recombinedto yield signalsdistributedalongtwo axes. The brain laterinterpretsone axisasgreento redandthe otherasblue to yellow,with yellowdefinedasa mixtureof greenand red.A particular ganglioncell,for example,maybe excitedby input fromredcones and inhibitedby inputfrom greencones.Howstrongan electricsignal it then transmitstellsthe brain how much red or greenthe retinais receiving. Collective information of this kind from vast numbersof conesand mediatingganglioncells is passedback into the brain, acrossthe optic chiasmato the lateralgeniculatenuclei of the thalaof nervecellscomposinga relaystationnear mus,which are masses of cellsin theprimaryvithe centerof the brain,and finallyinto arrays sualcortexat the extremerearof the brain. Within millisecondsthe visual information,now color-coded, deout to differentpartsof the brain.How the brainresponds spreads memories and the information pendson the input of other kindsof they summon.The patternsinvokedby manysuchcombinations,for example,may causethe personto think wordsdenotingthe patterns, suchas:"This is theAmericanflag;itscolorsarered,white,andblue." Keepthefollowingcomparisonin mind whenponderingtheseeming of human nature:An insectflying by would perceivedifobviousness and breakthem into differentcolorsor noneat all, ferentwavelengths, its species,and if somehowit could speak,its words dependingon would be hardto translateinto our own.Itsflagwould be verydifferent from our flag,thanksto its insect(asopposedto human)nature. The chemistryof the three cone pigments-the amino acidsof which they are composedand the shapesinto which their chainsare folded-is known.Sois the chemistryof theDNA in the geneson the X chromosomethat prescribethem,aswell asthe chemistryof the mutationsin the genesthat causecolorblindness. well understoodmolecularproSo, by inheritedand reasonably and brain breakthe continuously cessesthe human sensorysystem of visible light into the arrayof more or lessdisvaryingwavelengths creteunitswe call the color spectrum.The arrayis arbiharyin an ultimatelybiologicalsense;it is only one of manyarraysthat might have evolvedoverthe pastmillions of years.But it is not arbiharyin a cultural sense:Havingevolvedgenetically,it cannotbe alteredby learning or fiat. All of human culture involvingcolor is derivedfrom this

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ry5 unitaryprocess. Asa biologicalphenomenon colorperceptionexistsin conhastto the perceptionof light intensity,the otherprimaryquality of visiblelight. When we vary the intensityof light gradually,sayby moving a dimmer switch smoothly up or down, we perceivethe changeastle continuousprocessit truly is. But if we usi monochromaticlight-one wavelen$honly-and changethatwavelength gr"dually,the continuityis not perceived.What we see,in goingiro* th. short-wavelength endto the long-wavelenghend,is first a bioadband of blue (at leastonemoreor lessperceived asthatcolor),then green, then yellow,andfinally red. The creationof color vocabulariesworldwideis biasedby this samebiologicalconstraint. In a famousexperiment performedin the t96osat the universityof califomia at Berkeley,BrentBerlin andpaul Kay testedthe constraintin nativespeakers of twenty languages,includingArabic,Bulgarian,Cantonese, Catalan,Hebrew,Ibibio-,Thai, Tzeltal,and urdu. The volunteerswereaskedto describetheir color vocabulary in a directandprecisemanner.They wereshowna Munsellarray,a spreadof chipsvaryingacrossthe colorspectrumfrom left to right, and in brightnessfrom the bottomto the top, and askedto placeeachof the principalcolor termsof their languageon the chips closestto the meaningof the words.Eventhoughthe tirms varystrikingly from one languageto the nextin origin and sound;the speakers placedthem into clusterson the arraythat correspond, at leastapproximately,to theprincipalcolorsblue,green,yellow,and red. The intensityof the leamingbiaswasstrikinglyrevealedby an experimentconductedon color perceptionduring the late r96osby EleanorRosch,alsoof the universityof califomia at Berkeley.in looking for "naturalcategories" ofcognition, Roschexploitedthe fact that the Dani peopleof New Guinea haveno wordsto denotecolor: thev speakonly of mili (roughly,"dark") and,mola ("light").Roschconsideredthe followingquestion:If Dani adultssetout to learn a color vocabulary,would theydo so more readilyif the color termscorrespond to the principalinnatehues?In otherwords,would culturalinnovation be channeledto someextentby the innate geneticconshaints? Roschdivided68volunteerDani men into twogroups.Shetaughtone a seriesof newlyinventedcolor termsplacedon the principalhue categories of thearray(blue,green,yellow,red),wheremostof the natural vocabularies of otherculturesare located.she tauehta second

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group of Dani men a seriesof new terms placed off center, away from ihe main clustersformed by other languages.The first group of volunteers,following the "natural" propensitiesof color perception,learned about twice asquickly as thosegiven the competing,lessnatural color terms. They also selected these terms more readily when allowed a choice. Now comes the question that must be answered to complete the transit from genesto culture. Given the genetic basisof color vision and its generaleffect on color vocabulary how greathas been the dispersion of the vocabulariesamong differentcultures?We have at least a partial answer.A few societiesare relativelyunconcernedwith color. They get along with a rudimentary classification.Others make many fine distinctionsin hue and intensity within each of the basic colors. They have spacedtheir vocabulariesout. Has the spacingout been random?Evidently not. In later investigations, Berlin and Kay observed that each society uses from two to eleven basic color terms, which are focal points spread acrossthe four elementary color blocks perceived in the Munsell array.The full complement (to use the EnglishJanguageterminology) is black, white, ied, yellow, green, blue, brown, purple, pink, orange, and gray. The Dani language, for example, uses only two of the terms, the English language all eleven. In passingfrom societieswith simple classifications to those with complicated classifications,the combinations of basic color terms as a rule grow in a hierarchical fashion, asfollows: Languageswith only two basic color terms use them to distinguish black and white. Languageswith only three terms have words for black, white, and red. Languageswith only four terms have words for black, white, red, and either green or yellow. Languages with only five terms have words for black, white, red, green, and yellow. Languages with only six terms have words for black, white, red, green, yellow, and blue. Languageswith only seven terms have words for black, white, red, green, yellow, blue, and brown. No such precedenceoccurs among the remaining four basic colors, purple, pink, orange, and gray,when these have been added on top of the first seven.

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If basiccolor termswere combined at random, which is clearlvnot the case, human color vocabularies would be drawn helter-skelter from among a mathematicallypossible2,o36possibilities.The BerlinKay progressionsuggeststhat for the most part they are drawn from only twenty-hvo. At one level, the twenty-two combinations of basic terms are the dispersion of memes, or cultural units, generated by the epigenetic rules of color vision and semanticmemory. In simple la.rguag.,ou, genesprescribethat we seedifferent wavelengthsof light a certain way. our additional propensity to break the world into units and label them with wordscausesus to accumulateup to eleven basiccolor units in a particular order. That, however, is not the end of the story. The human mind is much too subde and productive to stop at eleven words that specifydifferent wavelengths.As the British linguist fohn Lyons has pointed out, the recognition of a color in the brain does not ,r.".rr"rily lead to a term that denotes only the light wavelength. color terms are often invented to include other qualities as well, particularly texture, lumi_ nosity,freshness,and indelibility. In Hanun6o, a Malayo-polynesian language of the Philippines, malatuy means a brown, wet, shiny surface,the kind seenin freshlycut bamboo, while mararais a yellowish, hardenedsurface,as in aged bamboo. EnglishJanguagespeakersare prone to hanslatemalahryas"brown" andmararaas "yellow,"but they would capture only part of the meaning and perhaps the lessimportant part' similarly, chlorosin ancient Greek is usually translatedas simpry "green" in English, but its original meaning was apparentlythe freshnessor moistnessof greenfoliage. The brain constantly searchesfor meaning, for connectionsbe_ tween objects and qualities that cross-cutthe sensesand provide information about external existence.we penehate that world through the constraining portals of the epigenetic rules. fu shown in the elementary casesofparalanguageand color vocabulary culture hasrisenfrom the genes and forever bears their stamp. With the invention of metaphorand new meaning, it hasat the same time acquireda life of its-own. In order to grasp the human condition, both the genes and culture must be understood, not separatelyin the traditional manner of scienceand the humanities,but together,in recognition of the realities of human evolution.

CHAPTER

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WHer IS humannature?It is not the genes,which prescribeit, or culture, its ultimateproduct.Rather,human natureis somethingelse It is the epigefor which we haveonly begunto find readyexpression. that bias netic rules,the hereditaryregularitiesof mentaldevelopment cultural evolutionin one directionas opposedto another,and thus connectthe genesto culture. Human natureis still an elusiveconceptbecauseour understanding of the epigeneticrules composingit is rudimentary.The rules I have used as examplesin previouschaptersare no more than fragmentscut from the vastmental landscape.Yet,comingfrom so many testimonyof the existence they offer persuasive behavioralcategories, of a geneticallybasedhuman nature.Considerthe varietyof examples sofar reviewed:the hallucinatorypropertiesof dreams,the mesmerizin preferences elementary phonemeconstruction, ing fearof snakes, facial exthe basic bonding, of mother-infant the senseof taste,details of inanimate the personalization the reificationof concepts, pressions, objectsand varying obiects,and the tendencyto split continuously into hvo discreteclasses.One more rule in particular,the processes treaking of light into the colorsof the rainbow,hasbeenplacedwithin a causalsequencerunningall the wayfrom the genesto the invention

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of vocabulary.It servesas a prototypefor future researchaimed at bridgingscience andthehumanities. Someepigeneticrules,includingcolorvision,are primatetraits tensof millionsofyearsold.others,suchasthe neuralmechanisms of language, areuniquelyhumanand possiblydatebackno morethan several hundredthousand years.The searchfor humannaturecanbe viewedasthearchaeology of the epigenetic rules.It is destinedto be a vitalpartof futureinterdisciplinary research. coevolutionasnow conceivedby biologistsand so_ ,In gene-culture cial scientists, causaleventsripple out from the genesto ihe cells to tissues andthenceto brainandbehavior. By interactionwith thephysical environment and preexisting culture,theybiasfurther.uol,rtio. of the culture.But this sequence*composing whatthe genesdo to cultureby wayof epigenesis-isonly harfthe circle.The Jtherhalf is whatculturedoesto the genes.The questionposedby the secondhalf of the coevolutionary circleis howcultureheipsto seiectthe mutating andrecombining genesthatunderliehumannature. By expressing gene-culture coevolution in sucha simplemanner,I . haveno wisheitherto overworkthe metaphorof the ,elfishg"rreo, io minimizethecreative powersof the mind.Afterall,thegeneJprescribing the epigeneticrulesof brain and behavior o.ly segments of "r. giantmolecules. Theyfeelnothing,carefor nothing, i.,i".,J nothing. Their role is simplyto higgerthe sequences of cf,emicalreactiois yjahi" the highly structuredfertilizedcell that orchestrate epigenesis. Theirwrit extends to thelevelsof molecule,cell,andorg".. Tlii, ."rly stageof epigenesis, consisting of a series of sequential physicochemical reactions, culminatesin the self-assembly of the sensorysystemand brain.only then,whentheorganismis completed, doesmentalactivip1appearas-an emergentprocess.The brain is a product of the very highestlevelsof biologicalorder,which areconstrained by epigenetic rules implicit i-nt]re organism'sanatomyand physiology.'Wlrli.,gin a chaoticfood of environmentalstimuli,it seesandlistens.Ieains. plansits ownfuture.By that meansthe braindeterminesthe fateof the genesthatprescribed it. Acrossevolutionarytime,theaggregate choices of manybrainsdeterminethe Darwinianfateof everyi[ir,! nrr*".,_ the genes,the epigeneticrules,the communicating minds,and the culture. Brains that choosewisely possess superiorDarwinian fitness, meaningthat statisticallythey survivelongerand leavemore offspring

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than brains that choosebadly. That generalization by itself, commonly telescopedinto the phrase "suryival of the fittest," soundslike a tautola ogy-the fit survive and those who suwive are fit-yet it expresses hunpowerful generativeprocesswell documentedin nature. During dredsof millennia of Paleolithichistory the genesprescribingcertain human epigeneticrules increasedand spreadat the expenseof others through the speciesby means of natural selection.By that laborious processhuman nature assembleditself' What is truly unique about human evolution, as opposedsay to chimpanzeeor wolf evolution, is that a large part of the environment shapingit hasbeen cultural. Therefore,constructionof a specialenvironment is what culture doesto the behavioralgenes.Members of past generationswho used their culture to best advantage,like foragers gleaning food from a surrounding forest, enloyed the greatestDarwinian advantage.During prehistory their genes multiplied, changing brain circuitry and behaviortraitsbit by bit to constructhuman nature as it existstoday. Historical accident played a role in the assembly,and there were many particular expressionsof the epigenetic rules that But by and large, natural selection,sustained proved self-destructive. and averagedoverlong periodsof time, wasthe driving force of human evolution. Human nature is adaptive, or at least was at the time of its origin. genetic Gene-culture coevolution may seem to create a paradox: At the sametime that culfure arisesfrom human action, human action arises from culture. The conhadiction evaporates,however, if we compare the human condition with the simpler form of reciprocity between environment and behavior widespreadin the animal kingdom' African elephants, while consuming the vegetation of large numbers of trees and shrubs,create the open woodlands in which they thrive. Termites, swarming at their feet, consume leftover dead vegetation and build tightly sealed nestsfrom soil and their own excrement, creating moist, high-carbondioxide microclimates to which-no surprisetheir phyiiolory is closely adapted. To view human beings evolving elephantsand termites in the same habitat during the Pleis"*ong Epoch, we need only replaceenvironment in part with culture. tocene While if is true that culture, strictly defined as complex socially learned behavior, is evidently limited to humans, and as a consequence the reciprocity between genes and culture-as-environment is also unique, the underlying principle is the same. There is nothing

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conhadictory in saying that culture arisesfrom human action while human action arisesfrom culture. The general biological imagery of the origin of human nature has repelled some writers, including a few of the most discerning scholars in the social sciencesand humanities.They are, I am sure, mistaken. They misunderstandgene-culturecoevolution,confusingit with rigid genetic determinism, the discreditedidea that genesdictate particular forms of culture. I believe reasonableconcerns can be dispelled by the following argument. Genes do not speci$,elaborate conventions such as totemism,elder councils, and religiousceremonies.To the best of my knowledgeno seriousscientistor humanitiesscholarhas eversuggestedsuch a thing. Instead,complexesof gene-basedepigeneticrules predisposepeople to invent and adopt such conventions. Ifthe epigenetic rules are powerful enough, they causethe behaviorsthey affect to evolve convergently acrossa great many societies.The conventionsevolvedby culture, biasedby epigeneticrules-are then spokenof as the cultural universals.Rare cultural forms are also possibleunder the samescenario.The whole matter can be expressedanother way by reverting to the imagery of developmental genetics. The norm of reaction of the underwriting genes is greatly narrowed in the case of a cultural universal; in other words, there are few if any environments availableto human beingsin which the cultural convention doesnot arise.In contrast, genesthat spawnmany rare conventions in response to changing environments, thus expanding cultural diversity,are those with broadernorms of reaction. Genetic evolution might have gone the other way by eliminating epigenetic bias altogether, expanding the norm of reaction of the prescribinggenesto indefinite degree,and thus causingcultural diversity to explode.That is a theoreticalpossibility,but the existenceof such a phenomenon does not imply that culture can be cut loose from the human genome. It meansonly that the prescriptivegenescan design the brain to learn and respondwith equal alacrity to any experience. Bias-freelearning, if it exists,is not an erasureof gene-culture coevolution but an extremelyspecializedproduct of it, basedon a very peculiar kind of epigeneticrule. For the time being, however,the argument is moot, because no example of bias-freemental development has yet been discovered.Some degree of epigenetic bias has been demonstratedin every one of the small number of cultural categoriesthus far testedfor the presenceor absenceofsuch bias.

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The swiftnessof cultural evolution in historicaltimes may by itself seem to imply that humanity has slipped its genetic inskuctions, or somehowsuppressedthem. But that is an illusion. The ancient genes and the epigenetic rules of behavior they ordain remain comfortably in place. For most of the evolutionaryhistoryof Homo sapiensand its antecedent speciesHomo habilis, Homo erectus,and Homo ergaster, cultural evolution was slow enough to remain tighdy coupled to genetic evolution. Both culhrre and the genesunderlyinghuman nature were probably geneticallyfit throughout that time. For tens of thousandsof yearsduring the PleistoceneEpoch the evolution of artifacts remained nearly static,and presumablyso did the basicsocialorganization of the huntergatherer bands using them. There was time enough, as one millennium passedinto another,for the genesand epigenetic rules to evolve in concert with culture. By Upper Paleolithic times, however,from about 4o,ooo to ro,oooyearsbeforethe present, the tempo of cultural evolution quickened.During the ensuing Neolithic agricultural advance,the pace accelerateddramatically. According to the theory of population genetics,most of the changewasfar too fastto be tracked closelyby geneticevolution.But there is no evidence that the Paleolithic genessimply disappearedduring this "creativerevolution." They stayedin place and continued to prescribethe foundational rules of human nature. If they could not keep up with culture, neither could culture expungethem. For better or worsethey carried human nature into the chaosof modern historv.

To rexs behavioralgenesinto account thereforeseemsa prudent human behavior.Sociobiology(or Darwinian anstep when assessing thropology, or evolutionary psychology, or whatever more politically acceptable term one choosesto call it) offers a key link in the attempt to explain the biological foundation of human nature.By askingquestions framed in evolutionary theory it has already steeredresearchin anthropology and psychologyin new directions.Its major research strategyin human studieshas been to work from the first principles of population geneticsand reproductivebiolory to predict the forms of social behavior that confer the greatestDarwinian fitness.The predictions are then tested with data taken from ethnographic archives and historical records,aswell asfrom fresh field studiesexplicitly designed

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for the purpose. Some of the tests are conducted on preliterate and other traditional societies, whose conseryative social practices are likely to resemble most closely those of Paleolithic ancestors.A very few societiesin Aushalia,New Guinea, and SouthAmerica in fact still have stone-agecultures, which is why anthropologistsfind them especially interesting. Other testsare conducted with data from modern societies, where fast-evolvingcultural norms may no longer be optimally fit. In all these studiesa full aray of anal:Jtictechniques is brought to bear. They include multiple competing hypotheses,mathematical models,statisticalanalysis,and even the reconstructionof the histories of memes and cultural conventionsby the same quantitative proceduresusedto hace the evolution ofgenesand species. In the past quarter-century human sociobiologr has grown into a large and technically complex subject. Nevertheless,it is possibleto reduce its primary evolutionary principles to some basic categories, which I will now briefly summarize. Kin selectionis the nahrral selection of genesbasedon their effects on individuals carrying them plus the effectsthe presenceof the genes has on all the genetic relativesof the individuals,including parents, children, siblings,cousins,and otherswho still live and are capableeither ofreproducing or ofaffecting the reproductionofblood relatives. Kin selection is especiallyimportant in the origin of altruistic behavior. Consider two sisters,who sharehalf their genesby virtue of having the samefather and mother. One sacrificesher life, or at leastremains childless,in order to help her sister.fu a result the sisterraisesmore than twice asmany children asshewould haveotherwise.Since half of her genesare identical to those ofher generoussister,the loss in genetic fitness is more than made up by the altruistic nature of the sacrifice. If such actions are predisposedby genesand occur commonly, the genes can spread through the population, even though they induce individualsto surrenderpersonaladvantage. From this simple premise and elaborations of it have come a wealth of predictions about pafterns of altruism, patriotism, ethnicity, inheritance rules,adoptionpractices,and infanticide.Many are novel, and most have held up well under testing. Parental inyestmentis behavior toward offspring that increasesthe fitness of the latter at the cost of the parent's ability to invest in other offspring. The different patterns of investment have consequencesfor

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the fitnessof the genes that predisposeindividuals to selectthe patterns.Choose one, and you leavemore offspring;chooseanother,and you leave fewer offspring. The idea has given rise to a biologically based"family theory" spinning offnew insightson sexratios,marriage contracts,parent-offspringconflict, grief at the loss of a child, child abuse,and infanticide. I will take up family theory again in the next chapter, in order to illustrate more fully the relevance of evolutionary reasoningfor the socialsciences. Mating strategyis influenced by the cardinal fact that women have more at stake in sexual activity than men, becauseof the limited age span in which they can reproduceand the healy investmentrequired of them with each child conceived.One egg,to put the matter in elemental terms, is hugely more valuable than a single sperm, which must compete with millions of other sperm for the egg.The achievement of pregnancy closes off further breeding opportunity of the mother for a substantialfraction of her remaining reproductivelife, whereas the father has the physical capacity to inseminate another woman almost immediately.With considerablesuccess,the nuances of this concept have been usedby scientiststo predict patternsof mate paterchoice and courtship, relative degreesof sexualpermissiveness, ni$ anxiety, treatment of women as resources,and polygyny (multiple wives,which in the past at leasthas been an acceptedarrangementin threenuarters of societies around the world). The optimum sexual instinct of men, to put the matter in the now familiar formula of popular literature, is to be assertiveand ruttish, while that of women is to be coy and selective. Men are expectedto be more drawn than women to pornography and prostitution. And in courtship, men are predicted to stressexclusive sexual access and guarantees of paternity, while women consistentlyemphasizecommitment of resourcesand material security. Sfatus is cenhal to all complex mammal societies,humanity included. To say that people generallyseekstatus,whether by rank, class,or wealth, is to sum up a large part of the catalogue of human social behavior. In traditional societiesgenetic fitnessof individuals is generallybut not universallycorrelatedwith status.In chiefdomsand despoticstatesespecially,dominant maleshaveeasyaccessto multiple women and produce more children, often in spectaculardisproportion. Throughout history, despots(absolute rulers with arbitrary pow-

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ers of life and death over their subiects)commanded accessto hundreds or even thousandsof women. Some statesused explicit rules of dishibution, as in Inca Peru, where by law petty chiefs were given sevenwomen, governorsof a hundred people eight, leaders of a thousandpeople fifteen,and lords and kings no fewer than sevenhundred. Commoners took what was left over. The fathering of children was commensuratelylopsided. In modern industrial states,the relationship between statusand genetic fitness is more ambiguous. The data show that high male status is correlated with greater longevity and copulation with more women, but not necessarilythe fathering of more children. Tenitoial expansion and defense by hibes and their modern equivalents the nation statesis a cultural universal. The conhibution to survival and future reproductive potential, especially of tribal leaders, is overwhelming, and so is the warlike imperative of tribal defense. "Our country!" declared Commodore Stephen Decatur, hard-fighting hero of the War of r8rz, "may she alwaysbe right; but our country, right or wrong." (Personalaggressiveness has its Darwinian limits, however; Decatur waskilled in a duel in r8zo.) Biologists have determined that territoriality is not unavoidable during social evolution. It is apparendyentirely absent in many animal species. The territorial instinct arises during evolution when some vital resourceseryesas a "density-dependentfactor." That is, the growth of population densityis slowedincrementallyby an increasing shortageoffood, water, nest sites,or the entire local terrain availableto individualssearchingfor theseresources.Death ratesincreaseor birth ratesdecrease,or both, until the two ratescome more or less into balance and population density levels off. Under such circumstances animal speciestend to evolve territorial behavior. The theoretical explanation is that individuals hereditarily predisposedto defend private resourcesfor themselvesand their social group passmore geneson to the next generation. In contrast,the growth of other speciesis not leveled offby limiting resourcesbut by rising amounts of emigration,disease,or predation. When such alternative densitydependent factors are paramount, and resource control is therefore not required, territorial defense usually does not evolveas a hereditary response. Humanity is decidedly a territorial species.Since the conhol of

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limiting resourceshas been a matter of life and death through millennia of evolutionarytime, territorial aggressionis widespreadand reaction to it often murderous. It is comforting to say that war, being cultural in origin, can be avoided.Unfortunately,that bit of conventional wisdom is only a half truth. It is more nearly correct-and far more prudent-to saythat war arisesfrom both genesand culture and can best be avoided by a thorough understandingof the manner in which these two modes of heredity interact within different historical contexts. Contractual agreementso thoroughly pervadeshuman social behavior, virtually like the air we breathe, that it attracts no special notice-until it goesbad.Yet it deserves focusedscientific researchfor the following reason.All mammals, including humans, form societies basedon a conjunction of selfishinterests.Unlike the worker castesof ants and other social insects,they resistcommitting their bodiesand servicesto the common good. Rather, they devote their energiesto their own welfare and that of close kin. For mammals, social life is a contrivanceto enhancepersonalsurvivaland reproductivesuccess. As a consequence,societiesof nonhuman mammalian speciesare far less organizedthan the insectsocieties.They dependon a combination of dominance hierarchies, rapidly shifting alliances, and blood ties. Human beings have loosened this constraint and improved social organizationby extendingkinshiplike ties to othersthrough long-term contracts. Contract formation is more than a culhrral universal.It is a human trait as characteristicof our speciesas languageand abstractthought, having been constructed from both instinct and high intelligence. Thanks to ground-breaking experiments by the psychologists Leda Cosmidesand fohn Tooby at the Universityof California at SantaBarbara, we know that conhact formation is not simply the product of a single rationalfaculty that operatesequallyacrossall agreementsmade among bargaining parties. Instead, one capacity, the detection of cheating, is developedto exceptionallevelsofsharpnessand rapid calculation. Cheater detection standsout in acuity from mere error detection and the assessment of alhuistic intent on the part of others.It is furthermore triggered as a computation procedure only when the cost and benefits of a social contract are specified.More than error, more than good deeds,and more even than the margin of profit, the pos-

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sibility of cheating by others attractsattention. It excitesemotion and servesas the principal source of hostile gossipand moralistic aggression by which the integrityof the political economyis maintained.

TH n c e NIn r I c F r r N E s s hlpothesis-that the mostwidely distributed haits of culture confer Darwinian advantageon the genes that predisposethem-has been reasonablywell borne out by the evidence. Widely distributed traits are usually adaptive, and their existence accordswith the first principlesof evolutionby natural selection. It is further true that by and large people behave in their daily lives as though somehow guided, whether consciously or unconsciously, by thesefirst principles.The value of the geneticfitnesshypothesislies in the insightsconcerning human nature it providesand the productive new directionsin scholarlyresearchit hasstimulated. There are nonethelessmany weaknessesin the genetic fitness hypothesis. For the most part the flaws are due not to contradictory evidence but to a scarcity of relevant information. Because human behavioral genetics is still in its infancy, there is a near-absenceof direct links between particular genesand behavior underlying the universal culfure traits. The observedfit between theory and fact is based mostly on statisticalcorrelation.One of the rare exceptions,described in the previouschapter,is the connection successfullymade between the geneticsand vocabularyofcolor vision. The epigenetic rules that guide behavioraldevelopmentare also largelyunexplored,and asa resultthe exactnature ofgene-culture coevolution can in most casesonly be guessed.It makesall the difference in the world whether epigeneticrules are rigid, specializedfunctions of the brain, and thus resemble animal instinct, or whether they are more generalizedrationalalgorithmsthat function acrossa wide range of behavioral categories.The evidence to date showsthat both kinds of epigeneticrules, narrow and broad, exist.For example,the use of the smile is narrowly channeled by one set of rules, while territorial responseis broadlychanneledbyanother. But until such rules are better documented and disentangled,along with the manner in which they guide mental development, it will be difficult to account for the wide cultural variationthat occursin a maiority of behavioralcategories. These shortcomingsin behavioralgeneticsand development are

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conceptual,technical, and deep.But they are ultimately solvable.Unlessnew evidence commands otherwise,hust is wisely placed in the natural consilience of the disciplinesnow addressingthe connection between heredity and culture, even if support for it is accumulating slowly and in bits and pieces.The resolutionof the difficultiesawaits the further expansion of biology and its coalescencewith psychology and anthropology.

THs cerncoRy or human behaviorthat providesthe fullesttest of the genetic fitness hypothesisto date is incest avoidance.A large amount of information concerning the phenomenon has become availableat different levels of biology and culture. The behavioritself is universal,or nearly so. It is also relativelyclear-cut in expression. Sexualactivity in all societiesis relativelyuncommon betweensiblings and between parents and their offspring;children produced by such activity are rare; and long-term unions made with the consensualpurposeof having such children are almostnonexistent. The current explanationof incestavoidance,which combinesgenetic and cultural evolution, is a straighforwardsociobiologicalexercise.Inbreedingat the level ofsiblings and parentsand children yields a high percentage of offspring with genetic defects. Humans tend to avoid this risk by unconsciousobedienceto the following epigenetic rule: Ifa boy and girl are brought togetherbefore one or the other is thirty months of age and then raisedin closedomesticproximity-use the same potty, so to speak-they are devoid of later sexual interest in each other, and the very thought of it arousesan acute aversion.This emotional incapacity, fortified in many societiesby a rational understandingof the consequenceof inbreeding,has led to the cultural incesttaboos,which prohibit incestby customand law. The risk of defectivechildren from incest- inbreedingdepression asit is called by geneticists-is now well understood.On average,each person carries somewhereon his twenty-threepairs of chromosomes two sitesthat contain recessivelethal genes.The sitescan be almost anywhereon the chromosomes.They alsodiffer in exactnumber and location from one personto the next. Only one of the two homologous chromosomesin the affectedpair carrieslethals at the site; the other homologouschromosome carriesa normal gene, which overridesthe effectsof the lethal gene. The reason is the lethality itself. When both

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chromosomes carry a lethal gene at a particular site, the fetus is aborted or the child dies in infancy. Considera woman with a lethal gene at one such site.If she is impregnated by her brother, and if their parents themselves are unrelated, her child has one chance in eight of dying as a fetus or as an infant. If shehaslethal genesat two such sites,her child has about one chance in four ofdying. There existin addition a horde ofother recessive genesthat causecrippling anatomical and mental defects.The total effect is that early mortality of children born of incest is about twice that of outbred children, and among ihose that survive, genetic defectssuch as dwarfism, heart deformities, severemental retardation, deaf-mutism, enlargement of the colon, and urinary hact abnormalities are ten times more common. The destructiveconsequenceof incest is a generalphenomenon not iust in humans but also in plants and animals.Almost all species vulnerableto moderateor severeinbreedingdepressionuse some biologically programmed method to avoid incest. Among the apes, monkeys,and other nonhuman primates the method is two-layered. First, among all nineteen social specieswhose mating patternshave been studied,young individualstend to practice the equivalent of human exogamy:Before reaching full adult size they leavethe group in which they were born and join another. In the lemurs of Madagascarand in the majority of monkey speciesfrom both the Old and New Worlds, it is the males who emigrate. In red colobus monkeys, hamadryas baboons, gorillas, and chimpanzees of Africa, the females leave. In howler monkeys of Cenhal and South America, both sexesdepart. The restlessyoung of these diverse primate speciesare not driven out of the group by aggressiveadults. Their deparhrre appears to be entirely voluntary. Whatever its ultimate evolutionary origin, and however else it affects reproductive success,the emigration of young primates prior to reaching full sexualmahrrity greatly reducesthe potential for inbreeding. But the barrieragainstinbreeding is reinforcedby a secondline of resistance.This is the avoidance of sexual activity by even those individualswho remain with their natal group. In all the socialnonhuman primate specieswhosesexualdevelopmenthas been carefully studied, including marmosets and tamarins of South America, Asian macaques,baboons,and chimpanzees,both adult malesand femalesdisplay the "Westermarck effect": They spurn individuals with whom

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they were closely associatedin early life. Mothers and sons almost never copulate,and brothersand sisterskept togethermate much less frequentlythan do more distantlyrelatedindividuals. This elemental responsewasdiscovered,not in monkeysand apes, but in human beings,by the Finnish anthropologistEdwardA. Westermarck and first reported in his r8gr masterworkThe History of Human Marriage. The existenceof the phenomenon has gained increasing supportfrom many sourcesin the interveningyears.None is more persuasivethan the study of "minor marriages"in Thiwan by Arthur P. Wolf of Stanford University.Minor marriages,formerly widespreadin southernChina, are those in which unrelated infant girls are adopted by families,raisedwith the biological sonsin an ordinarybrother-sister relationship, and later married to the sons.The motivation for the practice appearsto be to insure partnersfor sonswhen an unbalanced sexratio and economic prosperitycombine to createa highly competitive marriagemarket. Acrossfour decades,from 1957to rgg5,Wolfstudiedthe historiesof r4,zoo Taiwanese women contracted for minor marriage during the late nineteenth and early twentieth centuries.The statisticswere supplemented by personal interviews with many of these "little daughtersinJaw," or simfua,as they are known in the Hokkien language,aswell as with their friends and relatives. WhatWolf had hit upon wasa controlled-if unintended-experiment in the psychologicaloriginsof a maior piece of human socialbehavior. The sim-pua and their husbandswere not biologically related, thus taking away all of the conceivable factors due to close genetic similarity. Yet they were raisedin a proximity as intimate asthat experienced by brothersand sistersin Thiwanesehouseholds. The results unequivocally favor the Westermarck hypothesis. When the future wife was adopted before thirty months of age, she usually resistedlater marriage with her de facto brother. The parents often had to coercethe couple to consummatethe marriage,in some casesby threat of physical punishment. The marriagesended in divorce three times more often than "maior marriages"in the samecommunities. They produced nearly 4o percent fewer children, and a third of the women were reported to have committed adultery asopposedto about ro percent of wives in major marriages. In a meticulous seriesof cross-analyses, Wolf identified the key inhibiting factor asclosecoexistenceduring the first thirty months oilife

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of either or both of the partners.The longer and closer the association during this critical period, the stronger the later effect. Wolfs data allow the reduction or elimination of other imaginable factors that might have played a role, including the experienceof adoption, financial status of the host family, health, age at marriage, sibling rivalry and the natural aversionto incest that could have arisen from confusing the pair with true, geneticsiblings. A parallel unintended experiment has been performed in Israeli kibbutzim, where children are raised in crdchesas closely as brothers and sisters in conventional families. The anthropologist |oseph Shepher and his co-workersreported in r97r that among 2,769 marriages of young adults reared in this environment, none was between membersof the samekibbutz peer group who had lived togethersince birth. There was not even a single known caseof heterosexualactivity, despite the fact that the kibbutz adults were not especially opposed to it. From these examples, and a great deal of additional anecdotal evidence gleanedfrom other societies,it is evident that the human brain is programmed to follow a simple rule of thumb Have no sexual interestin thosewhom you knew intimately during the earliest yearsof your life. The Westermarck effect is also consistent with the principle of graded effect in psychology.The evidence from acrossmany societies showsthat the more intimate the associationduring the critical period of early childhood, the less likely is it that heterosexual activity will occur. Hence mother-sonincest, which is inhibited by the intense bonding during the infancy of the son, is by far the rarestkind. Next in scarcityis sibling incest,then sexualabuseof girls by their biological fathers (I say abuse becauseconsent is seldom given freely by the daughters),and finally sexualabuse ofgirls by their stepfathers. Yet, while the evidence makesa tidy and persuasivepicture, we are still far from a full explanationof incestavoidance.There is no conclusive proof that the Westermarck effect originated from genetic evolution by natural selection. Certainly all the signs point that way. Incest avoidancediminishesinbreeding and thereby increasesthe production of healthy offspring. Given even a small amount of genetic variato childhood associates, the differences bility in sexualresponsiveness in fitness based on it would have been shong enough, in population genetics theory at least, to spread the Westermarck effect throughout

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the population fiom a very low incidence to widespreadoccurrence in asfew asten generations.Further evidenceis the occurrenceof the effect in other primates,including our closestliving relativesthe chimpanzees,where it is unquestionablygenetic, not cultural, in origin. Still, no attempt has been made to measureheritability in the human responseor to discoverthe genesunderwriting it. A secondshortcomingon the researchfront is that we do not know the exactpsychologicalsourceof the Westermarckeffect.The stimuli from childmatesthat trigger the inhibition have not been pinpointed. It is not known whether they occur during play, eating together,unavoidableaggressiveexchanges,or other eventsmore subtle and perhaps only subliminally sensed.The critical stimuli could be anything, large or small, visual,auditory,or olfactory and not necessarilyunderstood in any ordinary adult sense.The essenceof instinct as interpretedby biologistsis that it is evokedby simple cuesthat need only be associatedin real life with the object to which it is directed.A scentor a singletouch at a critical moment can unleashcomplex behavior,or inhibit it. A further complication in the story of human incest avoidanceis the existenceof a third barrier, incesttaboos,the culturally hansmitted sets of rules that prohibit sexual activity among very close relatives. Many societiespermit or even encourage marriages between first cousins,especiallywhen the bonding servesgroup cohesionand consolidateswealth, but forbid it betweensiblingsand half siblings. The taboos,being consciousinventionsand not simple instinctive responses,vary enormously in detail from one society to the next. In many cultures they are interwoven with the strictures of kinship classification and exogamous marriage contracts. In preliterate societies incest is commonly thought to be connected with cannibalism, vampirism, and malign witchcraft, each of which is punishableon its own account. Modern societiesenact lawsto discourageincest.During the Commonwealth and Protectorateperiod of England, from 165oto the Restorationa decade later, it was punishable by death. In Scotland until 1887,it was nominally a capital offense,although transgressions seldom drew more than life imprisonment.In the United Statesincest has been generally heated as a felony punishable by fine, imprisonment, or both. The sexualabuseof children is consideredall the more abhonent when it is in addition incestuous.

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History as everhue for human moresgenerally,recordsexc€phaveincludedthe with somedegreeof permissiveness tions.Societies Nkole(Uganda),Bunyoro Thais,ancientEg,ptians, Incas,Hawaiians, (Uganda),Ganda (Uganda),Zande (Sudan),and Dahomeyansof WestAfrica.In eachcasethe practiceis (or in mostinstanceswas,having beendiscontinued)surroundedby ritual and limited to royaltyor the other groupsof high status.In all the incestuousarrangements in fathering children outbred male alsoconsortedwith other women, "pure" The rulingfamiliesareor werepatrilineal. progeny. additionto yieldingmaximumgeneticfitnessfor a high-rankingmale The strategy is to matewith his own sister,producingchildrenwho sharewith him insteadof the usual5o 75percentof theirgenesby commondescent, percent,and alsoto matewith womenwho aregeneticallyunrelated and morelikely to givebirth to normalchildren.Lesseasilyexplained are the common and well-documentedcasesof brother-sistermarin RomanEg1pt,from about3oB.c.to A.D. riagesamongcommoners 324.Papyrustextsfrom the period revealbeyond reasonabledoubt that at leastsomeof the siblingsengagedin full and unabashedsexual relations. Incesttabooshaveled us, once again,to the borderlandbetween the naturaland socialsciences.The questionthey raiseis asfollows: effect,which is biologiWhat is the relationbetweenthe Westermarck are cultural? cal,andthe incesttaboos,which The issuecan be drawn more sharplyby distinguishingthe two principalhypotheses that competefor the explanationof human incest which I will now summarizein The first is Westermarck's, avoidance. ofa hereditaryepigePeopleavoidincestbecause updatedlanguage: netic rule of humannaturethat theyhavetranslatedinto taboos.The opposinghypothesisis that of SigmundFreud. There is no Westermarckeffect,the greattheoreticianinsistedwhenhe learnedof it. ]ust lust amongmembersof the samefamily is the opposite:Heterosexual primal and compelling,and not forestalledby any instinctiveinhibirip tion. In orderto preventsuchincest,andthe consequentdisastrous ping apartof familybonds,societiesinventtaboos.One result,which Freud developedas part of his grand schemefor psychology,is the Oedipuscomplex,the unresolveddesireof a sonfor sexualgratificahatredfor the father,who is tion with his motherand his simultaneous "The in mankind,"he wrote in first of obiect rival. choice seenasa

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t9r7, "is regularlyan incestuousone, directedto the mother and sister of men, and the most stringent prohibitions are required to prevent this sustainedinfantile tendencyfrom being carried into effect." Labeling the idea of the Westermarckeffect "preposterous,"Freud carried the day from the very start.The findingsof psychoanalysis, he asserted,make the phenomenon untenable.He alsodrew heavilyon a rebuttal by JamesFrazer, the British anthropologist,classicist,and author of The Golden Bough.If the Westermarckeffect really existed, Frazer reasoned,no taboos would be required. "It is not easyto see why any deep human instinct should need to be reinforced by law." That logic prevailedin textbooksand scholarlyreviewsfor most of the rest of the twentieth century. Westermarck'sresponseto Frazerwas simple, equally logical, and supported by growing amounts of evidence,but ignored in the triumphant onrush of psychoanalytictheory.Individual humans,Westermarck said, reasonas follows: I am sexuallyindffirent to my parents and siblings.Yet occasionallyI wonderwhat it would be like to havesex with them. The thought is repugnant! Incestis forced and unnatural. lt would alter or break other bonds I have formed with them and must maintain on a day-to-day basisfor my own welfare. Incest by others is by extensionalso repugnant to my mind, and evidently to that of others too, and so the rare casesin which it occursshould be condemnedas immoral. Reasonable as that explanation may be, and supported by evidence, it is neverthelesseasyto seewhy Freud and a host of other influential social theorists reacted so vehemently to the Westermarck effect. It imperiled a foundation piece of modernist thought, calling into question what had come to be regarded as a major intellectual advance of the era. Wolf has expressedthe difficulty with precision: "Freud saw all too clearly that if Westermarck was right, he was wrong. The possibility that early childhood association suppressed sexual athaction had to be denied lest the basisof the Oedipus complex crumble and with it his conception of personality dynamics, his explanation of neuroses,and his grand view of the origins of law, art, and civilization." The Westermarckeffect rocks other boatsaswell. There is the matter of whether social regulation in general existsto represshuman nature or to expressit. And from that comes the not so trivial question of

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what incest taboosimply about the origins of morality. Orthodox social theory holds that morality is largely a convention of obligation and duty constructed from mode and custom. The alternative view, favored by Westermarckin his writings on ethics, is that moral concepts are derivedfrom innate emotions. In the clash of ethical theory at least,the matter of incest avoidance can be settled empirically. Either Westermarckor Freud was factually right. The evidence now leans shongly to Westermarck. Yet there is more to incest taboos than the mere grafting of cultural conventions onto personal preference. It is also possible for people to observethe effects of inbreeding directly. They are capable of recognizing in at leasta vagueway that deformed children are a frequent product of incestuousunions.William H. Durham, a colleagueof Arthur Wolfs at Stanford University, searched the ethnographic records of sixty societies chosenat random from around the world for referencesto any form of understandingof the consequencesof incest. He found that twenty showedsome degree of such awareness.The Tlingit Amerindians of the Pacific Northwest, for example, graspedin a straight'orward manner that defective children are often produced from matings of very closekin. Other societiesnot only knew that much, but alsodeveloped folk theoriesto explain it. The Lapps of Scandinaviaspokeof "bad blood" createdby incest.The Tikopian Polynesiansthought that mara,lhe doom generatedby partnersin incest,is transmittedto their young.The Kapaukuof New Guinea, in a similar theory,believedthat the act of incest causesa deteriorationof the vital substancesof the which is then passedon to their children. The Toradiaof transgressors, Sulawesi,Indonesia,were more cosmic in their interpretation.They said that wheneverpeople mate who have certain conflicting characteristics,asbetweenclosekin, nature is thrown into confusion. Curiously, while fifty-six of Durham's sixty societieshad incest motifs in one or more of their my'ths,only five contained accounts of evil effects.A somewhatlarger number ascribedbeneficial results,in particular the creation of giants and heroes.But even here incest was viewedassomethingspecialif not abnormal. In summary, the factual picture emerging from research on human incest avoidanceis one of multiple, successivebarriers.Up front is the Westermarck effect, the ancient sexual desensitization found in all other primatesthus far, and thus likely to be universalin

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humans. Next there is the dispersalof the young at sexual maturif, also a universal primate kait, manifestedin humans by adolescentrestlessnessand the formal practicesof exogamousmarriage.The deeper psychological motivations of the dispersalbehaviors and the epigenetic rules composingthem remain unknown. Finally, there are the cultural incesttaboos,which enhancethe westermarckeffectand dispersal.The taboosseemlikely to havearisenfrom the Westermarckeffect but also,in a minority of societies,from a direct perceptionof the destructive effectsof inbreeding. By translatingthe Westermarckeffect into incest taboos,humans appear to passfrom pure instinct to pure rational choice. But do they really? What is rational choice anyway?I suggestthat rational choice is the castingabout among alternativemental scenariosto hit upon the ones which, in a given context,satisfythe strongestepigeneticrules.It is these rules and this hierarchy of their relative strengthsby which human beings have successfullysurvived and reproduced for hundreds of millennia. The incest avoidancecasemay illustratethe manner in which the coevolution of genesand culture has woven not just part but all of the rich fabric of human socialbehavior.

cHAPTER

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THe Socter ScIBNCES

sociolPnopLe ExPEcr from the socialsciences-anthropology, to understand knowledge science-the ogy, economics,and political th.it liu.t and conhol their future. They want the Power to predict, not the preordained unfolding of events, which does not exist, but what will happen if societyselectsone course of action over another. Political life and the economy ate akeady pivoted upon the presumed existenceof such a predictive capacity.The social sciencesare striving to achieve it, and to do so largely without linkage to ttr-enatural sciences.How well are they doing on their own? Not very well, considering their track record in comparison with the resources placed at their command. The current statusofthe social sciencescan be put in perspective by comparing them with the medical sciences.Both have been entrusted with big, urgent problems. Medical scientistsare paid, for excorrect genetic birth defects,and repair severed ample, to cure ""na.r, are expected to tell us how to moderate scientists Social cords. nerve counkies into prosperous democdeveloping convert ethnic conflict, In both spheresthe problems have hade. racies, and optimize world been intractably complex, partly because the root causes are poorly understood. The medical sciences are neverthelessprogressing dramatically' Breakthroughs have been achieved in basic research and others are

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expectedat any time, perhapsleadingto more and more noninvasive, magic-bullet cures.Excitement runs high through global information networks connecting thousands of well-funded research groups. Neurobiologists,virologists,and moleculargeneticistsunderstandand encourageone anothereven asthey competein the racefor discovery. There is alsoprogressin the socialsciences,but it is much slower, and not at all animated by the same information flow and optimistic spirit. Cooperation is sluggish at best; even genuine discoveriesare often obscuredby bitter ideologicaldisputes.For the most part,anthropologists,economists,sociologists, and political scientistsfail to understand and encourageone another. The crucial difference between the two domains is consilience: The medical scienceshave it and the socialsciencesdo not. Medical scientistsbuild upon a coherent foundation of molecular and cell biology. They pursue elementsof health and illnessall the way down to the level of biophysical chemistry.The successof their individual proiectsdependson the fideliq' of their experimentaldesignto fundamental principles,which the researchers endeavorto make consistent acrossall levels of biological organizationfrom the whole organism down, stepby step,to the molecule. Social scientists,like medical scientists,have a vast store of factual information and an arsenalof sophisticatedstatisticaltechniquesfor its aaalysis.They are intellectually capable. Many of their leading thinkers will tell you, if asked,that all is well, that the disciplinesareon track-sort of, more or less.still, it is obviousto even casualinspection that the efforts of social scientistsare snarledby disunity and a failure of vision. And the reasonsfor the confusion are becoming increasingly clear. Social scientistsby and large spurn the idea ofthe hierarchical ordering of knowledgethat unitesand drivesthe natural sciences.split into independent cadres, they stressprecision in words within their specialty but seldom speak the same technical language from one specialty to the next. A great many even enjoy the resulting overall atmosphere of chaos,mistaking it for creativeferment. Some favor partisan socialactivism,directing theory into the serviceof their personal political philosophies.In past decades,socialscientistshave endorsed Marxism-Leninism,or-as much asthe misguidedbioloeish who usually receivethe blame-the worstexcesses oFsocial Daniinism. Today various factions favor ideological positions ranging from laissez-faire capitalism to radical socialism, while a few promote versions of post-

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modernistrelativismthat questionthe very idea of obiectiveknowledgeitself. for They areeasilyshackledby tribal loyalty.Much of what passes socialtheoryis still in thrallto the originalgrandmasters-abadsign, in a scientificdisciplinecan be meagiventhe principlethat progress suredby how quickly its foundersareforgotten.Simon Blackburn,in providesan instructiveexample: TheOxfordDictionaryof Philosoplry, is sometimesreferred "The haditionof semioticsthat followsSaussure in the of Kristeva, the term isaPprowork Confusingly, to assemiology. priatedfor the nonrationaleffluxesof the infantile part of the self." And soon throughthe bpvaysof criticaltheory,functionalism,historiand-if the postshucturalism, structuralism, cism, antihistoricism, mind is not steeledto resist-thenceinto the pits of Man
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socialtheorists,including thosewho spin out sophisticatedmathematical models, are equally happy with folk psychology.As a rule they ignore the findings of scientific psychologyand biology.That is part of the reason, for example, why social scientistsoverestimatedthe strengthof communist rule and underestimatedthe strengthof ethnic hostility. They were genuinely startled when the Soviet empire collapsed,popping the cap offthe superpowerpressurecooker,and were surprisedagain when one result of this releaseof energieswas the breakoutof ethnic strifeand nationalisticwarsin the spheresof diminished Russian influence. The theorists have consistentlymisiudged Muslim fundamentalism,which is religion inflamed by ethnicity.At home in America, they not only failed to foreseethe collapseoi the welfare state,but still cannot agreeon its causes.In short,socialscientistsas a whole havepaid little attention to the foundationsof human nature, and they havehad almostno interestin its deeporigins. The social sciencesare hampered in this lastregardby the residue of strong historical precedent. Ignorance of the natural sciencesby design was a strategyfashioned by the founders, most notably Emile Durkheim, Karl Max, Franz Boas,and Sigmund Freud, and their immediatefollowers.They aimed to isolatetheir nascentdisciplinesfrom the foundational sciencesof biology and psychology,which at the inception of the social scienceswere in any casetoo primitive to be of clear relevance. This stance was fruiffirl at first. It allowed scholarsto searchwidely for patternsin culture and socialorganizationunencumbered by the pahonageofthe natural sciences,and to composesuch lawsof social action as the prima facie evidencedemanded.But once the pioneering era ended, the theoristswere mistakennot to include biology and psychology.It was no Ionger a virtue to avoid the roots of human nature. The theorists were inhibited from probing in that direction by another problem endemic to the socialsciences:political ideology.Its effects have been especially clear in American anthropology. Franz Boas, aided by his famous students Ruth Benedict and Margaret Mead, led a crusade againstwhat they perceived (correctly) to be the eugenicsand racismimplicit in Social Darwinism.With caution swept aside by moral zeal, they turned opposition into the new ideologyof cultural relativism.The logic of the ideology,still sharedin varyingdegree by most professionalanthropologists, can be expressedasfollows:

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It is wrongto supposethat "civilized"peoplesare the winnersoyer "pimitive" peoplesin a Darwinianstrugglefor existence, hencesuperior; it is wrongto think that the differences betweenthem are due to their genesrather than a productof historicalcircumstance. Furthermore,cultureis wondrouslycomplexand tunedto the enyironmentin whichit hasevolved.Therefore, it is misleadingto think of culturesas evolvingfroma lowerto a higherstatus,and it is wrongtoentertainbiologicalexplanations of culturaldiversity. Believingit a virtueto declarethatall culturesareequalbut in differentways,Boasandotherinfuential anthropologists nailedtheir flag of culhrralrelativismto the mast.During the r96osand r97osthis scientific belief lent shen$h in the United Statesand other Western societies to political multiculturalism.Alsoknown asidentitypolitics, it holdsthat ethnics,women,andhomosexuals possess subculturesdeservingequalstandingwith thoseof the "majority,"evenif the doctrine demotesthe idea of a unifying nationalculhrre.The United States motto,E pluribusttnum,"out of the many,one,"wasturnedaroundto "out of the one,many";andthosewho wishedit soaskedthis question with a goodmeasureof reasonableness: What canbe wrongwith identity politicsif it increases the civil rightsof individuals?Many anthropologists,their instincts fortified by humanitarian puqpose,gr€w strongerin their supportof culturalrelativismwhile stiffeningtheir op positionto biologyin anyguise. So, no biology.The reasoningthen camefull circle with a twist that musthavebroughta smileto the little godsof irony.Where culturalrelativismhad beeninitiatedto negatebeliefin hereditarybehavioraldifferences amongethnicgroups-undeniablyan unprovenand ideologically dangerous conception-it wasthen turnedagainstthe ideaof a unified human naturegroundedin heredity.A greatconundrum of the human conditionwascreated:If neither culture nor a hereditaryhuman nature,whatuniteshumanityTThe questioncannot be justleft hanging,for if ethicalstandards aremoldedby culture,and culturesare endlesslydiverseand equivalent,what disqualifiestheocracy,for example,or colonialism? Or child labor,torture,andslavery?

IN coNrusED REspoNsn to the question, is today anthropology breakinginto two culturesof ib own,differentbut equal(of course)in

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merit. The biological anthropologistsattempt to explain culture as ultimately a product of the genetic history of humani$, renewed each generationby the decisionsof individualsinfluencedby that history.In sharp contrast,the cultural anthropologists,descendantsof Boas,see culture as a higher-orderphenomenon largely free of genetic history and diverging from one societyto the next virtually without limit. The view of the biological anthropologistscan be likened to the film series Star Wars, whose aliens have different physical anatomiesbut are rather disconcertinglyunited by an unshakablehuman nature. The view of the cultural anthropologistsis more that of the film lnvasion of the Body Snatchers,whose protagoniststake human form but retain their alien natures.(The film that got it right is lndependenceDay: If not human, it correcdy suggests, everythingis alien.) The schismatic state of contemporaryanthropologyis illustrated by the resolution passedby officersof the American Anthropological Associationin rg94, affirming on the one hand an "abiding commitment to biological and cultural variation"and on the other hand a "refusal to biologize or otherwise essentialize diversity." No way was spelledout to reconcile the two conhadictorygoals. How then is diversity to be addressedwithin anthropology?In the absenceof a common searchfor consilientexplanation,there is no solution. The schism between the two camps will continue to deepen. While biological anthropologistsincreasinglyfocuson heredityand reconstructionsof human evolution, cultural anthropologistswill drift farther away from the natural sciences.To an increasing degree they already align their scholarshipwith the humanities, analyzing each culture-say, Kwakiutl, Yanomamci,Kapauku,|apanese-as a unique entity. They see culture overall as neither predictable nor even definable by laws derived from the natural sciences.Some have gone so far as to adopt the extreme postmodernistview that scienceis just another way of thinking, one respectableintellechral subculture in the company of many.

C o N r n nap o RARy s o c r o L o cy s rA N D s evenfartherapartfrom the natural sciences than anthropology. Ao generally practiced, it can be defined as the anthropology of complex societies,especiallythose to which sociologiststhemselvesbelong. Anthropology can be conversely

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defined as the socioloryof simpler,more remote societies,thoseto which anthropologists do not belong.Where a representative sociologicaltopic is the relationshipof familyincometo Americandivorce rates,a typicalanthropologicaltopicis Sudanese bridewealth. Much of modernsociologyfeaturesexactmeasurementand statistical analysis.But apartfrom scatteredheretics,amongthe mostoutspokenof whom are Pierre L. van den Bergheof the Universityof Washington,Lee Ellis of Minot StateUniversity,fosephLopreatoof the Universityof Texas,andWalterL. Wallaceof PrincetonUniversity, academic sociologists haveremainedclustered nearthe nonbiological end of the culturestudiesspectrum.Many are,in Ellis' expression, biophobic-fearful of biolog, and determinedto avoid it. Even psychology is treatedgingerly.fames S. Coleman of the Universityof Chicago,a distinguishedand influential mainstreamtheoristproficient in the analyticmethodsof the natural sciences,could say(in r99o)that "the principaltaskofthe socialsciencesis the explanationof socialphenomena, not the behaviorof singleindividuals.In isolated casesthe socialphenomenonmay derive directly,through summation, from the behaviorof individuals,but more often this is not so. Consequendy, the focusmustbe on the socialsystemwhosebehavior is to be explained.This maybe assmallasa dyador aslargeasa society or evena world system,but the essentialrequirementis that the explanatoryfocusbe on the systemasa unit, not on the individualsor othercomponents which makeit up." To appreciate how far removedColeman'sresearchshategyisfrom that of the naturalsciences,substituteorganismfor sptem, cell for individual,and moleculesfor othercomponents,and his statementbecomes,"the essentialrequirementis that the explanatoryfocusbe oh the organismasa unit, not on the cell or moleculeswhich makeit up." Biolory would haveremainedstuckaroundr85owith sucha flat perspective,Instead,biologyis a sciencethattracescausationacrossmany levelsof organization, from brain and ecosystem down to atom.There is no obviousreasonwhy sociologyshouldnot havea similar orientation, guidedby a visionsweepingfrom societyto neuron. A centuryafterthe publicationof Durkheim'smanifestoThe Rutes of Sociological Method(t8g+),which helpedsetthe ground rules,the narrowlystratalapproachof the disciplineto the study of industrialized societiesremainsnearlyunchanged.RobertNisbet of Columbia

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University,in a revealinginterpretation of classicalsociology,seesthe field as having
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genetic determinism, the belief that human behavior is fixed in the genes,and that its most deshuctiveproperties,such asracism,war, and classdivision, are cons€quentlyinevitable.Cenetic determinism,proponents of the strong form of the SSSM say,must be resistednot only becauseit is factually incorrectbut becauseit is morally wrong. To be fair, I have never met a biologist who believesin genetic determinism as iust defined. Conversely,although the extreme form of the SSSM was widely held among seriousscholarsin the social sciences twenty years ago, today it is rare. Still, the clash of antipodean views is a staple of popular culture, and it is unfortunately perpetuated by journalists and college teachers.when the matter is drawn this way, scho]arsspring to their archaic defensivepostures.confusion continuesto reign, and angry emotionsflare.

EttoucH! A cenfury of misunderstanding,the drawn-out Verdun and Somme of Western intellectual history, has run its exhausting course,and the culture warsare an old game turned stale.It is time to call a truce and forge an alliance. Within the broad middle ground between the strong versionsof the Standard Social Science Model and genetic determinism, the social sciencesare intrinsically compatible with the natural sciences.The two great branchesof learning will benefit to the extent that their mod., of causal explanation ar! made consistent. The first step in the approach to consilience is to recognize that while the socialsciencesare truly science,when pursueddescriptively and analytically, social theory is not yet true theory. The social ,"i..,"., possessthe same general traits as the natural sciences in the earlv, natural-historyor mostly descriptiveperiod of their historicaldevelof ment' From a rich data basethey have ordered and classifiedsocial phenomena. They have discoveredunsuspectedpatterns of communal behavior and successfullyhaced interactions of history and cultural evolution. But they havenot yet crafteda web ofcausal explanation that successfullycuts down through the levels of organization from societyto mind and brain. Failing to probe this far, they lack what can be called a hue scientific theory. Consequently, even though they often speak of "theory" and, moreover, addressthe same speciesarrd the samelevel of organization,they remain disunited.

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One frequentlyencounteredword for naturalhistoryin the social In its original,restrictedusagethe expresis hermeneutics. sciences ("skilled in interpretahermcneutik6s Greek sion, drawn from the intelpretation of texts, and tion"), means the close analysisand Writersin the socialsciespeciallyof the Old and New Testaments. encesand humanitieshaveexpandedit to embracethe systematic explorationof socialrelationsand culture,in which eachtopic is exand cultures'Sound of differingviewpoints aminedby manyscholars usuallytakeslongperiodsof time,evenentirescholarly hermeneutics generations.Becauseexperimentscan seldom be conductedon human relationships,socialscientistsiudgesuchstudiespardyby the and partlyby the reputations and analysis, fullnessof the descriptions they the subiectandthe degreeofconsensus ofthe expertsaddressing to expectstatistical reach.In recentyearstheyhavecomeincreasingly circumwherever replicatesamples, of preciselymeasured treatments stancesallow this adoptionof the standardprocedureof the natural sciences. All thesecriteria alsomark the bestof naturalhistoryasit is still practicedthroughlargesectorsofbiology,geology,andotherbranches of the natural sciences.A respectfor fine analysisof factualinformahavein tion by hainedintellectsiswhatthesocialandnaturalsciences of Balinesereligionis comcommon.In this sensethe hermeneutics parableto the naturalhistoryof the Balinesebird fauna. But if naturalhistoryby whatevernameis the foundationof all the why is it not yet theory?The main reasonis that it includes sciences, little effortto explainphenomenaby websof causationacrossadiacent levelsof organization.The analysisis lateral,not vertical.In the Balineseexamples,naturalhistoryhavelswidelythroughculture,but not from brain to mind to culture,and it travelsacrossmanybird species Natural history but not from individual bird to speciesto ecosystem. generatesscientifictheorywhen it links the bestavailableknowledge acrossthe organizationallevels.It createsrigorousscientifictheory that capwhen scholarsproposecompetingand verifiablehypotheses levels. different the across plausible events operating of the ture all If socialscientistschooseto selectrigoroustheoryastheir ultimate theywill succeedto the extentthey goal,ashavethe naturalscientists, traversebroad stretchesof time and space.That meansnothing less with thoseof the naturalsciences.It than aligning their explanations alsomeansavoiding,exceptat cocktailtime, playfuldefinitionsof the

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kind proposedby the distinguishedphilosopherRichardRorty,who hascontrasted hermeneutics with epistemology, the systematic theory of knowledge:"We will be epistemological when we understandpeifectlywell whatis happeningbut wantto codifi it in orderto extend,or stren$hen,or teach,or'ground'it. We mustbe hermeneutical where we do not understand what is happeningbut are honestenoughto admit it. . . ." In Rorlyt proposal,hermeneuticsis not the name-fora disciplineor a programofresearch, asI haverecognized it, but.,anexpressionof hope that the cultural spaceleft by the demiseof epistemologywill not be filled-that our culture shouldbecomeone in which the demandfor constraintand confrontationis no longerfelt." Discourseamong scholars,in short, can proceedwithout worryrng aboutconsilience. Aboutrigortoo,it wouldseem.Althoughthisconcessionis welcomedby postmodernist scholars, it is a prematuresurrenderthat would drain much of the power and ioy from scholarly inquiry.Creativityin researchcan occur unexpectedlyin anyform of inquiry of course,but to resistlinking discoveries by causalexplanation is to diminishtheir credibility.It wavesasidethe syntheticicientific method, demonstrablythe most powerful instrumenthitherto createdby the humanmind.Lazily,it devalues intellect.

PnscrsnLy wHAr FoRMmighttheunionbetween thesocial and naturalsciences take?considerfour disciplines in a stackencompassing successively largerspansof spaceand time, asthey might be describedby theirpractitioners. The sociologist says,with justifiablepride, "We are interestedin the hereand now,the fine analysisof life in particularcomplexsocieties,and causeand effectacrossrecenthistory.We standcloseto the fine details,and we ourselves areoftenpart of if literallyswimmingin the details.From our perspective variationin humansocialbehavior seems enormous, perhaps indefinitelyplastic." 'Yes, The anthropologisf responds. that'shue asfar asit goes.But let's standback and look again.Consider:We anthropologists study thousands of culfures,many preliterateand nonindustrial,and the variationwe record is even greaterthan that encounteredby the sociologists. But I grantit is far from infinite in possiblerange.we have observed clearlimits andpatternswithin them. The informationfrom so manyseparateexperiments in cultural evolution,thoseconducted

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separately for many centuries, may allow us to formulate laws of human socialaction." 'fhe primatologist,impatient, ioins in. "True enough, comparative information about simple and complex societiesis the bone and sinew ofthe socialsciences.Still, your conceptionsneed to be put in an even broader perspective.The variation in human behavior is enormous, but it doesn't begin to encompassall the social arrangementswe have discoveredin the apes,monkeys, and other primates, which were created not by millennia but by fifty million yearsof evolution.It's there, among the more than one hundred speciesgeneticallyclosestto humanity, that we should look for the principles of socialevolution if we are to understandthe originsof culture." The sociobiologistadds,'Yes, the key is perspective.So why not make it really wide?My discipline,which has been developediointly by biologistsand social scientists,examinesthe biological basisof social behavior in all kinds of organisms.I know that the very idea of a biological infuence on human behavior in particular hasbeen controversial,especiallyin the political arena,but considerthis. Human beings may be unique in degreeof behavioral plasticity,and they may be and foresightedalone in the possessionof language,self-awareness, ness,but all of the known human systemstaken together form only a small subset of those displayed by the thousands of living speciesof highly social insectsand vertebrates.Ifwe hope to createa true science of social behavior, we will need to trlce the divergent evolution of these groups of organisms,through a time scale of hundreds of millions of years.It is also useful to recognize that human social behavior originated ultimately through biological evolution." Each discipline of the social sciencesrules comfortably within its own chosen domain of spaceand time so long as it stayslargely oblivious of the others. But from the lack of a hue social theory comes the debilitating failure of the social sciencesto communicate with the natural sciencesand even with one another. If the social and natural sciencesare to be united, the disciplines of both need to be defined by the scalesof time and spacethey individually encompassand not just by subjectmafter as in pastpractice,and then they need to be connected' A convergencehas in fact begun. The natural sciences,by their own swift expansion in subiect matter during the pastseveraldecades, are drawing close to the social sciences.Four bridges acrossthe divide are in place. The first is cognitiveneuroscience,or the brain sciences,

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with elements of cognitive psychology,whose practitioners analyzethe physical basis of mental activity and aim to solve the mystery of consciousthought. The secondis human behavioralgenetics,now in the early,stages ofteasing apartthe hereditarybasisofthe process,including the biasing influence of the geneson mental development.The third bridging discipline is evolutionary biology, including the hybrid offspring sociobiology, whose researchershave set out tolxplain the hereditary origins of social behavior. The fourth is the environmental sciences.The connection of the last field to sociartheorv mav at first seem tenuous, but is not. The natural environment is the theater in which the human speciesevolvedand to which its physiolog, and behavior are finely adapted.Neither human biology nor theiociar sciencescan make full senseuntil their world viewstake account of that unyielding framework.

Ir rs Nor DrFFrcuLT to visualizehow the stepping-stones be_ hveenthe natural and socialsciencesmight be arrangedand haversed. consider a particular macrosocial eue't"su"h as theiecay of families in the American inner city, the implosion of rural populations into Mexico city, or middle-classresistanceto the prospectiveintroduction of euro currency in France. Social scientistsaddressingsuch issues start at the level of conventional analysis.They bring order to the facts, quantifyingthem in tables,graphs,and statisticalinterpretations.They examinethe historical background.They draw comparisonwith similar phenomena in other places, examine the constraintsand biasesof the surrounding culture, and determine whether the genre to which the event belongs is widespreador instead unique to that time and place.From all this information they intuit the causesof the event and they ask:What does the event mean, will it continue, will it occur again? Most present-daysocial scientistsstop there, and write their reports. With consilient theory, however, future analysts will probe more deeply and finish with greater understanding and predictive power. In the ideal scenario during the decades to come, they will factor in the_principles of psychology,and especially social psychology. By theselast two words I do not mean the intuition of a singie p"rro' o. " team, howevergifted, or folk beliefsabout human behavioi, however emotionally satisfying. I mean full knowledge from a mature, exact

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discipline of psychology.In short,the subiectusuallyignoredby social scientists. From this point forward let me suggesta full scenarioo[ consilient research.Our future analystsunderstandverywell how socialbehavior arisesfrom the summation of individual emotion and intention within designatedenvironments.They know how individual behaviorin turn originates from the intersectionof biology and environment. Their graspofcultural change is enhancedby insightsfrom evolutionarybiology,which interpret the species-widepropertiesof human behavior as products of genetic evolution. They are careful how they express that idea-avoiding the assumptionthat genesprescribebehavior in a simple one-on-onemanner. Instead,the analystsuse a more sophisticated formula that conveys the same meaning more accurately: Behavioris guided by epigeneticrules. Epigenesis,originally a biological concept, means the development of an organism under the joint influence of heredityand environment. Epigenetic rules, to summarizevery briefly my account in the previoustwo chapters,are innate operationsin the sensorysystem and brain. They are rules of thumb that allow organismsto find rapid solutions to problems encountered in the environment. They predisposeindividuals to view the world in a particular innate way and automatically to make certain choices as opposedto others.With epigenetic rules,we seea rainbow in four basiccolorsand not in a continuum of light frequencies.We avoid mating with a sibling, sPeakin grammatically coherent sentences,smile at friends, and when alone fear strangersin first encounters.Typically emotiondriven, epigenetic rules in all categories of behavior direct the individual toward those relatively quick and accurate resPonsesmost likely to ensure survival and reproduction. But they leave open the potential generationofan immense arcayof cultural variationsand combinations.Sometimes, especiallyin complex societies,they no longer contribute to health and well-being. The behavior they direct can go awry and militate againstthe best interestsof the individual and society. At this point my imagined analysts,by plumbing the irrational in human affairs, will have traced an Ariadne's thread of causal explanation from historical phenomena to the brain sciencesand genetics; hence they will have bridged the divide between the social and natural sciences.Such is the optimistic forecastsharednowadaysby a small number of scholarson both sidesof the divide. It is opposedby at least

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an equal number of critics who find it philosophicallyflawed,or if not flawedat leasttechnicallytoo difficult everto achieve.AII my instincts tell me it will happen.If the union can be achieved,the socialsciences will span a wider scaleof time and spaceand harvestan abundance of new ideas.Union is the bestway for the socialsciencesto gain in predictive power.

How ro ExpAND the scaleof time and space?There are manypotential entries acrossthe whole range of human behavior, including those entailing art and ethics that I will take up in succeedingchapi ters.For one immediatelyrelevantto the socialsciences,considerthe fundamental theory of the family, developed during the past thirty by evolutionary biologistsand psychologists.In 1995Stephen T. 1ea1s Emlen of cornell universitycompleteda reworkingof the theory with specialreferenceto cooperationand conflict betweenparentsto their grown offspring who form social groups. The basic assumption is evolution by natural selection:cooperation and conflict have evolvedas instincts becausethey improve the survival and reproduction of the individuals displaying them. The data Emlen ur.d to expand the assumption, and to test the theory built from it, were drawn from sfudies

by many independentinvestigators of over one hundredspeciesof birdsandmammalsaroundtheworld. The patternspredictedby the theory were by and large closely matchedby the evidence.Although the data weredrawne*crusively from the instinctivebehaviorof animals,the relevanceof the patterns to core themesin the socialsciencesand humanitieswill L""o*. quicklyobvious: ln birdsand nonhumanmammals,familiesare basicallyunstable, but theleastsoin thosecontrollinghighguality resources. Dynasties, in whichonegeneticlineagepersists overmanygenerations, arisein territoies permanently rich in resources. Thecloserthegeneticrelationships of thefamily members, asfor ex_ amplefather-to-son asopposed to uncle-to-nephew, thehigherthedegree of cooperation. Due thiscooperativeness and thegeneralinstinctiveavoiclance of ,to incest,the closerthe geneticrelationshipof the family members,the Iowerthefrequency of sexualconflict. How closelyfamilymembers arerelatedalsoaffectsformsof conflict

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in ffipringwhen patemity investless Breedingmales and commihnent. of a singleconiugalpah, and oneof is uncertain.If the family consists offspringcompetewith the suniving the parentsis lost,the opposite-sex parentfor breederstatus.When the fatherdies,for example,a still fe' cundmotheris likely to enterintoconflictwith her sonoverthestatusof a mate he may newly acquire,and a sonis likely to discouragehis a newsexualrelationshipmotharfrom estabkshing is that Onegeneralresultof thispattemof conflictand commitment are lessstablethan biologicallyintact families.Stepparents stepfamilies investlessin existingoffspringthanbiologicalparents.ln manyspecies of theirownre' the success they kiUcunentyoungif suchactionspeeds belongsto the production.Thisis especiallylikelywhenthe stepparent dominantsex. Reproductionwithin a family (usingmatesacquiredfrom the out' in thealtemasharedwhenthereis an improvement side)is increasingly and startfamiliesof their members to disperse tiveoptionfor subordinate aregenetiis greatestof aII whenthe members own. Suchforbearance individualsare siblingsrather and whenthecooperating callyveryclose, than parentsand offspring. theoryto humans,it is of courseever In applyingthisdocumented massiveintervention of cultural of the prudent to remain aware great change.The resultingvariationof conventionsis sometimes the we call enoughto includethe bizarreandperverse-whatelsecan former eatingof the kuru-riddenbrainsof deadrelativesby the Fore peopleof New Guinea,which condemnedthem unknowinglyto a has in behaviorsuchasincestavoidance But experience fataldisease? shownthat the hard instinctsof animalsare hanslatableinto epigenetic rulesof human behavior.Like ancientsettlementmoundson the spade,theyarewherethe Euphratesplain awaitingthe archaeologist's The practicalroleof sought' long historyof a culture is mostefficiently evolutionarytheoryis to point to the mostlikely locationof the epigeneticrules.

bestpoisedto THs ENTERpRIsEwITHIN the socialsciences resembles that most the one sciences, natural to the the gap bridge fortiThis discipline, is economics. them in styleand self-confidence, Nobel own its by annually fied with mathematicalmodels,garlanded

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Memorial Prize in Economic Science,and rewardedwith power in businessand government, deservesthe title often given it, eueen of the SocialSciences.But its similarityto "real" scienceis often superficial and hasbeen purchasedat a steepintellectualprice. The potential and price of economic theory can be most clearly understoodagainsta historical background.frirg Niehans, in his magisterialworkA History of EconomicTheory,recognizes three periodsin the evolution of mainstream economics. In the Classical Era of the eighteenth and early nineteenth centuries the founding fathers, including Adam Smith, David Ricardo, and Thomas Malthus, envisionedthe economy as a closedsystemof circulating income. Driven by supply and demand, the economy conhols the world's resources and converts them to beneficial ends. The central postulate of freemarket economicswas introduced during this period by Adam Smith. According to his conception of the invisible hand, individual producers and consumerswill, when freed to pursue their own best interests, propel the economy forward and thereby work to the best interestsof the societyasa whole. In the Marginalist Era, which began around r83o and peaked some forty yearslater, the focus shifted toward the properties of the invisible hand. The imagined inner workingsof the economy were broken down into individual decisionsby those agents-persons, firms, governments-whose activities could be examined with the aid of mathematical models. Within the framework of abstract, physicslike theory the analystscould then manipulate the economy as a virtual world, assessingand predicting the effectsof shifting levels of production and consumption. Differential calculus was employed to evaluate e€onomicchangeasthe consequenceof verysmall, hence "marginal" shifts in production and consumption. With growing or declining scarcityand demand,each unit of new production-say of gold, oil, or housing-correspondingly rises or falls in price. In aggregate,these shifts,working through complex webs of exchange,drive the economy either toward or awayfrom steadystatesin supply and demand. Thus was constructedthe foundation of microeconomics,which purports to plot economic change in exact measures:marginal cost, the increasein total cost incurred by the production of one additional unit of product; marginal product, the growih in total output from one additional unit of productive input; marginal revenue, the growth of

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total revenuefrom the saleof a unit of output; and marginal utilig the satisfactionaddedby the consumption of a unit of production. In the manner of the natural sciences,the modelsof marginalisteconomics allow the variablesto change alone or in combination while holding the remainder constant.When played skillfully, the models make a tidy picture. The macroanalysisof the ClassicalEra was then combined with the analytic microanalysisof the Marginalist Era, most influentially byAlfred Marshall in his r89o Principlesof Economics.The result, in the phrasecoined by Thorstein Veblen in r9oo, was neoclassicaleconomics. Neoclassicaleconomicsis what we have today,but there was one more overlappingperiod, the Era of Model Building, that brought it to fruition. Beginning in the r93os,theoristsaddedlinear programming, game theory and other powerful mathematicaland statisticaltechniques in their effortsto simulatethe economicworld in ever finer detail. Invigoratedby the senseof their own exactitude,they continued to return to the themes of equilibria and perturbationsfrom equilibria. They specified,as faithfully as they could, supply and demand, impulsesof firms and consumers,competition, market fluctuations and failures,and the optimal usesof labor and resources. The cutting edge of economic theory today remains the equilibrium models of neoclassicaltheory. The emphasisis alwayson rigor. Analystsheartily agreewith Paul Samuelson,one of the most influential economistsof the twentieth century that "economics focuseson conceptsthat actuallycan be measured." of presentdayeconomic Therein lie the shengthsand weaknesses theory. Because its strengthshave already been abundantly celebrated by legions of textbook writers and journalists, Iet me dwell on the weaknesses.They can be summarized in two labels:Newtonian and hermetic. Newtonian, becauseeconomic theoristsaspireto find simple, general lawsthat cover all possibleeconomic arrangements.Universality is a logical and worthy goal, except that the innate traits of human behavior ensurethat only a minute setof such arrangementsis probable or evenpossible.Justasthe fundamentallawsof physicscannot be used alone to build an airplane, the general constructionsof equilibrium theory cannot be used alone to visualize an optimal or even stable economic order. The models also fall short becausethey are hermetic-that is, sealedofffrom the complexitiesof human behavior and the constraintsimposed by the environment. As a result,

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economic theorists, despite the undoubted genius of many, have enjoyed few successesin predicting the economic future, and they have sufferedmany embarrassingfailures. Among the successes are partial stabilizationsof a few national economies. In the United Statesthe Federal Reserve Board now has enough knowledge and legal power to regulate the flow of money and prevent-we trust!-the economyfrom spinning into catastrophicinflations and depressions.On another front, the driving force of technological innovation on growth is reasonablywell understood, at least roughly and in retrospect.On yet another,capital-asset pricing models havea maior influence on Wall Street. We are better offif the economistsspeakthan if they remain silent. But the theorists cannot answer definitively most of the key macroeconomic questions that concern society, including the optimal amount of fiscal regulation, future income distribution within and between nations, optimal population growth and dishibution, long-term financial securityof individual citizens,the roles of soil, water, biodiversity, and other exhaustible and diminishing resources,and the stren$h of "externalities" such as the deteriorating global environment. The world economy is a ship speedingthrough uncharted waters strewn with dangerousshoals.There is no general agreement on how it works. The esteem that economists enjoy arises not so much from their record ofsuccessesas from the fact that businessand government havenowhereelseto turn. This is not to say that economistswould do better to abandon mathematical models in favor of intuition and description. The great merit of models, at least in the natural sciences,is that they force investigatorsto provide unambiguous definitions of units, such asatoms and genes,aswell asprocesses, such asmovementand change.When well conceived, a model leavesno doubt about its assumptions.It lists the important factors and offers educated guessesabout their interaction. Within this self-imposed framework, the investigator makes predictions about the real world, and the more precise the prediction, the better. He thus puts the product of his thinking on the line by exposing it to evidential proof or disproof. There is nothing in science more provocativethan a cleanly defined and surprising prediction, and nothing held in higher regard than such a prediction confirmed in detail. To this end, scientistslook for four qualities in theory generally and

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mathematical models in particular. The first is parsimony:the fewer the units and processes usedto account for the phenomenon,the better. Becauseof the successof parsimony in the physicalsciences,we do not today need an imaginarysubstancecalledphlogistonto explain the combustion of firewood, or nonexistentether to fill the void of space.The second quality is generality: the greater the range of phenomena covered by the model, the more likely it is to be true. In reagent chemistry the periodic table precludesa separatetheory for each element and compound. One theoryworksexactlyfor all. Next is consilience.Units and processesof a discipline that conform with solidly verified knowledge in other disciplineshave proven that consistentlysuperiorin theory and practiceto units and processes do not conform. That is why, in everyscrapof data from everylevel of biology,from the chemistryof DNA to the dating of fossils,it hasbeen the casethat organicevolution by natural selectionbeatsCreationism. God may exist, He may be delighted with what we are up to on this minor planet, but His fine hand is not needed to explain the biosphere.And finally, drawing from all of the abovevirtues, the definitive quality of good theory is predictiveness.Those theories endure that are precise in the predictions they make acrossmany phenomena and whosepredictionsare easiestto test by observationand experiment. Before evaluatingeconomic theory by thesecriteria,I think it only fair to assessa branch of biolog, with a comparable level of technical difficulty. Population genetics addressesthe frequencies and distributions of genesand other hereditaryunits within entire populations(an example of a population is all the members of a speciesof fish inhabiting a lake). Populationgenetics,having accumulated,like economic theory a vast encyclopedia of models and equations, is arguably the most respecteddiscipline within evolutionary biolory. Its Ur-model is the Hardy-Weinberg principle, or "law," a simple probability formula based on elementary Mendelian genetics.The Hardy-Weinberg principle tells us that if in a sexually reproducing population there are two forms, or alleles, of the same gene, say each prescribinga different blood type or ear shape,and if we know the percentagesof the two alleles in the population, we can accurately predict the percentagesof individuals possessingdifferent pairs of the alleles. Conversely, from the known percentageof just one such pair, we can at once statethe percentageof the allelesfor the whole population.Here is an example to show how it works.The earlobe in different people either hangs free

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or is attached to the side of the head, and the difference is due to two forms of the samegene.Call the free earlobealleleA and the attached earlobeallele a. Freeearlobeis dominant over attachedearlobe.Then all individuals in the population have one or the other of the three folIowing combinations: AA, free earlobe Aa,free earlobe aa,attachedearlobe Following convention in genetics, the frequency (ranging from o to r.o, that is, zero to roo percent)of A is labeledp, and the frequencyof a is labeled q. The Hardy-Weinbergprinciple is the consequenceof Mendelian heredity and the randomnesswith which an allele in an egg is matched with an allele in a sperm at fertilization. It is writter\ as a simple binomial expansion,since by definition p + q : r.o and therefore(p + q)' : (r.o), : r.o, and therefore p + q:

(p + qI:

p , + z p q* q , : r . o ,

where p, is the frequency of AA, zpq the frequency of Aa, and q, the frequency of aa. The rationale of the formula is the following: There is p chance that an egg containsA, and p chance that the sperm fertilizing it is also A, so there is p, chance (hence, frequency) that the individual created is AA, and so on through pq and q,. Suppose that 16percent (the frequency is o.16)of the members of a population have an attached earlobe, in other words, their two alleles are aa. Then the Hardy-Weinberg formula predicts that 4o percent (o.4, the square rootof o.16)of the allelesin the population are a, and 6o percentA. It also predictsthat 36 percent (o.36,or o.6o X o.6o) of the individuals have the combinationAA, and 48 percent (o.48,or z X o.4 x o.6) have Aa. There are some large conditions attached to the use of the HardyWeinberg formula in the real world. But these are not crippling. Instead,they are what make H-W interesting and even more useful. The simple H-Wpredictions will be exactly correct if natural selection does not favor one of the gene combinations over the others, if all the members of the population mate at random, and if the population is infinitely large. The first two conditions are improbable and the third impossible. In order to get closer to reali$, biological theorists "relax" theserestrictionsone at a time, and then in variouscombinations.For

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example,they reduce the number of imaginedorganismsfrom infinite to the numbersactually found in real populations,usuallysomewhere from ten to a million, according to species.They then take into account chancevariation in the genefrequenciesfrom one generationto the next. The smaller the population, the greater the variation. The sameprinciple dictatesthat if a sampleof one million unbiasedcoins are flipped in repeatedtrials, the resultwill almostalwaysbe very close to half heads,half tails, whereasif only ten coins are flipped at a time, an exactsplit will be obtained only occasionally;and in one in an average 5r2trials all the coins will be either all headsor all tails. Now think of sexual reproduction as the equivalent of coin flipping, and each generationasa new coin-flipping trial. The change in genefrequencyfrom one generationto the next by chanceis evolution by genetic drift. In populations with a hundred individuals or fewer, genetic drift can be a potent force. Its rate can be preciselydescribed by statistical measuresthat tell us about the fate of large samplesof populations of the same size. These measuresrevealthat the main effect of genetic drift is to reduce variation by eliminating some of the gene forms. That, combined with the randomnessof the change,meansthat genetic drift is a far lesscreativeprocessthan natural selection. As natural selection is added to the models,it reducesthe impact of genetic drift while driving the gene frequenciesin one direction or another at predictable velocities. Population geneticistsmake their models still more complex and presumablycloserto nature in various ways. For example, they decree mating to be nonrandom, or break populations into fragments that continue to exchange migrants, or arrangefor constellationsofgenesratherthan singlegenesto prescribe the characterhaits. The models of population geneticistsyield exactpredictionsin the virtual worlds bounded by the assumptions selected for evaluation. They can often be matched by carefully managedpopulationsof animals and plants in the laboratory. They are notoriously poor, however, at predicting evolution in nature. The flaw is not in the internal logic of the theory but in the unpredictability of nahrre itself. The environment constantly shiffs, altering the values of the parameters that geneticistsput into their models. Climatic changeand weathercatastrophesbreak up some populationswhile freeingothersto expandand coalesce. New predators and competitors invade as old ones retreat.

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Diseasesweepsthe habitats.Traditionalfood sourcesvanishand new onesaPpear. Evolutionary biologists,like weatherforecasters,are confounded by the turbulence of the real world. They have had some successin predicting changesin small ensemblesof genesand traits over a few generations.They can explain rehospectivelymany of the maior twists and turns of long-term evolution from the fossil record and from the logical reconshuctionof family treesof living species.But rarely have they been able to predict future eventswith any degree of accuracy. They have equal difficulty rehodicting past events-that is, predicting the occurrence of such past eventsbefore a search is made for haces of the eventsand reconshuctionsare performed.They are unlikely to do so until ecolory and the other environmental sciences have sufficiently matured to become predictive themselvesand thus provide the full and exactcontextin which evolutionoccurs. Economics,at the cutting edge of the social sciences,sharesthe same difficulties as population geneticsand the environmental sciences. It is battered by "exogenousshocks,"all the unaccountable eventsof history and environmental changethat push the parameter valuesup and down. That alone limits the accuracyof economic predictions. Except in the most general and statisticalterms, economic models cannot forecastthe onset of bull and bear markets, or the decadesJongcycles triggered by war and technological innovation. They cannot tell us whether tax cuts or national deficit reduction is the more effectivein raising per capita income, or how economic growth will affectincome distribution. Economic theory is impeded by a second, equally fundamental difficulty.Unlike population geneticsand the environmental sciences, It has not acquiredor it lacksa solid foundation of units and processes. even attemptedseriousconsiliencewith the natural sciences.All analystsunderstand that the broad patternsof economic processoriginate in some fashion or other from vast numbers of decisions made by human beings,whether as individuals or as members of firms and governmental agencies.The most sophisticatedmodels of economic theory attempt to translate such microeconomic behavior into the larger aggregatemeasuresand patterns broadly defined as "the economy." In economics and in the remainder of the social sciencesas well, the translation from individual to aggregatebehavior is the key analytic problem. Yet in these disciplinesthe exact nature and sources

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of individual behavior are rarely considered.Instead,the knowledge used by the modelersis that of folk psychology,basedmostly on common perception and unaided intuition, and folk psychologyhas alreadybeen pushedway pastits limit. The flaw is not fatal. Economic theory is not Ptolemaic, not so structurally defectivethat a revolution in conception is needed.The most advancedof the micro-to-macromodels are on the right hack. But the theoristshave unnecessarilyhandicappedthemselvesby closing off their theory from seriousbiology and psychology,comprising principles drawn from close description, experiments,and statistical analysis.They have done so, I believe,in order to avoid entanglement in the formidable complexities of these foundation sciences.Their strategyhas been to solve the micro-to-macro problem with the fewest possibleassumptionsat the micro level. In other words,they have carried parsimony too far. Economic theories also aim to create models of the widest possibleapplication, often crafting abstractionsso extreme as to representlittle more than exercisesin applied mathematics. That is generalitycarried too far. The resultof such stringencyis a body of theory that is internally consistentbut little else.Although economics, in my opinion, is headed in the right direction and provides the wedge behind which social theory will wisely follow, it is still mostly irrelevant. The strengthsand weaknesses of economictheoryare illustratedin the work of Gary S. Becker of the University of Chicago, awarded the r99z Nobel Prize in Economic Science for "having extended the domain of economic theoryto aspectsof human behaviorwhich had previously been dealt with-if at all-by other socialsciencedisciplines such as sociology, demography, and criminology." What Becker accomplished wasto cut more deeply than previouseconomistsinto the sourcesof human preferences.He recognizedthat most of economic reasoningis basedon the implicit assumptionthat people are driven by basic biological needsfor food, shelter,and recreation.But there are other incentives,he said,such asthe type of housing and furniture, the restaurants,and forms of leisure they prefer, that lie outside the elemental imperatives.All these choices and more depend on variations in personalexperienceand social forcesbeyond individual control. If human behavior is to be explained fully, the utility of the choices (that is, their value perceivedby the consumer) must be entered into economicsmodels.

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The inviolable assumptionof Becker'sthinking is the principle of rational choice. Inhoduced by earlier economistsas the keystone of quantitative modeling, it sap simply that people maximize their satisfaction by acts basedon calculation. Economic models using this conception had been largely limited to utility based on narrow selfinterest. Becker urged his fellow economiststo broaden their vista to include the subject matter of the other social sciences.They should consider desiresthat are variouslyaltruistic,loyal, spiteful, and masochistic.These too, he argued,are forcesthat governrational choice. Extending the reach of formal models, Becker and other economists of like mind have addressedwith greater confidence some of industrial societyt most vexing problems. Turning to criminology, they have recommended methods of optimal deterrence-economic of course-for differentclassesof offense,from capital crimes and armed robbery to embezzlement, tax evasion, and the breaking of laws that regulatebusinessand environmental protection.Venturing into sociology, they have assessed the impact of racial discrimination on production and unemployment,and of economic classon marital choice. In public health, they have analyzedthe effectsof legalization and tax loadson the useofcigarettesand conholled substances. Their models contain elegant graphical representationsand analytic solutions to theoretical problems of equilibria. Yet seen through the establishedprinciplesof the behavioralsciences,they are simplistic and often misleading.The choicesin personalbehavior reduce to a small number of options, such as whether to smoke or not, to marry within the same socioeconomicclass or not, to risk committing a crime, or to move to a same-raceneighborhood. The predictions consist of "more of this, less of that" and they approximate thresholds at which trends will commence, taper off, or reversedirection. Typically the predictions arisefrom the commonsenseintuitions of the modeler, that is, from folk psychology,and following a seriesof formal analytical steps, confirm commonsense beliefs. We are told in crisp technical languagethat a permanentincreasein the price of cigareftesreduces consumption from the outset more than a temporary increase, that in order to preservetheir wealth the rich take measuresto avoid meeting and falling in love with the poor, that people gain satisfaction from going to aheadypopular restaurantseven if competitors are as good in price and cuisine,and so forth. Seldom are the premisesof such modelsexaminedclosely.Seldom are their conclusionstestedto any depth

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with quantitativefield data. Their appealis in the chrome and roar of the engine,not the velocity or destination. The goal of psychologically oriented analystssuch as Becker, as well as Jack Hirshleifer, Thomas Schelling, Amartya Sen, George Stigler,and othersof similar interests,is to strengthenmicroeconomics and draw from it more accuratepredictionsof macroeconomicbehavior. That, of coutse, is admirable. To advancemuch further, however, they and other socialscientistswill haveto crossthe boundarybetween the social and natural sciencesand hade with the biologistsand psychologiststhey find on the other side. fust as, in his Nobel Lecture, Becker statedthat his contribution was "to pry economistsawayfrom narrow assumptionsabout self-interest," the next stepis for economists to free themselvescompletely, at long last, from the StandardSocial Science Model of behavior and take seriously the biological and psychologicalfoundations of human nature.Amazingly,despiteoverwhelming evidenceagainstit, the great majority still cling to the view that asidefrom meeting basicbiological needs,people in modern societies make choices, in Becker's words, that "depend on childhood, social interactions, and cultural influences." Not, apparendy,the hereditaryepigeneticrules of human nature.The impoverishingconsequenceof this view has been the acceptanceof folk psychologyin even the most ingeniousmodels.

T o r N p u s s p s y c H o L o c y a n d b i o l o g yi n t o e c o n o m i ca n d o t h e r social theory which can only be to its advantage,means teasing out and examining microscopically the delicate concepts of utility, by asking why people ultimately lean toward certain choices,and being so predisposed,why and under what circumstances they act upon them. Beyond this task lies the micro-to-macro problem, the ensemble of processesby which the massof individual decisionsare translatedinto social patterns.And beyond that, framed by a still wider scale of space and time, is the coevolution problem, the means by which biological evolution influences culture, and the reverse.Together these domains-human nafure, micro-to-macrotransition,and the coevolution of genesand culture-require the full traversefrom the socialsciencesto psychologyand thence to the brain sciencesand genetics. The evidence from scattered studies in psychology and biology alreadysuggestcertain generalizationsabout utility:

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. The categoriesof choice, the major activities in moment-bymoment thought and behavior, are epistatic: Needs and opportunities in one categoryalter the shength of others. The rank order in dominance among categoriessuch as sex, status protection, and play appearsto be geneticallyprogrammed. . Some needs and opportunities are not iust epistatic but preemptive. Conditions such as drug addiction and sexual possessiveness can hiiack emotionsto focus on unitary goalsso powerful as to virtually deleteactivitiesin many other categories. . Rational calculation is basedon surgesof competing emotions, whose interplay is resolved by an interaction of hereditary and environmental factors.Incest avoidance,for example, is underlaid by a shong hereditary epigenetic rule. It can be reinforced by cultr:ral taboosor overcomeby special,increasinglywell understoodpersonal experiences. . Rational calculation is often unselfish.For complex, still poorly understood reasons,some of the most powerful emotions are patriotism and altruism.It remainsa surprisingfact that a substantialpercentage of people are willing at a moment's notice to risk their lives to save those ofstrangers. . Choicesare groupdependent; that much is obvious.But what is less well known is that the power of peer influence varies strikingly from categoryto category of behavior. Clothing style, for example, is almostwholly dependenton peer influences,while incestavoidanceis largely independent. Do these differences have a genetic basis and thus an evolutionary history? Probably they do, and it is time to start examining them for this possibility more carefully. . Decision-making is shaped category by category by epigenetic rules, which are the innate propensitiesto learn certain options in the first place and then to select particular ones among them. On average many of the propensitiesdiffer according to age and gender. The psychobiological subtlety of decision-making is nicely illustrated by the r-K continuum of reproductive strategies.When resources are few and unstable, people tend to adopt an r shategy, preferring many children to insure that at least a few will survive. When resourcesare abundant and stable, they lean toward a K strategy, in which fewer, "high-quality" offspring are carefully protected

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level.(Thesymbolr for entryatan uppersocioeconomic and educated to the rateof populationgrowth,which riseswith refersin demography the r strategy;andthe symbolK to the carryingcapacityof the environOverlyingthe r-K ment, the sizeat which populationgrowthceases.) continuumis the generaltendencyof sociallypowerfulmalesto acage,therebyboostingtheirDarquiremultiplewomenof reproductive winianedge.

Tne Fur,L uNDERSTANDINcof utilitywill comefrombiolory by reductionto the elementsof humanbehaviorfoland psychology lowed by bottom-upsynthesis,not from the socialsciencesby top It is in basedon intuitiveknowledge. down inferenceand guesswork will and othersocialscientists that economists biologyand psychology models, as predictive needed fashion more premises to find the iust it thatuppremises found wasin physicsandchemistrythat researchers gradedbiolog,. The performanceof future social theory also dependson a ofreasonitself.At presunderstanding ofthe process psychobiological rational ent the dominantmodeof explanationis the aforementioned then spreadto political choicetheory.Firstconceivedin economics, its centralconceptionis that aboveall scienceand otherdisciplines, rational in theiractions.They examineasbest elsehumanbeingsare they can all the pertinentfactorsand weighthe likely outcomeof following eachpotentialchoicein hrrn. They add in costand benefitrisk,andemotionalandmaterialreturn*beforedeciding. investment, The preferredoptionis that which maximizesutility. pictureof how peoplethink' The human This is not an adequate brain is not a veryswiftcalculator,and mostdecisionshaveto be made rather quickly,in complexsettingsand with incompleteinformation. So the questionof importancein rationalchoicetheoryis, how much informationis enough?In otherwords,atwhatpointdo peoplestopreflecting and makeup their minds?One simplestraterythat providesa cut-off point is "satisficing,"a Scottishterm that combines"satisfring" in ry57by HerbertSimon, and "sufficing."Introducedto psychology meanstaking satisficing an economistat CarnegieMellon University, choiceencounteredout ofthoseperceivedandreathe first satisfactory sonablyavailablein the shortterm, asopposedto visualizingthe optiuntil it is found.A youngman mum choicein advanceand searching

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readyfor mariage is morelikely,by satisficing,to proposeto the most athactiveprospectamongthe availablewomen of his acquaintance than to searchat len$h for a preconceived idealmate. An alternativeto this and otherconceptionsof traditionalrational choiceis thatpeoplefollowrulesof thumb,knownmoretechnicallyas "heuristics."The idea wasfirst advancedby the American psychologistsDaniel KahnemanandAmosTverskyin rg74.Ratherthan calculatecostsandbenefits,peopleact uponsimplecuesand heuristicsthat work most of the time. By this meansthe complextasksof assessing probabilitiesand predictingoutcomesarereducedto a few iudgmental operations. Usuallyheuristicswork, and savea greatdealof time and enerry, error.An example but in manysituationstheyleadto largesystematic is the heuristicusedin rapid arithmeticalcalculationand known as "anchoring."You can seehow it worksby comparingthe two setsof multiplied numbersbelowfor five secondsand guessingthe products: 8x7x6x5X4X3XzXt rXzX3x4x5X6X7X8 Most peoplegive the top row the highervalue,eventhough the two setsof numbersare identical.Readingleft to right, they anchortheir guesson the first numbersencountered.Th"y also underestimate both. High schoolstudentstestedby Kahnemanand Tverskyaveraged z,z5ofor the upperrow and 5rzfor the lower,whereasthe correctanswerfor both is 4a12o. inaccurateheuristicin the Here is an exampleof a systematically realm of probability.A majorityof people,watchinga coin being tossed,believethatthe followingsequence of sixalternatingheadsand tails, H-T-H.T:]:H is more likely to occur than one with the sameelementsrepeatedin groups,suchas H-H-H-T:T:T In fact,both areequallyprobable. Why aresuchconsistenterrorsmadeby mindsthat can be trained to graspcalculusand statistics? The correctanswermay lie in genetic

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evolution: Over thousandsof generationsthe brain evolvedto handle simple numbersand proportionsbut not complex problemsrequiring abstract quantitative reasoning. The heuristics illustrated by the two examples above are therefore folk mathematics. Although their solutions are skewedin attemptsat complex formal calculation,they may work very well in real life, where most first impressionsaccuratelyprefigure eventsto follow. The same explanation fits other odd mistakesmade by heuristics. For example, a familiar dish with a different taste is likely to be passed over, even though the ingredients are demonstrably fresh and wholesome.Following a plane crash,many intercity travelersswitch to automobiles, even though they know the fatality rate per passengermile is much higher on the road. Irrational choicesyes,but perhapsobedient to the superordinateheuristic of risk aversion,which can be translated in these two examples as follows: Thke no chances whatsoeverwith food poisoning,and stay awayfrom placeswhere othershave been recendy killed, regardlessof what the mathematical laws of probabilig tell you. Further researchmay reveal that the brain sometimesoperatesasa computerlike optimizer and sometimes as a quick decision-maker ruled by powerful and inborn heuristics. Whatever the mix, rational choice theory, though still the light and the way to many social theo. rists,is a subjectof conhoversywithin psychology.It is too dependent, critics say, on analogies with computer algorithms and abstract optimality solutions. It pays too little attention to the properties of the real brain, which is a stone-ageorgan evolvedover hundredsof millennia and only recently thrust into the alien environment of indushialized society.It is thus inconsistent with the evidence of how people in preliterate cultures reasonand have likely reasonedthroughout evolutionary time. These qualities have been summarizedby C. R. Hallpike in The Foundations of Primitive Thought, as follows: intuitive and dogmatic, bound up with specific emotional relationshipsrather than physical causality,preoccupied with essencesand metamoqphosis, opaque to logical abstraction or arrays of the hypothetically possible, prone to use languagefor social interaction rather than as a concePtual tool, limited in quantification mostly to rough imagesof frequency and rarity, and inclined to view mind as stemming partly from the environment and able to proiect back out into it, so that wordsbecomeentities with power unto themselves.

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It will be at once apparent,and should be a working premise of economists and other social scientists,that the same preliterate traits are commonplacein citizensof modern industrial societies.They are intensified among cult members, the deeply religious, and the less educated.They permeateand enrich the metaphorsof art. They are, Iike it or not, part of modern civilization. Systematiclogico-deductive thought, which is very much a specialized product of Western culture, comeshard on the other hand, and is still rare.While perfecting it we will be wise, I think, to discipline the old ways of thought but never to abandon them, never to forget that as part of adaptive human nature they conducted us alive and fecund all the way to the present age.

TH s trdA,c N I r u D E o F the technical problems facing the social theorists in particular is, I readily concede, extremely daunting. Some philosophersof sciencehavethrown up their hands,declaringthat the borderlandsbehveenthe natural and social sciencesare too complex to be masteredby contemporaryimagination and may lie forever beyond reach. Questioning the very idea of consilience from biology to culture, they point to the nonlineari$ of the viable equations,to second-and third-order interactions of factors, to stochasticity,and to all the other monstersthat dwelleth in the Great Maelstrom Sea, and they sigh, No hope, no hope. But that is what philosophersare suP posedto do. Their taskis to define and explain the limits of sciencein the larger scheme of things, where the full dimensions of rational processare betterleft to-well, philosophers.For them to concedethat sciencehas no intellectuallimits would be unseemly;it would be unprofessional.Their misgivingslend strength to that dwindling number of social theorists who wish to keep the borders of their dominions sealedand the study of culture unroiled by the dreams of biology. Scientiststhemselvesare fortunatelynot so bound. If pastgenerations had been so deeply reflective and humble before the unknown, our comprehension ofthe universe would have stoppedgrowing in the sixteenth century. The chastening sting of the philosopher's tongue is needed bui should be taken with the antidote of self-assurance,and never allowed to be fatal. It is the opposite conviction, blind faith if you prefer, that has propelled science and technology into the modern age. Bear in mind that the original Enlightenment died within

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philosophers philosophy but not within science. The morepessimistic maybe right aboutthe socialsciences, of course,but it isbetterto press on asif theywerewrong.There is only one wayto find out. The more forbiddingthe task,the greaterthe prize for thosewho dareto undertakeit.

CHAPTER

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Tnn Anrs AND Tsern INTeRPRETATIoN

to consilient challenge IN ueNv RESpEcrs, the mostinteresting the latter I mean explanationis the transitfrom scienceto the arts.By the creativearts,the personalproductionsof literature,visual arts, drama,music,and dancemarkedby thosequalitieswhich for lack of betterwords(andbetterwordsmay neverbe coined)we call the true andbeautiful. The artsare sometimestaken to meanall the humanities,which includenot only the creativeartsbut also,followingthe recommendationsof the ry7g-8oCommissionon the Humanities,the coresubjects of history philosophy,languages,and comparativeliterature, plus jurisprudence,the comparativestudyof religions,and "thoseaspects whichhavehumanisticcontentand employhuof the socialsciences the arts in the primary and intuimanisticmethods."Nevertheless, tivelycreativesense,arsgratia artis,remainthe definitionmostwidely and usefullyemployed. Reflectionleadsus to two questionsabout the arts:where they come from, in both historyand personalexperience,and how their essentialqualitiesoftruth andbeautyareto be describedthroughordinary language.Thesemattersare the central concernof interpretation, the scholarlyanalysisand criticism of the arts.Interpretationis

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itselfpartly an art, since it expresses not iust the factual expertiseofthe critic but also his characterand aestheticjudgment. When of high quality, criticism can be as inspired and idiosyncratic asthe work it addresses.Further, as I now hope to show,it can also be part ofscience, and sciencepart of it. Interpretationwill be the more powerful when braided together from history, biography,personal confession-and science. The profaneword now having been spokenon hallowedground,a quick disclaimer is in order. While it is true that scienceadvancesby reducing phenomenato their working elements-by dissectingbrains into neurons, for example,and neurons into molecules-it doesnot aim to diminish the integrity of the whole. On the contrary synthesis of the elementsto re-createtheir original assemblyis the other half of scientificprocedure.In fact, it is the ultimate goal of science. Nor is there any reasonto supposethat the arts will decline as science flourishes. They are not, as suggestedrecently by the distinguishedliterary critic George Steiner,in a twilight, pasthigh noon in Western civilization, thus unlikely to witnessthe reappearanceof a Dante, a Michelangelo, or a Mozart. I can conceive of no intrinsic limit to future originality and brilliance in the artsas the consequence of the reductionist understanding of the creativeprocessin the artsand science. On the conhary, an alliance is overdue, and can be achieved through the medium of interpretation. Neither science nor the arts can be complete without combining their separatestrengths.Science needs the intuition and metaphorical power of the arts, and the artsneed the freshblood ofscience. Scholarsin the humanities should lift the anathemaplaced on reductionism. Scientistsare not conquistadorsout to melt the Inca gold. Science is free and the arts are free, and as I argued in the earlier account of mind, the two domains,despitethe similaritiesin their creative spirit, have radically different goals and methods. The key to the exchange between them is not hybridization, not some unpleasantly self-consciousform of scientific art or artistic science,but reinvigoration of interpretation with the knowledge of science and its proprietary senseof the future. Interpretation is the logical channel of consilient explanationbetweenscienceand the arts.

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chosen, F o n a p R o M I s r N G E X A M p L Eo u t o f m a n y t h a t m i g h t b e consider the episode in ParadiseLnst-Book IV, when, in a riveting narrative,Milton sendsSatanto Eden. Upon arrival the arch-felon and grand thief leaps a barrier of impenehable bramble and a high wall and settles"like a cormorant" in the branches of the Tree of Life. He waits for the fall of night, when he can enter the dreams of innocent Eve. Milton now unleasheshis imaginative powers to tell us what humanity is about to lose.All around the roosting schemer is the environment designedby God to aestheticperfection: "Crispbd brooks,rolling on orient pearl and sands of gold" descend to "a lake, that to the fringbd bank with myrtle crowned her crystal mirror holds." All through the blessed oasisgrow "flowers of all hue and without thorn the tose." Milton, though now blind, has retained a fine senseof biophilia, the innate pleasure from living abundance and diversity,particularly as manifested by the human impulse to imitate Nature with gardens. But he is far from satisfiedwith the mere dream of natural harmony. In eight lines of astonishing symphonic power he hies to capture the mythic core of paradise: Not thatfair field Of Enna,whereProserpingatheringflowers, Herselfa fairerflower,by gloomyDis Wasgathered,which costCeresall that pain To seekher throughthe world,nor that sweetgrove Of Daphne,by Orontesandthe inspired Castalianspring,mightwith this Paradise Of Eden strive. How can anyone hope to expressCreation's heart at the dawn of time? Milton tries. He summons archetypesthat have descendedundiminished from ancient Greece and Rome to his own time, and thereafter to ours. They are of a kind, as I will suggestlater, that are also innate to the human mental process.He shadowsbeauty with a hint of tragedy,giving us the unhammeled and fertile world awaiting corruption. He hansforms the beauty of the garden into that of a young woman, Proserpine,about to be seized and taken away to the underworld by the god Dis. She, as Nature'sbeauty,will be concealedin darkness becauseof confict between gods. Ceres, Proseqpine'smother and

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goddessof agriculture, turns in grief from her duties and the world plunges into famine. The passion of Apollo for beautiful Daphne is unrequited; in order to escapeshe turns into a tree, a laurel, in a garden ofher own. Milton means to play on the emotions of readersof his own time, the seventeenthcentury when Hellenic my"thologywassecondnature to the educated mind. He counterposes emotions to magnifi, their force. Beauty clasheswith darkness,freedom with fate, passionwith to arrive, denial. Building tension,he leadsus through lesserparadises suddenly, at the mystical prototype of Eden. [n yet another wellgrounded artifice, reliance on authority,Milton choosesallusionsnot to his own time, not for exampleto Cromwell and CharlesII and the Restoration,from which he himself has narrowly escapeddeath (he had championed revolution and the Commonwealth), but to ancient textsof another civilization, ancient Greeceand Rome, robustenough to havesurvivedin remembranceacrosscenturies.He conveysby their use that what we are not told, we must know neverthelessto be true. The defining quality of the artsis the expressionof the human condition by mood and feeling, calling into play all the senses,evoking both order and disorder. From where then doesthe ability to create art arise?Not cold logic basedon fact. Not God's guidance of Milton's thoughts,as the poet himself believed.Nor is there any evidenceof a unique spark that ignites such genius as is evident inParadise Losf. Experimentsusing brain imaging,for example,havefailed to disclosesingular neurobiological haih in musically gifted people. lnstead, they show engagement of a broader area of the same partsof the brain used by those less able. History supports this incremental hypothesis. Behind Shakespeare, Leonardo,Mozart, and othersin the foremostrank are a vastlegion whose realizedpowersform a descendingcontinuum to those who are merely competent. What the mastersof the Western in common was a canon, and those of other high cultures, possessed combination of exceptional knowledge, technical skill, originality, sensitivityto detail, ambition, boldness,and drive. They were obsessed; they burned within. But they also had an intuitive grasp of inborn human nature accurate enough to select commanding images from the mostly inferior thoughts that streamthrough the minds of all of us. The talent they wielded may have been only incrementally greater,but their creationsappearedto othersto be quali-

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iativelynew.They acquiredenoughinfluenceand longevityto translate into lastingfame,not by magic,not by divinebenefaction,but by a quantitativeedge in powerssharedin smaller degreewith those lessgifted. They gatheredenough lifting speedto soar above the rest. Artistic inspirationcommon to everyonein varyingdegreerises from the artesianwells of human nature. Its creationsare meant to be delivereddirectlyto the sensibilitiesof the beholderwithout analytic explanation.Creativity is thereforehumanistic in the fullest sense.Worksof enduringvaluearethosetruestto theseorigins.It followsthat even the greatestworls of art might be understoodfundamentallywith knowledgeof the biologicallyevolvedepigeneticrules thatguidedthem.

Tnls ls Nor the prevailingview of the arts.Academictheorists havepaidlitde attentionto biology;consilienceis not in their vocabuIary. To varyingdegreesthey have been more infuenced by postmodernism,the competinghypothesisthat deniesthe existenceof a universalhuman nature.Applied to literary criticism, the extreme manifestationof postmodernism is the deconshuctivephilosophyformulatedmostprovocatively by |acquesDerrida and Paul de Man. In this view,truth is relativeand personal.Each personcreateshis own innerworld by acceptance or rejectionof endlessly shiftinglinguistic signs.There is no privilegedpoint,no lodestar,to guideliteraryintelligence.And given that scienceis just anotherway of looking at the world, there is no scientificallyconstructiblemap of human nature from which the deepmeaningof textscan be drawn.Thereis only unlimited opportunityfor the readerto invent interpretationsand commentariesout of the worldhe himselfconstructs."The authoris dead" is a favoritemaximof the deconshuctionists. Deconstructionistscholarssearchinsteadfor contradictionsand ambiguities.They conceiveand analyzewhat is left out by the author. The missingelementsallowfor personalizedcommentaryin the postmoderniststyle.Postmodernists who add political ideologyto the mix alsoregardthe traditionalliterarycanonaslittle morethana collection confirmingthe world view of ruling goups, and in particularthat of Westernwhite males.

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The poshnodernist hypothesis does not conform well to the evidence. It is blissfully free of existing information on how the mind works. Yet there is surely some reason for the popularity of postmodernism other than a love of chaos. If the competing biological approach is correct, its widespread appeal must be rooted in human nature. Postmodernismin the arts is more than a School of Resentment-Harold Bloom's indictment in The WestemCanonand more than the eunuch's spite, to borrow a phrasefrom Alexander Pope, and it is sustainedby more than the pathetic reverencecommonly given Gallic obscurantism by American academics.There is alsoa surgeof revolutionaryspirit in postmodernism,generatedby the real-not deconstructed-fact that large segmentsof the population, most notably women, have unique talents and emotional lives that have been relativelyneglectedfor centuries,and are only now beginning to find full expressionwithin the mainstream culture. If we are to believe evidencefrom the biological and behavioral sciencesgatheredespeciallyduring the past quarter century, women differ genetically from men in ways other than reproductive anatomy. In aggregate,on average,with wide statisticaloverlap,and in many venuesofsocial experience, they speakwith a different voice. Today it is being heard loud and clear.But I do not read the welcometriumph of feminism, social, economic, and creative, as a brief for postmodernism. The advance,while opening new avenuesof expression and liberating deep pools of talent, has not explodedhuman nature into little pieces. Instead, it has set the stagefor a fuller exploration of the universal traits that unite humanity. tooked at with a different perspective,postmodernism can also be viewed as one exheme in an historical oscillation in literary world view. The great American critic Edmund Wilson noted, in 1926,that Western literature seems"obliged to vibrate" in emphasisbetween the two poles of neoclassicismand romanticism. Conceivedvery broadly, the cycle can first be picked up in the Enlightenment with Pope, Racine,and other poetswho drew on the scientists'visionof an orderly world. They were replaced in public esteemby the rebellious romantic poeb of the nineteenth century who yielded in turn to Flaubert and others returning to rational order, who gave way to a flow in the opposite direction as embodied in the modernist writings of the French Symbolish, including Mallarmd and Val6ry and of their British peers Yeats, foyce, and Eliot. Because each of the extremes

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provedultimately "unbearable"asa reigningfashion,Wilson said,it guaranteed reversiontowardthe oppositepole. The samemood swingcanbe seenin recent,post-Wilsonian literary criticism.Earlier in this centuryscholarsstressed the personalexperiencesof the authorsand the historyof their times.In the r95osthe New Critics insistedon drawingout the full meaningof the text,without much concernfor the personalhistoryof the author.They agreed with fosephConrad'sfamousdictumthata workof art "shouldcarryits justificationin everyline." In the r98osthe New Criticsquitesuddenly gaveway to the postmodernists, who arguedthe oppositeapproach. Search,they said,for what the text doesnot control, and explainthe entiretyasa socialconshuctionon the partof the author.Their stance hasbeensummarizedin a pointedmannerby the poetand critic Frederick Turner, as follows:Artistsand poets should dismissthe conshaintsof Nature evenin a time of ecologicalcrisis,ignorescience, abandonthe formsand disciplinesof the artsand hencetheir own culture's shamanichadition, turn awayfrom the idea of a universal human nature,and, havingfreedthemselvesfrom such stifling confinement,favorsnideness and rageoverhopeand otheruplifting emo. tions.Accordingto Turner,a reversalin fashionis alreadybeginning. "The traditionof Homer, Dante,Leonardo,Shakespeare, Beethoven, andGoetheis not dead.It is growingup in the cracksof the poshnodernconcrete." Edmund Wilson hopedfor a dampingof this perpetualcycle in thearts,which he considereda peculiaraffiictionof the modernmind. Favoringsynthesis in principle,he wroteof his admirationfor Berhand Russelland AIfred North Whitehead,the two greatculture unifiersof the firsthalf of the twentiethcentury.We envythe classics, he said,for the equilibriumtheyappearto haveachieved."Regularityandlogic in Sophocles do not excludeeithertenderness or violence;and,in Virgil, the sortof thing that Flaubertcando;the exactobjectivereproduction of thingsdoesnot excludethe sortof thing that Wordsworthand Shelley can do, the mlnterious,the fluid, the pathetic,and the vague."I like to think that Edmund Wilson would havebeen favorableto the ideaofconsilience.

C e,N r Hr o p p o s ED Apollonianand Dionysianimpulses,cool reasonagainstpassionate abandonment, which drive the moodswingsof

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the arts and criticism, be reconciled?This is, I believe,an empirical question.Its answerdependson the existenceor nonexistenceof an inborn human nature. The evidence accumulatedto date leaveslittle room for doubt. Human nature exists,and it is both deep and highly structured. If that much is granted,the relation of scienceto interpretationof the arts can be made clearer, as follows. Interpretation has multiple dimensions,namely history,biography,linguistics,and aestheticiudgment. At the foundation of them all lie the material processesof the human mind. Theoretically inclined critics of the past have tried many avenuesinto that subterraneanrealm, including most prominently psychoanalysisand postmodernistsolipsism.These approaches, which are guided largelyby unaided intuition about the way the brain works, have fared badly. In the absenceof a compassbased on sound material knowledge,they make too many wrong turns into blind ends. If the brain is ever to be charted, and an enduring theory of the arts createdas part of the enterprise,it will be by stepwiseand consilient contributions from the brain sciences,psychology,and evolutionary biology. And if during this processthe creative mind is to be understood, it will need collaboration between scientistsand humanities scholars. The collaboration,now in its early stages,is likely to conclude that innovation is a concretebiological processfounded uPon an intricacy of nerve circuitry and neurotransmitter release.It is not the outpouring of symbolsby an all-purposegeneratoror any coniuration therein by ethereal agents. To fathom the origin of innovation in the arts will make a great deal of difference in the way we interpret its creations. The natural sciences have begun to form a picture of the mind, including some of the elements of the creative Processitself. Although they are still considerably far from the ultimate goal, they cannot help in the end but shengthen interpretation of the arts. Charles Lumsden and I reachedthis conclusionin the early r98os while developing the full theory of gene-culhrre coevolution, described earlier. A similar position has been reachedfrom different directions by a small but growing circle of artistsand theoristsof the arts, among whom the more prominent have been JosephCarroll, Brett Walter Koch, RobertStorey,and Frederick Cooke, Ellen Dissanayake, Turner. Some of these scholarsrefer to their approach as biopoetics or

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bioaesthetics.The analyseshave been independently bolstered by Ireniius Eibl-Eibesfeldt, the German ethologist,in his global studiesof human instinct; by the American anthropologistsRobin Fox and Lionel Tiger in their accountsof ritual and folklore; and by numerousresearchersin Artificial Intelligence, whosework on artistic innovation is summarized (to take one excellent exposition) by Margaret Boden in The CreatiyeMind. The body of the researchto date can be fitted together into the following narrativeofcoevolution ofgenesand culture: . Duing human eyolution there was time enough for natural selection to shapethe processes of innovation For thousandsof generations, sufficientfor genetic changesin the brain and sensoryand endocrine systems,variationamong people in thought and behavior causedper_ sonaldifferencesin survivaland reproductivesuccess. . The vaiation was to some degreeheritable. Individuals differed then, asthey do today,not just in what they learnedfrom their culture but alsoin their hereditarypropensityto learn certain things and to respondby statisticalpreponderancein particularways. . Genetic evolution inevitably ensued.Natural selection, favoring some of the gene ensemblesover others,molded the epigeneticrules, which are the inherited regularitiesof mental development that compose human nature.Among the most ancient epigenetic rules I have described to this point are the Westermarck effect, which inhibits incest,and the natural aversionto snakes.Those of more recent origin, perhapsno more than a hundred thousandyearsago, include the swift programmedstepsby which children acquire languageand, we may reasonablypresume,some of the creativeprocesses of the arts as well. . Uniyersalsor near-universalsemergedin the evolution of culfure. Becauseof differencesin strengthamong the underlying epigenetic rules, certain thoughts and behavior are more effective than others in the emotional responsesthey causeand the frequency with which they inhude on reverie and creative thought. They bias cultural evolution toward the invention of archetypes,the widely recurring abstractions and core narrativesthat are dominant themes in the arts. Examples of archetypesI have already mentioned are Oedipean tragedy (violating the Westermarckeffect) and the serpent images of my,th and religion.

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. The artsare innately focused toward certain forms and themes but are otherwise freely constructed- The archetypes sPawn legions of metaphors that compose not only a large part of ihe artsbut also of ordinary communication. Metaphors, the consequenceof spreadingactivation of the brain during learning, are the building blocks of creative thought. They connect and synergisticallystrengthendifferent spheres of memory.

G e N e - c u L T U R E c o E v o L U T I o N t s , I b e l i e v et,h e u n d e r l y i n g processby which the brain evolved and the arts originated.It is the conceivable means most consistent with the ioint findings of the brain sciences, psychology, and evolutionary biology' Still, direct evidence with referenceto the arts is slender.It is possiblethat new discoveries concerning the brain and evolution will yet changethe picture-fundamentally. Such is the nature of science.The uncertainty makesthe searchfor the alignment of scienceand the humanitiesall the more interestinga prosPect. Thii muctr can be said with confidence, however: The growing evidence of an overall strucfured and powerful human nature, channeling development of the mind, favors a more kaditionalist view of the nrt . The artsare not solely shapedby errant genius out of historical circumstances and idiosyncratic personal experience' The roots of their inspiration date back in deep history to the genetic origins of the human brain, and are Permanent. while biology has an important part to play in scholarly interpretation, the creative arts themselves can never be locked in by this or any other discipline of science. The reason is that the exclusive role of the arts is the transmissionof the intricate details of human experience by artifice to intensify aesthetic and emotional response.Worls of art communicate feeling directly from mind to mind, with no intent to explain why the impact occu6. In this defining quality, the arb are the antithesisof science. When addressinghuman behavior, science is coarse-grainedand encompassing,asopposedto the arb, which arefine-grainedand interstitial. That is, sciince aims to create principles and use them in human biology to define the diagnostic qualities of the species;thearts use fine details to flesh out and make strikingly clear by implication

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those samequalities.works of art thatprove enduring are intensely humanistic. Born in the imagination of individuals, they nevertheless touch upon what was universally endowed by human evolution. Even when, aspart of fantasy,they imagine worlds that cannot possiblyexis! they stayanchored to their human origins. fu Kurt Vonnegut, fi., master fantasist,once pointed out, the arts place humanity in the center of the universe,whether we belong there or not. Several special powers were granted the arts by the genetic evo_ lution of the brain. First is the ability to generate metaphors with ease and move them fluidly from one context to another. Consider the technical language of the arts themselves.A plot first meant a physicalsite and building plan, then the stagedirector'splot or blocking plan, then the action or story blocked out. In the sixteenthcentury a frontispiece was a decorated front of a building, then the title page of a book ornamented with a figure, usually the allegorical representation of a building, and finally the illushated page that precedesthe fitle page. A stanza,which in Italian is a pubiic room or restingplace,has been appropriatedin English to mean the roomlike set of four or more lines separatedtypographically from other similar sets. In both the arts and sciencesthe programmed brain seekselegancerwhich is the parsimonious and evocativedescription of pattern to make senseout of a confusion of detail. Edward Rothstein,a critic trained in both mathematics and music, compares their creative Processes: Welegin with objectsthat look dissimilar.We compare,find patterns, analogies with what we alreadyknow.We distanceourselvesand create abstractions, laws,systems, usingtransformations, mappings,and metaphors.This is how mathematicsgrowsincreasinglyabstractand powerful;it is how musicobtainsmuch of its po*.r, *ith grandstruchrresgrowingout of smalldetails.This form of comprehension under_ liesmuch of Westernthought.We pursueknowledgethat is universal in itsperspective but its powersaregroundedin the particular.We use principlesthataresharedbut revealdetailsthat aredistinct.

Now comparethat insightwith the followingindependentaccount of creativityin the physicalsciences. The writeris Hid;ki yukawa.who spenthis careerworkingon the nuclearbindingforcesof the atom,

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for which he becamethe first fapaneseto receive making discoveries the Nobel Prizein physics' Suppose there is something which a Person,cannot understand' He h"ip""t to notice the similarity of this something to some other thing *hich h" uttd"rstands quite well. By comparing them he may come to understand the thing which he could not understand up to that moment. If his understanding hrrns out to be appropriate and nobody else has ever come to such an understanding, he can claim that his thinking was reallYcreative.

startin the realworld'They thenreach The arts,like the sciences, out to all possibleworlds, and finally to all conceivableworlds. Throughoui they proiect the human Presenceon everythingin the uniuerre.Given the powerof metaphor,perhapsthe artsbeganwith what may be calledih. "Pi"rrro effect."The artistis reported-byhis photographerand chronicler Brassaito havesaid in rg43 "lf it occurred to man to createhis own images,it's becausehe discovered them all aroundhim, almostformed,alreadywithin his grasp'He saw of cavernwalls,in a pieceof them in a bone,in the irregularsurfaces wood. One form might suggesta woman'anothera bison,and still anotherthe headof de-oo" They mayhavecomethat routeby per" ception of whatGregoryBatesonandTylervolk havecalledmetapattems, thosecircles,spheres,bordersand centers,binaries,layers, cycles,breaks,and other geometricconfigurationsthat occur repeat.dly i' natureand providi easilyrecognizedcluesto the identity of more complicatedobiects. It wasa shortstepnot iust to seebut to re-createimageson rock wallswith charcoallinesor by etchingson stone,bone,and wood'The first falteringstepswere attemptsto stimulateand therebyhumanize externalNatre.^The art historianVincent Scullyhasobservedthat in earlyhistoricaltimes,peopleconstructedsacredbuildingsto-resemble mountains,rivers,and animals.By sodoingthey hopedto drawupon the powersof the environment.The greatestceremonialsite of preColumbianAmerica,in Scully'sopinion,is Teotihuacdnin central Mexico. "TheretheAvenueof the Deadrunsdirectlyto the baseof the Templeof the Moon, behindwhich risesthe mountainthat is called is Tenan('Our Ladyof Stone').That mountain,runningwith springs, the And in the center. notched and shaped and pyramiial basically

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temple imitates the mountain's shape, intensifies it, clarifies it, geo_ metricizes it, and therefore makes it more potent, as if to draw water down from the mountain to the fields below.,' Imitate, make it geometrical, intensi!,: That is not a bad three-part formula for the driving pulse of the arts as a whole. somehow innovators know how it all is to be done. They select imagesfrom nature that are emotionally and aestheticallypotent. In the course of history as techniquesgrew more sophisticated,the artistsproiected feelings back out to nature. Those in architecture and the visual arts createddesigns basedon the idealized featuresof the human body and what tiev imagined to be gods modeled from the human boiy. Supplicatio,l reverence,love, grief, triumph, and maiesty,all emotion-chargedcon_ structions of the human mind, were captured as abstract images and forced onto both living and inanimate landscapes. futists, while free-rangingin the details selected,generally remain faithful to the innate universalsof aesthetics.In his r9o5-o8 variations of The Farm Weltevredenat Duivendrecht, the young piet Mondrian depicted a row of spindly trees in front of a shadowyho,rr". The spacing of the tree hunks seemsintuitively right, the redundancyin the canopy lacework is close to what (as I will describeshortly) modern EEG monitoring suggestsis most arousingto the brain. The arrangement of open spaceand water nearby are those that recent psychological studieshave revealedto be innately among the most attractive olut of all such possiblearrangements.Unaware of these neurobiological correlates,probably uncaring even if he had been told, Mondrian repeatedthe tree-row theme many times over a ten-yearperiod as he felt his way toward new forms of expression.With the influences of Vermeer and van Gogh put well behind him, he discoveredand experi_ mentedwith cubism. lnstudy of TreesII (r9r3) the canopiesof severar trees are brought forward, dorninating fences and other skeletonized and unfocused structures,yet all still balanced in composition and close to optimally complex by measure of brain arousal. other variations of the same period increasingly abshact the whole into a mazelike configuration of reticulate lines. The interspacescapture patterns of light and color that change from one compartment toihe next. The overall efFectis not unlike that of a mottled sky viewed upward ihrough a woodlandcanopy.Other subjects,including buildingi, dunes,piJrs, and the sea,are similarly transformed.In the end Mondrian attained the pure abshact designsfor which he was to be celebrated: ,.nothing

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human, nothing specific,"ashe put it. In this sensehe liberatedhis art' But it is not tr,tly fi"", and I doubt that inwardly he everwishedit to be. It staystrue to the ancient hereditary ground mles that define the human aesthetic. we do not seein the evolution of Mondrian a localizedproduction of Westernculture. The sameprocesswasat work in the confluenceof Asian art and writing. chinese characterswere invented three thou.r,rd. pictographs resembling the obiects they represand years "go ", *oon, mountains and rivers,people and animals, sent.The srit arrd dwellings and utensilsare all instantly recognizabletoday in the ancient c-hinese script. They too approach the optimum level of complexity by EEG standards.over centuries the charactersevolved into th. .i"g"r,t karayo calligraphy of standard script. An early version of karayoiafte, its introduction to fapan, gave rise to new forms, includi.rg ihe flowing wayo scriptunique to that cguntry' As in Western calIigraphy ar,,dth. ornamental initial letters of medieval hand scripts,art i*posed on the written word its own aestheticstandards'

B v r N r u I r I o N AL o N E, and a sensibilitythat doesnot submit easily to formulas, artists and writers know how to evoke emotional and aesthetic response.Adding one artifice to another, obedient to the dictum ars estielare artem, it is art to conceal art, they steerus awayfrom explanations of their productions. As Louis Armshong is reported to have said about iazz: If you have to ask, you'll never know. Scientists, in conhast, try to know. They are anxious to tell you everything,and to make it all clear. But they must respecsullywait until the curtain falls or the book coversclose. The arb are eternally discursive.They seek maximum effect with novel imagery. And imagery that burns itself into the memory so that *her, .ecalled it retains some of its original impact' Among examplesI especially appreciate is the perfect opening of Nabokov's pedophilic nivel. LoJie-ta: the tip of the tongue taking a trip of three stepsdown the palate to tap, at three,on the teeth. Lo. Lee. Ta. Thus with anatomical accuracy,ailiterative f-sounds,and poetic meter Nabokov drenches the name, the book title, and the plot in sensuality' Surprise, wit, and originali$ characterize the memorable use of metaphor. In another genre,the poet Elizabeth spirestells us about a theological lesson given by a nun at St. foseph'sElementary School in

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circleville,ohio, on a snowywintermorning.The subjectwaseschatologyfor beginners. Howlongwill thoselostsoulspayfor their sins?Forall etemity.Eter_

nity. How can we, at elevenyearsold, shemustbe thinking, possibly be able to conceiveof just how long eternityis?Imagineiti torgurt mountainin theworld,madeof solidrock.Onceeveryiundred yeals,a bird fliespast,thetip of it$wingbrushinglightly againstthemountain_ top. Etemity is as long as it wouldtakefor the bird,swing to wearthe mountaindownto nothing.Everafter,I connecthell anJ eternitynot with fire and flames,but with somethingcold and unchanging,a snowytundra overshadowed by a hugegranitemountainthatlasltsa pall overthelandscape.

Wser cAN wE trulyknowaboutthe creativepowersof the human mind?The explanation of their materialbasiswill be found at the iunctureof scienceandthehumanities. The firstpremiseof the scientific contributionis that Homosapiensis a biologicalspeciesborn of naturalselectionin a bioticallyrich environment. Its corollaryis that the epigenetic rulesaffectingthe humanbrainwereshapedduringgeneticevolutionbytheneedsof Paleolithic peoplein thisenviron-.i-,t. The premiseand corollaryhavethe followingconsequence. Cul_ ture,risingfrom the productions of manymindsthatinterlaceand reinforce one anotherover many generations, expandslike a growing organisminto a universe of seemingly infinitepossibility. But not all directionsare equallylikely. Beforethe scientificrevolution,everyculture wassharplycircumscribedby the primitivestateof that culiure's empiricalknowledge. The cultureevolvedunderthe local influence of climate,waterdistribution,and food resources. Lessobviouslv.its growthwasprofoundlyaffectedby humannature. Which bringsus backto the arts.The epigeneticrulesof human nature bias innovation,learning,and choice.They are gravitational centersthat pull the development of mind in certaindiiectionsand awayfrom others.Arrivingat the centers,artists,composers, and writ_ ers over the centurieshavebuilt archetypes, the themesmost pre_ dictablyexpressed in originalworksof art. Although recognizable through their repeatedoccurrence,archetypescannotbe easilydefinedby a simplecombinationof generic traits.They arebetterunderstoodwith examples, collectedinto groups

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that sharethe same prominent features.This method-called definition by specification-works well in elementarybiological classification, even when the essentialnature of the speciesas a category remainsdisputed.In myth and fiction asfew astwo dozen suchsubiecsuch' tive groupings cover most of the archetypesusually identified as following' Somi of the most fiequently cited are the ln the beginning, the people are createdby gods, or themating of at giants, or the*clashof tit"ttt; in any case,they begin as specialbeings the center of the world. The ttibe emigrates to a promised land (or Arcadia, or the Secret Vallev.or the New World). iiu t ib" meets the forces of nil in a desperatebattle for suwival; it triumphs againsthearY odds. Thi hero-descendsto hell, or is exiled to wilderness,or experiences past an iliad in a distant land; he returns in an odysseyagainstall odds fearsomeobstaclesalong the way, to complete his destiny' The woid. ends in apocalypse, by flood, fire, alien conquerors' or avenginggods;it is restoredby a band ofheroic survivors' i ,ulir"" of great power is found in the tree of life, the river of life, philosopher'bsto.re, sacred incantation, forbidden ritual, secret formula. The ruraningwoman is apotheosizedas the Great Goddess' the GreatMother, HolyWoman, Divine Queen, Mother Earth' Gaia' The seet has special knowledge and powers of mind, available to holy those worthy to reieive it; he is the wise old man or woman' the shaman' man, the magician,the great

of sacredstrengh, inuV*fi"has the fower of purity,is thevessel up to propitiate surrendered mustbe protectedat all costs,andperhaps the godsor demonicforces' Fernale sexualawakeningis bestowedby the unicorn' the gentle beast,the powerfulshanger,the magicalkiss' ' The Tri"k tn disturbsestablishedorder and liberatespassionas the god of wine, king of the carnival,eternalyouth, clown, iester' cleverfool. A rnotutet threatenshumanity,appearingas the serpentdemon (Satanwrithingat the bottomof hell), dragon,gotgon,golem'vampire'

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Ir rHs ARTS are steeredby inborn rules of mental development, they are end products not iust of conventional history but also of genetic evolution.The questionremains:Were the genetic guidesmere blproducts*epiphenomena-of that evolution, or were they adaptations that directly improved survival and reproduction? And if adaptations, what exactJywere the advantagesconferred?The answers,some scholarsbelieve, can be found in artifactspresewed from the dawn of art. They can be testedfurther with knowledge of the artifacts and customs of present-dayhunter-gatherers. This is the picture of the origin of the arts that appears to be emerging.The most distinctivequalitiesof the human speciesare exhemely high intelligence, language,culture, and reliance on longterm social contracts. In combination they gave early Homo sapiensa decisiveedgeover allcompeting animal species,but they also exacted a price we continue to pay, composed of the shocking recognition of the self,ofthe finitenessofpersonal existence,and ofthe chaosofthe environment. These revelations, not disobedience to the gods, are what drove humankind from paradise. Homo sapiensis the only speciesto suffer psychologicalexile.All animals,while capableof some degreeof specialized learning,are instinctdriven, guided by simple cues from the environment that trigger complex behavior patterns. The great apes have the power of self-recognition, but there is no evidence that they can reflect on their own birth and eventual death. Or on the meaning of existence-the complexity of the universemeansnothing to them. They and other animals are exquisitely adapted to just thoie parts of the environmenton which their livesdepend,and they pay littL or no attention to the rest. The dominating influence that spawnedthe arb was the need to imposeorder on the confusion causedby intelligence.In the era prior to mental expansion,the ancestralprehuman populations evolved like any other animal species.They lived by instinctive responsesthat sustainedsurvival and reproductive success.when Homo-level intelligence was attained, it widened that advantageby processinginformation well beyondthe releasercues.It permitted flexibility of response and the creationof mental scenariosthat reachedto distantpla".s a.rd far into the future. The evolving brain, nevertheless,could not convert to general intelligence alone; it could not turn into an all-purpose computer. So in the courseof evolution the animal instincts of survival

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and reproductionwere transformedinto the epigeneticalgorithmsof to keep in placetheseinborn programs human nature.It wasnecessary sexual conduct, and other language, of acquisition for the rapid algorithmsbeen erased,the the Had olmental development. processes is that the lifeiime of leason The specieswould have faced extinction. to an individual human being is not long enough sort out experiences by means of generalized,unchanneled learning. Yet the algorithms were jerry-built: They worked adequatelybut not superbly well' Becauseof the slownessof natural selection,which requirestensor hundreds of generationsto substitutenew genesfor old, there was not enough time for human heredityto cope with the vastnessof new contingent possibilitiesrevealedby high intelligence.Algorithms could be built, but they weren't numerousand preciseenough to respondautomatically and optimally to every possibleevent. The arts filled the gap. Early humans invented them in an attempt to expressand control through magic the abundance of the environment, the power of solidarity,and other forcesin their lives that mattered mosito survivaland reproduction.The arts were the meansby which theseforcescould be ritualized and expressedin a new, simulated reality.They drew consistencyfrom their faithfulnessto human nature, to ihe emotion-guided epigeneticrules-the algorithms-of mental development.They achievedthat fidelity by selectingthe most evocativewords, images,and rhythms, conforming to the emotional guides of the epigenetic rules, making the right moves.The arts still perform this primal function, and in much the same ancient way' Their quality is measuredby their humanness,by the precision of their adherence to human nature. To an overwhelming degree that is what we mean when we speakof the true and beautiful in the arts'

s rcd ABour THIRTY THousAND YEARs LGo Homosapienu the visualartsto bring the representationof largeanimals into shelters. Some of the oldestand most sophisticatedof such works are the wall paintings, engravings,and sculpturesfound in cavernsofthe southern half of Ice Age Europe. More than two hundred such cavernscontaining thousands of images have been found during the past century in Ita1y,Switzerland,France, and Spain. The most recently discovered, and oldest of all, is the spectacularly painted cave at Chauvet, in the valley of the Ardbche River, a tributary of the Rh6ne. chemical tests

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haveestablishedthe ageof the art at)2,410+ Tzoyears.The youngest cavegalleriesare Magdalenianpaintings,etchings,and sculpturescreated as recently as ten thousand years before the present, near the dawn of the Neolithic era. The best of the animal drawingsare accurate and beautiful even by exactingmodern standards.They are rendered with clean, sweeping lines,someof which are shadedto one side as though to conveythreedimensionality. Th.y present a veritable field guide to the largest mammalsof the region,from lion to mammoth, bear to horse,rhinoceros to bison, most of which are now extinct. The figures are more than abstract images. Some are clearly male or fernale, of different ages.A few of the females are swollen with young. Some wear recognizable winter or summer pelages.At Chauvet two rampant male rhinoceroslock horns in battle. Given the antiquity of Chauvet and the scarcity of even older representationalart, it is tempting to conclude that the skills of the cavern artistsemerged quickly, perhapswithin a few generations.But that would be premature.On the basisof geneticand fossilevidence,it appears that anatomically modern Homo sapiens evolved in Africa by about two hundred thousand yearsbefore the present, and entered Europe as recendy as fifty thousand yearsago. In the succeeding interval, up to the time of the Chauvet paintings, they slowly displacedthe Neanderthal people, now consideredby some anthropologists to be a distinct human species.It is reasonableto supposethat during this era, and before occupying the particular cave sitesthat today harbor the oldest known works, the artistsimproved their techniques and style on surfacesnow lost. Many of the earlypaintingsmight havebeen applied to outdoor rock walls, a practice still followed by huntergatherers in Australia and southern Africa, and asa result failed to survive the harsh climate of Ice Age Europe. It may never be known whether European cavern art sprang fullblown or was perfected in small stepsacrossmillennia, but at least we have stronghints asto wlzTit wascreated.A number of the examples,as many as z8 percent at Cosquesnear Marseilles,for example,are depicted with arrows or spearsflying about the bodies of the animals. A bison at Lascaux has been evisceratedby a spear that enters its anus and emergesthrough its genitals.The simplest and most persuasiveexplanation for the embellishment is the one proposed in the early rgoos by Abb6 Breuil, the pioneer explorer and interpreter of European

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Paleolithic art. It is hunting magic, he said,,the belief that by recreatinganimalsand killing their images,the hunterswill more readily overcomereal preywhen the chasebeginsoutdoors. Art is magic: That has a modern ring, for aswe often hear, the purposeof the artsis enchantment.Breuil's hypothesisis supportedby an intriguing piece of additional evidence,the repeateddepiction of the same animal specieson the same rock-surfacepanels. In one case, chemical tests indicate ihat the portraits were drawn centuries apart. Duplicates are also commonly drawn-or in some casesetched on bone fragments-on top of the original' Rhinoceroshorns are replicated, mammoths bear multiple head domes,lions have two or three complete heads.Although we will never be able to read the minds of the aitists,it is a fair guessthat they meant the imagesto be reborn with each duplication in order to serve the purPose of new rituals. Those rituals might have been part of full-blown ceremonies,accompanied by early forms of music and dancing. Flutes made of bone have been discoveredin the caves,in good enough condition to be cleanedand played,and the paintingsthemselvesare consistendylocatedin places where the acousticsare excellent. Hunting sorceryof one form or another has survivedin huntergatherer societiesto the presenttime. It is a form of sympatheticmagic, an expressionof the near-universalbelief among prescientificpeoples that the manipulation of symbolsand imagescan influence the obiects they represent.Sticking pins in dolls and other practicesof malign voodoo are among the most familiar examplesfrom popular culture' Most religious rituals contain elements of sympatheticmagic. Children selected for sacrifice to Tlaloc, the Aztec god of rain and lightning, were first forced to shed tears, in order to bring raindrops to th9 ValLy of Mexico. Christian baptism takes awaythe sins of the world' To be cleansed, to be born again, you must be washedin the blood of the Lamb. Belief in astrology and exhasensoryperception, particularly psychokinesis, is built from similar elements in the sorcerer'stoolkit. The near-universal faith in sympathetic r4agic of one form or another is easilyexplained.In a bewildering and threateningworld, people reach out for power by any means they can find' Combining art with symPathetic magic is a quite natural way to make that attempt, In opposition to the hunting magic hypothesis it can be argued that the cave art images servedthe much simpler PurPoseof instruct-

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ing the young.Perhapsit wasindeedonly a prehistoricPeterson's Field Guideto theLargeMammalsof Pleistocene Europe.But with no more thana dozenspecies to learn,it remainsunclearwhytheportraitswere drawnrepetitivelyon the samepanels.Or why the skillsof hunting couldnot havebeenbetterlearnedby adolescent apprentices when they accompaniedtheir eldersin the field-the method used by hunter-gatherer peopletoday. The magichypothesis of animalart is reinforcedby otherformsof behaviordisplayedby extantstone-age people.Their huntersare intenselypreoccupiedwith the livesof the big animalsaroundthem, especiallymammalsthatcanbekilledonlyby trackingor ambush.They arelessconcernedwith smallerspecies, suchasharesandporcupines, that can be snaredor dug from burrows.They often impute to their largepreythe possession of mindsandspecialpowersthatprojecttheir ownfiercehumandesires. The animalstheykill theysometimes propitiate with ceremony.Huntersof many culturescollect skulls,claws, and skinsashophiesto memorializetheir own prowess. The totemic animals,investedwith supernaturalqualitiesand honoredwith reverential art, are then usedassymbolsto bind membersof the clan together.Their spiritspresideovercelebrationsof victory and seethe peoplethroughthe darkhoursof defeat.They remindeachindividual of theexistence of something greaterthanhimself,somethingimmortal of which he is a part.The totemsenforcemoderationin dispute, and theysoftendissension within the hibe. They are sourcesof real power.It is not surprisingto find that amongthe few well-rendered human beingsin Ice Age art are shamanswearingheadgearof stag antlersor the headof a bird or lion. It seemslogicalthatgodsin the form of animalsruledthe ancientcivilizations of the FertileCrescent andMesoamerica.Sucheffectsof sympatheticmagicradiateout. Not just hunter-gatherer bandsbut alsogroupsand nationsat the level of high civilizationareproneto adoptanimal speciesastotemsto reflect the qualitiesthey most value in themselves. Americanfootball fans, havingat lastfound a wayto form their own Paleolithictribes,cheer for theDetroitLions,Miami Dolphins,andChicagoBears.

TH r s I o L o c r cA L o Rr c r N of the artsis a workinghypothesis, dependenton the realityof the epigeneticrulesand the archetypes they generate. It hasbeenconshucted in the spiritofthe naturalsciences,

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and assuch is meant to be testable,vulnerable,and consilientwith the restof biolory. So how then is the hypothesisto be tested?One way is to predict from evolutionary theory the themes and underlying epigenetic rules most likely to be encountered in the arts.We know that such nearuniversal themes do exist, and in fact form the scaffolding of most worksof fiction and the visualarts.Their generalityis the reasonHollywood plays well in Singapore, and why Nobel Prizesin Literature are given to Africans and Asiansas well as to Europeans.What we do not of mental develunderstandvery well is why this is so, why processes opment direct attention so consistentlytowardcertain imagesand narratives. Evolutionary theory is a potentially powerful means of predicting the underlying epigenetic rules and understandingtheir origins in genetic history. Earlier I describedone important exampleof the evolutionaryaPproach, in studiesihat addressincest avoidanceand taboos.The incausingthesephenomenahavereverberated torn inhibitory responses that in m1"thand the artsthroughout recordedhistory.Other responses can connect biological theory to the arts are parent-infantbonding, and defense. family cooperationand conflict, and territorial aggression A second, wholly different means of discoveringepigeneticrules affecting the arts is simply to scan directly for them with methods from the neurosciences and cognitive psychology' In a pioneering study of "bioaesthetics"published in 1973,the Belgian psychologistGerda Smets asked subiects to view abstract designs of varying degrees of complexity while she recordedchangesin their brain wave patterns. To register arousal she used the desynchronization of alpha waves,a standard neurobiological measure. In general, the more the alpha waves are desynchronized, the greater the psychological arousal subjectively reported by subiects.Smetsmade a surprisingdiscovery.She found a sharp peak of brain responsewhen the redundancy-repetitivenessof elements- in the designswas about zo percent.This is the equivalentamount of order found variouslyin a simple maze, in two complete turns of a logarithmic spiral,or in a crosswith asymmetrical arms. The zo percent redundancy effect appearsto be innate' Newborn infants gaze longest at drawings with about the same amount of order. What does this epigenetic rule have to do with aestheticsand art?

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The connection is closer than may be immediately apparent. Smets' high-arousal figures, even though generated by a computer, have an intriguing resemblanceto abstractdesignsused worldwide in friezes, grillwork, logos,colophons,and flag designs.They are also close in order and complexity to the pictographs of written Chinese, Japanese, Thai, Thmil, Bengali, and other fuian languagesof diverse origin, as well as the glyphs of the ancient Eg,ptians and Mayans. Finally, it seemslikely that some of the most esteemedproducts of modern abstract art fall near the same optimal level of order, as illustrated in Mondrian's oeurre. Although this connection of neurobiology to the arts is tenuous, it offers a promising cue to the aesthetic instinct, one that has not to my knowledge been explored systematicallyby either scientistsor interpretersof the arts. Analyzing the beauty of a young woman's face is another way to scan directly for epigenetic rules relevant to aesthetics.For more than a century it has been known that photographic composites of many facesblended together are considered more athactive than most of the individual facesviewedseparately. The phenomenonhasled to the beIief that ideal facial beauty is simply the averagecondition for the population as a whole. That entirely reasonableconclusion turns out to be only half true. In 1994new studies revealed that a blend of individual faces considered attractive at the outset is rated higher than a blend of all the faceswithout prior selection.In other words, an average face is attractive but not optimally attractive. Certain dimensions of the face are evidently given more weight in evaluation than others. The analysesthen produceda real surprise.When the critical dimensions were identified and exaggeratedin artificially modified composites,attractivenessrose still more. Both Caucasianand Japanese female faceshad this effect on young British and fapanesesubiectsof both sexes.The features thought most attractive are relatively high cheek bones, a thin jaw, large eyesrelative to the size of the face, and a dightly shorter rather than longer distance between mouth and chin and betweennoseand chin. Only a small percentageof young women fall at or close to the average.That is to be expectedin a genetically diversespecieswhose precise combinations of featuresare created anew within and between families of every generation. What is more puzzling is the divergence of the optimum from the average. Few women-extremely few in

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fact-approach it. If the perception of facial beauty resultedin the higher survivaland reproductivesuccessof the most beautiful conceivable, then the most beautiful should be at or close to the average within the population. Such is the expectedresult of stabilizingnatural selection:Deviationsfrom the optimum dimensionsin any direction are disfavored,and the optimum is sustainedasthe norm through evolutionarytime. The explanationfor the rarity of great beauty may be (and I continue to speculate)the behavioralphenomenon known as the supernormal stimulus. Widespread among animal species, it is the preference during communication for signals that exaggeratethe norms even if they rarely if everoccur in nature.An instructiveexample is female attractivenessin the silver-washedfritillary a silver-dappled orange butterfly found in woodland clearings from western Europe to )apan. During the breeding seasonmales instinctively recognize females of their own speciesby their unique color and flight movements. They chasethem, but they are not what the males teally prefer. Researchersfound that they could attract male fritillaries with plastic replicas whose wings are flapped mechanically. To their surprise, they also learned that males turn from real femalesand fly toward the models that have the biggest, brightest, and most rapidly moving wings.No such fritillary super-femaleexistsin the species'natural environment. Males of the silver-washedfritillary appear to have evolved to prefer the strongestexpressionof certain stimuli they encounter,with no upper limit. The phenomenon is widespreadin the animal kingdom. While experimentingwith anole lizardsof the West Indies a few years ago,I found that malesdisplayenthusiasticallyto photographsof other members of the same species,even though the imagesare the size of have learned that herring gulls a small automobile. Other researchers ignore their own eggs when presented with appropriately painted wooden modelsso large they cannot even climb on top of them. In the real world the supernormal response works because the monstrousforms created by experimentersdo not exist,and the animals can safelyfollow an epigenetic rule expressibleas follows: "Thke the largest(or brightestor most conspicuouslymoving) individual you find." Female fritillaries cannot be gigantic insects with brilliant whirring wings. Such creaturescould not locate enough food to get through the caterpillarstageand survivein the Eurasianwoodlands.In

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parallel manner, women with large eyesand delicate featuresmay have lessrobust health, especiallyduring the rigors of childbearing, than those closer to the population average.But at the same timeand this could be the adaptive significance-they present physical cuesofyouth, virginity,and the prospectofa Iong reproductiveperiod. The off-c'enteroptimum of female attractivenessis no more peculiar than most of the rest of human social behavior. The entire beauty industry can be interpreted as the manufacture of supernormal stimuli. Eyelid shadowand mascaraenlargethe eyes,lipstick fills out and brightens the lips, rouge brings a permanent blush to the cheeks,pancake makeup smoothesand reshapesthe face toward the innate ideal, fingernail paint addsblood circulation to the hands, and teasingand tinting render the hair full-bodied and youthful. All these touches do more than imitate the natural physiological signs of youth and fecundity. They go beyond the averagenormal. The sameprinciple is true for body adomment of all kinds in men and women. Clothing and emblemsproject vigor and advertisestatus. Thousands of years before artists painted animals and costumed shamanson the cave walls of Europe, people were fasteningbeads onto clothing and piercing belts and headbandswith carnivoreteeth. Such evidence indicates that the original canvasof the visual arts was the human body itself. Ellen Dissanayake,an American historian of aesthetics,suggests that the primal role of the arts is and alwayshas been to "make special" particular features of humans, animals, and the inanimate environment. Such features,as illushated by feminine beauty, are the ones toward which human attention is alreadybiologically predisposed.They are among the best placesto searchfor the epigeneticrules of mental development.

Tun ,tnts, while creating order and meaning from the seeming chaosof daily existence,alsonourish our craving for the mystical.We are drawn to the shadowy forms that drift in and out of the subconscious.We dream of the insoluble,of unattainably distant placesand times. Why should we so love the unknown? The reason may be the Paleolithicenvironment in which the brain evolved.In our emotions, I believe, we are still there. As a naturalis! I use an explicit geographic imagery in reveriesof this formative world.

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At the centerof our worldis homeground.ln the centerof the cen' ter are sheltersbackedagainsta rock wall From the sheltersradiate pathswhereeverytreeand rockis familiar.Beyondliesopwell-traveled portunityfor expansion and riches.Downa river,throughawoodedcorridor lining the oppositeshore,are campsitesin grassyplaceswhere game and food plantsdre seasonallyabundant.Such opportunities are balancedby 'isk. We might loseour wayon a too-distantforay.A cannibals,notfully stormcancatchus.N eighbonngpeople- poisoners, guess theirintentions. human-will eithertradeor attack;we cdnonly banier.On theothersideis the im In any casethq arean impassable of the world,perhapsglimpsedas a mountainfront, or a drop toward the sea.Anythingcouldbe out there:dragons,demons,gods,paradise, camefrom there.Spiits we knowlive closer etemallife. Our ancestors by, and at fall of night are on the move.So much is intangibleand strange!Weknowa little, enoughto survive,but all therestof theworld is a mystery. What is this mysterywe find so athactive?It is not a mere ptzzle still too amorwaitingto be solved.It is far morethan that,something phous,too poorly understoodto be brokendown into puzzles.Our mindshavel easily*eagerlyl*fromthe familiarand tangibleto the mystic realm. Today the entire planet has becomehome ground. Global information networksare its radiatingtrails. But the mystic realm hasnot vanished;it hasiust reheated,firstfrom the foreground andthenfromthedistantmountains.Now welookfor it in thestars,in the unknowablefuture, in the still teasingpossibilityof the supernatural.Both the known and the unknown,the two worldsof our ancestors,nourishthe humanspirit.Their muses,scienceand the arts, whisper:Followus,explore,find out.

mind, we are IN rnvtNc to comprehendthis auraof the ancestral Anthropologists fantasy. not entirely dependenton introspectionand havecarefullystudiedbandsof contemporaryhuntergathererswhose lifewaysappearto resemblethoseof our common Paleolithicforethe and conversations, daily activities, bears.In recordinglanguages, inferencesconcerningthe thought havedrawnreasonable researchers processes of theirsubiects. such accounthasbeenprovidedby Louis Liebenbergon the One "Bushman"huntergatherers of the centralKalahari, San-speaking

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more particularly the fu/wasi (or !Kung), /Gwi, and lXo of Botswana and Namibia. He has drawn on his own researchesand those of other anthropologists,most prominently Richard B. Lee and George B. Silberbauer,to record the vanishingculture of theseremarkablepeople. The Kalahari bands, in order to live on the sparseresourcesof the desert,must plan and act very carefully. Knowledge of the local terrain and of seasonalecology is particularly important. The bands understand that the dishibution of water resourceswithin their territory is most important of all. In Liebenberg'swords: During the rainy seasonthey live at temporarypoolsin the midst of nut forests.Only the mostpalatableand abundantfoodsthat are the leastdistancefrom waterarecollected.As time goeson theyhaveto havelfurther andfurtherto collectfood.They usuallyoccupya camp for a periodof weeksor monthsandeattheir wayout of it. During the dryseason, groupsarebasedat permanentwaterholes. Theyeatout an inincreasingradiusofdesirablefoods,andasthe water-food distances creasethe subsistence effortincreases. The Kalahari bands are expertson Iocal geographyand the many plants and animals on which their lives depend. Plant gatherers, usually women but also men on their way home from unsuccessful hunts, use knowledge of the botanical communities to pinpoint edible species.They are conservationistsby way of necessity.Liebenbergcontinues: They avoid strippingan areaof a species,leavinga residueso that regenerationis not imperiled.Locally scarcespecimensare not exploitedevenwhenthesearefoundwhile gatheringotherspecies. The hunters are also equally expert on the details of animal life. Their skills at hacking large animals depend on this knowledge. When freshspooris found,hunterswill estimateits ageand how fast the animal wasmovingto decidewhetherit is worth followingup. In thick bush,wheretheremaybe no clearfootprints,or on hardground, whereonly scuffmarksmay be evident,hackersmay not be able to identifythe animal.When this happensthey will haveto follow the hail, looking for signssuch asdisturbedvegetationand scuffmarks, until clearfootprintsarefound.Theywill reconstructwhatthe animal wasdoingand predictwhereit wasgoing.

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In the Kalahari, as throughout all of the huntergathererworld for countlessmiJlennia,the hunt holds a central place in the sociallife of the band. In storytellingaroundthe campfireat night mengivegraphicdescriptionsof hunts of the recentand distantpast.To find animalsrequires all the information on their movementsthat can be gainedfrom others' observationsand the hunter's own interpretationof signs. the habitsand movements Hunterswill spendmanyhoursdiscussing of animals. The life of the Kalahari band, optimally comprising fifty to seventy members,is intenselycommunal and cooperative.Becausethe group on their backs, must move severaltimes a yearwith all their possessions individualsaccumulatefew materialgoodsnot essentialto survival. Ownershipis limited to an individual'sclothing, a man'sweapons and implementsanda woman'shouseholdgoods.The band'sterritory and all its assetsare not ownedindividuallybut communally,by the wholeband. To hold the group together, decorum and reciprocity are shictly observed. While hunting is an importantactivityin huntergatherersubsistence, are hunters,who maynafurallybe pleasedwith themselves, successful To the fu/wasi,for examexpectedto showhumility and gentleness. ple, announcinga kill is a sign of anoganceand is shonglydiscouraged.Many good huntersdo no hunting for weeksor monthsat a hunts a hunter will stophunting in time. After a run of successful orderto giveother men the chanceto reciprocate. While the IGlahari hunters are close studentsof animal behavior, they are thoroughly anthropomorphic in their intelpretation. They strain to enter the minds of the animals they hack. They imagine, they project thoughts directly to the world around them, and they analogize. Animal behaviouris perceivedas rational and directedby motives basedon values(or the negationof thosevalues)that are eitherheld themselves or by peopleknownto them.The by the hunter-gatherers

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behaviourof animalsis seenby the /Gwi asboundby the naturalorder beis perceivedto havecharacteristic of Nladima (God).Eachspecies haviour,which is govemedby its kxodzi(customs),and eachhasits Animalsarebelievedto haveacparticularftrwisa(speech, language). quiredspecialcapabilities by meansofrationalthought. Knowing the belief of preliterate people in the equivalency of the material and immaterial worlds, and of rational and irrational explanation, it is easyto seehow they invent narrative forms loaded with m1'ths and totems. The acceptanceof mystery is central to their lives. possess The /Gwi believethatsomespecies knowledgethattranscends thatof humans.The bateleureagleis believedto knowwhena hunter will be successful andwill hoveroverhim, therebyactingasan omen of suresuccess. Somesteenbokare thoughtto havea magicalmeans from a hunter'sarrows,while the duiker is of protectingthemselves believedto practicesorceryagainstits animal enemiesand even againstconspecificrivals.Baboons,becauseof their legendarylove of on huntersand to pass trickeryand teasing,arebelievedto eavesdrop on their plansto the intendedpreyanimals. The world that preliterate humans factually perceive is only a small fragment of the full natural world. Thus by necessitythe primitive mind is continuously tuned to mystery.For the Kalahari and other contemporary hunter-gatherersthe experience of daily life grades imperceptibly into their magical surroundings. Spirits dwell in trees and rocks, animals think, and human thought proiects outward from the body with a physical force. We are all still primitives compared to what we might become. Hunter-gatherers and college-educated urbanites alike are aware of fewer than one in a thousandof the kinds of organisms-plants, aniaround them. mals,and microorganisms-that sustainthe ecosystems They know very little about the real biological and physical forces that createair. water, and soil. Even the most able naturalistcan trace no more than a faint outline of an ecosystemto which he has devoted a lifetime of study. Yet the great gapsin knowledge are beginning to be filled. That is the strength of cumulative science in a literate world. People learn and forget, they die, and even the shongest institutions they erect deteriorate, but knowledge continues to expand globally while passingfrom

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one generation to the next. Any trained person can retrieve and augment any part of it. By this means all the speciesof organismsin ecosystemssuch as the Kalahari Desert will eventually come to be known. They will be given scientific names.Their place in the food web will be discovered,their anatomy and physiologypenetratedto the level of cell and molecule, the instinctive behavior of the animalsreduced to neuron circuitry, then to neurohansmifters and ion exchange. If the history of biology is a guide, all the facts will prove consilient.The explanationscan be joined in spacefrom molecule to ecosystem,and in time from microsecondto millennium. With consilient explanation, the units at different levels of biological organization can be reassembled.Among them will be whole plants and animals as we normally see them-not as collections of moleculesin biochemical time, too small and fast-changingto be visible to the unaided eye,not aswhole populationsliving in the slowmotion of ecologicaltime, but as individual plants and animalsconfined being orto the sliver of organismictime where human consciousness, ganismic itself, is forced to exist. Returning to that narrow sliver after the science-ledgrand tour of space-time,we arrive home in the world for which the evolution of the brain prepared us. Now, with science and the arts combined, we have it all. Poet in my heart, walk with me acrossthe mystenousland. We can still be hunters in the millionlear dreamtime. Our minds are filled with calculation and emotion. We are aesthetestense with anxiety. Once again the bateleur eagle wheelsaboveour heads,trying to tell us somethingwe overlooked,somethingwe forgot. How can we be surethat eagles nwer speak,that everythingcan be known about this land? Nearby is spoor of the elusiveduiker leading into the scrub: Shall we follow? Magic entersthe mind seductively,like a drug in the veins.Accepting its emotivepower, we knowsomethingimportant about human nature. And something important intellectually-that in expanded space-timethe fiery circle of scienceand the drtl can be closed. Within the larger scale,the archaic world of myth and passionis perceived as it truly is, acrossthe full range of cause and effect. Every contour of the terrain, every plant and animal living in it, and the human intellect that mastersthem all, can be understood more completely as a physicalentity.Yet in so doing we have not abandonedthe instinchral world of our ancestors. By focusing on the peculiarly

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human niche in the continuum, we can if we wish (and we so desperately wish) inhabit the productions of art with the same senseof beauty and mysterythat seizedus at the beginning. No barrier standsbetween the material world of scienceand the sensibilitiesof the hunter and the poet.

CHAPTER

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C n N r u n I E S o F D E B A T E o n t h e o r i g i n o f e t h i c sc o m e d o w n t o this: Either eihical precepts, such as iustice and human rights, are independent of human experienceor else they are human inventions. The distinction is more than an exercisefor academic philosophers. The choice between the assumptionsmakesall the differencein the way we view ourselvesas a species.It measuresthe authority of religion, and it determinesthe conduct of moral reasoning. The two assumptionsin competition are like islands in a sea of chaos,immovable, as different as life and death,matter and the void. Which is correct cannot be learnedby pure logic; for the presentonly a leap of faith will take you from one to the other. But the true answer will eventuallybe reachedby the accumulationof obiectiveevidence. Moral reasoning,I believe,is at everylevel inhinsically consilientwith the natural sciences. Every though$ul person has an opinion on which of the premises is correct.But the split is not, aspopularly supposed,betweenreligious believersand secularists.It is between transcendentalists, those who think that moral guidelinesexistoutsidethe human mind, and empiricish, who think them contrivancesof the mind. The choice between religious or nonreligiousconviction and the choice betweenethically transcendentalistor empiricist conviction are cross-cuttingdecisions

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believing made in metaphysicalthought. An ethical transcendentalist, ethics to be independent,can either be an atheistor else assumethe existenceof a deity. In parallel manner, an ethical empiricist, believing ethicsto be a human creation only, can either be an atheistor else believe in a creator deity (though not in a law-giving God in the traditional fudaeo-Christiansense).In simplestterms the option of ethical foundation is asfollows: I believein the independenceof moral talues, whether from God or not, versus I believe that moral values come from humans alone; God is a separateissue. Theologians and philosophers have almost alwaysfocused on transcendentalism as the means to validate ethics. They seek the grail of. natural law,which comprisesfreestandingprinciplesof moral conduct immune to doubt and compromise. Christian theologians, following St. Thomas Aquinas' reasoning in Summa Theologiae, by and large considernaturallaw to be the expressionof Godt will. Human beings, in this view, have the obligation to discoverthe law by diligent reasoning and weaveit into the routine of their daily lives. Secularphilosophers of transcendentalbent may seem to be radically different from theologians, but they are actually quite similar, at least in moral reasoning. They tend to view natural law asa set of principles so powerful as to be self-evidentto any rational person, whatever the ultimate origin. In short, transcendentalism is fundamentally the same whether God is invoked or not. For example, when Thomas fefferson, following fohn Locke, derived the doctrine of natural rights from natural law, he was more concerned with the power of transcendental statements than in their divine or secular origin. In the Declaration of Independence he blendedthe secularand religiouspresumptionsin one transcendentalist sentence,thus deftly covering all bets: "We hold these Truths to be self-evident,that all Men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness." That assertion became the cardinal premise of America's civil religion, the righteous sword wielded by Lincoln and Martin Luther King, and it endures as the central ethic binding together the diversepeoplesof the United States.

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So compelling are such fruits of natural law theory especially when the deity is also invoked, that they may seem to place the transcendentalistassumptionbeyond question.But to its noble successes must be addedappalling failures.It has been pervertedmany times in the past, used for example to argue passionatelyfor colonial conquest, slavery,and genocide.Nor wasany greatwar everfought without each side thinking its cause transcendentallysacredin some manner or other. "Oh how we hate one another," observedCardinal Newman, "for the love of God." So perhapswe can do better,by taking empiricism more seriously. Ethics, in the empiricist view, is conduct favoredconsistentlyenough throughout a societyto be expressedasa code ofprinciples. It is driven by hereditarypredispositions in mental development-the "moral sentiments" of the Enlightenment philosophers-causing broad convergence acrosscultures, while reaching preciseform in each culture according to historical circumstance.The codes,whether iudged by outsidersasgood or evil, play an important role in determining which cultures flourish, and which decline. The importance of the empiricist view is its emphasison obiective knowledge. Becausethe successof an ethical code dependson how wisely it interpretsthe moral sentiments,those who frame it should know how the brain works,and how the mind develops.The successof ethics also dependson the accurateprediction ofthe consequenceof particular actionsasopposedto others,especiallyin casesof moral ambiguity. That too takesa great deal of knowledgeconsilient with the natural and social sciences. The empiricist argument, then, is that by exploring the biological roots of moral behavior, and explaining their material origins and biases,we should be able to fashion a wiser and more enduring ethical consensusthan has gone before. The current expansion of scientific inquiry into the deeper processesof human thought makes this venture feasible. The choice between transcendentalism and empiricism will be the coming cenfury's version of the strugglefor men's souls. Moral reasoning will either remain centered in idioms of theology and philosophy, where it is now, or it will shift toward science-basedmaterial analysis. Where it settleswill depend on which world view is proved correct, or at leastwhich is more widely perceivedto be correct.

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m THn rluu HAs coME to turn the cardsfaceup. Ethicists,scholars who specializein moral reasoning,arenot prone to declarethemselves on the foundations of ethics, or to admit fallibility. Rarely do you see an argument that opens with the simple statement: This is rn1 starting point, and it could be wrong. Ethicists instead favor a fre$rl passage from the particular into the ambiguous, or the reverse,vaguenessinto at heart,but hard cases.I suspectthat almostall are transcendentalists they rarely sayso in simple declarativesentences.One cannot blame them very much; it is difficult to explain the ineffable, and they evidently do not wish to suffer the indignity of having their personal belieft clearly understood. So by and large they steer around the foundation issuealtogether. That said, I will of course try to be plain about my own position: I am an empiricist. On religion I lean toward deism but consider its proof largely a problem in astrophysics.The existence of a cosmological God who createdthe universe(asenvisionedby deism) is possible, and may eventually be seftled, perhaps by forms of material evidence not yet imagined.Or the matter may be foreverbeyond human reach. In conhas! and offar greaterimportance to humanity, the existenceof a biological God, one who directs organic evolution and intervenesin human affairs(asenvisioned by theism) is increasingly contravened by biology and the brain sciences. The same evidence,I believe, favorsa purely material origin of ethics,and it meetsthe criterion of consilience:Causal explanationsof brain activity and evolution, while imperfect, already cover the most facts known about moral behavior with the greatestaccuracy and the smallestnumber of freestandingassumptions.While this conception is relativistic, in other words dependent on personal viewpoint, it need not be irresponsibly so. If evolved carefully, it can lead more directly and safelyto stablemoral codesthan transcendentalism,which is also, when you think about it, ultimately relativistic. And yes-lest I forget-I may be wrong. In order to sharpenthe distinction between transcendentalism and empiricism, I have constructed a debatebetween defenders of the two world views. To add passionateconviction, I have also made the transcendentalista theist, and the empiricist a skeptic. And to be as fair as

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possible,I have drawn their arguments from the most closely reasoned sourcesin theologyand philosophyof which I am aware.

THn TneNscENDENTALrsr "Before taking up ethics,let me affirm the logic of theism, becauseif the existenceof a law-givingGod is conceded,the origin of ethicsis instantly settled.So pleaseconsider carefullythe following argument in favor of theism. "I challenge your rejection of theism on your own empiricist grounds. How can you ever hope to disprovethe existenceof a personal God? How can you explain away the three thousand yearsof spiritual testimony from the followers of fudaism, Christianity, and Islam?Hundredsof millions of people,including alargepercentageof the educatedcitizensof industrializedcountries, know there is an unseen sentientpower guiding their lives.The testimonyis overwhelming. According to recent polls, nine in ten Americans believe in a personalGod who can answerprayersand perform miracles.One in five has experiencedHis presenceand guidanceat least once during the year previousto the poll. How can science,the underwriting discipline of ethical empiricism, dismisssuch widespreadtestimony? "The nucleus of the scientific method, we are constantly reminded, is the rejection of certain propositions in favor of others in strict conformity to fact-basedlogic. Where are the facts that require the reiection of a personalGod? It isn't enough to saythat the idea is unnecessaryto explain the physical world, at least as scientistsunderstand it. Too much is at stakefor theism to be dismissedwith that flip of the hand. The burden of proof is on you, not on those who believe in a divine presence. "Looked at in proper perspective, God subsumesscience, science doesnot subsumeGod. Scientistscollect data on certain subiectsand build hypothesesto explain them. In order to extend the reach of objective knowledge asfar asthey can, they provisionally accept some hypotheseswhile discarding others. That knowledge, however, can cover only part of reality. Scientific research in particular is not designedto explore all of the wondrous varieties of human mental experience. The idea of God, in contrast, has the capacity to explain everything, not just measurablephenomena, but phenomenapersonallyfelt and

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subliminallysensed,includingrevelationsthat can be communicated solelythroughspirihralchannels.Why shouldall mental experience be visiblein PET scans? Unlike science, the ideaof God is concerned with more than the materialworld given us to explore.It opensour mindsto whatliesoutsidethat world. It instucts usto reachout to the mysteries that arecomprehensible throughfaith alone. "Confine your thoughtsto the materialworld if you wish.Others know that God encompasses the ultimate causesof the Creation. Wheredo the lawsof naturecomefrom if not a powerhigherthan the lawsthemselves? Scienceoffersno answerto that sovereign questionof theology.Put anotherway,why is theresomethingratherthan nothing?The ultimatemeaningof existencelies beyondthe rationalgrasp of humanbeings,andthereforeoutsidethe provinceof science. "A.reyou alsoa pragmatist? There is an urgentlypracticalreason for belief in ethicalpreceptsordainedby a supremebeing.To deny suchan origin,to assume that moralcodesareexclusively man-made, is a dangerouscreed.As Dostoyevsky's Grand Inquisitorobserved,all thingsare permittedwhen there is no ruling hand of God, and freedom tums to misery.In supportof that caveatwe have nothing less than the authorityof the original Enlightenmentthinkersthemselves. Virtually all believedin a God who createdthe universe,and many were devoutChristiansto boot. Almostnone waswilling to abandon ethicsto secularmaterialism. fohn Lockesaidthat'thosewho deny the existenceof the Deity are not to be toleratedat all. Promises, covenantsand oaths,which arethe bondsof human society,can have no hold upon or sanctityfor an atheist;for the taking awayof God, evenonly in thought,dissolves all.' RobertHooke,a geat physicistof the seventeenth century in composinga brief on the newly created RoyalSociety,wiselycautionedthat the purposeof this quintessential Enlightenmentorganizationshould be 'To improve the knowledge of naturall things, and all useful Arts, Manufactures,Mechanick practises, Enrynesand Inventionsby Experimenb-(not meddling with Divinity,Metaphysics, Moralls,Politicl$,Grammar,Rhetorickor Logick).' "Thesesentimentsare just asprevalentamongleadingthinkersof the modernera,aswell asa largeminorityof workingscientists. They are reinforcedby queasiness over the ideaoforganic evolutionasespousedby Darwin. This keystoneof empiricismpresumesto reduce

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the Creation to the productsof random mutationsand environmental circumstance. Even George Bernard Shaw, an avowed atheist, responded to Darwinism with despair.He condemned its fatalism and the demoting of beauty,intelligence,honor, and aspirationto an abstract notion of blindly assembledmatter. Many writers have suggested,not unfairly in my opinion, that such a sterile view of life, which reduceshuman beings to little more than intelligent animals, gave intellectual iustification to the genocidalhorrors of Nazism and communism. "So surely there is something wrong with the reigning theory of evolution. Even if some form of genetic changeoccurswithin species in the manner proclaimedby the new Darwinism,the full, stupendous complexity of modern organismscould not have been createdby blind chance alone. Time and again in the historyof sciencenew evidence has overturned prevailing theories.Why are scientistsso anxious to stay with autonomousevolution and to discount the possibilityof an intelligent designinstead?It is all very curious.Design would seemto of millions of be a simpler explanationthan the random self-assembly kinds of organisms. "Finally, theism gains compelling force in the caseof the human mind and-I won't shrink from saying it-the immortal soul. Litde wonder that a quarter or more of Americans reiect totally the idea of any kind of human evolution, even in anatomy and physiology.Science pushedtoo far is sciencearrogant.Let it keep its proper place,as the God-given gift to understand His physical dominion."

Tnr Euprnrcrsr "I'll beginbyfreelyacknowledging thatreligionhasan overwhelming athactionfor the human mind, and that religiousconvictionis largely beneficent.Religion risesfrom the innermostcoils of the human love,devotion,and,aboveall, hope.Peoplehunger spirit.It nourishes for the assuranceit offers.I can think of nothing more emotionally compellingthan the Christiandoctrinethat God incarnatedhimself of all humanlife, evenof the slave,and in testimonyof the sacredness promise of eternallife for everyone. that he diedandroseagainin "But religiousbelief has another,deshuctiveside,equalingthe of materialism.An estimatedone hundredthousandbeworstexcesses haveexistedin history and manyhavefosteredethnicand lief systems

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tribal wars.Each of the threegreatWesternreligionsin particularexpandedat one time or anotherin symbiosis with military aggression. Islam,which means'submission,' wasimposedby force of armson large portions of the Middle East, Mediterraneanperimeter, and southernAsia. Christianitydominatedthe New World as much by colonialexpansionasby spiritualgrace.It benefitedfrom a historical accidenl Europe,havingbeenblockedto the Eastby the Muslim Arabs,turnedwestto occupythe Americas,whereuponthe crossaccompaniedthe swordin one campaignof enslavementand genocide afteranother. "The Christianrulershad an inshuctiveexampleto follow in the earlyhistoryoffudaism.Ifwe areto believethe Old Testament,the Israeliteswereorderedby God to wipe the promisedland cleanof hea'Of then. thesepeopleswhich the LORD your God givesyou as an inheritance,you shall let nothingthat breathesremain alive,but you shall utterly destroythem: the Hittite and the Amorite and the Canaaniteand the Perizziteand the Hivite and the |ebusite,as the LORD your God has commandedyou,' thus reportsDeuteronomy, zo16-17.Overa hundredcitieswereconsumedby fire and death,beginning with foshua'scampaignagainstfericho and ending with Davidt assault on theancient)ebusite strongholdof ferusalem. "I bring up thesehistoricalfactsnot to castaspersions on presentdayfaithsbut ratherto castlight on their materialoriginsand thoseof the ethicalsystems they sponsor.All greatcivilizationswerespreadby conquest, andamongtheir chiefbeneficiaries werethe religionsvali datingthem. No doubt membershipin state-sponsored religionshas alwaysbeendeeplysatisfyingin manypsychologicaldimensions,and spiritual wisdomhas evolvedto moderatethe more barbarictenets obeyedin the daysof conquest.But everymajor religiontodayis a winner in the Darwinianstrugglewagedamongculfures,and none ever flourishedby toleratingits rivals.The swiftestroad to successhasalwaysbeensponsorship by a conqueringstate. "To be fair, Iet me now put the matterof causeand effectstraight. Religiousexclusionand bigotryarisefrom tribalism,the belief in the innatesuperiorityand specialstatusof the in-group.Tribalismcannot be blamedon religion.The samecausalsequencegaveriseto totalitarian ideologies.The pagancorpusnrysticumof Nazism and the classwarfaredoctrine of Marxism-Leninism,both essentiallydogmasof religionswithout God, were put to the serviceof hibalism, not the

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reverse.Neither would have been so fewently embraced if their devoteeshad not thought themselveschosenpeople,virtuous in their mission, surroundedby wicked enemies,and conquerorsby right of blood and destiny.Mary Wollstonecraftcorrectly said, of male domination 'No man choosesevil becauseit but extensibleto all human behavior, is evil; he only mistakesit for happiness,which is the good he seeks.' "Conquest by a tribe requiresthat its membersmake sacrificesto the interestsof the group, especiallyduring conflict with competing groups. That is simply the expressionof a primal rule of social life throughout the animal kingdom. It ariseswhen lossof personal advantageby submissionto the needsof the group is more than offsetby gain in personal advantagedue to the resulting successof the group. The human corollary is that selfish,prosPerouspeoplebelonging to losing poor membersof winreligionsand ideologiesare replacedby selfless, ning religions and ideologies.A better life later on, either an earthly paradiseor resurrectionin heaven, is the promisedreward that cultures invent to iustifr the subordinatingimperativeof socialexistence. Repeatedfrom one generation to the next, submissionto the group and its moral codesis solidified in official doctrine and personal beliefBut it is not ordained by God or plucked from the air as self-evident truth. It evolvesasa necessarydevice of survival in social organisms. "The most dangerousof devotions,in my opinion, is the one endemic to Christianig: I wasnot bom to be of this world. With a second life waiting, suffering can be endured-especially in other people. The natural environment can be used up. Enemiesof the faith can be savagedand suicidal martyrdom praised. "Is it all an illusion?Well, I hesitateto call it that or, worse,a noble lie, the harsh phrasesometimesused by skeptics,but one hasto admit that the obiective evidence supporting it is not strong. No statistical proofs exist that prayer reduces illness and mortality, except perhaps through a psychogenicenhancementof the immune system;if it were otherwise the whole world would pray continuously.When two armies blessedby priestsclash,one still loses.And when the martyr'srighteous forebrain is explodedby the executioner'sbullet and his mind disintegrates,what then? Can we safely assumethat all those millions of neural circuits will be reconstituted in an immaterial state,so that the consciousmind carrieson? "The smart money in eschatologyis on BlaisePascal'swager:Live well but accept the faith. If there is an afterlife, the seventeenth-

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century French philosopherreasoned,the believer has a ticket to paradiseand the bestof both worlds.'If I lost,'Pascalwrote,'I would have lost little; if I won I would have gainedeternallife.' Now think like an empiricist for a moment. Consider the wisdom of turning the wager around as follows: If fear and hope and reason dictate that you must acceptthe faith, do so,but heat this world as if there is none other. "I know hue believerswill be scandalizedby this line of argument. Their wrath falls on outspoken heretics, who are considered at best troublemakersand at worst traitors to the social order. But no evidence hasbeen adducedthat nonbelieversare lesslaw-abidingor productive citizensthan believersof the same socioeconomicclass,or that they face death less bravely. A 1996 survey of American scientists 1to take one respectablesegmentof society)revealedthat 46 percent are atheistsand r4 percent doubtersor agnostics.Only 36 percent expresseda desire_forimmortality, and most of thoseonly moderatelyso; 64percent claimed no desireat all. "Tiue characterarisesfrom a deeperwell than religion. It is the internalization of the moral principles of a society,augmented by those tenetspersonallychosen by the individual, strong enough to endure through trials of solitude and adversity.The principles are fitted together into what we call integrity, literally the integrated self, wherein personaldecisionsfeel good and true. Characteris in turn the enduring source of virtue. It standsby itself and excitesadmiration in others. It is not obedience to authority, and while it is often consistent with and reinforcedby religiousbelief, it is notpiety. "Nor is sciencethe enemy.It is the accumulationof humanity'sorganized,obiective knowledge, the first medium devised able to unite people everywherein common understanding.It favorsno hibe or religion. It is the baseof a truly democraticand global culture. 'You say that science cannot explain spiritual phenomena.Why not?The brain sciencesare making important advancesin the analysis of complex operations of the mind. There is no apparent reason why they cannot in time provide a material account of the emotions and ratiocinationthat composespiritualthought. 'You askwhere ethical preceptscome from if not divine revelation. Consider the alternative empiricist hypothesis,that precepts and religious faith are entirely material products of the mind. For more than a thousand generationsthey have increasedthe survival and reproductive successof those who conformed to tribal faiths. There was more

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than enough time for epigeneticrules-hereditary biasesof mental moralandreligioussentiments. development-toevolvethatgenerate Indoctrinabilitybecamean instinct. underthe guidreachedby consensus "Ethicalcodesareprecepts Religionis the enanceof the innaterulesof mentaldevelopment. that explainthe originof a people,their sembleof mythic narratives to particularritualsand to subscribe obliged are they destiny,andwhy from the bottom are created beliefs religious moralcodes.Ethicaland from the top down, come do not up, from peopleto their culture.They of culture' way by from God or othernonmaterialsourceto thepeople or empiricist,fits the obiec"Which hypothesis, transcendentalist tive evidencebest?The empiricist,by a widemargin.To the extentthat will be placed in moralreasoning moreemphasis thisviewis accepted, authority' ideological and religious less on and choice, on social "Sucha shifthasin factbeenoccurringin Westernculturessince but the pacehasbeenveryslow.Partof the reason the Enlightenment, is a grossinsufficiencyof knowledgeneededto iudgethe full consefor the long term, saya especially quencesof our moral decisions, and the decadeor more.We havelearneda greatdealaboutourselves world in which we live, but need a grea!dealmore to be fully wise' There is a temptationat everygreatcrisisto yield to transcendental authoriSr,and perhapsthat is betterfor a while.We arestill indoctrinable,we still areeasilygod-struck. "Resistance to empiricismis alsodue to a purelyemotionalshortPeople It is bloodless' it promotes: comingof the modeof reasoning they affirmation, need mote than reason.They need the poetryof other and at ritesof passage cravean authority greaterthan themselves wish for the imA maioritydesperately momentsof high seriousness. mortalitythe ritualsseemto underwrite. "Great ceremoniessummonthe historyof a peoplein solemnrethe sacredsymbols.That is the endurmembrance.They showcase ing value of ceremony,which in all high civilizationshashistorically assu-ed a mostly religiousform. Sacredsymbolsinfiltrate the very bonesof culture.Theywill takecenturiesto replace,if ever' "So I may surpriseyou by grantingthis much: It would be a sorry day if we abandonedour veneratedsacraltraditions.It would be a tragicmisreadingof historyto expungeunderGod from the American Pledgeof Allegiance.Whether atheistsor hue believers,let oathsbe takenwith hand on the Bible,andmaywe continueto hearSohelpme

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God.Call uponpriestsandministersandrabbisto blesscivil ceremony with prayer,and by all meanslet us bow our headsin communalrespect.Recognize thatwheninhoitsand invocations pricklethe skinwe arein the presenceof poetry and the soulof the tribe,somethingthat will outlivetheparticularities of sectarian belief,andperhapsbeliefin God itself. "But to sharereverence isnot to surrender thepreciousselfandobscurethe true natureof the human race.We shouldnot forgetwho we are.Our strengthis in truth andknowledgeandcharacter,underwhateversign.fudaeo-Christians aretold by Holy Scripturethat pridegoeth beforedestruction.I disagree; it'sthe reverse: Destructiongoethbefore pride.Empiricismhasturnedeverything aroundin the formula.It has destroyedthe giddyingtheorythat we are specialbeingsplacedby a deity in the centerof the universein orderto serveasihe summii of Creationfor the gloryof the gods.We can be proud asa speciesbecause,havingdiscovered that we arealone,we owethe godsverylittle. Humility is bettershownto our fellow humansand the restof life on thisplanet,on whomall hopereallydepends. And if anygodsarepaying attention,surelywe haveearnedtheir admirationby makingthat discovery andsettingout aloneto accomplish the bestof which ,. "r. capable."

THs encuMENT or the empiricist, to repeatmy earlierconfession,is my own.It is far from novel,havingrootsthat go backto fuis_ totle'sNicomacheanEthics and,in the beginningof the modernera,to DavidHume'sATreatiseof Human Nature(rllg-+o). The Erstclear evolutionaryelaborationof it wasby Darwin inThe Descentof Man (rB7r). The argumentof the religioustranscendentalist, on the other hand,is the oneI firstlearnedasa child in the Christianfaith.I have reflectedon it repeatedly since,andam by intellectandtemperament boundto respect itsancienttraditions. It is alsothe casethat religioustranscendentalism is bolsteredby seculartranscendentalism, with which it has fundamentalsimilarities.ImmanuelKant fudgedby historythe greatest of secularphiloso. phers,addressed moral reasoningvery much asa theologiar,.Hr.r*"r, beings,he argued,are independentmoral agentswith a wholly free will capableof obeyingor breakingmoral law: "There is in man a

CorqstltnNcn power of selfdetermination, independent of any coercion through ,"rrr,ro,r, impulses."Our minds are subiectto a categoricalimperative, he said, of what our actions ought to be. The imperative is a good in iL and it can be recognized selfalone,apartfrom all other considerations, which you wish also it maxim through that on only ,,.lei"Act this by transcendental,ought and important, Most law." become a universal of causeand efsystem is a said, Kant has no place in nature. Nature, there is no which for will, free fect, while moral choice is a matter of mere inrising above causeand effect. In making moral choices,in stinct, human beingstranscendthe realm of nature and enter a realm of freedomthat belongsto them exclusivelyas rational creatures' Now this formulation has a comforting feel to it, but it makes no senseat all in terms of either material or imaginableentities,which is why Kant, even apart from his tortured prose,is so hard to understand' Sometimesa concept is baffiing not becauseit is profound but becauseit is wrong. It doesnot accord,we know now, with the evidence of how the brain works. ln Pincipia Ethica (r9o3) G. E. Moore, the founder of modern ethical philosophy, essentiallyagreedwith Kant. Moral reasoningin his viewcannot dip into psychologyand the socialsciencesin order to locate ethical principles,becausethey yield only a causalpicture and fail to illumi.rate th. basisof moral fustification.So to passfrom the factual is to the normative ought commits a basic error of logic, which Moore called the naturalisticfallacy.fohn Rawls,inATheory of lustice (r97r), once again traveled the transcendentalroad' He offered the very plausiblepremisethat iusticebe definedasfairness,which is to be as an intrinsic good. tt is the imperative we would follow if """.pt.d no starting information about our own statusin life. But in had we making such an assumption, Rawlsventured no thought on where the hu-an brain comes from or how it works. He offered no evidencethat is consistentwith human nature, hence practicable iustice-as-fairness as a blanket premise. Probably it is, but how can we know except by blind trial-and-error? I find it hard to believe that had Kant, Moore, and Rawls known modern biology and experimental psychology they would have reasoned as they did. Yet as this century closes, transcendentalism remains firm in the hearts not iust of religious believers but also of countless scholars in the social sciencesand humanities who, like

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Mooreand Rawlsbeforethem, havechosento insulatetheir thinking from the naturalsciences. Manyphilosopherswill respondby saying,But waitl What areyou saying? Ethicistsdon't needthatkind of information.you reallycan't passfrom is to ought.Youarenot allowedto describea geneticpredispositionand supposethat becauseit is part of human nature,it is somehowtransformedinto an ethical precept.We must put moral reasoningin a specialcategory, and usetranscendental guidelinesas required. No, we do not haveto put moral reasoningin a specialcategory, and usetranscendental premises, because the posingof the natuialistic fallacyis itselfa fallacy.For lf oughtis not is, whatis?To hanslateis into oughtmakessenseif we attendto the obiectivemeaningof ethical precepts. They are veryunlikelyto be etherealmessages outsidehumanityawaitingrevelation,or independenttruthsvibratingin a non_ materialdimensionof the mind. They are more Iikely to be physical productsof the brain and culture.Fromthe consilientperspective of the naturalsciences, they are no morethan principlesof the sociar contracthardenedinto rules and dictates,the behavioralcodesthat membersof a socie$ferventlywish othersto follow and arewilling to acceptthemselves for the commongood.Precepts aretheexhemein a scaleof agreements that rangefrom casualassentto public sentiment to lawto thatpartof thecanonconsidered unalterable andsacred. The scaleappliedto adulterymightreadasfollows: Let'snotgofurther;it doem'tfeelright,and it wouldleadto trouble. (Weprobablyought not.) Adulterynotonly causes feelingsof guilt, it is generallydisapproved of by society, sotheseareotherreasons to avoid it. (Weought not.) Adulteryisn't iust disapproved of, it'sagainstthe law. (We almost certainlyoughtnot.) Cod commandsthat we ayoid this mortal sin. (We absolutelv oughtnot.) In transcendental thinking the chain of causationruns downward from the givenoughtin religionor naturallaw throughjurisprudence to education andfinallyto individualchoice.The arsumentfromtranscendentalism takesthe following general[or^, fhn e is a supreme pinciple, eitherdivineor intrinsicin theorderof nature,and wewill be wiseto leam about it and find the meansto conformto it Thus fohn

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Rawls opens A Theoryof lusticewith a proposition he regardsas irrevo'in a just socief' the liberties of equal citizenshipare taken as cable' settled;the rightssecuredby iusticeare not subiectto political bargaining or to the falculus of socialinterests."As many critiqueshave made when apclJar, that premisecan lead to many unhappy consequences and control of social tightening the including world, real plied to ihl is sugtherefore premise different A very initiative. decline of personal gestedby Robert Nozick in Anarchy, State,and't'ltopia (1974):"Indiiid,r"l, have rights, and there are things no Personor group may do to them (withouiviolating their rights). So strongand far-reachingare these rights that they raise the question of what, if any'thing,the state and its offi"i"lr may do." Rawlswould point us toward egalitarianism regulated by the state, Nozick toward libertarianism in a minimalist state. The empiricist view in contrast, searching for an origin of ethical reasoningthat can be obiectivelystudied,reversesthe chain ofcausation. The individual is seenaspredisposedbiologically to make certain choices.By cultural evolution some of the choicesare hardened into precepts, then laws, and if the predispositionor coercion is shong .r,o,r!h, belief in the command of God or the natural order of the " univeise. The general empiricist principle takes this form: Strong innate feeling oid hittori"ol experiencecausecertain actions to be prednd their consequences, fnoei; *u tave experiencedthem, and weighed 'agree upon oath an us take Let them. to conform with codesthat express tie codes,investour personal honor in them, and suffer punishment for their violation. The empiricist view concedesthat moral codesare devised to conform to some drives of human nature and to suppressotherc.Ought is not the hanslation of human nature but of the public will, wh'ich can be made increasinglywise and stable through the understandingof the needsand pidalls of human nature.It recognizes that the strenlth of commitment can wane as a result of new knowledge and e*p-erience,with the result that certain rules may be desaJralized,old l"*, rescinded,and behaviorthat was once prohibited freed. lt also recognizesthat for the same reasonnew moral codes may need to be devised,with the potential in time of being made sacred.

l r r u E E M P I R I c I s T w o R L D v I E w i s c o n e c t ,o u g h t i s i u s t shorthand for one kind of factual statement,a word that denotes what

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societyfirst chose(or wascoerced)to do, and then codified.The naturalistic fallacy is thereby reduced to the naturalistic dilemma. The solution of the dilemma is not difficult. It is this: oughtis the product of a materialprocess.The solutionpointsthe way to an obiectivegraspof the origin of ethics. A few investigatorsare now embarked on just such a founda_ tional inquiry. Most agree that ethical codes have arisen by evolution through the interplay of biology and culture. In a sensethey are reviving the idea of moral sentimentsdevelopedin the eighteenthcentury by the British empiricistsFrancisHutcheson,David Aume, and Adam Smith. By moral sentimentsis now meant moral instincts as defined by the modern behavioral sciences,subject to iudgment according to their consequences. The sentimentsare thus derivedfrom epigen"etic rules, hereditary biasesin mental development,usually co'ditio'ed by emotion, that influence conceptsand decisionsmade from them. The primary origin of the moral instincts is the dynamic relation between cooperation and defection. The essentialingredient for the molding of the instinctsduring geneticevolution in any speciesis intelligencehigh enough to judge and manipulatethe tensiongenerated by the dynamism. That level of intelligence allows the building of complex mental scenarioswell into the future, as I describedin"the earlierchapteron the mind. It occurs,so far asknown, only in human beingsand perhapstheir closestrelativesamong the highei apes. A way of envisioning the hypothetical earliest stagesof moral evo_ Iution is provided by game theory,particularlythe solutionsto the famous Prisoner'sDilemma. consider the following typical scenarioof the Dilemma. Two gang membershavebeen arrestedfor murder and are being questioned separately.The evidence against them is strong but not compelling. The first gang member believesthat if he turni statet witness,he will be grantedimmunity and his partnerwill be sentenced to life in prison. But he is also awarethat his partner has the same option. That is the dilemma. Will the two gang members inde_ pendently defect so that both take the hard fall? They will not, because they agreedin advanceto remain silent if caught. By doing so, both hope to be convicted on a lessercharge ot punishrient alto"r""p. gether.criminal gangshave turned this principle oi calculation into an ethicalprecept:Never rat on anothermember; alwaysbe a stand-up guy.Honor doesexistamong thieves.If we view the gangasa societyof

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sorts, the code is the same as that of a captive soldier in wartime obliged to give only name, rank, and serialnumber' In orr. for- or another, comparable dilemmas that are solvableby cooperation occur constanily and everywherein daily life' The payoff is variously money, status,power' sex' access'comfort, and health' Most of these proximate rewardsare converted into the universal bottom line of Darwinian genetic fitness:greaterlongevityand a secure, growing family. " AnJ so it has likely always been. Imagine a Paleolithic hunter band, saycomposedof five men. one hunter considersbreakingaway from the othe$ to look for an antelopeon his own. If successfulhe will gain a large quantity of meat and hide, five times greaterthan if he stayswith ihe band and they are successful.But he knowsfrom experience that his chances of successalone are very low, much lessthan the chancesof a band of five working together.In addition, whether successfulalone or not, he will sufferanimosityfrom the othersfor lessening their own Prospects.By custom the band members remain tolether and shaie the animalsthey kill equitably.So the hunter stap. HI also obsewes good manners while doing so, especially if he is the one who makes the kill. Boasdul pride is condemnedbecauseit rips the delicate web of reciProcitY. Now supposethat human propensitiesto cooperateor defectare heritable: Some members are innately mole cooPerative,others less so. In this respect moral aptitude would simply be like almost all other mental traits studied to date. Among traits with documented heritability, those closest to moral aptitude are empathy to the dishess of others and certain processesof attachment between infants and their caregivers.To the heritability of moral aptitude add the abundant evidenJe of history that cooperative individuals generally survive lo_nger and leave more offspring. It is to be expectedthat in the course of evo' lutionary history genespredisposingpeople toward cooperativebehavior wouid have come to predominate in the human population as a whole. such a process repeated through thousandsof generationsinevitably g"u. bitth to the moral sentiments. with the exception of stone psy-chopaths(if any huly exist), these instincts are vividly experiencedby every person variously as conscience, self-respect,remorse, humility, and moral outrage. They bias cultural empathy, ,h"*., conventions that exPressthe universal moral the toward evoiution

Ethics and Religion codesof honor, patriotism,altruism, iustice, compassion,mercy, and redemption. The dark side to the inborn propensityto moral behavior is xenophobia. Becausepersonalfamiliarity and common interestare vital in social transactions,moral sentimenb evolved to be selective.And so it has ever been, and so it will ever be. People give trust to shangerswith effort, and true compassionis a commodity in chronically short supply. Tiibes cooperateonly through carefully defined treatiesand other conventions.They are quick to imagine themselvesvictims of conspiracies by competinggroups,and they are prone to dehumanize and murder their rivals during periods of severeconflict. They cement their own group loyalties by means of sacredsymbols and ceremonies.Their mythologiesare filled with epic victories over menacing enemies. The complementary instincts of morality and hibalism are easily manipulated.Civilization hasmade them more so.Only ten thousand years ago, a tick in geological time, when the agricultural revolution beganin the Middle East,in China, and in Mesoamerica,populations increasedin density tenfold over those of huntergatherer societies. Familiessettledon small plots of land, villagesproliferated,and labor wasfinely divided asa growingminority of the populacespecializedas crafumen, haders,and soldiers.The rising agricultural societies,egalitarian at first, became hierarchical. As chiefdoms and then states thrived on agricultural surpluses,hereditaryrulers and priestly castes took power. The old ethical codes were transformed into coercive regulations, always to the advantageof the ruling classes.About this time the idea of law-giving gods originated. Their commands lent the ethical codes overpoweringauthority, once again-no surprise-to the favor ofthe rulers. Becauseof the technical difficulty of analyzing such phenomena in an objectivemanner, and becausepeople resistbiological explanations of their higher cortical functions in the first place, very little progresshasbeen made in the biologicalexplorationof the moral sentiments. Even so, it is an astonishingcircumstance that the study of ethics has advanced so little since the nineteenth century. As a result the most distinguishingand vital qualities of the human speciesremain a blank spaceon the scientific map. I think it an error to pivot discussionsof ethicsupon the free-standing assumptionsof contemporary philosopherswho have evidentJynever given thought to the evolutionary origin and material functioning of the human brain. In no other

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domain of the humanitiesis a union with the naturalsciencesmore urgently needed. When the ethical dimension of human nature is at last fully opened to such exploration,the innate epigeneticrules of moral reasoning will probably not prove to be aggregatedinto simple instincts or altruism. Instead,the rules most such asbonding, cooperativeness, probably will turn out to be an ensemble of many algorithmswhose interlocking activitiesguide the mind acrossa landscapeof nuanced moods and choices. Such a prestructuredmental world may at first seem too complicated to have been createdby autonomous genetic evolution alone. But all the evidence of biology suggeststhat iust this processwas enough to spawnthe millions of speciesof life surroundingus' Each kind of animal is furthermore guided through its life cycle by unique and often elaboratesetsof instinctual algorithms,many of which are beginning to yield to genetic and neurobiologicalanalyses.With all these examples before us, it is not unreasonableto conclude that human behaviororiginatedthe sameway.

M e aN w n t r,n , the m6langesof moral reasoningemployedby modern societiesaie, to put the matter simply, a mess'They are chimeras, composedof odd partsstuck together.Paleolithicegalitarianand tribalistic instinctsare still firmly installed.As part of ihe geneticfoundation of human nature,they cannot be replaced.In somecases,such as quick hostility to strangersand competing groups, they have become generally ill-adapted and persistentlydangerous.Above the fundamenof argumentsand rulesthat accommotal instinctsrise superstructures date the novel institutions created by cultural evolution. These accommodations,which refect the attempt to maintain order and further tribal interests,have been too volatile to track by genetic evolution; they are not yet in the genes. Little wonder, then, that ethicsis the most publicly contestedof all philosophical enterprises.Or that political science,which at foundation is primarily the study of applied ethics, is so frequently problematic. Neither is informed by anything that would be recognizableas authentic theory in the natural sciences.Both ethics and political science lack a foundation of verifiable knowledge of human nature sufficient to produce cause-and-effectpredictions and sound iudgments

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basedon them. Surely it will be prudent to pay closer attention to the deep springs of ethical behavior. The greatestvoid in knowledge in such a venture is the biolog, of the moral sentiments.In time this subject can be understood, I believe, by paying attention to the following topics. . The definition of the moral sentimenfs:first by precise descriptions from experimental psycholog', then by analysis of the underlying neural and endocrineresponses. . The genetics of the moral sentimenfs: most easily approached through measurements of the heritability of the psychological and physiological processesof ethical behavior, and eventually, with difficulty, by identification of the prescribing genes. . The develofment of the moral sentimentsas produck of the interactions of genesand environment.The researchis most effective when conducted at two levels: the histories of ethical systemsas part of the emergence of different cultures, and the cognitive development of individuals living in a variety ofcultures. Such investigationsare already well along in anthropology and psychology.In the fuhrre they will be augmented by contributions from biology. .The deef historyof the moral sentiments:why they exist in the first place, presumably by their contributions to survival and reproductive successduring the long periodsof prehistorictime in which they genetically evolved. From a convergence of these several approaches,the true origin and meaning of ethical behavior may come into focus. If so, a more certain measure can then be taken of the stren$hs and fexibility of the epigenetic rules composing the various moral sentiments. From that knowledge,it should be possibleto adapt the ancient moral sentiments more wisely to the swiftly changing conditions of modern life into which, willy-nilly and largely in ignorance, we have plunged ourselves. Then new answersmight be found for the truly important questions of moral reasoning. How can the moral instincts be ranked? Which are best subdued and to what degree,which validated by law and symbol? How can preceptsbe left open to appeal under extraordinary circumstances? In the new understanding can be located the

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most effectivemeans for reaching consensus.No one can guessthe form the agreementswill take. The process,however, can be predicted with assurance.It will be democratic,weakeningthe clashof rival religions and ideologies.History is moving decisivelyin that direction, and people are by nahrre too bright and too contentiousto abide anything else. And the pace can be confidently predicted:Change will come slowly, acrossgenerations,becauseold beliefs die hard even when demonstrablyfalse.

T H n s e u n R E A S o N I N G t h a t a l i g n se t h i c a lp h i l o s o p h yw i t h s c i ence can also inform the study of religion. Religionsare analogousto superorganisms.They have a life cycle. They are born, they grow, they compete, they reproduce, and, in the fullness of time, most die. In each of thesephasesreligions reflect the human organismsthat nourish them. They expressa primary rule of human existence,that whateveris necessaryto sustainlife is alsoultimately biological. Successfulreligionstypically begin ascults,which then increasein powerand inclusivenessuntil they achievetoleranceoutsidethe circle of believers.At the core of each religion is a creation myth, which explains how the world began and how the chosenpeople-those subscribing to the belief system-arrived at its center. There is often a mystery a set of secret instructions and formulas available only to hierophants who have worked their way to a higher stateof enlightenment. The medieval fewish cabala, the trigradal system of Freemasonry and the carvings on Aushalian Aboriginal spirit sticks are examples of such arcana. Power radiates from the center, gathering converts and binding followers to the group. Sacred places are designated where the gods can be importuned, rites observed,and miracles witnessed. The devoteesof the religion compete asa tribe with those of other religions. They harshly resist the dismissal of their beliefs by rivals. Theyvenerateself-sacrificein defenseof the religion. The tribalistic roots of religion and those of moral reasoningare similar and may be identical. Religious rites, as evidencedby burial ceremonies,are very old. In the late Paleolithicperiod of Europe and the Middle East,it appearsthat bodieswere sometimesplacedin shallow gravessprinkled with ochre or blossoms,and it is easyto imagine ceremonies performed there that invoked spirits and gods. But, as

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theoreticaldeduction and the evidencesuggest,the primitive elementsof moralbehaviorarefar olderthanPaleolithicritual.Religion aroseon an ethicalfoundation,and it hasprobablyalwaysbeenused in onemanneror anotherto iustifymoralcodes. The formidable influenceof the religiousdrive is basedon far more, however,than just the validationof morals.A great subterraneanriver of the mind, it gathersshengthfrom a broad spreadof tributary emotions.Foremostamong them is the survivalinstinct. "Fear,"asthe RomanpoetLucretiussaid,"wasthe first thing on earth to makegods."Our conscious mindshungerfor a permanentexistence.If we cannothaveeverlasting life of the body,then absorption into someimmortal wholewill sewe.Anythingwlll serve,aslong asit givesthe individualmeaningand somehowshetchesinto eternitythat swiftpassage of the mind and spirit lamentedby St.Augustineasthe shortdayof time. The understanding andcontrolof life is anothersourceof religious power.Doctrine drawson the samecreativespringsasscienceand the arts,its aim beingthe ertractionof orderfrom the mysteries of the materialworld.To explainthe meaningof life it spinsmythic narrativesof the tribal history,populatingthe cosmoswith protectivespiritsand gods.The existenceof the supematural,if accepted,testifiesto the existenceof thatotherworldsodesperately desired. Religionis alsoempoweredmightilyby its principalally,tribalism. The shamans and priestsimploreus,in sombercadence,Trustin the sacredrifuals,becomepart of the immortalforce,youdreoneof us.'\s yourlife unfolds,eachstephasmysticsignificance that wewholoveyou will markwith a solemnite of passage, the last to be performedwhen youenterthat secondworldfreeof pain andfear. If the religiousmythosdid not existin a culture, it would be quickly invented,and in fact it has been everywhere,thousandsof timesthroughhistory.Suchinevitabilityis the mark of instinctualbehaviorin any species.That is, evenwhen learned,it is guidedtoward certainstatesby emotion-drivenrulesof mental development.To call religioninstinctiveis not to supposeanyparticularpart of its mythosis untrue,only that its sourcesrun deeperthan ordinaryhabit and are in facthereditary,urgedinto birth throughbiasesin mentaldevelopment encodedin the genes. I havearguedin previouschaptersthat such biasesare to be expectedasa usualconsequence of the brain'sgeneticevolution.The

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logic applies to religious behavior,with the added twist of tribalism. There is a hereditaryselectiveadvantageto membershipin a powerful group united by devout belief and purPose.Even when individuals subordinatethemselvesand risk death in common cause,their genes are more likely to be transmittedto the next generationthan are those of competing groups who lack equivalent resolve. The mathematical models of population genetics suggestthe following rule in the evolutionaryorigin of such altruism. If the reduction of survival and reproduction of individuals due to genes for altruism is more than offsetby the increasedprobabilityof suwival of the group due to the altruism,the altruism geneswill rise in frequency throughout the entire population of competing groups. Put as conciselyas possible:The individual pays,his genesand tribe gain, altruism spreads.

L n r u n N o w s u c c n s r a s t i l l d e e p e rs i g n i f i c a n coef t h e e m p i r i cist theory of the origin of ethics and religion. If empiricism is disproved, and transcendentalismis compellingly upheld, the discovery would be quite simply the most consequentialin human history.That is the burden laid upon biology as it drawscloseto the humanities.If the obiective evidence accumulatedby biolog, upholds empiricism, consilience succeedsin the most problematic domains of human behavior and is likely to apply everywhere.But if the evidencecontradicts empiricism in any part, universal consilience fails and the division between scienceand the humanities will remain permanent all the way to their foundations. The matter is still far ftom resolved.But empiricism, as I have argued, is well supported thus far in the caseof ethics. The obiective evidence for or againstit in religion is weaker,but at leaststill consistent with biology. For example, the emotions that accompany religious ecstasyclearly have a neurobiologicalsource.At leastone form ofbrain disorder is associatedwith hyperreligiosity,in which cosmic significance is given to almost everything, including trivial everydayevents. Overall it is possibleto imagine the biological constructionof a mind with religious beliefs, although that alone does not dismisstranscendentalism or prove the beliefsthemselvesto be untrue' Equally important, much if not all religious behavior could have arisen from evolution by natural selection.The theory fits-crudely.

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The behaviorincludesat leastsomeaspectsof belief in gods.Propitiation and sacrifice,which are near-universals of religious practice,are actsof submissionto a dominant being.They are one kind of a dominance hierarchy,which is a generaltrait of organizedmammalian societies.Like humans, animals use elaboratesignalsto advertiseand maintain their rank in the hierarchy. The details vary among species but also have consistent similarities acrossthe board, as the following two exampleswill illushate. In packs of wolves the dominant animal walks erect and "proud," stiffJegged,deliberatelypaced,with head,tail, and earsup, and stares freely and casuallyat others.In the presenceof rivals, the dominant animal bristles its pelt while curling its lips to show teeth, and it takes first choice in food and space.A subordinateusesoppositesignals.It turns awayfrom the dominant individual while lowering its head, ears, and tail, and it keeps its fur sleekedand teeth covered. [t grovels and slinks,and yieldsfood and spacewhen challenged. In troopsof rhesusmonkeys,the alpha male of the troop is remarkably similar in mannerismsto a dominant wolf. He keepshis head and tail up, walksin a deliberate,"regal" manner while casuallystaringat others.He climbs nearby obiectsto maintain height above his rivals. When challengedhe stareshard at the opponent with mouth opensignaling aggression,not surprise-and sometimes slapsthe ground with open palms to signal his readinessto attack. The male or female subordinateaffectsa furtive walk, holding its head and tail down, turning awayfrom the alpha and other higher-ranked individuals. It keeps its mouth shut exceptfor a fear grimace, and when challenged makesa cringing retreat.It yields spaceand food and, in the caseof males,estrousfemales. My point is the following. Behavioral scientists from another planet would notice immediately the semiotic resemblancebetween animal submissivebehavioron the one hand and human obeisanceto religious and civil authority on the other. They would point out that the most elaboraterites of obeisanceare directed at the gods, the hyperdominant if invisible members of the human group. And they would conclude,correctly,that in baselinesocial behavior,not iust in anatomy,Homo sapienshas only recently diverged in evolution from a nonhuman primate stock. Countless shrdiesof animal species,with instinctive behavior unobscured by cultural elaboration, have shown that membership in

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dominance orderspays off in survival and lifetime reproductivesuccess.That is hue not iust for the dominant individuals,but for the subordinates as well. Membership in either class gives animals better protection against enemies and better accessto food, shelter, and mates than doessolitary existence. Furthermore, subordination in the group is not necessarilypermanent.Dominant individualsweakenand die, and as a result some of the underlingsadvancein rank and appropriate more resources. It would be surprising to find that modern humans had managed to erasethe old mammalian genetic programsand deviseother that they have means of distributing power.All the evidencesuggests not. True to their primate heritage,people are easilyseducedby confident, charismatic leaders,especially males. That predispositionis strongestin religious organizations.Cults form around such leaders. Their power growsif they can persuasivelyclaim specialaccessto the supremelydominant, typically male figure of God. fu cults evolveinto religions, the image of the supreme being is reinforcedby myth and liturgy. In time the authority of the founders and their successorsis graven in sacredtexts.Unruly subordinates,known as "blasphemers," are squashed. The symbol-forminghuman mind, however,never stayssatisfied with raw apish feeling in any emotional realm. It strivesto build cultures that are maximally rewarding in every dimension. In religion there is ritual and prayer to contact the supreme being directly, conso' lation from coreligionists to soften otherwise unbearable grief, explanations of the unexplainable,and the oceanic senseof communion understanding. with the largerwhole that otherwisesurPasses Communion is the key, and hope rising from it eternal;out of the dark night of the soul there is the prospect of a spiritual journey to the light. For a specialfew the iourney can be taken in this life. The mind reflects in certain ways in order to reach ever higher levels of enlighu enment until finally, when no further progressis possible,it entersa mystical union with the whole. Within the great religions, such enlightenment is expressedby the Hindu samadhi,Buddhist Zen satori, Sufi fana, Taoistwu-wei, and PentecostalChristian rebirth. Something like it is also experiencedby hallucinating preliterateshamans.What all thesecelebrantsevidentlyfeel (asI once felt to some degreeasa reborn evangelical)is hard to put in words, but Willa Cather came as closeaspossiblein a singlesentence."That is happiness,"her fictional

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narratorsaysin My Antonia,"to be dissolved into somethingcomplete andgreat." Of coursethat is happiness, to find the godhead,or to enterthe wholeness of Nature,or otherwise to graspand hold on to something ineffable,beautiful,and eternal.Millionsseekit. Theyfeelotherwise Iost,adrift in a life withoutultimatemeaning.Their predicamentis summarized in an insuranceadvertisement of 1997:Theyearis ry99. Youaredead.What do you do now?They enterestablished religions, to in succumb cults,dabble NewAgenostrums.They pushTheCelestineProphecy and otheriunlt attemptsat enlightenmentontothe bestsellerlists. Perhaps, as I believe,it can all eventuallybe explainedas brain circuitryand deep,genetichistory.But this is not a subjectthat even the mosthardenedempiricistshouldpresumeto trivialize.The idea of themysticalunionisan authenticpartof the humanspirit.It hasoccupiedhumanityfor millennia,and it raisesquestions of utmostseriousness for hanscendentalists andscientists alike.What road,we ask, wastraveled,whatdestinationreachedby the mysticsof history? No onehasdescribedthe true journeywith greaterclaritythan the greatSpanishmysticSt.Teresaof Avila,who in her 1563-65 memoir the stepsshetookto attaindivineunion by meansof prayer. describes At the beginningof the narrativeshemovesbeyondordinaryprayersof devotionand supplication to the secondlevel,the prayerofthe quiet. Thereher mind gathersits facultiesinwardin orderto give"a simple consentto becomethe prisonerof God."A deepsenseof consolation and peacedescends upon her whenthe Lord suppliesthe "waterof grandblessings and graces." Her mind then ceases to carefor earthly things. In the third stateof prayerthe saintt spirit, "drunk with love," is concernedonly with thoughtsof God,who conholsandanimatesit. O my King,seeingthat I am now,whilewriting this, still underthe power of thisheavenly madness . . . grant,I beseech Thee,thataIIthose withwhomI mayhaveto conyerse maybecome madthroughThy love, or let me conyersewith none, or order it that I may have nothine to do in the world, or take me away from it.

In the fourth stateof prayerSt.Teresaof Avila attainsthe mystical union:

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areaII occuThereis no senseof anything,only fruition . . . thesenses pied in thisfunctionin sucha waythat not oneof themis at libefi. . . . The soul,while thusseekingafterCod, is conscious, with a ioy excessive and sweet,that it is,asit were,utterlyfaintingawayin a trance;breathinto that of ing, and all the bodilystrengthfail it. The soulis dissolved of thegracesbeCod, and with the union at lastcomescomprehension stowedbyHim.

Fon ueNv the urge to believe in transcendentalexistenceand immortality is overpowering.Transcendentalism,especiallywhen reinforced by religious faith, is psychicallyfull and rich; it feelssomehow right.ln comparison empiricism seemssterileand inadequate.In the quest for ultimate meaning, the transcendentalistroute is much easier to follow. That is why, even as empiricism is winning the mind, transcendentalismcontinuesto win the heart. Sciencehasalwaysdefeated religious dogma point by point when the two have conflicted. But to no dvail. In the United Statesthere are fifteen million Southern Bap tists, the largest denomination favoring literal interpretation of the Christian Bible, but only five thousandmembersof the American Humanist Association,the leading organizationdevotedto secular and deistic humanism. Still, if history and science have taught us anything, it is that passion and desire are not the same as truth. The human mind evolved to believe in the gods. It did not evolve to believe in biology. Acceptance ofthe supernatural conveyeda great advantagethroughout prehistory when the brain was evolving. Thus it is in sharp contrast to biolory, which wasdevelopedasa product of the modern ageand is not underwritten by genetic algorithms. The uncomfortable truth is that the two beliefs are not factually compatible. fu a result those who hunger for both intellectual and religious huth will never acquire both in full measure. Meanwhile, theolog, tries to resolve the dilemma by evolving sciencelike toward abstraction.The gods of our ancestorswere divine human beings. The Egyptians, as Herodohrs noted, representedthem as Egrptian (often with body partsof Nilotic animals),and the Greeks represented them as Greeks. The great contribution of the Hebrews was to combine the entire pantheon into a single person,Yahweh-a patriarch appropriate to desert tribes-and to intellectualize His exis-

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tence. No graven images were allowed. In the process,they rendered the divine presencelesstangible.And so in biblical accountsit came to passthat no one, not even Moses approaching Yahweh in the burning bush, could look upon His face.In time the fews were prohibited even from pronouncing His true full name. Nevertheless,the idea of a theisticGod, omniscient,omnipotent,and closelyinvolved in human affairs,haspersistedto the presentday asthe dominant religious image of Westernculture. During the Enlightenment a growing number of liberal fudaeoChristian theologians, wishing to accommodate theism to a more rationalist view of the material world, moved away from God as a literal person.Baruch Spinoza, the preeminent fewish philosopher of the seventeenthcentury, visualized the deity as a transcendent substance present everywherein the universe.Deus sive nafura, God or nature, he declared,they are interchangeable.For his philosophical pains he was banished from Amsterdam under a comprehensive anathema, combining all cursesin the book. The risk of heresy notwithstanding, the depersonalizationof God has continued steadily into the modern era. For Paul Tillich, one of the most influential Protestant theologians of the twentieth century the assertionof the existenceof God-asperson is not false; it is iust meaningless.Among many of the most liberal contemporary thinkers, the denial of a concrete divinity takes the form of processtheology. Everything in this most extreme of ontologies is part of a seamlessand endlesslycomplex web of unfolding relationships.God is manifest in everything. Scientists,the roving scouts of the empiricist movement, are not immune to the idea of God. Those who favor it often lean toward some form of processtheology. They askthis question: When the real world of space,time, and matter is well enough known, will that knowledge revealthe Creator'spresence?Their hopesare vestedin the theoretical physicistswho pursue the goal of the final theory the Theory of Everything, T.O.E., a systemof interlockingequationsthat describeall that can be learnedof the forcesof the physicaluniverse.T.O.E. is a "beautiful" theory, as Steven Weinberg has called it in his important essay Dreamsof a FinalTheory. Beautiful becauseit will be elegant, expressing the possibility of unending complexity with minimal laws, and symmetric, becauseit will hold invariant through all space and time. And inevitable, meaning that once statedno part can be changed without invalidating the whole. All surviving subtheories can be fitted into

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it permanently, in the mannerin which Einsteindescribedhis own contribution,the generaltheory of relativity."The chief athactionof If a single the theory" Einsteinsaid,"liesin its logicalcompleteness. one of the conclusions drawnfrom it proveswrong,it mustbe given up; to modifyit withoutdestroyingthe wholestructureseemsto be impossible." The prospectof a final theoryby the mostmathematicalof scientistsmight seemto signalthe approachof a newreligiousawakening. StephenHawking,yielding to the temptationin A Brief Historyof wouldbe the ulTime(ry88),declaredthatthisscientificachievement timatetriumph of humanreason,"for thenwe wouldknowthe mind of God." havealreadylaid in place Well-perhaps,but I doubtit. Physicists a large part of the final theory.We know the trajectory;we can see at roughlywhereit is headed.But therewill be no religiousepiphany, leastnone recognizable to the authorsof Holy Scripture.Sciencehas takenusveryfar fiom the personalGod who oncepresidedoverWestern civilization.It hasdone little to satis$,our instinctualhungerso poignantlyexpressed by the psalmist: himselfin vain andhedisquieteth Man livethhisdayslikea shadow, heknoweth notwhoshallgather histreasures, withpidefuldelusions; My hopeisin thee. them.Now,Inrd,whatismycomfort?

Tnr e sseNcE oF humanity'sspiritualdilemmais thatwe evolved another.Is therea way geneticallyto acceptone truth and discovered betweenthe hanto erasethe dilemma,to resolvethe contradictions scendentalist andempiricistworldviews? No, unfortunately,there is not. Furthermore,a choice between underthem is unlikely to remain arbituaryforever.The assumptions lying the two world viewsare being testedwith increasingseverityby cumulativeverifiableknowledgeabouthow the universeworks,from atom to brain to galaxy.Inaddition,the harshlessonsof historyhave madeit clearthat one codeof ethicsis not asgood-at least,not as durable-as another.The sameis trueof religions.Somecosmologies arefactuallylesscorrectthan others,and someethicalpreceptsareless workable,

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There is a biologicallybasedhuman nature,and it is relevantto ethicsand religion.The evidenceshowsthat becauseof its influence, peoplecan be readilyeducatedto only a narrowrangeofethical pre' cepts.They flourish within certainbelief systems,and wither under others.We needto knowexactlywhy. asto suggesthow the conTo that end I will be so presumptuous most likely be settled.The ideaof flict betweenthe world viewswill a genetic,evolutionaryorigin of moral and religiousbeliefswill be testedby the continuanceof biologicalstudiesof complexhuman behavior.To the extentthat the sensoryand nervoussystemsappearto haveevolvedby naturalselectionor atleastsomeotherpurelymaterial process,the empiricistinterpretationwill be supported.It will be further supportedby verificationof gene-culturecoevolution,the essenin earlierchapters. described tial linkingprocess Now considerthe alternative.To the extentthat ethical and religiousphenomenado not appearto haveevolvedin a mannercongenial to biology,andespeciallyto the extentthat suchcomplexbehavior and newoussystems, cannotbe linkedto physicaleventsin the sensory the empiricistpositionwill haveto be abandonedand a transcendentalistexplanationaccepted. For centuriesthe writ of empiricismhasbeen spreadinginto the belief, slowly at the start but ancient domain of transcendentalist quickeningin the scientific age.The spiritsour ancestorsknew intimatelyfirst fled the rocksand trees,then the distantmountains.Now they are in the stars,where their final extinction is possible.But we cannotlive withoutthem.Peopleneeda sacrednarrative.They must havea senseof largerpurpose,in oneform or other,howeverintellectualized.They will refuseto yield to the despairof animal mortality. They will continueto pleadin companywith the psalmist,Now,Lard, what is my comfort?They will find a wayto keepthe ancestralspirits alive. If the sacrednarrativecannotbe in the form of a religiouscosmology,it will be takenfrom the materialhistoryof the universeand That hend is in no waydebasing.The true evoluthe human species. tionaryepic, retoldaspoetry,is asintrinsicallyennobling asany reliby sciencealreadypossesses giousepic. Materialrealitydiscovered grandeur religious cosmologies combined. and than all morecontent The continuityof the human line hasbeentracedthrougha periodof

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deep history a thousandtimes older than that conceivedby the Western religions. Its study has brought new revelationsof great moral importance. It has made us realize that Homo sapiensis far more than a congeriesof tribes and races.We are a single gene pool from which individuals are drawn in each generation and into which they are dissolved the next generation, forever united as a speciesby heritage and a common future. Such are the conceptions,based on fact, from which new intimations of immortality can be drawn and a new mythos evolved. Which world view prevails,religious transcendentalismor scientific empiricism, will make a great difference in the way humanity claims the future. During the time the matter is under advisement,an accommodationcan be reachedif the following overridingfactsare realized. On the one side, ethics and religion are still too complex for present-dayscience to explain in depth. On the other, they are far more a product of autonomous evolution than hitherto concededby most theologians. Science faces in ethics and religion its most interesting and possiblyhumbling challenge, while religion must somehow find the way to incorporate the discoveriesof sciencein order to retain credibility. Religion will possessstrength to the extent that it codifies and puts into enduring, poetic form the highest values of humanity consistent with empirical knowledge. That is the only way to provide compelling moral leadership. Blind faith, no matter how passionately expressed,will not suffice. Science for ib part will test relentlessly every assumption about the human condition and in time uncover the bedrock of the moral and religious sentiments. The eventual result of the competition between the two world views,I believe,will be the secularizationof the human epic and of religion itself. However the process plays out, it demands open discussion and unwavering intellectual rigor in an atmosphere of mutual respect.

CHAPTER

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To Wner ENo?

I r t s r n n c u s r o M of scholarswhen addressingbehavior and culture to speakvariously of anthropological explanations, psychological explanations,biological explanations, and other explanations aPPropriate to the perspectivesof individual disciplines. I have argued that there is intrinsically only one class of explanation. It traversesthe scalesof space,time, and complexity to unite the disparatefacts of the disciplinesby consilience,the perceptionof a seamlessweb of cause and effect. For centuriesconsiliencehasbeenthe mother'smilk ofthe natural sciences.Now it is wholly accepted by the brain sciencesand evolutionary biology, the disciplines bestpoised to seryein turn as bridges to the social sciencesand humanities. There is abundant evidence to support and none absolutely to refute the proposition that consilient explanations are congenial to the entirety of the great branches of learning. The central idea of the consilienceworld view is that all tangible phenomena, from the birth of starsto the workings of social institutions, are based on material processesthat are ultimately reducible, however long and tortuous the sequences,to the laws of physics. In support of this idea is the conclusion of biologists that humanity is kin to all other life forms bv common descent. We share essentiallythe

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sameDNA geneticcode,which is transcribedinto RNA and translated into proteins with the same amino acids. Our anatomy places us among the Old World monkeys and apes.The fossil record showsour immediate ancestorto be either Homo ergasteror Homo erectus.ltsuggeststhat the point of our origin was Africa about two hundred thousand yearsago. Our hereditaryhuman nature, which evolvedduring hundreds of millennia before and afterward,still profoundly affectsthe evolution of culture. These considerationsdo not devalue the determining role of chance in history. Small accidentscan have big consequences.The characterof individual leaderscan mean the differencebetween war and peace;one technologicalinvention can changean economy.The main thrust of the consilienceworld view insteadis that culture and hence the unique qualitiesof the human specieswill make complete senseonly when linked in causalexplanationto the natural sciences. Biology in particular is the most proximate and hence relevantof the scientific disciplines. I know that such reductionism is not popular outside the natural sciences.To many scholarsin the socialsciencesand humanities it is a vampire in the sacristy.So let me hasten to dispel the profane image that causesthis reaction. fu the century closes,the focus of the natural scienceshas begun to shift awayfrom the searchfor new fundamental laws and toward new kinds of synthesis-"holism," if you prefer-in order to understand complex systems.That is the goal, variously,in studies of the origin of the universe, the history of climate, the functioning of cells, the assemblyof ecosystems,and the physical basis of mind. The strategythat works best in these enterprisesis the construction of coherent cause-and-effectexplanations across levels of organization. Thus the cell biologist looks inward and downward to ensembles of molecules, and the cognitive psychologistto patterns of aggregatenerve cell activi$. Accidents, when they happen, are rendered understandable. No compelling reasonhas ever been offered why the same strategy should not work to unite the natural scienceswith the social sciences and humanities. The difference between the two domains is in the magnitude of the problem, not the principles neededfor its solution. The human condition is the most important frontier of the nahrral sciences. Conversely, the material world exposedby the natural sciences is the most important frontier of the social sciencesand humanities.

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The consilience argument can be distilled as follows: The two frontiers are the same. The map of the material world, including human mental activity, can be thought a sprinkling of charted terrain separatedby blank expansesthat are of unknown extent yet accessibleto coherent interdisciplinary research.Much of what I have offered in earlier chapters has been "gap analysis,"a sketch of the position of the blank spaces, and an account of the efforts of scholarsto explore them. The gapsof greatestpotential include the final unification of physics, the reconstruction of living cells, the assemblyof ecosystems,the coevolution of genesand culture, the physicalbasisof mind, and the deep origins of ethicsand religion. If the consilience world view is correct, the haverseof the gapswill be a Magellanic voyagethat evenhrally encircles the whole of reality. But that view could be wrong: The exploration may be proceeding acrossan endlesssea.The current pace is such that we may find out which of the two imagesis correct within a few decades.But even if the journey is Magellanic, and even if the boldest excursionsof circumscription consequentlytaper off, so that the broad outline of material existence is well defined, we will still have mastered only an infinitesimal fraction of the internal detail. Exploration will go on in a profusion of scholarly disciplines. There are also the arts, which embrace not only all physically possible worlds but also all conceivable worlds innately interesting and congenial to the nervous system and thus, in the uniquely human sense,true. Placed in this broader context-of existencecoherent enough to be understood in a single system of explanation, yet still largely unexplored*the ambitionsof the natural sciencesmight be viewed in a more favorablelight by nonscientists.Nowadays,aspolls have repeatedly shown,most people,at leastin the United States,respectscience but are baffied by it. They don't understand it, they prefer science fiction, they take fantasy and pseudosciencelike stimulants to jolt their cerebral pleasurecenters.We are still Paleolithic thrill seekers,preferringlurassic Park to the )urassicEra, and UFOs to astrophysics. The productions of science, other than medical breakthroughs and the sporadic thrills of space exploration, are thought marginal. What really matters to humanity, a primate specieswell adapted to Darwinian fundamentals in body and soul, are sex,family, work, security, personal expression,entertainment, and spiritual fulfillment- in

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no particular order. Most people believe,I am sure erroneously,that sciencehaslittle to do with any of thesepreoccupations.They assume that the socialsciencesand humanitiesare independentof the natural sciencesand more relevant endeavors.Who outside the technically possessed really needsto define a chromosome?Or understandchaos

theory? Science,however,is not marginal.Like art, it is a universalpossession of humanity, and scientific knowledge has become a vital part of our species'repertory. It compriseswhat we know of the materialworld with reasonablecertainty. If the natural sciencescan be successfullyunited with the social sciencesand humanities,the liberal artsin higher educationwill be revitalized. Even the attempt to accomplishthat much is a worthwhile goal. Profession-bent studentsshould be helped to understandthat in the twenty-first century the world will not be run by those who possess mere information alone. Thanks to scienceand technology,accessto factual knowledgeof all kinds is rising exponentiallywhile dropping in unit cost.It is destinedto become global and democratic.Soon it will be available everywhereon television and computer screens.What then? The answeris clear: synthesis.We are drowning in information, while starving for wisdom. The world henceforth will be run by synthesizers,people able to put together the right information at the right time, think critically about it, and make important choiceswisely. And this much about wisdom: In the long haul, civilized nations have come to iudge one culture againstanother by a moral senseof the needsand aspirationsof humanity as a whole. In thus globalizingthe hibe, they attempt to formulate humankind's noblest and most enduring goals. The most important questions in this endeavor for the liberal arts are the meaning and purpose of all our idiosyncratic frenetic activity: What are we, Where do we come ftom, How shall we decide where to go? Why the toil, yearning, honesty, aesthetics, exaltation, love, hate, deceit, brilliance, hubris, humility, shame, and sfupidity that collectivelydefine our species? Theology,which long claimed the subject for itself, has done badly. Still encumberedby preceptsbased on Iron fue folk knowledge, it is unable to assimilatethe great sweep of the real world now open for examination. Western philosophy offers no promising substitute. Its involuted exercisesand professionaltimidity have left modern culture bankrupt of meaning.

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The future of the liberal arts lies, therefore, in addressing the fundamental questionsof human existencehead on, without embarrassmentor fear, taking them from the top down in easily understood language, and progressivelyrearranging them into domains of inquiry that unite the best of science and the humanities at each level of organization in turn. That of course is a very difficult task. But so are cardiac surgery and building space vehicles difficult tasks. Competent people get on with them, becausethey need to be done. Why should lessbe expectedfrom the professionalsresponsiblefor education? The liberal arts will succeedto the extent thatthey arc both solid in content and as coherent among themselves as the evidence allows. I find it hard to conceiveofan adequatecore curriculum in collegesand universitiesthat avoidsthe cause-and-effectconnections among the great branchesof learning-not metaphor, not the usual second-orderlucubrations on why scholars of different disciplines think this or that, but material cause and effect. There lies the high adventure for later generations, often mourned as no longer available. There lies great opportunity.

GnaNrnn rHERE ls also a whiffof brimstonein the consilient world view and a seeming touch of Faustto those committed to its humanistic core. And thesetoo need to be closely examined. What was it that Mephistopheles offered Faust, and how was the ambitious doctor to pay? From Christopher Marlowe's play to Goethe's epic poem the bargain wasessentiallythe same:earthly power and pleasure in exchange for your soul. Then there were the differences. Marlowe's Faust was irrevocably damned when he made the wrong choice; Goethe's Faust was saved because he could not feel the happiness promised him through material gain. Marlowe upheld Protestant piety, Goethe the ideals of humanism. In our perception of the human condition we have moved beyond Marlowe and Goethe. Today not one but two Mephistophelean bargains can be distinguished. From them, as from the original, hard choices must be made. Both illustrate the value of considering the consilientvision. The first Faustian choice was actually made centuries ago, when humanity acceptedthe Ratchet of Progress:The more knowledge peo

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ple acquire, the more they are able to increasetheir numbers and to alter the environment,whereuponthe more they need new knowledge iust to stay alive. In a human-dominatedworld, the natural environment steadilyshrinks,offering correspondinglylessand lessper capita return in energyand resources.Advancedtechnologyhas become the ultimate prosthesis.Thke awayelectric power from a tribe ofAustralian Aborigines, and little or nothing will happen. Take it away from residents of California, and millions will die. So to understandwhy humanity has come to relate to the environment in this way is more than a rhetorical question. Greed demands an explanation.The Ratchet should be constantlyre-examined,and new choicesconsidered. The secondMephistopheleanpromise,generatedby the first and strangely echoing the original Enlightenment, is due within a few decades.It says:You may alter the biological nature of the human speciesin any direction you wish, or you may leave it alone. Either way, genetic evolution is about to become consciousand volitional, and usher in a new epoch in the history of life. Let us examine the two bargains,the secondfirst for logical coherence, and consider the alternative fatesthey seemto imply. It is useful to know, before peering into the future, where we are now. Is genetic change still occurring in the old-fashioned way, or has civilization brought it to a haltT The questioncan be put more precisely as follows: Is natural selection still operating to drive evolution? Is it forcing our anatomyand behaviorto changein some particulardirection in responseto suwival and reproduction? The answer,like so many responsesrequired in subjectsof great complexity, is yes and no. To my knowledge no evidence existsthat the human genome is changing in any overallnew direction. It may come immediately to your mind that the forces most affiicting humanity, including overpopulation, war, outbreala of infectious disease,and environmental pollution, must somehow be pushing the speciesalong in a directed manner. But thesepressureshave existedaround the world for millennia, forcingthe periodic decline of populations and even the destruction and replacementof entire peoples.Much of the adaptation expected to arise has probably already done so. Contemporary human genes are therefore likely to reflect the necessitiesthese malign forces imposed in the past. We do not, for example, appear as a speciesto be acquiring genes for larger or smaller brains, more efitcient kidneys, smaller teeth,

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greateror lessercompassion, or any other important adjustmentsin bodyand mind. The one undoubtedglobalchangeis of lesserconsequence.It is the shift occurringworldwidein the frequenciesof racial traits such as skin color, hair type, lymphocyteproteins,and immunoglobulins,due to more rapid populationgrowth in developing countries.In r95o,68 percentof the world'spopulationlived in developingcounhies.By zooothe figurewill be 78 percent.That amountof changeis having an effecton the frequenciesof previouslyexisting genes,but none of the traitsinvolved,sofar aswe know,haveworldshapingconsequence. None affectintellecfualcapacityor the fundamentalsof humannature. A few local quirls havebeendetectedaswell. There is, for example, brachycephalization. Forthe pastten thousandyears,the headsof peoplehavebeengrowingrounderin populationsasfar apartasEurope,India,Polynesia, and North America.In rural Poland,between the CaryathianMountainsand the Baltic Sea,anthropologists have documentedthe trendin skeletons from aroundr3ooto the earlytwentieth century embracingaboutthirty generations.The changeis due principallyto the slightlyhighersurvivalrateof round-heads, and not to the influx of brachycephalics from outsidePoland.The hait hasa partialgeneticbasis,but the reasonfor itsgreaterDarwiniansuccess, if any,remainsunknown. Many hereditarydivergences of local populationshavebeen discoveredin blood types,diseaseresistance, aerobic capacity,and the abilityto digestmilk and otherfoodstuffs. Most suchdifferences canat least be tentativelylinked to higher survival and reproductionin known conditionsof the local environment.The frequencyof adults ableto digestmilk, one of the mostthoroughlystudiedtraits,is highest in populationsthat haverelied on dairyingfor many generations. Anotherlocal hend of adaptivenaturewasreportedin ry94by a groupof Russiangeneticisb.Turkmen-speaking peoplefrom the hot desertsof Middle Asia,they discovered,producemore heat shockproteinsin their skinfibroblasts(cellsthatform partof the looseconnectivetissue) than do peoplewho havelived for manygenerationsin nearbymoderate climates.The difference,which is genetically based,confers higherratesof survivalfollowingsevereheatstress. None of these regional trends appear to entail propertiesin anatomyor behaviorof major consequence. Even the changesdue to differentialpopulationgrowthare likely to proveshort-livedif-as in

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present-dayThailand*birth ratesin lessdevelopedcountriesdrop to the levelsprevailingin North America, Europe,and |apan. The big storyin recenthuman evolution is not directionalchange, not natural selectionat all, but homogenizationthrough immigration and interbreeding.Populationshave been in flux throughout history. Tribes and stateshave pressedinto and around the territories of rivals, often absorbing theseneighbors, occasionallyextinguishing them altogether.The historicalatlasesof Europe and Asia,when their pagesare flipped chronologicallythrough five millennia, become film clips of changing ethnic boundaries. As we race forward from one decade to the next in the clips, chiefdoms and statesspring into existence,expand like hungry two-dimensional amoebae, and vanish as others move in to take their place. The mixing sharply acceleratedwhen Europeansconqueredthe New World and transportedAfrican slavesto its shores.Homogenization took a smaller leap in the nineteenth centurywith the European colonization ofAustraliaand Africa. In more recenttimes it hasquickened yet again through the spread of industrialization and democracy, the two signature traits of modernity that render people restlessand international bordersporous.Most human populationsremain differentiated on a geographicalbasis,and some ethnic enclaveswill probably endure for centuries more, but the trend in the opposite direction is unmistakablyshong.It is also irreversible. Homogenizationis not dynamic on a globalscale.It changeslocal populations, often swiftly, but cannot by itself consistentlydrive evolution of the human species as a whole in one direction or another. Its main consequence is the gradual erasure of previous racial differences-those statistical differences in hereditary traits that distinguish whole populations. It also increasesthe range of individual variation within the populations and acrossthe entire species.Many more combinations of skin color, facial features,talents, and other traits influenced by genes are now arising than ever existed before. Yet the averagedifferences between people in different localities around the world, not very great to start with, are narrowing. Genetic homogenization has similarities to the stirring together of liquid ingredients.The contents change dramatically,and many new kinds of products emerge at the level of gene combinations within individuals. Variance increases,the extremesare extended, new forms of hereditarygenius and pathologyare more likely to arise.But the most

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elementalunits,the genes,remainunperturbed.They stayaboutthe samein bothkind and relativeabundance. Continuedovertensor hundredsof generationsthe presentrates of emigrationand intermarriagecould in theoryeliminateall population differences aroundthe world.Peopleresidingin Beijingmight becomestatistically the sameasthosein Amsterdamor Lagos.But this is not the key issueof future genetichends,becausethe rules under which evolutioncan occurareaboutto changedramaticallyand fundamentally.Thanksto advances of geneticsand molecularbiologlrunderway,hereditarychangewill soondependlesson natural selection than on socialchoice.Possessing exactknowledgeof its own genes, collectivehumanityin a few decadescan,if it wishes,selecta new direction in its evolutionand movetherequickly.Or, if future generationspreferthe freemarketof geneticdiversitythat existedin the past, they can choosesimplyto do nothing and live on their million-yearold heritage. The prospectof this "volitional evolution"-a speciesdeciding whatto do aboutits own heredity-will presentthe mostprofoundintellectualand ethicalchoiceshumanityhaseverfaced.The dilemma at its core is far from sciencefantasy.Medical researchers, motivated by the needto understand the geneticbasisofdisease, havebegunin earnestto map the fifty thousandto one hundred thousandhuman genes.Reproductivebiologistshave cloned sheep,and presumably could do the samefor humanbeings,if the procedurewereallowed. And thanksto the Human GenomeProject,geneticistswill be ableto readoff the completesequence of our DNA letters,3.6billion in all, within one or two decades.Scientisbare alsoexperimentingwith a limited form of molecularengineering,in which genesarealteredin a desireddirectionby substitutingsnippetsof DNA. Still anotherfastmovingenterprisein the biologicalsciencesis the trackingof individual developmentfrom genesto protein synthesisand thence to the final productsof anatomy,physiolory,andbehavior.It is entirelypossible that within fifty yearswe will understandin considerabledetailnot only our own heredity,but alsoa greatdealabout the way our genes interact with the environmentto producea human being. We can then tinker with the productsat any level:changethem temporarily without alteringheredity,or changethem permanendyby mutating the genesandchromosomes. If theseadvances in knowledgeareevenjustpartlyattained,which

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seemsinevitableunlessa greatdeal of geneticand medical researchis halted in its tracks,and if they are made generallyavailable,which is problematic,humanity will be positionedgodlike to take control of its own ultimate fate. It can, if it chooses,alter not iust the anatomyand intelligenceof the speciesbut alsothe emotionsand creativedrive that composethe very core of human nature. The engineeringof the genome will be the final of three periods that can be distinguishedin the historyof human evolution.During almost all of the two-million-yearhistory of the genusHomo, culminating in Homo sapiens, people were unaware of the ultramicroscopic hereditary codesshaping them. In historical times, over the past ten thousand years, populations still experiencedracial differentiation, largely in responseto local climatic conditions, iust as they had throughout the more distant past. During this passagethrough evolutionary time, shared with all other organisms,human populations were also subfectto stabilizing selection;gene mutants that causeddiseaseor infertility were weeded out in each generation. These defective alleles were able to persist only when recessivein their expression,which means their effects could be overridden by the activity of dominant genes paired with of two recessivegenes,however,causesgeneticdisorthem. Possession ders, asexemplified by cystic fibrosis,Tay-Sachsdisease,and sickle+ell anemia.Their double-dosecarriersdie young. Stabilizingselection,in this case through early death, continually sheds the genes from the population, making them mercifully rare. With the advent of modern medicine, human evolution has entered its second period. More and more of the hereditary defects can be deliberately moderated or averted,even when the genesthemselves remain unaltered and present in double dose.Phenylketonuria, for example, until recent time afflicted one out of ten thousand infants with severe mental retardation. Researchersdiscoveredthat the cause of phenylketonuriais a single recessivegene,which in double doseprevents normal metabolism of phenylalanine,a common amino acid. Abnormal metabolic products of the substancebuild up in the blood, causing brain damage.With this elementaryfact in their reference books, physiciansare now able to prevent the symptoms entirely by restricting phenylketonuric infanh to phenylalanine-freediets. Examples like the circumvention of phenylketonuria are becoming common and will be multiplied many times over in the years

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immediately ahead. For the first time people are using scientific knowledge to gain conscious conhol over their heredity, progressing one gene at a time. The evolutionary effect will be to relax stabilizing selectionat an increasingrate and thereby increasethe geneiic variability of humanity as a whole. This secondperiod, the suppressionof stabilizing selection,is only beginning. Over many generations,the moderation of the effectsof harmful genescould result in a substantial changein human heredityat the populationlevel. The benefitsaccruing will have to be bought, of course,with a growing dependenceon exacting and often expensive medical procedures. The age of gene circumventionis alsothe ageof medicalprosthesis. We should not, however, worry that such destabilizing of selection will go too far.The secondperiod of human evolution is ephemeral.It will not last enough generationsto have an important impact on heredityof the speciesas a whole, becausethe knowledgethat made it possiblehas brought us swiftly to the brink of the third period, that of volitional evolution.If we understandwhat changesin the genescause particular defects, down to the nucleotide letters of the DNA code, then in principle the defect can be permanentlyrepaired.ceneticists are hard at work to make this feat, called gene therapy, a reali$. They are hopeful that cystic fibrosis, to cite the most advanced current project, can be at leastpartly cured by introduction of unirnpaired genes into the lung tissuesof patients. Another classof defectsthat seemperr manently treatablewithin a few yearsincludeshemophilia, sickle-cell anemia,and certain other inherited blood diseases. ?rogressin gene therapy has admittedly been slow in the early period. But it will accelerate.Too much hope is at stake,and too much venture capital poised,to permit failure. Once establishedas a practical technology,gene therapy will become a commercial iuggernaut. Thousandsof genetic defects, many fatal,are already known. More are discoveredeach year. Each such gene is carried in single or double doseby thousandsto millions of peoplearound the world, and each individual personbearson averageat leastseveraldifferent kinds ofdefective genessomewhereon his chromosomes.In most casesthe genes are recessive and loaded in single dose;but the carrier, even if he does not suffer the defect, risks having a child with a double dose and fullblown symptoms.It is obvious that when genetic repair becomes safe and affordable,the demand for it will grow swiftly. Some time in the next century that trend will lead into the full

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volitional period of evolution. The advancewill createa new kind of ethical problem, which will be the Faustiandecisionof which I spoke: How much should people be allowed to mutate themselvesand their whom you may wish to Consider that your descendants, descendants? be my descendantsalso may well manner, beneficent in some alter in mind, can we that With years ahead. in the through intermarriage In making such is moral? tinkering ever agree on how much DNA the remedy of between choicei, there is an important line to be drawn clear-cut geneticdefectson one side and the improvement of normal, healthy traits on the other. The scientific imagination will think it but a small step from, say,severedyslexia(one gene region discoveredin r9g4 on chromosomenumber 6) to mild dyslexia,and another short hop to unimpaired learning ability, and, finally one stepmore to superior learning ability. I suffer from a mild form of dyslexiacalled visual sequencingdisability,habitually reversingnumbers(8652too easilybecomes 8562) and struggling to grasp words spelled out to me letter by letter (I apologizeand ask to see them in writing). I would certainly prefer not to sufferthis minor but inconvenientdebility. If it is genetic in origin, I would be pleased to leam instead that it had been fixed whenl was an embryo. My parents,had they known and been able, would probably have agreedand taken care of the problem. Faii enough, but what about altering genesin order to enhance mathematical and verbal abilityz To acquire perfect pitch? Athletic talent? Heterosexuality?Adaptability to cyberspace?In a wholly different dimension, citizensof statesand then of all humanity might chooseto make themselves less variable, in order to increase compatibility. Or the reverse:They might chooseto diversify in talent and temperament, aiming for variedpenonal excellenceand thus the creationof communities of specialistsable to work together at higher levels of productivity. Above all, they will certainly aim for greater longevity. Ifsuch engineering for long life proves even iust partly successful,it will create vast social and economic dislocations. The present traiectory of science ensuresthat future generations will acquire the technical ability to make such choices.We are not in the volitional period yet, but we are close enough to make the prospect worth thinking about. Homo sapiens, the first truly free species, is about to decommission natural selection, the force that made us' There is no genetic destinyoutside our free will, no lodestarprovided

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by which we can set course.Evolution, including genetic progressin human nature and human capacity,will be from now on increasingly the domain of science and technology tempered by ethics and political choice. we have reachedthis point down a long road of travail and selfdeception. soon we must look deep within ourselvesand decide what we wish to become.Our childhood having ended, we will hear the true voice of Mephistopheles. We will also come to understand the hue meaning of conservatism. By that overworked and confusing term I do not mean the pietistic and selfishlibertarianisminto which much of the American conservativemovementhaslately descended.I mean insteadthe ethic that cherishes and sustainsthe resourcesand proven best institutions of a community. In other words,true conservatism,an idea that can be appliedto human natureaswell asto socialinstihrtions. I predict that future generations will be genetically conservative. Other than the repair of disabling defects,they will resisthereditary change. They will do so in order to savethe emotions and epigenetic rules of mental development,becausethese elements compose the physical soul of the rp."i.r. The reasoning is asfollows. Alte, ihe emotions and epigeneticrulesenough,and people might in somesensebe "better,"but they would no longer be human. Neuhalize the elements of human nature in favor of pure rationality, and the result would be badly constructed,protein-basedcomputers. Why should a species give up the defining core of its existence,built by millions of years of biologicaltrial and error? What lifts this question above mere futurism is that it reveals so clearly our ignoranceof the meaning of human existencein the first place. And illustrateshow much more we need to know in order to decide the ultimate question: To what end, or ends, if any in particular, should human seniusdirect itself?

THn pRosr,EM oF collectivemeaningand purposeis both urgent and immediatebecause,if for no other reason,it determinesthe environmental ethic. Few will doubt that humankind hascreateda planetsizedproblem for itself No one wished it so, but we are the first species to become a geophysicalforce, altering Eartht climate, a role previously reservedfor tectonics, sun flares, and glacial cycles. We are also

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the greatest destroyer of life since the ten-kilometer-wide meteorite that landed near Yucatdn and ended the Age of Reptiles sixty-fivemillion yearsago. Through overpopulation we have put ourselvesin danger of running out of food and water. So a very Faustian choice is upon irs, whether to accept our corrosiveand risky behavior as the unavoidable price of population and economic growth, or to take stock of ourselvesand searchfor a new environmentalethic. That is the dilemma already implicit in current environmental debates.It springsfrom the clash of two opposinghuman self-images' The first is the naturalistic self-image,which holds that we are confined to a razor-thin biospherewithin which a thousand imaginable hells are possiblebut only one paradise.What we idealize in nature and seekto re-createis the peculiar physical and biotic environment that cradled the human species.The human body and mind are precisely adapted to this world, notwithstanding its trials and dangers, and that is why we think it beautiful. h-r this respectHomo sapiens conforms to a basic principle of organic evolution, that all species prefer and gravitate to the environment in which their geneswere assembled. Ii is called "habitat selection." There lies survival for humanity, and there lies mental Peace,as prescribedby our genes'We are consequentlyunlikely ever to find any other place or conceiveof any other home as beautiful as this blue planet was before we began to change it. The competing self-image-which also happens to be the guiding theme of western civilization-is the exemptionalistview. In this conception, our species exists apart from the natural world and holds dominion ou.i it. We are exempt from the iron laws of ecology that bind other species.Few limits on human expansionexistthat our sPecial status and ingenuity cannot overcome. We have been set free to modify Earth's surface to create a world better than the one our ancestors knew. For the committed exemptionalist, Homo sapiens has in effect become a new species,which I will now provide with a new name, Homo proteus,or "shapechangerman." In the taxonomic classification of Earth's creatures,the diagnosisof hlpotheticalHomo profeusis the following: Cultural. lndeterminatety flexible, with vast potential. Wired and informationiiven. Can travel almostanytvhere,adapt to any environmrent. Restless,getting crowded. Thinking about the colonization of

To WhatEnd? space'Regrets thecunent lossof Natureandall thosevanishingspecies, but it's the price of progressqnd haslittle to do with our futuri anyway. Nowhereis the naturalistic, andI believecorrect,diagnosis of oid Homosapiens, our familiar"wiseman": cultural with indeterminate intellectualpotentialbut biorogicaily constrained. Basieallya pimate species in bodyandemotionalrebertory (memberof the Order Primates,lnfraorderCatanhini, fo*ity Uiminidae).Huge comparedto other animals, panihirsute, bipeilal, porous,squishy,composedmostlyof water.Runs on millions of coordi, nateddelicatebiochemicalreactions.Easily shutdownby trace toxins and transitof pea-sized proiectiles.Short-lived, emotionaliyftagile.Dependentin bodyand mind on otherearthboundorganisms. Coloniza_ tion of spaceimpossible without massive supplylines.starting to regret deeplythe lossof Natureand aII thoseotherspecies. The dreamof man freedfrom the naturalenvironmentof Earth wastestedagainstrealityin the earlyr99oswith Biosphere2, a 3.15-aqe closedecosystem bui]t on deserttenainin oracle, ,\rizona.paneiedin glass, stocked with soil,air,water,plants,and.animals, it wasdesigned to be a miniatureworkingEarth independentof the motherplanet. The plannerssynthesizedfragmentsof rain forest,savanna,thornscrub,desert,pond, marsh,coral reef,and oceanto simulatethe natural habitatsof home.The only connectionsto the outsideworld were electricalpower and communication,both reasonable concessions madefor a primarilyecological experiment. The designandconstruction of Biospherez cost$zoomillion. It incorporatedthe mostadvancedscientificknowledgeand state-of-the-art engineering.Success of the experiment,if achieved,wasexpectedto provethat human life canbe independently sustained in hermeticbubblesanywherein the solarsystemnot lethallysearedby heator hard radiation. On September26, r9gr,eight volunteer"Biospherians,, walked into the completedenclosureand sealedthemselves off For a while everything wentwell, but then camea seriesof nastysurprises. After five monthsthe concentrationof oxygenin Biospherez beganto drop from itsoriginal zrpercent,evenhrally reaching14percen! an amount that normallyoccursat 17,5oofeet,too low to sustainhealth.At this point, to keepthe experimentgoing,oxygenwaspumpedin from the outside. Duringthe sameperiodcarbondioxidelevelsrosesharply, despitethe useof an artificialrecyclingprocedure.concentrationsof nitrousoxideincreasedto levelsdangerous to brain tissue.

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Species used to build the ecosystemswere drastically affected' Many declined to extinction at an alarmingly high rate. Nineteen of the twenty-five vertebratesand all of the animal pollinators vanished. At the same time, a few speciesof cockroaches,katydids,and ants multiplied explosively. Morning glory, passionflower, and other vines, pianted to serve as a carbon sink, grew so luxuriantly they threatened Lther plant species,including the crops, and had to be laboriously thinned by hand. The Biospherians coped heroically with these ordeals, managing to stay inside the enclosurethe full two yearsoriginally planned. And asan experiment, Biosphere 2 was not at all a failure. It taught us many things, the most important of which is the vulnerabilityof our species arrd the living enviionment on which we depend. Two senior biologistswho ,eui.w.d the data as part of an independentteam, Joel E' bohen of Rockefeller University and David Tilman of the University of Minnesota, wtote with feeling, "No one yet knows how to engineer systemsthat provide humans with the life-supporting sewicesthatlatural ecosystemsproduce for free," and "despiteits mysteriesand hazards, Earth remains the only known home that can sustain life'" In its neglect of the fragility of life, exemptionalismfails definitively. To move ahead as though scientific and entrepreneurial geni-us will solve each crisis arising in turn implies that the decline of the global biosphere can be similarly managed.Perhapsthat might be pos,ibl" i" future decades(centuriesseemmore likely), but the meansare not yet in sight. The living world is too complicated to be kept as a garden on a planet that has been converted into an artificial spacecaP sule. No bioLgical homeostatis known that can be worked by humanity. To believeltherwise is to risk reducing Earth to a wasteland, and humanity to a threatenedspecies. How pressing is the risk? Enough, I think, to change thinking about human seli-preservationfundamentally. The current stateof the environment can be summarizedthus: The global population is precaiously large, and will becomemuch mofe so Uu1or"peaking some time after zo5o.Humanity oyerall is improving .percapita production, health, and longevity.But it is doing-so by eating up the planet's capital, including natural resourcesand biological iliversity millions of yearso/d. Homo sapiensis approaching the lilnit of itsfood and water supply. IJnIike any speciesthat lived before,it

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is alsochangingtheworld'satmosphere and climate,loweringand polluting watertables,shinking forests,and spreadingdeserts.Iiost oi the stressoiginatesdirectlyor indirectlyfrom a handful of industialized countries.Theirprovenformulasfor prospeityarebeingeagerlyadopted by therestof theworld.Theemulationcannotbe sustainei,notwiti the samelevelsof consumption and waste.Evenif the industialization of developingcountiesis only partly successful, the environmentar aftershockwill dwarfthepopulationexplosion that precededit. Somewill, of course,call this synopsis environmentalalarmism. I earnestlywish that accusationwere true. unfortunatelv. it is the reality-grounded opinion of the overwhelming majori$ of statrrr.d scientistswho studythe environment.By staturedscientistsI mean thosewho collectandanalyzethe data,build the theoreticalmodels, interpretthe results,and publisharticlesvettedfor professional journalsby,otherexperts,ofteninclirdingtheir rivals.I do not meanby staturedscientists the manyjournalists,talk-showhosts,and think-tani< polemicists who alsoaddress the environment, eventhoughtheiropinionsreachavastlylargeraudience. Thisis not to devalu"ih.ir professions,which haveseparatehigh standards, only to suggestthai there are better-qualifiedsourcesto consultfor factual infoimation about the environment.seenin this light, the environmentis much lessa conhoversial subiectthansuggested by routinecoverage in the media. Consider,then, the assessment madethrough ttre mid+99osby the staturedscientists. Their quantitativeestimatesdiffer ,""ordrn* io the mathematicalassumptions and procedures variouslyused,iut moststill fall within limits from which trendscan be projectedwith confidence. By ,ggl the globalpopulationhad reached5.8billion, growingat . the rateof 9o million peryeaLIn 16ootherewereonryabouihalf a"uillion peopleon Earth,and in r94o,2billion.The amountof increase d-uringthe r99osalone is expectedto exceedthe entire population alive in 16oo.The globalgrowthrate,afterreachinga peakduring the -each r96os,has been dropping ever since. In ry63, ior erample, womanborean average of 4.r children.In 1996the numberhad de_ clinedto 2.6.ln orderto stabilizethe worldpopulation,the number mustbe z.r childrenper woman(theextrao.r allowingfor child mortality).Long-termpopulationsizeis extremelysensitiveto this replacement number,asshownby the followingprojections.If the number

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were 2.r, there would be 7.7 billion people on Earth in zo5o,leveling off at 8.5 billion in zr5o. If z.o, the population would peak at 7'B billion, then drop byzr5o to 5.6billion, the total in the mid-rggos'lf z'z,it would reach iz.1 billion in zo5o,zo.Bbillion in zr5o; and if z'z could miraculously be maintained thereafter,the human biomass would eventually equal the weight of ihe world and then, after a few millennia, expanding outward at the speedof light, it would exceedthe mass of the visible universe. Even if the global birth rate were reduced drastically and immediately, say to the Chinese goal of one child per woman, the population would not peak for one or two generations' The overshootis ensured by the disproportionatenumber of young alreadyin existence,who look to long livesahead' people i-to* many people can the world supportfor an indefinite period? Expertsdo not agree,but a majority put the number variouslybetween depend on the quality of life 4 ind fi billion. The true number will If everyoneagreedto beaccept. to are willing ihat future generations the presentr'4 billion livestock, for u.g.t"rian, leaving nothing "o*. about ro billion supply hectares-ofarableland (3.5billion acres)would by plant caphrred people. [f humans utilized as food all the energy photosynthesis,some 4o hillion watts, Earth could support about iO bittio" people.From such a fragileworld, almostall other life forms would haveto be excluded. Even if, by force maieure, the populaiion levels off at well under ro billion by mid-century, the relatively extravagantlifestyle now enWestern Europe, and ioyed by the middle classesof North America, world. The reasonis the fapan cannot be attained by most of the restof that the impact of each country on the environment is multiplicative. It is depend-ent,in a complex manner' on the formula called PAT: pop ulation size times per capita affluence (hence consumption) times a measureof the voracity of the technology used in sustaining consumPtion. The magnitude of PAT can be usefully visualized by the "ecological footprint; of productive land needed to support each member of the society with existing technology. In Europe the footprint is 3'5 hectares (a hectare is z-5 acres), in Canada 4.3 hectares,and in the United States5 hectares.In most developingcountries it is lessthan half a hectare. To raise the whole world to the U.S. level with existing technologywould require two more planet Earths' It mailers little that North Dakota and Mongolia are mostly emPty' lt makes no difference that the 5.8 billion people in the world today

To What End?

3og could be logstackedout of sight in a corner of the Grand Canyon. The datum of interest is the averagefootprint on productive land, which must somehowbe loweredif significantlymore people are to achievea decent standardof living. To supposethat the living standardof the rest of the world can be raised to that of the most prosperous countries, with existing technolory and current levelsof consumptionand waste,is a dream in pursuit of a mathematical impossibility. Even to level out presentday income inequitieswould require shrinkingthe ecologicalfootprintsof the prosperous countries. That is problematic in the market-based global economy, where the main players are also militarily the most powerful, and in spite of a great deal of rhetoric largely indifferent to the sufferingof others.Few people in industrializedcountriesare fully awareof how badly offthe poor of the world really are. Roughly r.3 billion people, more than a fifth of the world population, have i.,""rh comes under one U.S. dollar a day. The next tier of r.6 billion earn $r-3. Somewhatmore than r billion live in what the United Nations classifiesasabsolutepoverly, uncertain of obtaining food from one day to the next. Each year more than the entire population of Sweden, between r3 and r8 million, mostly children, die of starvation,or the side effectsof malnutrition, or other poverty-relatedcauses.In order to gain perspective,imagine the responseif Americansand Europeanswere told that in the coming year the entire population of Sweden,or Scotland and Walescombined, or New England would die of poverty. Of coursethe exemptionalistswill saythat new technologyand the rising tide of the free-marketeconomy can solvethe problem. The solution, they explain, is straighforward: Just use more land, ferti]izer, and higher-yield crops, and work harder to improve distribution. And, of course, encouragemore education, technology transfer, and free trade.Oh, and discourageethnic strifeand political corruption. All that will certainly help, and should have high priority, but it cannot solve the main problem, which is the finite resourcesof planet Earth. It is true that only rr percent of the world'sland surfaceis under cultivation. But that alreadyincludesthe most arablepart. The bulk of the remaining 89 percent has limited use, or none at all. Greenland, Antarctica, most of the vast northern taiga, and the equally vast ultradry desertsare not available.The remnant tropical forests and savannas can be clearedand planted,but at the costof most of the speciesof plants and animalsin the world, with minor agricultural gain. Nearly

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half their expanseis underlaid by soilsof low natural fertility-42 percent of the untapped area of sub-saharanAfrica, for example, and and defor46 percent of that in Latin America. Meanwhile, cultivated ested lands are losing topsoil to erosion at ten times the sustainable level. By 1989,u percentof the world'scroplandhad been classifiedby soil expertsas severelydegraded.From r95o to the mid-r99osthe area of cropland per personfell by half, from o.z3hectareto o.rz hectare, lessthan a quarter the size of a soccer field. Widespread starvationwas avoidedbecausethe Green Revolution during the sameforty-yearperiod boostedper hectare yield dramaticallywith new varietiesof rice and other crops, better pesticide application, and increaseduse offertilizer and irrigation. But even thesetechnologieshave limits. By r9B5 the growth in yield slowed;that trend, when combined with the relentlessgrovvthof population, initiated a decline in per capita production. The shordallfirst becameapparentin the developingcountries,whose grain self-sufficiencyfell from 96 percent in t969-7r, at the height of the Green Revolution, to 88 percent in r993i5. By ryg6 the world grain carryoverstocks,humanity's emergencyfood supply, had declined 5o percentfrom the all-time peakreachedin 1987.At the beginning of the r99os only a handful of countries-including Canada, the United States,Argentina, the European Union, and Australiaaccounted for more than three-fourths of the world's grain resources. Perhapsall thesesignswill miraculouslydisappear.If not, how will the world cope? Perhapsthe desertsand nonarable dry grasslandscan be irrigated to expand agricultural production. But that remedy also has limitations. Too many people alreadycompetefor too little water' The aquifersof the world, on which so much agriculture in drier regions depends,are being drained of their groundwaterfasterthan the i.r.*.t can be replacedby natural percolationof rainfall and runoff. The Ogallala aquifer, a principal water source of the central United States,experienced a three-meter drop through a fifth of its area during the r98osalone. Now it is half depletedbeneatha million hectares in Kansas,Texas,and New Mexico. Still worse deficits are building in other countries,and often where they are leastaffordable.The water table beneath Beiiing fell 77 meters between 1965 and 1995.The goundwater reservesof the Arabian peninsula are expected to be exhaustedby zo5o.In the meantime the oil-rich countriesthere are making up the deficit in part by desalinizing seawater-trading their

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preciouspetroleum for water.On a global scale,humanity is pressing the limit, using a quarter of the accessiblewater releasedto the atmosphere by evaporationand plant hanspiration, and somewhatmore than half that availablein riversand other runoffchannels.By zoz5,4o percent of the world's population could be Iiving in countries with chronic water scarcity.New dam construction can add ro percent to the runoffcapture during the next thirty years,but the treadmill opposing it is unceasing:In the samethree decadesthe human population is expectedto grow by a third. As the land gives out, might we turn to Earth's last frontier, the boundlesssea?Unfortunately,no. It is not really boundless,having already given most of what it has to offer. All seventeenof the worldt oceanic fisheriesare being harvestedbeyond their capacity.Only those in the Indian Ocean havecontinuedto rise in yield, a trend destinedto end becausethe presentrate ofcatch is not sustainable.Severalfisheries, including most famously the northwestern Atlantic banks and the Black Sea,havesuffereda commercial collapse.The annual world fish catch, after rising fivefold from r95o to rg9o, has leveled off at about 9o million tons. The history of marine fisherieshas been one of increasinglyefficient masscapture and on-siteprocessing,which increasesyield by cutting ever deeper into existing stocks.By the r99os proliferating fish farms had taken up part of the slack,adding zo million tons to the total harvest.But aquaculture,the fin-and-shellrevolution, also has limits. Expanding marine farms preempt the mangrove swamps and other coastalwetland habitats that serveas the spawning grounds for many offshorefood fishes.Freshwaterfarms have more growth potential but must compete with conventional agriculture for the shrinking supplies of runoffand aquifer-bornewater. Meanwhile, in accordancewith the general principle of life that all large perh:rbations are bad, Earth's ability to support the voracious human biomassis becoming even dicier through the accelerationof climatic change. During the pastr3o yearsthe global averagetemperafure hasrisen by one degreeCelsius.The signsare now strong-some atmosphericscientistssayconclusive-that much of the changeis due to carbon dioxide pollution. The connection is the greenhouseeffect, in which carbon dioxide, along with methane and a few other gases, work like the glassenclosuresusedby gardeners.They admit sunlight

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but trap the heat generatedby it. For the past 16o,oooyears'as testsof air bubblesin fossilice show,the concentrationof atmosphericcarbon dioxide has been tightly correlated with the global averagetemperature. Now, boostedby combustion of fossil fuels and the destruction of hopical forests,the carbon dioxide concentration standsat 36o parts per million, the highestmeasurein the r6o,ooo'yearperiod. The idea of climatic warming by human activityhasbeen disputed by severalscientists,with valid reasons.Atmospheric chemistry and climatic change are both extremely complex sublects.When compounded, they make exact predictions nearly impossible.Nevertheless,traiectoriesand velocitiesof the changescan be estimatedwithin broad limits. That has been the goal of the IntergovernmentalPanel on Climate Change (IPCC), a grouP of more than two thousand sciincoming dataand build modelsof entistsworking worldwide to assess future change with the aid of super-computers. The more difficult variablesthey must incorporateinclude the industrialdischargeof sulfate aerosols,which counteract the greenhouseeffect of carbon dioxide, together with the long-term capture of carbon dioxide by the ocean, which can throw off calculationsof atmosphericchange,and of local climatic change. the tricky idiosyncrasies have made the following assessment' IPCC scientists the Overall, rise in the global averagetemperature of There will be an additional (r.8 to 6.3 degreesFahrenheit)by the year r.o to 3.5 degreesCelsius zroo. Multiple consequencesare likely, with few if any likely to be pleasant.Thermal expansionof marine watersand the partial breakup of the Antarctic and Greenland ice shelveswill raisethe sealevel by as much as 3o centimeters(rz inches), causing problemsfor coastalnations. Kiribati and the Marshall Islands,two small atoll countries in the Western Pacific, risk partial obliteration. Precipitation patternswill change,and most likely asfollows:Large increaseswill be experienced in North Africa, temperate Eurasia and North America, Southeast fuia, and the Pacific coast of South America, and comparable decreasesin Australia and most of South America and southern Africa. Local climates will turn more variable, as heat wavesincreasein frequency. Even a small rise in average temperature results in many more instancesof extremely high temperatures.The reasonis a purely statistical effect. A small shift in a normal statisticaldistribution in one direction lifu the former extreme in that direction from near zero to a

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proportionatelyfar highernumber.(Thus,to takeanotherexample,if the averagemathematicalabilityof the humanspecieswereraisedten percent,the differencein the massof peoplemight not be noticeable, but Einsteins wouldbe commonplace.) Because cloudsand stormcentersaregenerated overmarinewatersheatedabovez6oC,tropicalcycloneswill increasein averagefrequency.The easternseaboardof the United States,to select one heavilypopulatedregion,will therebysufferboth moreheatwavesin the springand morehurricanesin the summer.We canexpectthe hotter climatic zonesto expandtowardthe North and SouthPoles,with the greatestchangesoccurringat the highestlatihrdes.The tundra ecosystems will shrinkand may disappear altogether.Agriculturewill be affected,in someareasfavorably, in othersdeshuctively. In general, developingnationscan expectto be hit harderthan thosein the industrializedNo*h. Many naturalsystemsand the speciesof microorganisms, plants,and animalscomposingthem, unableto adaptto the shift in local conditionsor emigrateto newly habitable areas quicklyenough,will be extinguished. To summarizethe futureof resources and climate,the wall toward which humanityis evidentlyrushingis a shortagenot of mineralsand energy,but of food and water.The time of arrivalat the wall is being shortened by a physicalclimategrowinglesscongenial. Humankindis like a householdliving giddilyoff vanishingcapital.Exemptionalists are riskinga lot when they adviseus, in effect,that "Life is goodand gettingbetter,becauselook aroundyou, we are still expandingand spendingfaster.Don't worry about next year. We're such a smart bunchsomethingwill turn up. It alwayshas." They,and mostof the restof us,haveyet to learn the arithmetical riddleof the lily pond.A lily padis placedin a pond.Eachdaythereafterthe pad and then all of its descendants double.On the thirtieth day the pond is coveredcompletelyby lily pads,which can grow no more. On which day was the pond half full and half empty?The twenty-ninthday. Shallwe gamble?Suppose theoddsareeventhathumankindwill miss the environmentalwall. Better, make it two to one: passon throughor collide.To bet on safepassage is a terriblechoice,because the stakeson the table are just abouteverything.You savesometime and energynow by makingthat choiceand not taking action,but if

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you lose the bet down the line, the cost will be ruinous.In ecolory, as in medicine, a falsepositivediagnosisis an inconvenience,but a false negativediagnosiscan be catastrophic.That is why ecologistsand doctors don't like to gamble at all, and if they must, it is alwayson the side of caution. It is a mistaketo dismissa worried ecologistor a worried doctor asan alarmist. At best,an environmental bottleneckis coming in the twenty-first century. It will causethe unfolding of a new kind of historydriven by environmental change. Or perhaps an unfolding on a global scale of more of the old kind of history which sawthe collapseof regional civilizations,going back to the earliestin history,in northern Mesopotamia, and subsequentlyEgypt, then the Mayan and many others scatteredacrossall the inhabited continents exceptAustralia.People died in large numbers, often horribly. Sometimesthey were able to emigrateand displaceother people,making them die horribly instead. Archaeologistsand historians strive to find the reasonsfor the collapseof civilizations.They tick off drought, soil exhaustion'overpopulation, and warfare-singly or in somepermutation.Their analyses are persuasive.Ecologists add another perspective,with this explanation: The populations reached the local carrying capacity, where further growth could no longer be sustained with the technology available. At that point life was often good, especially for the ruling classes,but fragile.A changesuch as a drought or depletion of the aquifer or a ravaging war then lowered the carrying capacity. The death rate soared and the birth rate fell (from malnutrition and disease)until lower and more sustainable population levels were reached. The principle of carrying capacity is illustrated by the recent history of Rwanda,a small and beautiful mountainousland that once rivaled Uganda as the pearl of Central Africa. Until the present century Rwanda supported only a modestpopulation densi$. For five hundred years a Tutsi dynasty ruled over a Hutu maiority. In 1959the Hutu revolted, causing many of the Tutsi to flee to neighboringcountries.In 1994the conflict escalated,and Rwandan army units massacredover half a million Tutsi and moderateHutu. Then an army of the Tutsi, the Rwandan Patriotic Front, struck back, capturing the capital town of Kigali. fu the Tutsi advanced acrossthe countryside, two million Hutu refugees ran before them, spreading out into Zaite, Tanzania, and Burundi. In 1997 Zaire, newly renamed the Republic of the

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Congo, forced many of the Hutu refugees back to Rwanda. In the maelstrom, thousandsdied of starvationand disease. On the surface it would seem, and was so reported by the media, that the Rwandan catastrophewasethnic rivalry run amok. That is true only in part. There wasa deepercause,rooted in environment and demography. Between r95o and 1994the population of Rwanda, favored by better health care and temporarily improved food supply, more than tripled, from 2.5 million to 8.5 million. In r99z the country had the highest growth rate in the world, an averageof 8 children for every woman. Parturitionbeganearly,and generationtimes were short.But although total food production increaseddramatically during this period, it wassoon overbalancedby population grow"th.The averagefarm size dwindled, as plots were divided from one generation to the next. Per capita grain production fell by half from 196o to the early r99os. Water was so overdrawn that hydrologistsdeclared Rwanda one of the worldt twenty-sevenwater-scarcecounhies. The teenage soldiers of the Hutu and Tutsi then setout to solvethe population problem in the most direct possibleway. Rwanda is a microcosm of the world. War and civil shife have many causes,most not related directly to environmental stress.But in general,overpopulationand the consequentdwindling ofavailableresourcesare tinder that peoplepile up around themselves.The mounting anxiety and hardship are translatedinto enmity, and enmity into moral aggression.Scapegoats are identified, sometimesother political or ethnic groups,sometimesneighboringtribes.The tinder continues to grow, awaiting the odd assassination,territorial incursion, ahocity, or other provocative incident to set it off. Rwanda is the most overpopulatedcountry in Africa. Burundi, its war-torn neighbor,is second. Haiti and El Salvador,two of the chronically most troubled nations of the Western Hemisphere, are also among the most densely populated, exceededonly by five tiny islandcountriesof the Caribbean.They are also arguably the most environmentally degraded. Population growth can iustly be called the monster on the land. To the extent that it can be tamed, passagethrough the bottleneck will be easier.Let us supposethat the last ofthe old reproductivetaboosfade, and family planning becomes universal. Suppose further that governments createpopulation policies with the same earnestness they devote to economic and military policies. And that as a result the global population peaks below ten billion and starts to decline. With NPG

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(negativepopulation growth) attained, there are groundsfor hope. If not aftained, humanity'sbest effortswill fail, and the bottleneckwill closeto form a solid wall. Humanity's best effortswill include everytechnologicalfix for an overcrowdedplanet that geniuscan devise.Endlessstand-byschemes are already on the board. Conversion of nitrogenasedpetroleum to food is one remote possibility.Algal farms in shallowseasis another. The water crisis might be easedby desalinizationof seawaterwith energ, from controlled fusion or fuel cell technology. Perhapsas polar ice shelvesbreak up from global warming, more fresh water can be drawn from icebergsherded to dry coasts.With a surplusof energyand fresh water, the agricultural revegetationof arid wastelandis attainable. Pulp production can be increasedin such recoveredlands with "wood grass,"fast-growing,nitrogen-fixingtree speciesthat can be harvestedwith giant mowersand then sprout new shootsfrom the severed stocks.Many such schemeswill be tried as demand rises,and a few will succeed.They will be driven by venture capital and government subsidyin the global free-marketeconomy. Each advancewill reduce the risk of short-term economic calamity. But be carefull Each advanceis also a prosthesis,an artificial device dependent on advancedexpertiseand intensecontinuing management. Substitutedfor part of Earth's natural environment, it adds its own, long-term risk. Human history can be viewedthrough the lens As these of ecologyas the accumulation of environmental prostheses. manmade proceduresthicken and interlock, they enlargethe carrying capacityof the planet. Human beings,being typical organismsin reproductive response,expandto fill the added capacity.The spiral continues. The environment, increasingly rigged and strutted to meet the new demands,turns ever more delicate. It requiresconstantattention from increasinglysophisticatedtechnology. The Ratchet of Progressseemsirreversible. The messagethen for the primitivists,who dream of nature'sbalancein Paleolithicserenity: Too late. Put away your bow and arrow, forget the harvest of wild berries; the wilderness has become a threatened nature reserve.The messagefor the environmentalists and exemptionalists:Gef together. We must plunge aheadand make the best of it, worried but confident of success,our hope well expressedby Hotspur'slines in Henry IV: I tell you, my lord fool, out of this nettle, danger, we pluck this flower, safety.

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The common aim must be to expandresourcesand improve the quality of life for as many people as heedlesspopulation growth forces upon Earth, and do it with minimal prostheticdependence.That, in essence,is the ethic of sustainabledevelopment.It is the dream that acquired generalcurrency at the Earth Summit, the historic United Nations Conferenceon Environment and Development held in fune r99z in Rio de faneiro. The representatives of r7z nations, including ro6 headsof government,met to establishguidelinesby which a susiainable world order might be reached.They signedbinding convbntions on climate change and the protection of biological diversity. They agreed to the forty nonbinding chapters of Agenda zr, offering proceduresby which virtually all of the generalproblems of the environment can be addressed,if not solved,Most of the initiativeswere blunted by political squabblesarising from national self-interest,and global cooperationafterward was principally limited to rhetorical exercise on stateoccasions.The $6oo billion additional expenditurerecommended to put Agenda zr into effect,with $rz5 billion donated to developingcountriesby industrializedcountries,has not been forthcoming. Still, the principle of sustainabledevelopmenthas been generally accepted, an idea previously little more than the dream of an environmentalist elite. By ry96 no fewer than u7 governments had ap pointed commissionsto developAgendazr strategies. In the end, the measureof successof the Earth Summit and all other global initiativeswill be the diminishmentof the total ecological footprint. fu the human population soarstoward eight billion around zozo, the central question will be the areaof productive land required on averageto provide each person in the world with an acceptable standard of living. From i! the overriding environmental goal is to shrink the ecological footprint to a level that can be sustainedby Earth'sfragileenvironment. Much of the technologyrequiredto reachthat goal can be summarized in two concepts.Decarbonizationis the shift from the burning of coal, petroleum, and wood to essentiallyunlimited, environmentally light energysourcessuch as fuel cells, nuclear fusion, and solar and wind power. Dematerialization,the secondconcept, is the reduction in bulk of hardwareand the energyit consumes.All the microchips in the world, to take the most encouraging contemporary example, can be fitted into the room that housed the Harvard Mark r elechomagnetic computer at the dawn of the information revolution.

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The singlegreatestintellectual obstacleto environmental realism, as opposedto practical difficulg is the myopia of most professional economists.In Chapter 9 I describedthe insularnature of neoclassical economic theory. its models, while elegantcabinet specimensof ap plied mathematics, largely ignore human behavior as understood by contemporarypsychologyand biology.Lacking such a foundation,the conclusionsoften describeabstractworldsthat do not exist.The flaw is especiallynoticeablein microeconomics,which treatsthe patternsof choicesmade by individual consumers. The weaknessof economicsis mostworrisome,however,in its general failure to incorporatethe environment.After the Earth Summit, and after veritableencyclopediasof data compiled by scientistsand resource expertshave shown clearly the dangeroustrends ofpopulation size and planetaryhealth, the most influential economistsstill make recommendationsas though there is no environment. Their assessments readlike the annual reportsof successfulbrokeragefirms. Here, for example, is Frederick Hu, head of the World Economic Forum's competitivenessresearch team, explaining the conclusions of the Forum's infuential Global CompetitivenessReport ry96: Shortof military conquest,economicgrowthis the only viablemeans for a countryto sustainincreasesin nationalwealthand living standards . . . An economyis internationallycompetitiveif it performs stronglyin three generalareas:abundantproductiveinputs such as capital,labour,infrastructureandtechnology;optimaleconomicpoliciessuchaslow taxes,little interferenceandfreetradeandsoundmarket institutionssuchasthe rule of law and the protectionof property rights. This prescription, resonant with the hard-headed pragmatism expected in an economics journal, is true for medium-term growth of individual nations.It is surely the bestpolicy to recommend during the next two decadesfor Russia (competitivenessindex -2.76) and Brazil Gr.Z) if they wish to catch up with the United States(*r.34) and Singapore(+2.r9). No one can seriouslyquestionthat a better quality of life for everyone is the unimpeachable universal goal of humanity. Free trade, the rule of law, and sound market practices are the proven means to attain it. But the next two decadeswill also see the global population leap from six to eight billion, mostlyamong the poorestna-

To What End?

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tions. That interval will witness water and arable soil running out, forestsbeing stripped, and coastal habitats used up. The planet is alreadyin a precariousstate.What will happen as giant China (-o.68) stoivesto overtakelittle Thiwan (+o.96) and the other Asian tigers?We tend to forget, and economists are reluctant to stress,that economic miraclesare not endogenous.They occur most often when countries consumenot only their own material resources,including oil, timber, water,and agricultural produce, but thoseof other countriesas well. And now the globalization of commerce, acceleratedby technology and the liquidity of paper assets,has made the masstransfer of material assetsfar easier.The wood products of Japan are the destroyedforests of tropical Asia, the fuel of Europe the dwindling peholeum reseryes of the Middle East. In national balance sheetseconomistsseldom use full-cost accounting, which includes the lossofnatural resources.A country can cut down all its hees, mine out its most profitable minerals, exhaustits fisheries,erode most of its soil, draw down its underground water, and count all the proceedsas income and none of the depletion as cost.It can pollute the environment and promote policies that crowd its populace into urban slums,without chargingthe result to overhead. Full-costaccounting is gaining some credibility within the councils of economists and the finance ministers they advise. Ecological economics, a new subdiscipline,has been formed to put a green thumb on the invisible hand of economics.But it is still only marginally influential. Competitive indexes and gross domestic products (GDPs) remain seductive,not to be messedup in conventional economic theory by adding the tricky complexities of environment and social cost.The time has come for economistsand businessleaders,who so haughtily pride themselvesas mastersof the real world, to acknowledgethe existenceof the real real world. New indicators of progressare needed to monitor the economy, wherein the natural world and human well-being, not just economic production, are awarded full measure.

To rHE sAME END I count it paramount, and feel obliged to plead, that the new reckoning include a powerful conservation ethic. We hope-surely we must believe-that our specieswill emerge

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from the environmental bottleneck in better condition than we entered. But there is another responsibilityto meet as we make the passage:preservingthe Creation by taking as much of the rest of life with us aspossible. Biological diversity,or biodiversityfor short-the full sweepfrom thence to geneswithin ecosystemsto specieswithin the ecosystems, the species-is in trouble. Mass extinctionsare commonplace, especially in tropical regionswhere most of the biodiversityoccurs.Among the more recent are more than half the exclusivelyfreshwaterfishesof peninsular Asia, half of the fourteen birds of the Philippine island of Cebu, and more than ninety plant speciesgrowing on a single mountain ridge in Ecuador. In the United Statesan estimatedr percent of all specieshave been extinguished;another 3z percent are imperiled. Conservationexperts,respondingto what they now perceive as a crisis, have in the pastthree decadesbroadenedtheir focus from the panda, tiger, and other charismaticanimalsto include entire habitats whosedestructionendangersthe existenceof many species. Familiar "hot spots"of this kind in the United Statesinclude the mountain forestsof Hawaii, the coastalheath of southern California, and the sandy uplands of central Florida. fuguably the nations with the most hot spots in the world are Ecuador, Madagascar,and the Philippines. Each of thesecountries has lost two-thirdsor more of its biologically rich rain forest,and the remainderis under continuing assault. The logic of conservationexpertsin addressingthe issueis simple: By concentrating conservation efforts on such areas, the largest amount of biodiversity can be savedat the lowesteconomic cost. If the effort is also made part of the political processduring regional planning, the rescueof biodiversitycan alsogain the widestpossiblepublic support. It is notoriously difficult to estimate the overall rate of extinction, but biologists,by using severalindirect methodsof analysis,generally agree that on the land at least, speciesare vanishing at a rate one hundred to a thousand times fasterthan before the arrival of Homo sapiens. Tropical rain forests are the site of most of the known damage. Although they cover only 6 percent of the land surface,they contain more than half the speciesof plants and animalsof the entire world. The rate of clearing and burning of the surviving rain forestsaveraged about r percent a year through the r98os and into the r99os, an area about equal to the entire country of lreland. That magnitude of habitat

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lossmeansthat eachyearo.z5percentor moreof the forestspeciesare doomedto immediateor earlyextinction.How much doesthe rate translateinto absolutenumbers?If thereareten million speciesin the still mostlyunexploredforests,which somescientiststhink possible, the annuallossis in the tensof thousands. Even if therearea "mere" onemillion species,the lossis still in the thousands. Theseprojectionsare basedon the known relationshipsbetween the areaof a given naturalhabitatand the number of speciesable to mayin factbe on livefor indefiniteperiodswithin it. Suchprojections the low side.The outright eliminationof habitat,the easiestfactorto measure,is the leadingcauseof extinction.But the introductionof aggressive they carrycomeclosebehind exoticspeciesand the diseases in destructiveness" followed in turn by the overharvesting of native species. All thesefactorswork togetherin a complexmanner.When asked which onescausedthe extinctionof anyparticularspecies,biologists arelikelyto givethe Murderon theOientExDressanswer:They all did it. A commonsequence in tropicalcountriesstarbwith thebuildingof suchasthosecut acrossBrazil'sAmazonianstate roadsinto wilderness, settlerspour in, of Rond6niaduring the r97osand '8os.Land-seeking pollute introduce forest both of the road, the streams, clearthe on sides alienplantsand animals,andhunt wildlife for extrafood.Many native entirely.The soilwearsout species becomerare,and somedisappear within severalyears,andthe settlerscut andburn their waydeeperinto the forest. The ongoinglossof biodiversityis the greatestsincethe end of the MesozoicEra sixty-fivemillion yearsago. At that time, by curent scientificconsensus, the impactof one or more giant meteoritesdarkatmosphere, ened the altered much of Earth's climate, and extinguishedthe dinosaurs.Thus beganthe next stageof evolution,the CenozoicEra or Ageof Mammals.The extinctionspasmwe arenow inflicting can be moderatedif we sochoose.Otherwise,the next centurywill seethe closingof the CenozoicEraanda newonecharacterizednot by new life formsbut by biologicalimpoverishment.It might appropriately be calledthe "EremozoicEra,"theAgeof Loneliness. I havefound, during many yearsof studyingbiologicaldiversity, that peoplecommonlyrespondto evidenceof speciesextinctionby enteringthreestagesof denial.The firstis simply,Why worry?Extinction is natural.Specieshavebeendyingout through more than three

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billion yearsof life's historywithout permanentharm to the biosphere. Evolution has alwaysreplacedextinct specieswith new ones. AII these statementsare true, but with a terrible twist. Following the Mesozoic spasm, and after each of the four greatestprevious spasmsspaced over the earlier 35o million years,evolution required about ro million years to restore the predisasterlevels of diversity. Faced with a waiting time that long, and aware that we inflicted so much damage in a single lifetime, our descendantsare going to behow bestto sayit?-peeved. Bntering the second stage of denial, people commonly ask, Why do we need so many speciesanyway?Why care, especiallysince the vast maiority are bugs, weeds, and fungi? It is easy to dismissthe creepy-crawliesof the world, forgetting that lessthan a cenhrry ago, before the rise of the modern conservationmovement,native birds and mammals around the world were treatedwith the samecallow indifference. Now the value of the litde things in the natural world has become compellingly clear. Recent experimental studieson whole ecosystemssupport what ecologistshave long suspected:The more speciesthat live in an ecosystem,the higher its productivity and the greaterits ability to withstanddrought and other kinds of environmental stress.Since we depend on functioning ecosystems to cleanseour water,enrich our soil,and createthe very air we breathe,biodiversityis clearly not something to discard carelessly. Each speciesis a masterpieceof evolution, offering a vast source of useful scientific knowledgebecauseit is so thoroughly adaptedto the environment in which it lives.Speciesalive todayare thousandsto millions ofyears old. Their genes,having been testedby adversityover so many generations, engineer a staggeringlycomplex array of biochemical devices to aid the survival and reproduction of the organismscarrying them. This is why, in addition to creating a habitable environment for humankind, wild speciesare the source of productsthat help sustain our lives. Not the leastof theseamenitiesare pharmaceuticals.More than 4o percent of all medicinals dispensedby pharmacies in the United Statesare substancesoriginally extractedftom plants, animals, fungi, and microorganisms.fupirin, for example,the most widely used medicine in the world, was derived from salicylicacid, which in hrrn was discovered in a speciesof meadowsweet.Yet only a fraction of the

To What End?

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species-probablyfewer than r percent-have been examinedfor natural productsthat might serveas medicines.There is a critical need to press the search for new antibiotics and antimalarial agents.The substancesmost commonly usedtoday are growing lesseffective asdiseaseorganismsacquire genetic resistanceto the drugs.The universal staphylococcusbacterium, for example,has recently re-€mergedas a potentiallylethal pathogen,and the microorganismthat causespn€umonia is growing progressivelymore dangerous.Medical researchers are locked in an arms race with the rapidly evolving pathogensthat is certain to grow more intense.They are obliged to turn to a broader arrayof wild speciesin order to acquirenew weaponsof medicine in the twenty-first century. Even when all this much is granted, the third stage of denial emerges:Why rush to saveall the speciesright now? Why not keep live specimensin zoosand botanical gardensand return them to the wild later? The grim truth is that all the zoos in the world today can sustain a maximum of only two thousandspeciesof mammals, birds, reptiles, and amphibians out of trventy-four thousand known to exist. The world's botanical gardens would be even more overwhelmed by the quarter-million plant species.These refugesare invaluable in helping to save a few endangered species.So is freezing embryos in liquid nitrogen. But such measurescannot come close to solving the problem as a whole. To add to the difficulty, no one has yet deviseda safe harbor for the legion of insects,fungi, and other ecologically vital small organisms. Even if all that were accomplished,and scientistspreparedto return speciesto independence,the ecosystemsin which many lived would no longer exist. Raw land doesnot suffice. Pandasand tigers,for example,cannot survivein abandonedrice paddies.Can the natural ecosystemsbe reconstituted by just putting all the species back together again?The feat is at the present time impossible, at least for communities as complex asrain forests.The order of difficulty, as I describedit in Chapter 5, is comparableto that of creating a living cell from molecules,or an organismfrom living cells. In order to visualize the scope of the problem more concretely, imagine that the last remnant of rain forest in a small hopical country is about to be drowned beneath the rising lake of a hydroelectric proiect. An unknown number of plant and animal speciesfound nowhere

t'+

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else in ihe world will disappearbeneath the waters.Nothing can be done. The electric power is needed; local political leadersare adamant. Peoplecome first! In the final desperatemonths, a team of biologistsscramblesto savethe fauna and flora. Their assignmentis the following: Collect samplesof all the speciesquickly,beforethe dam is closed.Maintain the speciesin zoos,gardens,and laboratorycultures, or else deep-freezeembryosbred from them in liquid nitrogen.Then bring the speciesback together and resynthesizethe community on new ground. The stateof the art is such that biologistscannotaccomplishsuch a task,not if thousandsof them came with a billion-dollar budget.They cannot even imagine how to do it. In the forestpatch live legionsof life forms: perhaps 3oo speciesof birds, 5oo butterflies,zoo ants, 5o,ooo beetles,r,ooo trees,!,ooo fungi, tens ofthousandsofbacteriaand so on down the long rosterof maior groups.In many of the groupsa largeminority of the speciesare new to science,their propertieswholly unknown. Each speciesoccupies a precise niche, demanding a certain place, an exact microclimate, particular nutrients, and temperature and humidity cyclesby which the sequentialphasesof the life cycles are timed. Many of the speciesare locked in symbiosiswith other species, and cannot survive unless arrayed with their partners in the correct configurations. Thus even if the biologistspulled offthe taxonomic equivalentof the Manhattan Project, sorting and preservingcultures of all the species,they could not then put the community back togetheragain. Such a task anywhere in the world is like unscrambling an egg with a pair of spoons.Eventually,perhapsin decades,it can be done. But for the present the biology of the microorganismsneededto reanimate the soil is mostly unknown. The pollinators of most of the flowers and the correct timing of their appearancecan only be guessed.The "assembly rules," the sequencein which speciesmust be allowed to colonize in order to coexist indefinitely, are still largely in the realm of theory. In this matter the opinion of biologists and consewationistsis virtually unanimous: The only way to save the Creation with existing knowledge is to maintain it in natural ecosystems. Considering how rapidly such habitatsare shrinking, even that straighforwardsolution will be a daunting task. Somehow humanity must find a way to squeezethrough the bottleneck without destroyingthe environments on which the restof Iife depends.

To What End?

j2,

m TH n r, n c e c v of the Enlightenment is the belief that entirely on our own we can know, and in knowing, understand,and in understanding, choose wisely. That self-confidence has risen with the exponential growth of scientific knowledge, which is being woven into an increasingly full explanatory web of cause and effect. In the course of the enteqprise,we have learned a great deal about ourselvesas a species. We now better understand where humanity came from, and what it is. Homo sapiens,like the rest of life, was self-assembled.So here we are, no one having guided us to this condition, no one looking over our shoulder,our future entirely up to us. Human autonomy having thus been recognized,we should now feel more disposedto reflect on where we wish to go. In such an endeavor it is not enough to saythat history unfolds by processestoo complex for reductionistic analysis.That is the white fag of the secular intellech:al , the lazy modernist equivalent of The Will of God. On the other hand, it is too early to speakseriouslyof ultimate goals, such as perfect green-belted cities and robot expeditions to the neareststars.It is enough to getHomo sapienssettled down and happy beforewe wreck the planet. A greatdeal of seriousthinking is needed to navigatethe decadesimmediately ahead.We are gaining in our ability to identify options in the political economy most likely to be ruinous. We have begun to probe the foundations of human nature, revealing what people inhinsically most need, and why. We are entering a new era of existentialism, not the old absurdist existentialism of Kierkegaardand Sartre, giving complete autonomy to the individual, but the concept that only unified learning, universally shared, makes accurateforesightand wise choice possible. In the course of all of it we are learning the fundamental principle that ethics is every"thing.Human social existence,unlike animal sociality, is basedon the genetic propensity to form long-term conhacts that evolve by culture into moral precepts and law. The rules of contract formation were not given to humani$ from above, nor did they emerge randomly in the mechanics of the brain. They evolved over tens or hundreds of millennia becausethey conferred upon the genes prescribing them survival and the opportunity to be representedin future generations.We are not errant children who occasionally sin bydisobeying instructions from outside our species.We are adults who

3?6

CoNsrr,rENcE,

have discoveredwhich covenantsare necessaryfor survival, and we have acceptedthe necessityofsecuring them by sacredoath. The searchfor consiliencemight seemat first to imprison creativity. The opposite is true. A united systemof knowledge is the surest meansof identifying the still unexploreddomainsof reality.It provides a clear map of what is known, and it framesthe most productive questions for future inquiry. Historiansof scienceoften observethat asking the right questionis more important than producing the right answer. The right answer to a trivial question is also trivial, but the right question, even when insoluble in exactform, is a guide to major discovery. And so it will everbe in the future excursionsof scienceand imaginative flights of the arts. I believe that in the processof locating new avenuesof creative thought, we will also arrive at an existentialconservatism.It is worth asking repeatedly:Where are our deepestroots?We are, it seems,Old World, catarrhineprimates,brilliant emergentanimals,defined genetically by our unique origins, blessedby our new4oundbiological genius, and s€curein our homeland if we wish to make it so.What doesit all mean? This is what it all means.To the extentthat we depend on prosthetic devicesto keep ourselvesand the biospherealive, we will render everything fragile. To the extent that we banish the rest of life, we will impoverishour own speciesfor all time. And if we should surrender our genetic nature to machine-aidedratiocination, and our ethics and art and our very meaning to a habit of carelessdiscursionin the name of progress,imagining ourselvesgodlike and absolvedfrom our ancient heritage,we will become nothing.

NOTES

Tsr IoNreNENcn.lNrlteut Autobiographicaldetails of my inhoductionthrough religiousexperienceto scientificsynthesis aregivenin my memoirNaturalist(WashingBooks,1994). ton, DC: IslandPress/Shearwater The ideaof the Ionian Enchanbnentis inhoducedand Einstein'sexpressionof it usedasan illustrationby GeraldHolton in Einstein,His(Woodbury,NY: AmericanInstituteof Physics tory,and Other Passions Press, r995). Arthur Eddington,in orderto celebrateboldnessand risk-takingascomnarratedthe storyof Daedalusand ponentsof majorscientificendeavor, Addressof r9zo.The metaphorwasthen Icarusin his BritishAssociation to characterizethe research used by SubrahmanyanChandrasekhar styleof his friend in Eddington:The Most Distinguished'\strophysicistof HisTime (NewYork CambridgeUniversityPress,1983).

CHAPTER 2

oF LEARNING THe Gneer Bn.q,NcHrs rr-rz The dividedand oftencontentiousnatureof the philosophyof science is gaphically revealedin interviewsand conversationsrecordedby WernerCallebad in Takingthe N aturalisticTum, or, How RealPhilosophy of Scienceis Done (Chicago:Universityof Chicago Press,1993).

3zB

N o t e sr r - 3 o

rr-rz AlexanderRosenbergon scienceand philosophy:ThePhilosophyof rsted.(Oxford:OxfordUniversityPress,1988),p. r. SocialScience, rz-r3 Sir CharlesScott Sherringtonspeaksof the enchantedloom as follows:"Swiftly the head-mass becomesan enchantedloom wheremillions of flashingshuttlesweavea dissolving pattern,alwaysa meaningful patternthoughneveran abidingone;a shiftingharmonyofsubpatterns" (Man on His Nature,the Gifford Lectures,Edinburgh,1937-8;New York:Macmillan,r94r),p. zz5. r3 I first presentedthe conceptof deep history,a seamless continuitybetweenprehistoryand traditionalhistory,in "Deep history" Chronicles, r4: 16-18(r99o). u-r4 On scientific illiteracy in the United States:Morris H. Shamos,Tha Myth of ScientificLiteracy (New Brunswick,Nf: RuQersUniversity "Afterthebig crunch,"TheWilson Press, 1995), andDavidL. Goodstein, Quarterly,ry: 57-6o(ry95). r3 Data on the historyof generaleducationin the United Statesareprovidedby StephenH. Balch et al.,TheDissolutionof CeneralEducation: 1914-rgg3,a report preparedby the NationalAssociationof Scholars (Princeton, NJ:The Association, 1996).

.,""fJi';",:1,"*, r7 IsaiahBerlin praisedthe achievementsof the Enlightenment in The (NewYork: Ageof Enlightenment:TheEighteenth-Century Philosophers OxfordUniversityPress,rg79). 17- My sourceson Condorcet were: Sketchfor a HistoricalPictureof the

Progress of the Human Mind, by fean-Antoine-Nicolas de Caritat,the Marquis de Condorcet\4)*1794, a partialEnglish translationby Edward Goodell (citationbelow);The Centenaryof Condorcet,by Henry Ellis (London:William Reeves,1894) FromN aturaI Philoso ; Condorcet: phy to SocialMathematics,by Keith Michael Baker(Chicago:University of ChicagoPress,1975);andTheNoblePhilosopher: Condorcetand the Enlightenment,by Edward Goodell (Buffalo, NY: Prometheus Books,1994). 24- The sketchof the life and work of FrancisBacon providedhere was

drawnfrom his writingsand from manysecondary sources,the mostimportant beingJamesStephens,FrancisBaconand the Styleof Science (Chicago:Universityof ChicagoPress,1975);BeniaminFarringon, FrancisBacon:Philosopherof IndustrialScience(New York Octagon Books,1979);PeterUrbach, FrancisBacon'sPhilosophyof Science: An Account and a Reappraisal(La Salle, IL: Open Court, 1987);and

Notes 3o-43

3zg

CatherineDrinker Bowen,FrancisBacon:TheTemfurof a Man (New York:FordhamUniversityPress,1993).Urbach,in a highly appreciative analysis, arguesthat Baconadvocatedimaginativehypothesis formation at all stagesof researchand wasnot committedto the gatheringof raw dataat the outsetof investigation, thus makinghim a much more modern thinkerthangrantedby traditionalinterpretations ofhis texts. My placement the Enlightenment of founders rolesof an epic in mythic 3o adventurewasinspiredby JosephCampbellt TheHerowith aThousand Faces(NewYork:PantheonBooks,1949)and its applicationto popular cultureby ChristopherVoglerinTheWriter'sloumey:IvlythicStructures (StudioCity, CA: Michael WieseProand Storytellers for Screenwriters ductions,r99z). )o- An excellentrecent accountof Descartes'life and achievemenbis An IntellectualBiograplry 7r given by StephenGaukrogerin Descartes: (NewYork:OxfordUniversityPress,1995). fosephNeedham'sinterpretationof Chinese sciencewastaken from t) 74 The ShorterScienceand Civilisdtionin China: An Abidgementof loseph Needham's Oiginal Tert,volumeI, preparedby Colin A. Ronan(New York:CambridgeUniversityPress,1978). 35 Einstein'sremarkto Emst Strausis quotedby GeraldHolton inThematic Oigins of ScientificThought(Cambridge,MA: HarvardUniversig Press, 1988). Goethe on all-seeingNafure is taken ftom Gesammte Werke,Goethe, volume)OQ((Stuttgart:Cotta,1858),p. 3r3,astranslatedby Sir Charles ScottSherrin$onin Coetheon Natureand on Science,secondedition (NewYork:CambridgeUniversityPress,1949). The translationof Pico della Mirandola's instruction from God is one of the more poeticallypleasingones,and is found inThe Renaissance Philosophy of Mdn, editedby ErnstCassirer,PaulO. IGisteller,andJohn H. Randall,fr. (Chicago:Universityof ChicagoPress,ry48),p.zz5. +- The growth of sciencesince rToo is documentedand discussedby + DavidL. Goodsteinin "Afterthe big crunch,"TheWilsonQuarter$,ry: 574o$s9)' On modernism:Carl E. Schorskein Fin4e-SiicleVienna:Politicsand Culture (New York: Knopf, r98o). Howard Gardner examinesmodemismfrom a psychologist's perspective inCreatingMinds:AnAnatomy of Creativity SeenThrcughthe Livesof Freud, Einstein, Picasso,Stravinsky,Eliot, Craham,and Candhi (New York BasicBooks, ryg)), p. 7g7. 43 C. P. Snowdeploredthe separationbetweenthe literaryand seientific culfuresin his celebrate d ftactTheTwoCulturesand theScientificRevo/ufion (NewYork CambridgeUniversityPress,1959),basedon his 1959 RedeLecture.

330

Notes 44-56

44- The worksby facquesDerrida on which I havebasedmy admittedly impressions are Of Crammatolog,translatedby +> less-than-enthusiastic GayatriChakravortySpivak(Baltimore:fohnsHopkinsUniversityPress, ry76); Writing and Dffirence. hanslatedby Alan Bass(Chicago: University of Chicago Press,1978);and Dissemination,hanslatedby Barbara |ohnson(Chicago:Universityof ChicagoPress,r98r),Given Derrida's givenby thetransladeliberatelysurrealstyle,much is owedthe exegeses torsin their introductions. Kenneth f. Gergen,"Correspon45- On root metaphorsin psycholog;,': 46 denceversusautonomyin the languageof understandinghuman action," in Donald W. Fiskeand RichardA. Shweder,eds.,Metatheoryin Social Science:Pluralismsand Subiecti'tities(Chicago:Universityof 1986),pp.14r-146. ChicagoPress, 46- GeorgeScialabbawrote about Michel Foucault in "The tormented of Michel Foucault, 47 questof Michel Foucault,"a reviewof The Passion by famesMiller (New York: Simon & Schuster,1993),in The Boston SundayGlobe,3 fanuary:99j, p. Arz. An earlierand fuller accountof Foucault'sscholarship,includinghis "archeologyof knowledge,"is providedby Alan Sheridanin Michel Foucault,TheWill to Truth (London: Thvistock,rg8o).

t'" *^"i,iJfftJ,"*"", 4E' Among the many textbooksand other introductoryaccounhof animal 5r sensesavailable,one of the bestand mostwidely usedis JohnAlcock's Animal Behavior:An EvolutionaryApproach,fifth edition(Sunderland, 1993). MA: SinauerAssociates, >5

Eugene P. Wigner's descriptionof mathematicsas the natural lan' of mathematics effectiveness guageof phpics is in "The unreasonable on Pureand AppliedMathein the naturalsciences," Communications ma;tics, r)t r-r4 (196o).

53- The accountof quantum electrodynamics(Q.E.D.) and measurement 54 of propertiesof the elechonis takenftom David f. Gross,"Physicsand of the NationalAcademyof Scimathematicsat the frontier,"Proceedings Kitences,USA, 85 837v5 (1988),and John R. Gribbin'sSchriidinger's tensand the Searchfor Reality:Solvingthe QuantumMysteies(Boston: Liftle, Brown,1995).ToGribbin I owethe imageryof the flight of a needle acrossthe United Statesto illustratethe accuracyof Q.E.D. and 55- The prospecbof nanotechnology,alongwith scanning-tunneling aredescribedby the multipleauthorsof Nano56 atomicforcemicroscopy, technology:Molecalar Speculationson Clobal Abundance,edited by

Notes 6z-73

j1r

B. C. Crandall(Cambridge,MA: MIT Press,1996).The manufactureof highdensity ROMs is describedin ScieneeNews,r48:58 (1995).The exacttiming of chemicalreactionsis describedby RobertF. Servicein "Getting a reactionin close-up,"Science,268::E46(1995);and membranelike self-assembled monolayen of moleculesby George M. Whitesidesin "Self-assembling materials)' ScientificAmerican, 277:

4|fi

(rsss).

6z Einstein'stribute to Planck hasbeenoften quoted.I do not know the originalathibution,but the wordscan be found,for example,in Walter Kaufrnann'sThe Futureof the Humanities(New York:Reader'sDigest Press,distributedby ThomasY. Crowell,1977). 6z- The individuality of the scientist,his frailties,and his pursuit of re64 searchasan art form aresearchinglyprobedby FreemanDysonin "The scientistasrebel,"TheNewYorkReview of Books,z5May ry9r,pp.7r-. His viewson the subject,independentlyevolvedas a physicist,are in manyrespects closelysimilarto my own. 64- The originalreporton conservedDNA duplication waspublishedby 65 Matthew S. Meselsonand Franklin W. Stahl in hoceedingsof the National Academyof Sciences, USA, 44 67rJz (1958).I am gratefulto Meselsonfor a personaldiscussion of the experiment. 67- My synopsisof the historyand content of logical positivism and the 7o questfor objectivetruth is basedon manytextsand informaldiscussions with scientists and others,but hasbeenmostinfluencedin recentyears by GeraldHolton'sScience (Cambridge,MA: Harvard and Anti-Science UniversityPress,1993),and AlexanderRosenberg's Economics:.MathematicalPoliticsor Science (Chicago:University of DiminishingRetums? of ChicagoPress,r99z). A. Simonhaswriften on the psychologyof oeative thought in 7o Herbert 'Discovery invention,anddevelopment:humancreativethinki ngl' Proceedings of the NationalAcademyof Sciences, USA (PhysicalSciences), 8o:4569-7r(1983).

o*,^:xxTT"t*"^, The Cretan labyrinth and Ariadne's thread have been given diverse over the years.The closestto my own, yet 7t metaphoricalinterpretations differentin keyrespects, is Mary E. Clark'sAriadne'sThread:TheSearch for NewModesof Thinfting(New York: St. Martin'sPress,1989).Clark perceives the labyrinthashumanityt complexenvironmentaland social problemsand the threadas the objectivehuths and realisticthinking neededto solvethem.

332

Notes74-99

The detailsof ant communicationcanbe found inThe Ants(r99o)and 77 loumeyto the Ants:A Storyof Scientifc Exploration(1994),by Bert HiillMA: BelknapPress of HardoblerandEdwardO. Wilson(Cambridge, Press). vardUniversity ?R- Ancestor-summoning by the fivaro is describedby MichaelJ. Harnerin 8o The ltvaro:Peopleof the SacredWatefal/s(GardenCity, M: Doubledayll.{aturalHistoryPress,r97z).The dreamsand art of PabloAmaringo of a Peru' TheReligiousIconography arepresentedin AyahuascaVisions: vian Shaman,by Luis EduardoLuna and PabloAmaringo(Berkeley, CA: No*h AtlanticBooks,r99r). of the biologyof dreamingis explainedby 8r- Currentunderstanding States:How the Brain 86 f . Allan Hobsonin The Chemishyof Conscious Changeslts Mind (Boston:Little, Brown, 1994)and S/eep(New York: ScientificAmericanLibrary,1995).Many of the technicaldetailsof current studiesof the structureand physiologyof dreamingarereviewedin a specialissueof "Dream consciousness: approach," a neurocognitive and Cognition,3: n28 (1994).Recentresearchon the Consciousness adaptivefunction of sleepis reportedby Avi Karni et al. in "Dependence on REM sleepof overnightimprovementof a perceptualskill,"Science, 265 679-82(t994). /a

85- The relationbetweenlive snakesand dream serpentsin the origin of 88 dreamsandmyth givenhereis basedlargelyon BalaiiMundkur'simportant monographTheCult of the Serpent:An InterdisciplinarySumeyof Its Manifestationsand Oigins (Albany,NY: State Universityof New I madein YorkPress,1983)plus,with litde modification,the extensions Biophilia (Cambridge,MA: HarvardUniversityPress,1984). 89- I first used the imagery of changing space-timescalesas magical 9r cinematographyin Biophilia (Cambridge,MA: Haward University Press,1984). 9r- In characterizingthe difficulty of predicting protein structurefrom 9z the interactionof its constituentatoms,I benefitedgreatlyfrom an unpublishedpaperpresentedby S. J. Singerat the AmericanAcademyof Arts and Sciencesin December1993;he hasalsokindly reviewedmy account. 92- Higher-orderinteractionsin rain foresbis describedin my book The 97 Diversityof Lifu (Cambridge,MA: BelknapPressof HarvardUniversity generallyin a specialsectioneditedby Press,r99z),and in ecosystems PeterKareivain the journalEcology,T5:r5z7-59$gg4). 95- An excellent introduction to the meaning and goals of complexity 99 theoryisgivenby HaroldMorowib in the main iournalof thediscipline, of which he is editor, Complexig,r: 4-5 (1995);and by Murray GellMann in the sameissue,pp. 16-19.Among the many full-scaleexposi

Notesror-r34

lolr02

333

tionsofthe subjectthat haveappeared in the r99os,the bestincludeTlre Oigins of Order:Self-Organizationand Selectionin Eyolution,by Stuart A. Kauffman(New York Oxford UniversityPress;1993);and The ColIapseof Chaos: Discoyeing Simplicily in a Complex World, by Jack Cohenand Ian Stewart(NewYork:Viking, 1994). The cell as a slntem of geneticnetworksis describedby William F. Loomisand PaulW. Sternbergin "Geneticnetworks,'. Sclance,269:649 (1995).Their accountis basedon the longer,more technicalreportby HarleyH. McAdamsand Lucy Shapiroin the sameissue(pp.6lo-6). The exponentialrisein computerperfonnanceis describedby lvarspetersonin "Petacrunchers: settinga coursetowardultrafastsupercomputing,"ScienceNews,r47: z7z-5{rg9); and by DavidA. Patterson in ..Microprocessors in zozo,"ScientificAmericen,273:62-7Q99). peta-refers to the orderof magnifudelou,or a thousandtrillion. The opinions of cell biologistson the mostimportantproblemsof cell arrd organismic developmentare reported by Marcia Barinagain "Lookingto development's future,"Science,266: 5614$9g4). cneprrn 6 Tuc MrNo

ro5- Manyof the leadingbrainscientists havewrittenrecentaccountsof their r34 subjectfor the broaderpublic. Fortunately, thoseof mostrecentvintage containamongthem the full rangeof viewsheld by membersof the researchcommunity.The bestsuchworkson the structureof the brain and the neural and biochemicalcorrelatesof behaviorinclude TheEngine of Reason,the Seatof the SouI:A Philosoph:icalloumey into the Brain,byPaulM. Churchland(Cambridge, MA: MIT press,1995); The AstonishingHypothesis:The ScientificSearchfor the Soul, by Francis Crick (New York, Scribner,g94); Descartes' Error: Emotion,Ruoror, and the Human Brain, by Antonio R. Damasio(New york: G. p. put1am,1994);Bight Air,Billiant Fire:On theMatterof theMind, by Gerald M. Edelman (New York: BasicBooks,rygz); The Chemistryof Conscious States:How the Brain Changeslts Mind, by f. Allan Hobson (Boston:Little, Brown,ry94);ImageandBrain:The Resolution of thelmageryDebate,by StephenM. Kosslyn(Cambridge,MA: MIT press, by StephenM. Kossry94);WetMind: TheN ewCognitiyeNeuroscience, lyn and Olivier Koenig (New York Free Press,tggz); How the Mind Worfts,by StevenPinker (New York:W. W. Norton, ry9); andImagesof Mind,by MichaelI. Posnerand MarcusE. Raichle(Newyork: Scientific AmericanLibrary 1994).A thoroughgoingreviewof contemporary researchon emotion is providedby -uttlpt. iuthors in The Naiureif Emotion:FundamentalQuestions, editedby paul Ekmanand Richardf .

314

Notes ro6-rz9 1994).The poeticallusion Davidson(NewYork:OxfordUniversityPress, and heartlesswas to the divisionsof the brain asheartbeat,heartshings, madeby RobertE. Poolin Eve'sRib:TheBiologicalRootsof SexDffirences(NewYork:Crown,1994). The contemporaryview of consciousexperienceis exploredto varying degreesof penetrationby the aboveworks.The many ramificationsin area principalfocusin philosophyopenedby neurobiologicalresearch Towarda Unifted Science the following notableworls: Neurophilosoplry: of the Mind-Brain, by PahiciaS. Churchland (Cambridge,MA: MIT Explained,by Daniel C. Denneft (Boston: Press,1986);Consciousness Little, Brown, ry91;Dawin's Dangerouslilea:Evolutionand the Mean1995); ingsof Life,by DanielC. Dennett(NewYork:Simon& Schuster, of the Mind, by f ohn R. Searle(Cambridge,MA: and,The Rediscovery r99z). MIT Press, of the Mind: A Searchfor the MissingSciRoger Penrose,in Shadows (New York:OxfordUniversityPress,1994),argues enceof Consciousne$ sciencenor artificialcomputationwill solve that neitherconventional arisingfrom the problemof mind. He visualizesa radicalnewaPProach' few brain scienquantumphysicsand a new look at cellularphysiology; tists,however,feel any urgencyto departlrom the Presentcourseof insodramaticallyto the presenttime. vestigation,which hasprogressed are exOther special aspectsof modern researchon consciousness by MargaretA plored in The CreativeMind: Myths 6 Mechanisms, by Daniel Boden (New York:BasicBooks , ry9r);EmotionalIntelligence, Computer, The Emotional 1995); Books, Goleman (New York:Bantam by |os€ A. J6uregui(Cambridge,MA: Blackwell,tggl); The Sexual Brain, by Simon l,eVay (Cambridge,MA: MIT Press,1993);and The Ianguage Instinct:The NewScienceof I'anguageand Mind, by Steven Pinker (NewYork W. Morrow,1994).

In conshuctingmy o$/nbrief account of the physicalbasisof mind, I have drawn to varyingdegreeson each ofthe foregoingworksand on in the consultationwith someof the authorsaswell asotherresearchers brain sciences.I havealsousedthe outstandingreviewsand PeercomandBrainSciences. mentariespublishedin the iournalBehavioral ro6 The number of genesengagedin human brain developmentis rez8 September1995, TheGenomeDirectory, portedin Naturemagazine's p. 8, table8. ro9- Referencesto certainspecificexamplescitedin the chapterarethe folr29 lowing. On the PhineasGage caseand the role of the prefrontallobe: Hanna Damasioet al., "The return of PhineasGage:cluesabout the brain from the skullof a famouspatient,"Science,264toz-5 (1994);and Enor; andon KarenAnn Quinlan and Antonio Damasioin Deseartes'

Notesr3z-r4o

375

the roleofthe thalamus,KathyA.Fackelmann in "The consciousmind,', ScienceNer,us, 146:ro-rr (1994).On the explorationof brain neurons: SantiagoRam6n y Caial, Recollections of My Lrfu (Memoirs of the AmericanPhilosophicalSociety,v. 8) (Philadelphia:Americanphilosophie.al Society,rg1il, p. 763.On the brain'scategoricalprocessingof animalsas opposedto tools:Alex Martin, Cheri L. Wiggs,Leslie G. Ungerleider,andfamesV. Haxby,"Neuralcorrelates of category-specific knowledge,"Nature, 779: 649-52(1996).The imaginaryexampleof interactionof body and brain is adaptedfrom one given by Antonio Damasioin Descartes' Enor.The "hard problem" of the brain science is explainedby David f . Chalmersin "The puzzleof consciousexperience,"ScientificAmerican, 277: 8o4 (December 1995).Daniel C. Dennetthasthoroughlyexploredand independentlysolvedit in Consciousness Explained(Boston:Little, Brown,r99r).Simon Leys'inteqpre_ tation of Chinesecalligraphyis presented in his reviewof TheChiiese Artof Writing,by f eanFrangoisBilleter(NewYork:Skira/Rizzoli,r99o), inThe NewYorkReviewof Books,43:z83r (ryg6). r3z- The definition of artificial intelligence(AI) used is from an essayby r35 GordonS. Novak,fr., in the AcademicPress Dictionaryof Scienceand Technology, editedby ChristopherMorris (SanDiego:Academicpress, rgg2),p.16o.An excellentaccountofthe useofAI in playingchessand otherdeterministicgames(checkers, go,andbridge)is providedby Fred Guterlin "Silicon Gambit," Discover, ry:48-56(June1996).

t-"* c:i:",lT6u"'u*u r37- The full conceptionof gene-culfurecoevolution(andthe term) wasinr4o troducedby Charlesf. Lumsdenand myselfin Genes,Mind, and CuIture:The CoevolutionaryProcess (Cambridge,MA: HarvardUniversity Press,r98r) and PrometheanFire (Cambridge,MA: HarvardUniversity Press,1983).Key modelsof the interactionof heredityand culture leadingto thisformulationwereconshuctedby RobertBoydandpeterf . Richersonin ry76, Mark W. Feldmanand L. Luca Cavalli-Sforzain 1976,William H. Durham in 1978,andmyselfin rg78.Recentreviewsof gene-culturecoevolutionasadvancedto dateinclude thoseby William H. Durham,Coeyolution:Cenes,Culture,and Human Diversity(Stanford, CA: StanfordUniversityPress,r99r);"The mathematicalmodelling of human culture and its implicationsfor psychologyand the humansciences," by Kevin N. Laland,Bitish loumal of psyihology,g4: t+S4g 0gSl); and "Sociobiologyand sociology,"by FrangoisNielsen, Annual ReviewofSociology,zo:267-7o3(1994).Theseauthorshaveall madeimportantoriginal contributions.Eachplacesdifferentemphases

Notesr4o-r45

96

cycle, on the differentsectionsofthe coevolutionary and interpretations and would no doubt questionsomedetailsin the brief interpretation presentedhere; but I believe the core of my argumentclosely aptheconsensus. proaches An Essayon the Nafural r4o facquesMonod's bookChanceand Necessity: Philosophyof ModemBiology(New York:Knopf,r97r) containsasepigraph this statementby Democritus:"Everythingexistingin the Uni verseis the fiuit ofchanceand necessity." r4r- On the definition of culture, seeAlfredL. Kroeber,Anthropology,wlth r4z supplementsry27-37(New York:Harcourt,Braceand World, 1933);AlnJ L Kroeberand Clyde K. M. Kluckhohn,"Culture: a critical review of conceptsand definitions"(Papersof the PeabodyMuseum of American Archaeologyand Ethnology,HarvardUniversity,v. 47, no. D, pP' Museum,r95z);andWalter MA: The Peabody 6a7-a,656)(Cambridge, in the SymbolicWor/d(CamThe Self Human Career: Goldschmidt,The bridge,MA: B. Blackwell,r99o).Foran accountof the corruptionof the term "culture" in recentpopularliterature,consult"Welcometo postScholar,65 culturalism,"by ChristopherClausen in The Attnerican

37e-88(rye6). aswell as 4z- The nahrreof intelligencein bonobosand other greatapes, r45 culture (or absenceof it), is the subiectof a largerecentliterature'The topicsI havecoveredherearepresentedin greaterdetail and in various and RogerLewin in Kanzi: TheApe part by E. Sue Savage-Rumbaugh it the Brinkof the Human Mind (NewYork:Wiley, 1994);Chimpanzee Cultures,editedby RichardW. Wrangham,W. C. McGrew, Fransde Waal, and Paul G. Heltne (Cambridge,MA: HawardUniversi$ Press, 1994);two generalreviewsby Fransde Waal from HarvardUniversity amongPimates(1989)and GoodNatured:TheOi' Ptess,Peacemaking gins of Right and Wrong in Humans and Other Animals (1996);and tNew cluessurfaceaboutthe makingof the mind,"by foshuaFischman in Science,z6zi r5r7(1993).The silenceof chimpanzeesin contrastto the compulsivevolubility of humansis describedby fohn L' Locke in "Phasesin the child'sdevelopmentof langtagel'Ameican Scientist,Sz: by $6-45 GSS+).The evaluationof speechand bondingis examined as biologito infants "Human vocalizations maternal in Crrne Fernald cally relevant signals:an evolutionaryperspective,"in Ierome H' Barkow,LedaCosmides,and fohn Tooby,eds-,TheMapted Mind: Evoand the Generationof Culture (New York Oxford lutionary Psychology pP.7gr-+8. Press, r99z), University N. Meltzoff 45 The precocityof infant imitation is describedby Andrew and M. f.ith Moore in "Imitation of facial and manual gesturesby human neonates,"Science,ry: 75-8 Qg7); and"Newborn infantsimiChild Development, tate adultfacialgestures," 54 7oz-9 ig87)'

Notesr45-r6o

ttl

r45- The earlystagesof human culfure asrevealedby recentarchaeological are reportedin "Old datesfor modern behavior,"bv "Ann 46 discoveries Gibbons,Science,268:495-6 (1995);"Did Homoerectustamefire first?," by Michael Balter,in Science,268:ry7o(1995);and .'Did Kenyatools root birth of modernthought in Africa?,"by ElizabethCulotta, in Sci_ ence,zTo:mG7 Qgg5).The modemproliferationof materialculture is describedby Henry Petroskiin "The evolutionof artifacb."Ameican Scientist,8o: 416-zo(rggz). 146 The distinctionbetweenthe two basicclasses of memory wasmadebv

EndelTulvingin E. TulvingandWayneDonaldson,eds.,Oryanizatioi of Memory(NewYork:AcademicPress,r97z),pp. 382-4o3. 148 The definition of memes,the units of culture, as nodesin semantic memorywasproposedby CharlesJ.Lumsdenand EdwardO. Wilson in "The relationbetweenbiologicaland culhrralevolution," loumal of Social and BiologicalStructures,8: 747-59Q985). r49- An introductionto the measures of norm of reactionand heritability is r54 now standardin introductorytextbookson genetics,aswell as in many on-generalbiology.More detailedaccountsand applicatior,,,r. pro_ vided,amongnumerousreferences available,in lntroductionto euinti_ tatiyeGenetics, fourth edition,by DouglasS. Falconerand Trudy F. C. Magfay (Essex,England:Longman,ryg6);Human Heredity:principles and Issues, fourth edition,by Michael R. Cummings(New york: West PublishingCompany,rg97);andBehayioralCenetics,third edition,bv RobertPlominet al. (NewYork:W. H. Freeman,rg97).A summaryof someimportantrecentresearchon the heritabilityof human behavioral traitsis givenby ThomasJ. Bouchard,fr., et al. in ..Sources of human psychologicaldifferences:the Minnesotastudyof twins rearedapart,. Science,z5o:zz3-8(rygo). 156- Recentresearch on thebiologicalbasisof schizophreniais summarized r58 by LeenaPeltonenin "All out for chromosomesix,',Nafure,77B:6654 (tggS);by B. Browerin "Schizophrenia: fetal rootsfor GABA loss,"Sci_ ence News,r47t 247 (1995);and, on brain activip during psychotic ' episodes, by D A. Silbersweig et al., A functional.reu.oanaiomyof hal_ lucinations in schizophrenia)' Nature,778: andR.j. Dolan ry6j (1995), et al., "Dopaminergicmodulationof impaired.ognitiue -Nanre,activationin the anterior cingulatecortex in schizophrenia," 778: rgo-z (rggs). ry9 "fhe estimatednumberof polygenesdetermininghuman skin color is discussed by Curt Sternin Pinciplesof Human Genetics,third edition (SanFrancisco: W. H. Freeman,ryT). 16o The universalsof culture were identified by George p. Murdock in "The commondenominatorof culfures,"in Ralph iirrto.r, ed.,The

N o t e sr 6 o - r 6 5 Scienceof Man in the World Crisis (New York: Columbia University Press,1945).An excellentupdateand evaluationwith the aid ofanthroprinciplesisprovidedby DonaldE' Brown pologicalandsociobiological (Philadelphia:TempleUniversityPress,r99r)' in Himan IJniversals r6o- My imaginaryexerciseon termite civilization,presentedto emphasize of human nature,istakenfrom "Comparativesocialthe16r the uniq:ueness onHumanValues,v.I(SaltLakeCity:UniverLectures ory,"TheTanner sityof Utah Press,r98o),pP.4g-7)' 16z The convergenceof institutions in advancedsocietiesof the old and New Worldswascharacterizedby AlfredV. Kidder in "Looking backof the Ameican PhilosophicalSocie$,87: 527-77 ward.,"Proceedings (r94o). The principle of prepared learning wasformulatedby Martin E P' 163 of I'eaming,compiledby oth"it in BiologicalBoundaries Seligman "ttd (New York: Appleton-Cenhrry-Crofts, Selilman and foanne L. Hager rg72), The epigeneticrules of human socialbehaviorwere enumeratedand 163r6'7 classifiedby Charles f. Lumsden and Edward O. Wilson in Cenes, Press)' MA: HarvardUniversity Mind, and Culturein r98r (Cambridge, recent years in the rules of treatments Among the bestcomprehensive h"ue been Human Ethology,by IrendusEibl-Eibesfeldt(Hawthorne, Genes,Culture,and Human NY: Aldine de Grul'ter, ry8g);Coevolution: Diversity,by William H. Durham (Stanford,CA: StanFordUniversity Press,r99r);and the authorsof TheAdaptedMind, editedby feromeH' Barkow,teda Cosmides,and JohnTooby(NewYork:OxfordUniversity Press,r99z), and especiallythe essayby Tooby and Cosmides,"The foundationsof culture,"pp. r9-r36. psychological 164- The hansitionfrom Moro's reflexof newbornsto the lifelongstartlere1,65 flex is drawnfrom Luther Emmett Holt and fohn Howland,Holt'sDis-

eases of Infancyand Childhood eleventhedition,revisedby L' E' Holt, RustinMclntosh (New York:D. Appleton-Centuryr94o)'The and Jr., of the sensesis basedon reuniversalaudiovisualbias in vocabularies presentedinGenes,Mind, E. O. Wilson, and searchby C. ). Lumsden and Culture (Cambridge, MA: Harvard UniversityPress,r98r), pp' facewasfirst es38-4o. The swift fixation by newbornson the mother's in reported a Ph'D' thesis by CarolynC. Jirari, lablishedin experiments Per' Evolutionary An Infanq: Human in Freedman cited by Daniel G. 1974)'The resultswere spectivi(Hillsdale,Nf: L. Erlbaum Associates, The confirmed and extendedin Biologyand CognitiveDevelopment: Morton and fohn Caseof Face Recognition,by Mark Henry fohnson (Cambridge, MA: B. Blackwell,r99r).

N o t e s1 6 6 - 1 7 7

Tg 166 The cross-culhrral patternof smiling is from the accountby Melvin J. Konnerin "Aspectsofthe developmental ethologyofa foragingpeople," in NicholasG. Blurtonfones,ed.,EthologicalSndiesof Chili ilehivior (New York CambridgeUniversityPress,r97z),p.77; twocontributions by IrendusEibl-Eibesfeldt,"Human ethology:conceptsand implica_ tions for the sciencesof man," Behavioraland Brain-Sciences, z: r_57 (ry79),andHumanEthology(Hawthorne,Ny: Aldinede Gruyter,r9g9j. The combinedaccountgivenhereis takenwith little changefro- b. . f Lumsdenand E. O. Wilson, Cenes,Mind, and Culture (Cambridge, MA: HarvardUniversityPress,r98r),pp.77-8. r66- The accountof reification and the dyadic principle is basedon C. . f 67 Lumsdenand E. O. Wilson,ibid., pp. 93-5,with-the exampleof the Dusunof BorneotakenfromThomasRhysWilliams,Introduition to Socialization:Human CultureTransmitted(St. Louis.MO: C. V. Mosbv. rg72). 168 The heredityof dplexia is discussed by chris Frith and uta Frith in 'A biologicalmarkerfor dyslexia,"Nature, 382:rg-zo (1996).The current statusof behavioralgeneticsof both animalsand humansis authoritatively evaluatedin a seriesof articlespublishedunderthe heading..Behavioralgeneticsin transition"in Science,264: 686-7 $994). 79 169 The Dutch "aggressiongene" is analyzedby H. G. Brunner et al. in "X-linkedborderlinementalretardationwith prominentbehavioraldishrrbance:phenotlpe,geneticlocalization,and evidencefor disfurbed monoaminemetabolism,"Americanloumal of Human Cenetics, 5z: toTzj Q99) The geneassociated with noveltyseekingis reportedby RichardP. Ebsteinet al. in "DopamineD4 receptor1O4Onj exon IIi polymoryhismassociated with the human personalitytrait of Novel$ Seeking,"NatureCenetics,rz: 78-8o(1996). ryz The accountof paralanguageis basedon a comprehensivestudy by IrendusEibl-Eibesfeldt,Human Ethology(Hawthorne;Ny: Aldine de Gruyter,1989),pp. 424112. t7)- The accountgivenhereon the origin ofcolor vocabularieshasbeenas177 sembledfrom manysources, but mostlyfrom the recentlypublishedand importantseriesof articlesby DenisBaylor,JohnGage,john Lyons,and John Mollon in Colour: Art 6 Science.editedby Tievor Lami and Janine Bourriau(New )brk CambridgeUniversitypress,1995).The description of the cross-culturalsfudiesof color vocabularyhas been modifiedfrom C. J.Lumsdenand E. O. Wilson,prometheanFire (Cambridge,MA: HarvardUniversityPress,1983).I havealsoweighed(and recommend)an informativecritique of the mainstreampsychophysiologicalexplanationprovidedby multiple authors,and stoutiyde-fended

340

N o t e sr 7 8 - r B 6 reviewiournal by others,formingthe maiority,in the peer-commentary zo (z):67-zz8 (ISSZ)'I am gratefulto Iiehavioraland Erain Sciences, william H. Bossertand GeorgeF. Osterfor calculatingthe theoretical maximumnumberof colorvomaximumand the acfual,constrained thatcanbe createdfromelevenbasiccolors. cabularies C H A P T E R8

Tns FrrNess oF HUMANNerunn

ry8- Many of the ideasconcerninghuman natureand the role of epigenetic

r8z rules presentedhere were first developedby CharlesJ' Lumsdenand MA: HarndwaidO. Wilson inGenes,Mind,andCulture(Cambridge, (Cambridge, MA: Fire Promethean r98r) and Press, vard University 1983).Epigeneticrulesarealsoa focusofTheAdapted UniversityPress, Mind, editedby JeromeH. Barkow,Leda Cosmides,and JohnTooby (NewYork:OxfordUniversityPress,r99z). r8z- The "classical"approachof sociobiologyto the evolutionof culture is r88 the subjectof an excellentcollectionof articlesand critiquesin Human Nature:ACritical Reader,editedby LauraL. Betzig(NewYork:Oxford publishedandsynthesized UniversityPress,1997).Much of the research in the r98osand r99oshasappearedin the iournalsEthologyandSocioandHuman Nature'The intelbiology,Behavioraland Brain Sciences, lectu-aihistory of sociobiologyand other evolutionaryapproachesto humanbehaviorisably analyzedby Carl N. Degler,In SearchofHuman Nature: The Decline 6 Revivalof Darwinism in Ameican Social Press, r99r)' Thought(NewYork:OxfordUniversity of the family,due chiefly theory and theory kin selection r83 - The originsof to Williim D. Hamilton and RobertL. Trivers,arereviewedin Edward (Cambridge,MA: Belknap The New Synthesis O. Wilson, Sociobiology: and Pressof HarvardUniversityPress,1975),andin manylatertextbooks HumanNafure: ed', L. Betzig, Laura most recently, reviews,including, A CritiealReader(NewYork:OxfordUniversityPress,1997)' r84 Welldocumentedaccountsof genderdifferencesand matingstrategies in particularare the subiectsof Despotismand DifferentialReproduc' tioi: A Darwinian View of History,by Laura L' Beuig (New York Alof Human Mating, by dine, 1986);The Evolutionof Desirc:Strategies and 1994); Eve'sRib,by Robert David ir4.Buss(New York:BasicBooks, 1994). Publishers, (NewYork: Crown E. Pool arisingasa-densityd-ependent r85- The conceptionofterritorial aggression rti6 factorof populationregulationwasintroducedby F'dwardo' wilson in behavior,"inMan andBeast:Comparutite "Competitiveand aggressive andWilton S.Dillon, eds'(WashingF. Eisenberg SocialBehavior, fohn ton, DC: SmithsonianInstitution Press,r97r), pp' :83-zr7'The deep

Notes186-zoz

t+r

rootsoftribal shifeand war are effectivelyillustratedin preliteratesocietiesby LaurenceH. KeeleyinWar BdoreCiyilization(New york: Oxford UniversityPress,1996)and in morerecenthistoryby R. paul Shaw and YuwaWong in CeneticSeedsof Warfare:Evolution,Nationalism, andPatriotism(Boston:Unwin Hyman,1989);DanielPatrickMoynihan in Pandaemonium: Ethnicityin IntemationalPolitics(Newyork: Oxford UniversityPress,r99l); and Donald Kaganin On theOriginsofWar and thePresemation of Peace(NewYork:Doubleday,1995). 186- The evidencefor specialized cheaterrecognitionin human mentalder87 velopmentis presentedin "Cognitiveadaptations for socialexchange," by LedaCosmidesandfohn Tooby,in feromeH. Barkowet al., eds.,The AdaptedMind (NewYork OxfordUniversityPress,r99z),pp. :fl7-228. r8&- Human incestavoidance,aswell asthat of nonhumanprimates,is au196 thoritativelyreviewedby Arthur P.wolf in sexual Attractionand chitdhood Association: A ChineseBrief for EdwardWestermarck (Stanford. CA: StanfordUniversityPress,1995).The evidencefor direct recognition of inbreedingdepression by traditionalsocieties, which servesasan enhancementof the Westermarckeffect in the formation of incest taboos,is givenby William H. Durham in Coeyolution: Cenes,Culture. press,r99r). andHuman Diversity(Stanford,CA: StanfordUni'versity

r," s::T;1::"^"", zoz The ambivalence of theAmericanAnthropologicalAssociationtoward the sourcesof human diversitywasexpressed by famespeacock,AAA president,in "Challengesfacing the discipline" (AnthropologyNewsIetter,v. )5, no. 9, pp. I 3), asfollows:"The May 1994retreatincluded planning headsofall Sectionsandrepresentatives from the Long-Range and Financecommittee.The assemblysubcommittees . . . both separatelyand as a body addressed two questions:whither the discipline and whither the AAA. The participantsaffirmedthe strengthof aUding commitmentsto biologicaland cultural variationand to the refusal to biologizeor otherwiseessentializediversity.At the sametime, the groupexpressed a goalof reachingout andstren$heningthe discipline's relevance." zoz Fora sampleof historiesand critiquesof anthropologyfrom widelydiffering viewpoints,seeHerbertApplebaum,ed.,Perspectives in Cultural Anthropology(Albany,NY: StateUniversityof New york, 1987);Donald E. Brown,Human Uniyersals(Philadelphia:Temple Universitypress, r99r);Carl N. Degler,ln Searchof Human Nature:TheDecline6 Revivalof Dawinism in Ameican SocialThougftt(Newyork: Oxford UniversityPress,r99r); Robin Fox, The Searih fo, Society:euest for a

)42

N o t e sz o 3 - z o 6 BiosocialScienceand Morality (New Brunswick,Nf : RutgersUniversity Esof Cultures:Selected Press,rg89);Clifford Geertz,TheInterpretation The Human dt, R. Goldschmi 1973); Walter says(NewYork:BasicBooks, Career:The Selfin the SymbolicWorld(Cambridge,MA: B. Blackwell' r99o);Marvin Harcis,The Riseof AnthropologicalTheory:AHistory of Theoiesof Culture (New York: ThomasY' Crowell, 1968);fonathan Marks,Human Biodiversi$:Cenes,Race,and History(Hawthorne,NY: of Social Philosophy Aldine de Gruy'ter,1995);andAlexanderRosenbery, r995). Press, secondedition(Boulder,CO: Westview Science,

zo3- Within academicsociology,the heresyof foundational biology and zo5 psychologyhasbeenpromotedby,amonga few others,|osephLopreato in Human Nature 6 BioculturalEvolution(Boston:Allen & Unwin, (NewYork: 1984);PierreL. vanden BergheinThe EthnicPhenomenon Elsevier,r98r);and WalterL. Wallace,Principlesof ScientificSociology (Hawthorne,NY: Aldine de Gruyter,1983).A thoroughgoinghistoryof periodis RobertW. Friedrichs'ASociology the disciplinein its classical (NewYork:FreePress,r97o).The later,model-buildingpeof Sociology riod,in which a partialattemptis beingmadeto connectindividualbehaviorto socialpatternin themannerof economictheoryisepitomized of SocialTheory(Cambridge,MA: by |amesS. Coleman'sFoundations BelknapPressof HarvardUniversityPress,r99o). zo3- RobertNisbetexploresthe rootsof the sociologicalimaginationin Sozo4 ciologyasan ArtForm (NewYork OxfordUniversityPress,1976). StandardSocialScienceModel (SSSM)was zo4 The felicitousexpression introducedby |ohn Toobyand Leda Cosmidesin "The Psychological Foundationsof Culture," in f . A. Barkowet al', eds.,TheAdaptedMind (NewYork OxfordUniversityPress,r99z),pp. 19-136.That it still flourisheswithin the socialsciencesis well illustratedby the stronglyconReportof the Gulbenkian shuctivisttone of Open the SocialSciences: Commissionon the Restructuingof the SocialSciences(Stanford,CA: StanfordUniversityPress,1996).The cenhal conceptionwithin it has been well characterizedby many earlierwriters,including Donald E' (Philadelphia:TempleUniversityPress, Brown-see Human lJniversals to Metatheoryin SocialScience: contributors multiple the r99r)-and editedby DonaldW FiskeandRichardA. Pluralisms and Subiectivifies, Shweder(Chicago:Universityof ChicagoPress,1986)'Toobyand Cosalso is by far the mostthoroughandpersuasive, mides,whoseasslssment introducethe IntegratedCausalModel (lCM) to denotethe new causal linkageof psychologyand evolutionarybiolory to the studyof cultures' zo6 The conceptionof hermeneuticsasa thick descriptioncraftedfrom difin Fiskeand Shweder(ibid'), esis well represented fering perspectives peciallyin the articles"Threescientificworldviewsandthe coveringlaw model; by RoyDAndrade,pp. r9-4r, and"science'ssocialsystemofva-

Notes zo7-zz8

347

lidity-enhancing collectivebeliefchangeand the problemsof the social sciences," pp. ro&-35. zo7 Richard Rorty's interpretation of hermeneutics is given in Philosophy and the Minor of Nafure (Princeton,NJ: Princeton Universitypress, r97q. zo7- The personalizedcharacterizations ofdisciplines in the naturalandsozo8 cial sciencesis basedlooselyon my earlieraccountin "Comparativeso. cial theory" TheTannerLectureson Human Values,v. I (SaltLakeCity: Universityof Utah Press,r98o),pp.49-73. zrr- StephenT. Emlen'ssynthesis of parent-offspringrelationsin birdsand zrz mammalsis givenin "An evolutionary theoryof the family,"Proceeilings of theN ational Academyof Sciences,IJSA, 9z: 8o9zj Q9g5). zzo- I have basedmy interpretationof Gary S. Becker's researchon his zzz maiorworkATreatiseon the Family,enlargededition,and collectionof essays, Accountingfor Tastes(bothfrom Cambridge,MA: HarvardUniversityPress,r99r and 196). I have also benefited from Alexander Rosenberg's insightful Economics: MathematicalPoliticsor Scienceof DiminishingRetums? (Chicago:Universityof ChicagoPress,r99z).We havesubstantiallydifferentassessments, however,of the prospectsfor linking the modelsof economicsto psychology and biology,with Rosenbergbeingthe morepessimistic, for reasons describedin the text. zz4 Rationalchoice theory is oftencalledby other namesin the socialsciences,including public choice,socialchoice, and formal theory.Its weaknesses, especiallyits excessive reliance on abstractand data-free models,have recently been exploredby Donald P. Green and Ian Shapiroin Pathologies of RationalChoiceTheory:A Citique of Ap.pticationsin PoliticalScience(NewHaven:YaleUniversityPress,1994). zz5- The examplesof heuristics("rulesof thumb") usedby peopleduringinzz6 tuitive quantitativereasoningare takenfrom "fudgment under uncertainty:heuristicsand biases,"by AmosTverskyand Daniel Kahneman, in Science,r85: rz4-3r Q974).An updatedexplanationof the concept, with othercasestudies,is providedby the sameauthorsin "On the reality of cognitiveillusions,"PsychologicalReview, ro3:582-9r(1996). ze6 On reasoningin preliterate people:ChristopherRobert Hallpike in The Foundationsof PrimitiveThought (New York Oxford University Press,1979). zz7- Forbleakviewsby leadingphilosophersof the reductionistapproachto zz8 humansocialbehavior,and hencethe entireprogramof uniting biology andthe socialsciences, seePhilip Kitcherin VauttingAmbition:Sociobiologyand the Questfor Human Nature (Cambridge,MA: MIT Press, 1985)andAlexanderRosenberg in his hilogy: Philosophyof SociatScience(Boulder,CO: WestuiewPress,ry88), Economics:Mathematical

744

N o t e sz z 9 - z 3 8 Politics or Scienceof Diminishing Retums?(Chicago: University of Chicago Press,r99z), andInstrumentalBiology,or the Disunityof Science(Chicago:Universityof Chicago Press,1994).Generallymore favorable stancesare taken, for example,by the philosopherswho editedby |amesH. Fetzer andEpistemology, contributedto Sociobiology (Boston:D. Reidel,1985),and by MichaelRusein TakingDarwinSeiously:ANaturalisticApproachtoPhilosophy(Cambridge,MA: B. Blackwell,rq86).

l?" *"*"totto* TsuAnrs^* Tf,*I"*., ""

zz9 The ry7g-8oReportof the Commissionon the Humanitieswaspublishedasa book:RichardW Lyman etal.,TheHumanitiesin Ameican Life (Berkeley:Universigof CaliforniaPress,r98o). z3o GeorgeSteineron the arts is quotedfrom his commencementaddress at KenyonCollege,publishedinThe Chronicleof HigherEducation,zr )une1996,p. 86. z7z Brain developmentin the musically gifted is reportedby G. Schlaug and co-workersin "Increasedcorpuscallosumsizein musicians,"Nauropsychologia, )7: ro47-r5 (1995),and "ln vivo evidenceof structural brain asymmetryin musicians,"Science,267: 699-7ot (r99). 274 Harold Bloom on postmodernism is cited ftom The WestemCanon: The Booksand Schoolof the Ages(Orlando,FL: HarcourtBrace,1994)' 44- The mood swingsof literary history are describedby EdmundWilson 235 in "Modem literature:betweenthe whirlpoolandthe rock)'NewRepub' EdmundWilson, /ic (November19z6),reprinted in FromtheUncollected selectedand inhoducedby JanetGroth and DavidCashonovo(Athens, OH: Ohio UniversityPress,1995). 235 FrederickTumer diagnosesliterary poshnodemismin "The birtfi of WilsonQuarterly,pp. zGTz(Winter 1996)'The imnaturalclassicism," on literarytheoryis lucidly describedin historipact of postmodemism of Englishstudies," in "The hansformation Abrams M. H. cal contextby D aedalus,n6: rc5-3r(1997). 235- Among the principalworksconhibuting to the biological theoryof arb 238 interpretationand historyare,in chronologicalorder,Charlesf . Lumsden and EdwardO. Wilson, Cenes,Mind, and Culture (Cambridge, MA: Haward UniversityPress,r98r); E. O. Wilson, Biophilia (Cambridge,MA: HarvardUniversityPress,1984);FrederickTurner, Natural on Literatureand Science(NewYork:ParagonHouse Essays Classicism: UniverPublishers,ry85),Beauty: The Valueof Values(Charlottesville: sityPressof Virginia, r99r),and TheCultureof HoP: ANew Bitth of the

Notes 239-z4r

1.45

ClassicalSptnf (New York:FreePress,1995);Ellen Dissanayake,What ls Art For? (Seattle,WA: Universityof Washingon Press,1988)and HomoAestheticus: WhereArt ComesFrom and lVhy (New York: Free Press,r99z); IreniiusEibl-Eibesfeldt,Human Ethology(New York: Aldinede Grufer, 1989);MargaretA. Boden,The CreativeMind: Myths6 Mechanisms(New York BasicBooks,r99r); Alexanderf. A,rgnos,A BlessedRagefor Order: Deconstruction,Evolution, and Chaos (lnn Arbor:Universityof MichiganPress,r99r);K"thfy" Coe,"A,rt:the replicableunit-an inquiryinto the possibleorigin of art asa socialbehavior," rS.217-74(1992);WalterA. loumal of Socialand EvolutionarySystems, Koch,The Rootsof Literuture,andW. A. Koch, ed.,TheBiologyof Literature(Bochum:N. Brockmeyer,gg1);RobinFox,TheChallengeof Anthropologt:OId Encountersand New Excursions (New Brunswick,N|: Tiansaction,1994);JosephCaroll, Evolutionand LiteraryTheory(Columbia,MO: Universityof MissouriPress,1995);RobertStorey,Mimesis and the HumanAnimal:On theBiogenetic Foundations of LiteraryRepresentation(Evanston,IL: NorthwesternUniversityPress,1996);Brett Cooke,"Utopia and the art of the visceralresponse," in GaryWesdahl, GeorgeSlusser,and Eric S. Rabin,eds.,Foodsof the God,s: Eating and the Eaten in Fantasyand ScienceFiction (Athens, GA: University of GeorgiaPress,1996),pp. r8&gS; Brett Cooke and FrederickTurner, eds., Biopoetics: Evolutionary Explorations in the Arts (New York: ParagonPress,in press). 239 The metaphorsof art and literary history are takenfrom an article by JohnHollander,"The poetryof architecture,"Bulletin of theAmeican Academyof Artsand Sciences,49:1735 $996). 239 EdwardRothstein'scomparisonofmusic and mathematicsis from his Emblemsof Mind: TheInnerLife of Musicand Mathemafics(NewYork: TimesBooks,1995). 239- Hideki Yukawadescribedcreativityin phpics in Creativityand Intuz4o ition: APhysicistl,ooksEast andWesf,translatedby fohn Bester(Tokyo: KodanshaInternational,distributedin U.S. by Harper & Row, New York,r93). z4o Picassoon the origin of art wasquotedby Brassai(originallyGyula Halasz)in Picasso 6 Co. (london: Thamesand Hudson,1967). z4o The idea of metapatternswasoriginatedby GregoryBatesonin Mind andNature: ANecessary Unif, (NewYork:Dutton, ry7g)andexpanded into biologyand art by Tyler Volk in Metapattemsacross Space,Time, andMind (NewYork:ColumbiaUniversityPress,1995). z4o- Vncent foseph Scully's conception of the evolution of architecture is z4r outlinedin Architecture : TheN atural and the Manmade(NewYork St. Martin'sPress,r99r).

346

Notesz4r-258

z4r Excellentaccountsof the evolution of Mondrian's art, amongmany available,include fohn Milner'sMondrian (NewYork AbbevillePress, r99z) and Carel Blotkamp'sMondian: The Art of Destruction(New York: H. N. Abrams,1995).The neurobiologicalinterpretationI have givenit is my own. z4z The historyof Chineseand fapanesescript is detailedbyYuiiro Nakata inThe Art of lapaneseCalligraphy(New York:WeatherhillAleibonsha, r97?,). z4z- TIre metaphor of eternityby ElizabethSpiresis givenin het Annonci' 243 ade (New York:Viking Penguin,1989),and is quotedby permissionof thepublisher. '11 The listing of archetypesis largelymy own contrivance,with its eleincludingespecially mentsgleanedfrom manysources, fosephCampbell's The Hero with a ThousandFaces(New York: PantheonBooks, 1949)and The Masksof God: Pimitive Mythology(New York:Viking ANatural Historyof the SeIf Archetypes: Press,1959);Anthony Stevens' (New York: William Morrow, r98z);ChristopherVogler'sThe Witer's loumey:Mythic Structurefor Storytellers6 Screenwiters(StudioCity, andRobinFox'sTheChallengeof CA: Michael WiseProductions,rygz); Anthropology:Old Encountersand New Excursions(New Brunswick, rg94). N): Transaction, 245- Of the many descriptionsof Europeancavernart and otherPaleolithic WhereArt 24g art, and its interpretation,may be citedHomoAestheticus: (New York: Free Press, ComesFrom and Why, by Ellen Dissanayake ry92); Dawn d Art: The Chauvet Cave,the Oldest Known Paintingsin the World, by |ean-MarieChauvet, Eliette Brunel Deschamps,and Christian Hillaire (New York:H. N. Abrams,1996);"Imagesof the lce Age,"by AlexanderMarshack , Archaeology, fuly/Augustrgg1,pp. 29-39; and "The miracleat Chauvet,"by E. H. f. Gombrich,NewYorkReview of Books,14November1996,pp. 8-rz. z5e- Gerda Smets' neurobiologicalstudy of visual arousalis describedin z5t Aesthetic ludgment and Arousal: An Expeimental Contribution to (Leuven,Belgium: LeuvenUniversityPress,1973). Psycho-aesthetics z5r- The experimentalstudiesof optimum femalefacialbeautyarereported by D. I. Perz5z in"Facial shapeand iudgementsof femaleathactiveness," rett, K. A. May, and S. Yoshikawa,Nature, 368:z7E-42(1994).Other aredescribedby David M. Buss studieson ideal physicalcharacteristics 1994). inThe Evolutionof Desire(NewYork:BasicBooks, 254- The account of the Kalahari hunter-gatherersusedhere is given by 258 touis Liebenbergin The Art of Tracking(Claremont,South Africa: and D. Philip, r99o).A comparabledescriptionof AushalianPleistocene Floodin Archaeologyof moderndayAboriginesis providedby Josephine

N o t e s2 5 8 - z 9 o

347

the Dreamtime:The Storyof Prehistoic Australiaand Its People,rcvised, edition(NewYork:Angus& Robetson, 1995).

25u Someof the themesof the chapteron artsand criticism,particularlythe significanceof mythic archetypesand the relation of scienceto the arts,arebrilliantly anticipatedin NorthropFrye'sAnatotrryof Criticism: Four Essays(Princeton,Nf: Princeton UniversityPress,1957).Frye could not, however,relatehis subjectto the brain sciencesand sociobiology,which did not existin their presentform in the r95os.

u,","l,"i,il"i#,.,o* z6o- Amongkey references to the foundationsof moral reasoning,and parz9o ticularly to the role of the natural sciencesin defining the empiricist world view,are,alphabetically by author:RichardD. Alexander,The Bi(Hawthorne,NY:Aldinede Gruyter,1987);Larry ologyof Morul Systems Arnhart,"The new Darwiniannaturalismin political theoryl'Ameican Political ScienceReview,89: 389-4oo (1995);Daniel Callahan and H. TristramEngelhardt,Jr.,eds.,The Rootsof Ethics:Scienee,Religion, and Values(New York:PlenumPress,1976);AbrahamEdel, In Search of the Ethical: Moral Theory in TwentiethCentury Arnerica (New Brunswick,NJ: Transaction,1993);PaulL. Farber,TheTemptationsof EvolutionaryEflrics (Berkeley:Universityof California Press,1994); MatthewH. Nitecki and DorisV. Nitecki, eds.,EvolutionaryEthics(Nbany: StateUniversityof New York Press,1993);famesG. Paradisand GeorgeC. Williams,Eyolution6 Ethics:T. H. Huxley'sEvolution and Ethics with New EssaTson Its Vicbrtan and SociobiologicalContext (Princeton,Nf : PrincetonUniversityPress,1989);VanRensselaer Potter, Bioethics:Bidge to the Future (EnglewoodCliffs, Nf: Prentice-Hall, r97r); Maft Ridley,The Oigins of Virne: Human Instinctsand the Eyolution of Cooperation(New York:Viking, 1997);Edward O. Wilson,Sociobiology:TheNew (Cambridge,MA: BelknapPressof Synthesis Harvard University Press,1975),On Human Nature (Cambridge, MA: HarvardUniversityPress,1978),and Biophilia (Cambridge,MA: HarvardUniversityPress, ry84);RobertWright, TheMoral Animal: EyoIutionaryPsychology and EverydayLife (New York: PantheonBooks,

rysd. The scholarlysourceson the relation ofscienceto religion from which I havedrawnideasand informationincludeWalterBurkert,Creationof the Sacred:Tracksof Biology in Early Religion (Cambridge, MA: Harvard UniversityPress,1996);|amesM. Gustafson,Ethicsfrom a TheocentricPerspective, vol. 4 Theologyand Ethics(Chicago:Universityof Chicago Press,r98r); John F. Haught, Scienceand Religion:From

348

Notes 264-278

Conflict to Conyersation(New York:PaulistPress,1995);HansJ. Mol, of ReIdentityandtheSacred:ASketchforaNewSocial-ScientifieTheory Intimationsof Re' Iigion (Oxford:Blackwell,1976);Arthur R. Peacocke, ality: Citical Realism in Scienceand Religion (Notre Dame, IN: Universityof Notre Dame Press,1984);VernonReynoldsand RalphE. S.Tanner,TheBiologyof Religion(BurntMill, Harlow,Essex,England: The EthicalAnimal (New Longman,1983);Conrad H. Waddington, York:Atheneum,196r);EdwardO. Wilson,On HumanNature(Cambridge,MA: HarvardUniversityPress,1978). 264- | have basedthe argument of the religious hanscendentaliston my 266 ownearlyexperiencein the SouthernBaptisttradition,and upon many by Karenfumstrongin A includingexcellentexpositions othersources, Historyof God:The4,ooo-Year of Quest ludaism,Christianity,andlslam (NewYork:AlfredA. Knopf/RandomHouse,1993);PaulJohnsonin The Questfor God:A PersonalPilgimage(NewYork:HarperCollins,g96); fackMiles in God:ABiography(NewYork AlfredA. Knopf,1995);and Richard Swinburnein Is Therea God?(New York: Oxford University Press, 1996).

26s fohn Locke'scondemnation of atheistsis in A Letter on Toleration, Latin text editedby RaymondKlibanskyandtranslatedby ]. W. Gough (Oxford:ClarendonPress, r968). 26:' Robert Hooke on the limits of scienceis quotedby CharlesRichard

Weld in A Historyof The RoyalSociety,with Memoirsof the Presidents, compiledfrom documents,in two volumes(London:)ohn Parker,West Shand,1848), vol. \ p. 46 266 The estimatecited of the number of religionsthroughouthuman history (roo,ooo)wasmadeby AnthonyF. C. Wallacein Religion:An An' thropologicalView(NewYork:RandomHouse,1966). Mary Wollstonecraft on evil: A Vindicationof the Righ* of Woman (London:f. fohnson,r79z). 269 The surveyofthe religiousbeliefofscientistswasconductedby Edward |. l,arson and l,arry Witham and is reportedinThe Chronieleof Higher Education,n April ry97,p. 1.16. The model of the evolution of moral behaviorfollowssimilarreasoning in my first work on the subject,On Human Nature (Cambridge, MA: HarvardUniversityPress,1978),and is consistentwith the theory of gene-culturecoevolutiondetailedin Chapters7 and 8 of the present work. The fundamentalsof the evolutionof cooperation,includingthe useof "/> ,NR the Prisoner's Dilemma,is givenby RobertM. AxelrodinTheEvolution of Cooperation(New York: BasicBoolc,1984)and Martin A. Nowack,

N o t e s2 7 6 - 2 9 3

349

RobertM. May,andKarl Sigmundin "The arithmeticsof mutual help," ScientificAmeican, fune 1995,pp. 7G8r. Proto-ethicalbehavior in chimpanzees, includingcooperationand refiibution towardthosefailing to cooperate,is describedby Fransde Waal in Peacemaking Among Pimates (Cambridge,MA: HarvardUniversityPress,1989),and Cood Natured:TheOigins of RightandWronginHumansand Other Animals (Cambridge,MA: HarvardUniversityPress,1996). 276 Evidencefor inherited differencesamongpeoplein empathy and in-

fant-caregiver bonding is citedby RobertPlominet al.inBehavioralGenetics,third edition(NewYork W. H. Freeman,1997). 283- Dominancecommunicationin mammalsis described widelyin the lit-

,84 erafureon animalbehavior,for examplein somedetail in my Sociobiol(Cambridge,MA: BelknapPressof HarvardUniogy:TheNewSynthesis versityPress,r975). 28s The accountby St. Teresaof Avila (r5r5-r583)of her mptical experienceof prayeris providedin TheLife of St.Teresa of lesusof the Orderof Our Lady of Carmel,Wiften by Herself,hanslatedfrom the Spanishby David Lewis;it is comparedwith the original autographtext and reeditedwith additionalnotesand introductionby BenedictZimmerman, fifth edition(Westminster, MD: The NewmanPress,1948). z8g- The closingstatementon the relation of scienceand religion is drawn z9o from the r99r-92 Dudleian Lecture I gave at the Haward Divinity School,which was publishedas "The return to natural philosophy," HarvardDivinityBulletin,zt rz-t5 $g9z).

To WHar Er.ro? 291

The genetickinship by common descentof all organismson Earth is detailedat the molecularlevelby f . PeterGogartenin "The earlyevolution of cellularlifel'Trends inEcologyandEvolution,ro: r47-5r(1995). The descentof modern humanity from earlierspeciesof Homo is authoritativelyreviewedby multiple authorsinThe FirstHumans:Human Oigins and Historyto ro,oooBC, Gdran Burenhult, ed. (New York: HarperCollins, r993).

293 Gap analysisis a term borrowedfrom the studyof biologicaldiversity and conservation; it refersto the methodof mappingthe distributionof plant and animal species,overlayingthem with mapsof biologicalreserves,and usingthe informationto selectthe bestsitesfor future reserves.See"Gap analysisfor biodiversitysurveyand maintenance,"by f. Michael Scottand Blair Csuti in Mariorie L. Reaka-Kudla,Don E.

35c.

N o t e s2 9 5 - 3 o 8

Wilson,and EdwardO. Wilson, eds.,Biodiversity II Understanding and (Washington,DC: fosephHenry ProtectingOur Biological Resources Press, 1997),pp.)2r-4o. 295- The sectionon presentand future human geneticevolutionhasbeen CeoExtra,no.t, 3o3 modifiedfrom my article"Quo Vadis,HomoSapiens?," The evolutionin headshapeduringthe pastmillenpp. ryq (1995). nium is documentedby T. Bielicki and Z. Welon in "The operationof naturalselectionin human headform in an EastEuropeanpopulation," in Carl f. Bajema, ed.,Natural Selectionin Human Populations: The Measurement Societies of OngoingCeneticEvolutionin Contemporary (New York:Wiley, r97o). The evidencefor recent evolutionin heatshockproteinsis given by V. N. Lyashkoet al. in "Comparisonof the heatshockresponse in ethnicallyand ecologicallydifferenthumanpop ulations," Proceedingsof the National Academyof Sciences,USA, 9r:tz49z-5Q994). The resultsof the Biospherez experimentare discussedby Joel E. 3o5Cohen andDavidTilman in "Biosphere z andBiodiversity: The Lessons 3o6 So Far,"Science274:rr5o4 (1996).A first-handaccountof the two-year AbigailAlling adventurehasbeenpublishedby two of the Biospherians, z and Mark Nelson,in Life UnderClass:TheInsideStoryof Biosphere (Oracle,AZ: Biosphere Press, 1993). 3o7- The mostthoroughand authoritativerecentaccountof human popula3o8 tion growth written for a broadaudienceis |oel E. Cohen'sHow Marry PeopleCan the Earth Support?(New York W. W. Norton, 1995).It is verydifficult to estimatethe total numberof humanswho can existsustainablyon Earth,due, asCohen argues,to factorsasspongyasthe ult! mate levels of food production technologyand averageacceptable qualityof life. Yetan absolutelimit existsandit is not much greaterthan ten billion. The estimatedlimit.of sixteenbillion peoplebasedon total energycaptureby photosynthesis convertedsolelyto humanuseis taken from JohnM. Gowdyand Carl N. McDaniel in "One world,oneexperiment: addressingthe biodiversity-economics conflict," EcologicalEconomics,r5: r8r-92(1995). 3o8 The PAI formula for estimatingimpactof populationon the environment wasdevelopedoriginallyby PaulR. Ehrlich and fohn P. Holdren in "Impact of populationgrowth,"Science,r7r: rze-r7 (r97r),and has in manyaspects since beendiscussed since."It is a roughapproximation, the three multiplicativefactorsare not independent. . . It is especially globalimpacts,wherewe normallymustfall backon usefulin assessing usingper-capitaenergyusein placeof AT": PaulEhrlich, "The scaleof the human enterprise,"in DenisA. SaunderseLal.,NafureConsenation (Chipping Norton, NSW, of FragmentedEcosystems 3: Reconstruction Aushalia:SurreyBeatty& Sons,1993),pp. l-8.

Notes3o8-3r7

3SL

308 The conceptof ecologicalfootprintsasa measureof environmentimpact wasintroducedby William E. Reesand Mathis Wackernagelin "Ecologicalfootprintsand appropriatedcarrying capacity:measuring the nafuralcapitalrequirements of the human economy,"in AnnMari fanssonet al., eds.,Investingin Natural Capital: The EcologicalEco(Washington, nomicsApproachto Sustainablli4, DC: IslandPress,1994), pp.76zjo. statementonpopulation and environment,coau309 An importantgeneral thoredby elevenleadingscientists whoseexpertisecoversvirtuallyall the relevantdisciplines,is "Economicgrowth,carryingcapacity,andthe environment,"by KennethA.rrowet al.,Science,268: 5zo-r(1995). upto.date,and accessiblesummariesof the 3og- The mostcomprehensive, on the global environmentareprovidedby the re3r3 immensedatabases portsof the WorldwatchInstitute,headquartered in Washin$on,D.C. They include the hvo annualseriesStateof the World andVital Signs: TheTrendsThat Are ShapingOur Future,publishedby W. W. Norton (NewYork),aswell asoccasionalspecializedWorldwatchPapers,publishedby the Institute.An independentassessment of availabledataby environmentalscientists,confirmingthe sametrendsI havedescribed here,are reportedin "Land resources: On the edgeof the Malthusian precipice?,"proceedings of a conferenceorganizedby D. I. Greenland et al., PhilosophicalTransactions of the RoyalSocietyof landon, SeiesB, 752:859-rq3Qg9). 3r4- Theserecent workson environmentalfactorsin the rise and fall of 3r5 civilizahonsare amongthosethat can be recommendedout of a large literature:"The genesisand collapseof third millennium North Meso. potamian civiliza|oon,"by H. Weissel d,, Science,z6t 995-roo4{lg97); "Climate and the collapseof civilization,"by Tom Abatein BioScience, (1994);andthe exceptionally broadand biologicallyinsightful 44 516-19 Guns,Germs,and Steel:The Fatesof Human Societies, by fared Diamond (NewYork:W W. Norton,1997). 17 An excellentaccountof the r99zUnited Nations Conferenceon Environmentand Development(UNCED), including a historyof the meeting and the substanceofthe bindingconventionsand ofAgendazr, is AdamRogers'TheEarth Summit:APlanetary Reckoning(LosAngeles: GlobalView Press, 1993). the accommodation On of technology,rand economic growth to the 3ry natural environment,seethe U.S.NationalResearchCouncil'sspecial rcpoft, Linking Scienceand Technologyto Society'sEnvironmental Goals,lohn F. Ahearneand H. Guyford Stever,co-chairs(Washington, DC: NationalAcademyPress,1996).Incisivedescriptionsof particular technologicalsolutionsare given by JesseH. Ausubelin "Can technologysparethe eafth? )' AmericanScientist,84 166-78(1996),and

Notes3r8-325

352

the multiple authorsof the Summer1996issueof Daedalus(fournalof the AmericanAcademyof Artsand Sciences) entitled"Liberationof the Environment." 3r8- The relationsbehveeneconomicsand the environmentisthe subjectof 3r9 a rapidly expandinglibrary of journalsand books.Excellentinhoductionsto the subjectareprovidedby |amesEggert,MeadowlarkBconom(fumonk,NY: M. E. Sharpe,r99z); ics:Work6 Leisurein theEcosystern R. Kerry Turner, David Pearce,and Ian Bateman,EnvironmentalEconomics:An ElementaryIntroduction (Baltimore, MD: fohns Hopkins UniversityPress,1993);PaulHawken,TheEcologyof Commerce: ADecIarationof SustainabilifT(NewYork:HarperCollins,1993);andThomas Michael Power,I-ostkndscapesand FailedEconomies: TheSearchfor a Valueof Place(Washington, DC: IslandPress,1996). 3r8 Frederick Hu on the economicgrowth of nations:"What is competition?,"WorldLinft, July/August 1996,pp. r4-r7. The account of biodiversity and extinction is modifiedfiom portionsof 3zo724 two of my own articles,"Is humanity suicidal?,"The New YorkTimes Magazine, 3o May ry97, pp. 24-9; and "Wildlife: legions of the doomed,"Time(lntemational),3o October1995,pp.j7-. 3zr- On the moral argumentfor the preservationof biodiversity:seemy ear723 liet presentationsin Biophilia (Cambridge,MA: HarvardUniversity Press,1984)and,TheDiversityof Life (Cambridge,MA: BelknapPressof HarvardUniversityPress,r99z); and StephenR. Kellert,The Valueof Life: BiologicalDiversityand Human Socief (Washington,DC: Island Press/Shearwater Boola, 1996)and Knship to Mastery:Biophilia in Human Eyolutionand Dewlopmenf (Washin$on,DC: Island Press,

rys7). 725 On the ultimatelymoral foundations of society:Democracyand Disagreement, byA*y Gutmannand DennisThompson(Cambridge,MA: BelknapPressof HarvardUniversityPress,1996).

A C K N O W L ED G M E N T S

in Fon ronry-oNE yEARs,endingwith my retirement intermediate in bilarge classes elementary and taught ryg7,I ologyat HarvardUniversity.In the secondhalf of that period the presentations were part of the core curriculum, commissionedby the Facultyof futs and Sciencesto teachthe basic and "waysofthinking" ofeach ofthe greatbranches substance of learning.The subjectfor which I had particularresponsibillocated ity, evolutionarybiology,is an intellectualcaravanserai It is a lognearthe boundaryof the naturalandsocialsciences. ical meetingplacefor scholarsof diverseinterestswho wishto tradebackand forth. Given that my primaryresearchinterests alsoincludethe evolutionof socialbehavior,I felt comfortable discussingthe key issuesof consiliencewith expertsacrossa largepartof the academy. It would be almostimpossibleto list all thoseI consulted duringthe threeyearsit tookto write Consi/ience.Theyrange in interestsfrom a scholarin Slavicliteratureto the speakerof from Nobel Laureatesin the U.S. House of Representatives, thephysicalsciences and economicsto the chief executiveofficer of an internationalinsurancecompany.Instead,I will take only thosewho readportionsof the spacehereto acknowledge

3r+

Acknowledgments manuscript. In expressingmy gratitude for their invaluable help, I also exonerate them from errors and misconceptions that might remain as the book goesto press(September1997).

GaryS.Becker (economics) RodneyA. Brooks (artificial intelligence) TerenceC. Burnham (economics) JosephCarroll (literarytheory) I. BernardCohen (historyof science) foel E. Cohen (ecology) Brett Cooke (literarytheory) William R. Crout (religion) Antonio R. Damasio (neurobiology) DanielC. Dennett (philosophy of science,brainsciences) Ellen Dissanayake (arb theory) GeorgeB. Field (physicalsciences) NewtGingrich (general) PaulR. Gross(general) J.Allan Hobson (psycholory) foshuaLederberg (general) BarbaraK. Lewalski (literarycriticism)

Charlesf. Lumsden (general) MyraA. Mayrnan (thearts) MichaelB. McElroy (atmospheric physics) PeterJ. Mclntyre (evolution) MatthewS.Meselson (molecularbiology) Harold|. Morowitz (complexitytheory) William R. Page(general) RobertPlomin (psychology) William E. Rees (ecology) AngelicaZ.Rudenstine (artshistory) LoyalRue(general) MichaelRuse(general) SueSavage-Rumbaugh (primatology) S.f. Singer (molecularbiology) famesM. Stone(general) Frank|. Sulloway (general) Martin L. Weitzman (economics) IreneK. Wilson (poetry,theolory) Arthur P.Wolf (anthropologS,')

Acknowledgments

3s5

Finally, as I have for all my booksand articles back to 1966, I acknowledge with pleasure the meticulous and invaluable work of Kathleen M. Horton in bibliographic researchand preparation of the manuscript. I am also grateful to John Taylor Williams, agent and adviser,whosewise counsel helped make the project a reality, and to my editor at Knopf, Carol Brown faneway,for her important moral support and help in steering past at least some of the more dangerousreefs unavoidable in such a synthesis.

INDEX

Abate,Tom, 35r adaptation,seaevolution Adler, Mortimer, r3z aesthetics, seearts;facial beauty;optimum complexity Agassiz, Louis,4o t69, $54, 74o-4r aggression, agriculture,3o9-rr Ahearne,JohnF., 35r Alcock, fohn, 33o alcoholism,r54 Alexander,fuchardD., 347 Alling, Abigail, 35o altruism, 163,:f7, 277, 7483 Amaringo,Pablo,79, 89-9o, 772 AmericanAnthropologicalAssociation, 2oz,AL American HumanistAssociation,286 American PhilosophicalSociety,4z anaconda,T8 anthropicprinciple, 35 anthropology,z oo-2, 2o7,)41-+ ants,74-77,732 Apollo,47,z7z Applebaum,Herbert, 34: aquaculture,3rr aquifers,3ro Aquinas,St. Thomas,z6r

archetlpes, in creative afts, 24)-4, 746-47 architecfure, 239-4r, 45 Argyros,Alexander1., 745 Aristotle,z7r A"rmstrong,Karen,348 A,rmstrong,Louis, "1" Arnhardt,Larry,747 Arrow,Kenneth J., 35r artificial emotion (AE), tf+ artificial intelligence(N), 4z-5, 335 arts,the, 13,79, tz7-28, zzg-rg, 293, 744-7; adaptive advantage,245-46, 346;relation to sociolory,zo3-4 ashology,58,248 astronomy,32,58 Augustineof Hippo, St.,z8r Aushalianaboriginals,346 Ausubel,fesseH., 35r autism,r54 autonomic nervoussystem,r22 Axelrod,Robert M., 348 aydhuasca,Tg-8o Aztecgods,88 Bacon,Francis, 9, z4-3o, 42,328-zg Baiema,Carl |., 35o Balch,StevenH.,328

358

lndex

Bali, culfure and fauna,zo6 brain, 8&9o, rc6-t9, r74, r79; seealso Balter,Michael, 337 colorvision;mind baptism(Christianpractice),248 brain imaging,rr8, rz8-9, ry6, 169,265 Baptists(Christiandenomination),6, brain sciences(cognitive 286 neuroscience),rc8-9, 46, 269,zgr, Barinaga,Marcia,333 )33;see^Isobrain;mind Barkow,feromeH., ;36.1.9;.58,W,3aF,WBrassai,z4o,345 bat echolocation-
Index Christianity, 354, 266-8 Christian Science,58 Churchill, Winston, 37 Churchland, PahiciaS., 334 Churchland, Paul M., 333 civilization,origin of, rfr-2,277-8, 738, )>r

Clark, Mary E., 33r Clausen,Christopher,336 climate change,3rr-r3 Coe, Kathryn,345 cognitiveneuroscience,seebrain Cohen,jack,333 Cohen,JoelE.,7o6,75o Coleman,James 5., zo7,742 color, skin, ryg,3j7 color vision, 5o,rr7, rz7-8, :6,4,q3-7, 339-40 color vocabularyry 5-9, 3tg-4o Commissionon the Humanities,zz9 communication,animal, 42-5; arts and science,v7-8; chemical,T4-7; elechoreceptive , 5r; olfactory,r7z; touch, r7z; seea/so color hearing; vision;facial expressions; language;paralanguage communion, religious,284 complexitytheory,96-ro4, 77V-3 computers,rcr,3r7, J33;seealso complexity theory Comte, Auguste,33 Condorcet,Marquis de, ry-zz,3z8 Conrad,foseph,235 seemind, consciousness, consewation,biological, 319-24 consilience(interlockingof causal explanationacrossdisciplines),&-r4 6o, ry6, 48j, 167,ry8, zo9j, zn:1, za-1, 235-46,258,zgr-5, 3254 constructivism,44 contractformation,186-7,)41,)48 Cooke,Breft, 27.6,74, Cosmides,Leda, $6-7, 776,378,74o, 34r, J42 cosmologies,z89r-9o Crandall,B. C.,33o-r creationscience(Creationism),58,4r, z16 creative arts,seearts, the creativity,63-4, 7o-r, zo7,z)2-3, 43-4, 42-7,}tr

3r9

Cretan labyrinth, 72-j, 94, 1tr Crick, Francis,333 crime, zzr Csuti,Blair,349 Culotta, Elizabeth, 337 culfural relativism,zor-z culture, r3, r4r-8, r8o, 336;equivalency, zor-z; origins, t6z-7,243; universals,16o-2,377-8;seealso gene+ulfure coevolution Cummings,Michael R., 337 Daedalus,T, 327 Damasio,Anto nio R., n4-5, 333-5 Damasio,Hanna,734 Dani (New Guinea people),175-6 Daphne,W,2)r,zj2 Darwin, Charles,4o, 82,z7r Davidson, Richad j., 773-4 Decafur, Stephen,r85 decision-making,neurobiologyof, nz4 deconstruction(literary theory),44, 29-4,3)o DeepBIue (computer),r33 deephistory r3, 328 Degler,Carl N., 34o--4r deism,9-6 de Man, Pui,z37 Democritus, 54,r4o, 16 Dennett,Daniel C., :r,o,1A,)35 depression,clinical, r59 Derrida,]acques,44-j,2tt, 3to Descartes,Ren6, 3o-r,42, ro5, ro8, 329 determinism:genetic, t49-59, 84 zo5, 3oz-3;mental, rz9-3r Diamond, fared, 35r Dillon, Wilton S.,34o Dis,z3r Dissanayake, Ellen, 276,257,)45, A6 DNA (deoryribonucleic acid), 54,65, 95,99,t4o, r74,292,299,J}r Dolan,R. f.,337 dominance b ehavior, 287-4, 749 Dostoyevsky,Fyodor, 265 dreams,8r4,37z drugs,79-8o; saea/so neurohansmitters dualism:mind-body, ro8; in concept formahon,t6T Durham,William H., 196,1;,S,1;'8, Ar

300

Index

Durkheim, 6mile, zoo, zo1',2o4 Dusun (Borneopeople),66-7,339 Dutch aggressiongene,169,]39 dyadicinstinct, t67, 11.g dyslexia,168,g9 Dyson,Freemanl.,]3r Earth Summit,Rio de Janeiro,jr7, 35r Ebstein,Richard P.,339 ecologicalfootprint, 3o8,35r ecology,gz3, I 5, ::23,)07-24, 350-2 economic growth, 3r8 economrcs,212-24,3r7-rg, 343,j52 ecosystems, 92-3 ecstasy,religious, z8z,2844, 149 Eddington, Arthur 5., 7, 327 Edel,Abraham,347 Edelman,GeraldM., 333 Eden, z3r-z edgeofchaos, theory,g7-8 education,r3 Eggert,fames,352 Egpt, empire,3r4;incest,r93 Ehrlich, Paul R.,35o Eibl-Eibesfeldt,Irendus,L73, zj7, )11g, )'t> Einstein,Albert, 5, A4, 62, rc6, 288, 127,729,31r Eisenberg,fohn F., 34o Ekman, Paul,65-6, 771 electroencephalograms, 16,9, z4t--2, 250 electromagnetic spechum, 5o-.1 electroreception,fish, 5r,rz7 elephants,r8o Ellis, Henry 328 Ellis, Lee, zo3 Emerson,Ralph Waldo, 4o Emlen, StephenT., zrr^rz,341' emotion, rzz-6 empathy,276,349 empiricism, ethical,z6o-74 Engelhardt, H. Tiistram, |r., 347 Enlightenment, 8, 15-48,66, 44, z7o, 287,729 environment: current stafus,3o)-4, 35o-z; interactionwith genes, r4g-r1,,2oS,3o3-24;technological maintenance,SrT

enzymes,9r, roo, j32 epic, religiousvs.evolutionary z89jo epigeneticrules(hereditaryregularities in development,including mental), r63jg,zro,11'8,34o; in the arts, z7z-7,z4g-53 defined,163;in ethicsand religion,269-7o,278, zSvz episodicmemory,146 epistasis,genetic,169 epistemology, zo7, z8z,z9z-3 ethics,36,4r, z6o-8o, 347-9 ethnicity, rgg-zoo, 3r+r5 eugenlcs,zoo,)o2-3 evolution:human, rc6-7, 1454, r8z, 245-9,2gr-2,295-jo3, j37, ]'o; naturalselection,57,84-5, ro5-6, rr2, 133-4,t37-4r, 179-82,zt9-ry, zzz-3, 2454, 265, 277, zSvz evolutionarybiolog4 52,zgt evolutionaryepic, z89jo evolutionarypsychology,seesociobiol'og exemptionalism(environmentalethic), 30.4 exogamy,r8g explanation, scientific, 7z-ro4 exploratory instinct, 253-4 extinction,species,1.2o-rt352 exhasensory perception(ESP),rz9, 2.48 facial expressio ns, :64-5, t7z-3 facial beauty,z5r-7, 346 Fackelmann,KathyA., ff S Falconer,DouglasS., 337 fallacies:affirming the consequent,95; nafuralistic,273 family theory zn-\z, ]4J Farber,Pat:,1L.,747 Farrington,Benjamin, 328 Faust,295 FederalReserveBoard,zr5 Feldman,Mark W., 335 feminism,234 Fernald,Anne, 136 Fetzer,famesH., 344 Fischman,|oshua,336 fisheries,global,3rr Fiske,DonaldW.,33o,l+ Flood, Josephine, j46-7

lndex folk psychology(untestedby science), 2OO,224-7

footprint, ecological,3o8,35r forestmanagement,ro Foucault,Michel, 4G7, 33o Fox,Robin, 237,j4r,745, y6 Frazer,famesG., r94 Freedman,Daniel G., 338 Freemasonryz8o free will, r3o-z Freud, Sigmund, 47,8r-2, 8r, tgi.-+, 2@

Friedrich, RobertW., 342 Frith, Chris and Uta, 339 Frye,Northrop,347 fundamentalism,Muslim, zoo GABA (neurotransmitter),156 Gage,John, 339 Gage,PhineasP.,rcg-rc, jA Galileo Galilei, 35 gapanalysis,293,349 Gardner,Howard,3zg Gaukroger,Stephen,329 Geertz,Clifford,34z Gell-Mann, Murray,3Sz genderdifferences,genetic,t7o-r, t84, 2)4,340 gene-culturecoevolution(linkageof geneticand cultural evolution), r18-4o, 17v8z, 237-+, 278-1,,Bs genes,seedeterminism:genetic;genetgene therapy, 3or-z geneticdeterminism,seedeterminism: genetic geneticdisease,157-8,r88j, 299-3or geneticleash,r7r genetics,98j, 156-6o,167-7r,z8z, 2g5-3o3ipopulation genetics, zr6-tg; seealsoDNA; gene-culhrre coevolution;heritability; interaction genius,z1z genotype-environment correlation, r53 Gergen,Kenneth f.,45-6, 33,o Gibbons,Ann, 337 God, 34-6, z16,z7t, z6o-7t,284-8 gods,88, z3r, z4t,286 Goethe,JohannWolfgangvon, 39,295, J29

76r

Gogarten,f. Peter,349 Goldschmidt, Walte4 736, 742 Goleman,Daniel,334 Gombrich,ErnstH.,346 Goodell, Edward,SzS Goodstein,David L., 728,329 Gowdy,john M., 35o 265 Grand Inquisitor, Dostoyevsky's, Greece,ancient, myIh, Tz-7, z7t; philosophy, 77, 66, ry9; religpon, 286 Green, Donald P.,343 Greenland,D. I., f lt Gribben, fohn, 33o Gross,David f., 33o Grossman,Marcel, 5 Groth, Janet,344 Gustafson,famesM., 347 Guterl, Fred, 135 Gutmann, Amy, 352 habit, biological basisof, rr7 habitat selection,3o4 Hallpike, ChristopherRobeft,zz6, 343 hallucination, T&8o Hamilton, William D., 34o Hanun6o (Philippine lan gnage),ry7 Hardy-Weinbergprinciple, :16-18 Hamer, Michael |., 332 Harris, Marvin, :42 Haught, |ohn F., 347 Hawken,Paul, 352 Hawking,Stephen,288 headshape,evolution of,297 hearing,164 hereditarianism,r54-5 heredity,seegenetics;gene-culture coevolution heritability, r5r-5, 317 hermeneutics,z6-1, W-l Herodotus,286 Hennstein, Richard )., r5z heuristics,225-7,347 Hilbert, David,48 Hirshleifer,fack, zzz historicalmaterialism,4r history rr, r5o, r8o, z8o,z9z,Jr4, )25,

)45

Hobson,). Allan,8z, t9,373 Holdren,fohn P.,35o holism, seesynthesis Hollander, fohn, 345

36,

Index

Holldobler, Beft,73z Holt, Luther 8.,338 Holton,Gerald,4, 327,7zg,i3r Hooke, Robert, 265,348 Hu, Frederick, 3l8,352 human epic, z89jo Human Genome Proiect,299 humanism,movement, 37,286 humanities,rz human nature, ry8j6, 46, 48, 34o-r; defined. rz8 Human RelationsArea Files, 16o Hrme,David,,z7r,275 huntergatherers,16r-2, r8z,zz6, 254-8, 34G7 Hutcheson,Francis,275 hyperreligiosity,z8z,z854 hlpothesisformation, 64-5 Icarus,7,327 imitation, infant, 45, 336 incestavoidanceand taboos,188-96, 2rr-r2,34r incomplete penetrance,in heredity, r59 induction, FrancisBacon on,28, 328-9 information, in artsand science,compared,nT-8; saealso commumcation inspiration,seecreativity insulin,gr intelligence, optimum for science,63 interaction,of genesand environment,

4v55

Ionian Enchantrnent (preoccupation with unification of knowledge),4-7, 327 Islam,earlyconquesbof,267 Israelikibbutzim, r9r |ackson,Frank, rz7 fames,William,64 fansson,AnnMari, 35r Japanesecalligraphy, z4z, z5r, 746 fduregui,los€4.,3y pzz,242 fefferson,Thomas, z6r |esus,8o, r3o firari, Carolyn G., 338 livarc,78j,77z

|ohnson,Mark H.,338 fohnson,Paul, 348 f udaism, origins, 267,z8o, 286-7 fung, Carl,85 Kac,Mark,6+ Kagan,Donald,34r Kahneman, Daniel, zz5-7, 343 Kalaharihuntergatherers,t66, 754-8,

l+6-t

Kant, Immanuel, zt, ro5,z7r-z IGnzi (bonobo),42-3 Kareiva,PeterM., 332 Karni, Avi, 332 Kasparov,Gary,93 Kauffman,StuartA., 9ffi , Bt Kaufmann,Walter, 33r Kay,Paul,ry5-7 Keats,fohn, r3z Keeley,LaurenceH., 34r Kekule von Shadonitz,Friedrich August,88 Kellert, StephenR., 352 kibbutzim, Israeli,rgr Kidder, Alfred V., 162,738 kin selection,:E3,74o King, Martin Luther, Jr.,z6r Kitcher, Philip, 343 Kluckhohn, Cly de, 42, 96 knowledge,natureo{ 65-7r Koch, Walter,236,345 Koenig,Olivier, 333 Konner, Melvin f., 339 Kosslyn,StephenM., 333 Kroeber,Alfred, W, B6 lKung (fuAMasi),IGlahari Desert,166, 254-8,746*7 labyrinth, of knowledge,7z-4 [,aland, Kevin N., 335 l,amartine,Bruce, 55 Langton,Christopher,96 language,4V-5, 161,, ryS-7, B6 Larson,Edwardf., 348 Lavoisier,Antoine, 55 Leary Timothy,8o Lee, RichardB.,255 Leeuwenhoek,Anton van, 55 Leibniz, Gottfried, 3z Lespinasse, fulie de, r9

,T-

lndex l,eucippus,54 LeVay,Simon,334 Lfvi-Shauss,Claude, 167 Lewis,David, 34g Leys,Simon,D9,]35 liberal arts,r3, 295 Liebenberg,Lods, 254{, 346 light, visible, 50 Lincoln, Abraham,z6r Linnaeus,Carolus,4 Locke,fohn, 264 265,748 tocke, fohn L., 336 logical positivism, 67-7r, 33r Loomis,WilliamF., ror Lopreato,f oseph,zo3,342 love:biological origin, r84;role in religion,266 Lucretius,z8r Lumsden,Charlesf ., 48, 276,y5-4o Luna, Luis Eduardo,332 Lyashko,V. N., 35o Lyman, RichardW., 344 Lyons,|ohn,ry7,19 Mackay,Trudy F.C., yl magic,z48-9 Malthus, Thomas,zr3 Marks,|onathan, 342 Marlowe,Christopher,295 Marshack,Alex ander,746 Marshall,Alfred, zr4 Martin, Alex, 335 Marx, Karl, 2oo,2o4 Maxism-l,eninism,267 mathematics:basicnature,6&-9, ro3-4, 33o,345;comParisonwith music,239;role in science,52,zr4 mating shategy,r84 Maxwell, |amesClerk, 93 May, RobertM., 349 Mayas,3r4 Map, Emst,4 McDaniel,Carl N.,35o Mead, Margaret,zoo meaning,neurobiologrof, rz54, 46 Meltzoff, Andrew N., 336 memory nt-2, 146-9,337;unib,

44

meme,r48,337 Meselson,Matthew S., 65, 33r

Z6l

Mesopotamia,3r4 metapattems,in afi, 2.4o,745 metaphor,q7, 2jg-4o, 13o,)46 microscopy,historyof, 55 Miles, fack, 348 Mill, fohn Stuart,47 Milner, fohn, 346 Milton, John,z3r mimicry, in human infants,r45 mind, nature of, 66-74 ro1-t1, 231,, 334;FrancisBaconon, u&9; dreaming, 8r-6; drug effects,79-8o mind script, rz8-29 "minor marriages,"Taiwan, r9o Minsky, Marvin L., r34 modernism,in the arts,4r*3, 329 Mol, Hans|., 348 molecular bioloSy,,#o, 65, 74, 9r-z Mollon, fohn, 339 Mondrian, Piet, z4t, z5r,346 monkeys,86, 89, 283 Monod, |acques, r4o, 736 mood, 83,rz6, r59 Moore, G. E., z7z Moore,M. Keith,336 Moro refex, 165,98 Morowitz,Harold,33z Morris, Christopher,335 Morton, fohn, 338 Moses,287 y6 mother-infantbonding, :165, Moynihan, Daniel Pahick,34r multiculturalism, 44, zor-2 multiple competinghypotheses,64-5 Mundkur, B alaii, 86, 772 Murdock, GeorgeP., t6,c,777-8 Murray, Charles,r5z music, in ceremony,248 music, qualities of, 49, V45 musical ability, r5z-3, z3z,144 mutations,r57-6o, 188-9 mysticalexperience,251-4,2844 m1rth,7z-3, z7t-2, z8r, 7zg Nabokov,Madimir, "1' Nakata,Yujiro, 346 nanotechnology,55,ti'o-r narrative,sacred,z8gjo National Academyof Sciences,U.S.A.,

+

*+

Index

natural history zo5-7 naturalism(environmentalethic),3o4 naturalisticfall acy,z7z natural resources,global, 3o9-rr natural sciences,z8-g, 49-7t, zo8-g, 48-9,265,29r-5 naturafscientists,qualities oI, 4t-2, 57-8,6z-7, 67-7r, r37, zrz,zz7,269. 287-8,33r Nazism,267 Needham, Joseph,31,729 Nelson,Mark, 35o neurobiology,85, t3^t5, 346;seealso brain;mind neurotransmitters,79-8o, 8z-5, ry6, 169,)37 New Agephilosophy,46,285 New Critics, in literature, 235 New Guinea,culture,t66,ry5-6 Newman, John Henry Cardinal,,z6z Ner.+'ton,lsaac, 3r-2, 39 Niehans,Jtirg,zr3-4 Nielsen,Frangois,335 Nisbet, Robert,zoj-4, j+ Nitecki, Matthew and Doris V., 347 NK model, evolution, 97-8 Nobel Prize, 2r2-zr], 24o, z5o norm ofreaction, in genetics,149-5r, 337 Novak,Gordon S.,Ir., llS novelty-seekinggene,169,37g Nowack,Martin A., 348 Nozick, Robert,274 nurfurism, ry4*5,2o4 obesity,r5o Occam'sruzot,57 odor,human,r7z OGOD (one gene,one disease)principle, 158-9 ophidiophobia(fearofsnakes),86 optimum complexity,in the arts,z5o-r, 346 Oster,GeorgeF.,34o Ouroboros,88 Ovid,t47 painting, Tg-8o Paradis, famesG., 347 (nonverbalcommunicaparalanguage tion), r7z-3,319

parentalinvestment,183-4 Pascal,Blaise,z68j Pascal's wager,268-9 PAT (environmentalformula),3o8,35o Patterson, DavidA., 333 Peacock,James,34r Peacocke,Arthur R., 348 Peltonen,Leena,337 Penfield,Wilder, rrr Penrose,Roger,334 Perrett,D. I., 346 personality,heredityof, t6849; seealso heritability;mood PET (positronemissiontomography) imaging,rr8, r56 Peterson,Ivars,333 Petroski,Henry,337 phenylketonuria, 17o, 3oo-r pheromones,human,r7z philosophy,generalqualitiesof, rr-rz, ,1o5,227-6, ^ - - - - a 294, 327, 34)-4 phobias, S6 physical sciences,7z-4 physics, 5j-4, Sg,74-5, g3-4, 239-4o,

345;unificationin, 5,288 Picasso,Pablo,z4o, 345 Pico della Mirandola, Giovanni,4r, 329 Pinker,Steven,,t,334 Planck,Max, i'r, 57, t3r Plomin, Robert,337,349 poetry,spiritual effectof, z7r polygenes,169 Pool,RobertE.,374,Ao Pope,Alexander,3:.,2r4 population genetics,z16-19,z8z, 296-7o7,75o-t. population growth,z9&9, 3o&-ro, 714-17 positivism,67-7r Posner,Michael L, 333 postmodernism,4;.-8,21;.-5,729,)44 Potter,Van Rensselaer, 347 Power,Thomas Michael, 352 pragmatism,4t,67,265 prediction, scientific,74 preparedlearning, 86;seealsoepigenetic rules primitivethought,n6, 254-8,3$, Aq Prisoner'sDilemma, 275-6 Progress,asconcePt,1o7

Index Prometheanknowledge,37 propitiation,283 Proserpine,z3r proteins, gr-2, gg-ro2, 2g7,372 psychoanalysis, 276;seealsodreams; Freud,Sigmund psychology,58,85;Baconon, z&-9; in the arts,236;in economics, zr9-27 quantumelechodynamics (Q.E.D.), 57-4,57,730 Qu€telet Adolphe, 33 Quetzalcoatl,88 Quinlan, KarenAnn, Do-rr,3j4-5 race,r59 racism,37,zoo-r Raichle,MarcusE., 333 rain forest,gz-j, fzo Ram6ny Cajal,Santiago, rr4,335 RatchetofProgress, 295,316 rationalchoice theory,zz4-7, 743 Rawls,fohn, z7z-3 Reaka-Kudla,Marjorie L., 349 reductionism,B, 5y6o,74, gL-3,2o3, z3o,292 Rees,William E.,35r refexes,rzz-3 Regnier,Fred,75 reification(furning conceptsinto imaginedobjects);r6G7, 379 ReignofTerror, France,16 relativism,cultural, zoo-z religion,z6o-r, 28o-9o,347j; aruthor's,6, 27r,348;ofscientists, 6z religiousecstasy,z8z-3, 2844, 349 revelation,divine, 263,269-7o Reynolds,Vernon, 348 Ricardo,David, zr3 Richerson,Peter1., 135 Ridley,Matt,347 Rio Conference,on environment, 3r7-r8,3Sr ritual, 167,248,z8o-r ritualization,r73 r-K continuum, in evolutionarybiology,223-4 Robespierre,Maximilien de, 16 Rogers,Adam, 35r Romanticism,37-40,47 ROMs (read-onlymemories),55,33r

^aJw>

Ronan,Colin A., 329 Rorty,Richard, 2o7,J43 Rosenberg, Alexander,rr-rz, 328,34,

3+,341

Rothstein,Edward, zfg, As Rousseau,/ean-/acques,16,38-9,44 Roux,Wilhelm, roz Ruse,Michael,344 Russell,Bertrand,45 Rwanda,34-15 Ryle,Gilbert,66 sacrednarrative,z8g-9o sacrifice,248,268,287 Samuelson,Paul, 57,zt4 SantaFe Institute,q6 Satan,z3r,295,)o7 satisficing,in rational choice,zz4 Saunders, DenisA., 35o Savage-Rumbaugh, E. Sue,4j, i,t6 scaling,space-time,+ 8gj4 zzz-23, 256,332 Schelling, Friedrich, 39 Schelling,Thomas?z2z schizophrenia, $4-8, 17 Schlaug,G.,344 Schlick, Moritz,67 Schorske,Carl E., 43,729 Scialabba, George,46, 33o science,seenaturalsciences; socialscienbes sciencefiction,293 scientists,seenafural scientists Scott,f. Michael, 349 Scully,Vincent, 24o-r, J4S Searle,JohnR.,334 sel{ neurobiologyo{ r3o-r self-assembled monolayers (SAMs),55-6 Seligman,Martin E. P.,318 semanticmemory 46 semrotlcs,lgg Sen,AmartyaK., zzz serpents,seesnakes Service,RobertF., 33r Shamos,Moris H., 328 Shapiro,lan,347 Shaw,GeorgeBernard,266 Shaw,R. Paul,34t Shepher,foseph,r9r Sheridan,Alan, 33o

366

Index

Sherrington,Charles, 728,729 Shweder,RichardA., 11.o,W-) Sigmund, Kail,749 Silberbauer, GeorgeB., 255 D.L.,ZZl Silbersweig, Simmel, Georg,zo4 Simon, Herbert 4., 7o, zz4, 73t S i n g e rS, .J . , m , 3 3 2 sleep,r8z-3 Smets,Gerda, zgo-r, 346 smile, rzz-3, t66.,g1.9 Smith,Adam,zr3,275 snakes, 7&9, 85-8, r38-9, 237,332 Snow,C. P., 43,ry6-7, 329 SocialDarwinism,2oo socialism,3T socialsciences,n, 4o, r97-228, 34r-4 sociobiology,r63j6, 34o;seealso gene-culturecoevolution sociology,zoz- 5, 2o7,7+ sorcery,248-9 Sovietempire, zoo space-timescale,seescaling,spacetime Spinoza,Baruch,287 Spires,ElizabelJ:.,r+-2, Z+6 spirit sticks,Australian,z8o Stahl,FranklinW.,65, 33r StandardSocial SciencesModel (SSSM),2c'4-5,222,7+ stafus,r7o Steiner,Ceorge,z7o, 344 Stephens,James,328 Stern,Curt, 337 Sternberg,Paul W., 333 Stevens,Anthony, 346 Stever,H. Guyford, 35r Stewart,lan,777 Stigler,Georgef., zzz Storey,Robert, 46, 1.45 Straus,Ernst, 35 stronginference,64-5 strucfuralism,r67 Stutz,Roger,55 subiectiveexperience,neurobiolory of, rz6-9 Sulloway,Frank |., r5o supernormalstimulus,z5z-3 Swedenborg,Emanuel, 8o Swinburne, Richard, 348

symbolism,46-7; seealsolanguage; mind Symbolists,in literature,234 synthesis,,g, 73-4, 9:-3, zgz,294 taboos,incest,r9z Tanner,RalphE. S.,348 taste,neurobiologicalaspectsof, 164-5 technology,and environment,3rGr8, 35r-2 Teotihuacdn,z4o Teresaof Avila, St., 285-6,349 termites,16o*r,r8o, 3,38 territorial instinct, $5-6, 267-8,34o-r Thailand,zq8 theism, 35-6, 264-7r, 287 theology,r)o,294 theory,fundamentalnature of,57-8 Theory of Everything(T.O.E.), in physics,287 Thompson,Dennis,35z Thoreau, Henry David,4o Tiger,Lionel,277 Tillich, Paul,287 Tilman, G. David, 3o6,75o Tlaloc (Aztecgod), 88, 248 Tocqueville,Alexisde, zo4 Toennies,FerdinandJ.,zo4 Tooby,John,r8G-7, 1;16,378,3+o,)+, )+ tool-making:animal, 144-5;human, r45 totems,z4g touch, communicationby, r7z transcendentalism:ethical,z6o-74; New England, 39-4o tribalism, 267-8,z77, z8o-r, 298, )r4-r5 higradal system,in Freemasonryz8o Trivers,RobertL., 34o truth, criteria of, 65-7t Tulving, Endel, 146,337 Turgot,Anne Robertfacques,zr Turing, Alan, r3z Turing test,r3,2,r35 Turkmen protein, evolution of,297 Turner, Frederick,275,216,344,Aj Turner, R. Kerry 352 Tversky,Amos, nS-27, 347 Two.Cultures(literary scientific), 4)-4, rj6-7, 23o, 329

Index ufology,58 universals,cultural, 16o-z Urbach,Peter,328 van den Berghe,Piene L., zo3,34z variableexpressivi$,heredity,r59 Veblen,Thorstein,zr4 Vienna Circle, 67-7o v6ron, color, 50 Vogler,Christopher, 329,346 volitional evolution, 299 Volk,Tyler,z4o,745 Waal,Fransde, 41, 376,34g Wackernagel,Mathis, 35r Waddington,Conrad H., 148 Wallace,Anthony F. C., 348 Wallace,Walter L., zo3,342 war, 67, t854, zoo,zg8, T4-r1.,,1,4L watersupplies,3ro-u Weber, Max, zo4 Weinberg,Steven,287 Weiss,H., 35r Weld,CharlesRichard,348 Welon,2.,35o Westermarck,EdwardA., 189-96 Westermarckefie ct, r8gj6, 277,74t

z6z

Whewell,William,S Whitehead, AlftedNorth,6r,235 Whitesides, GeorgeM., 5r4,17r Wightman,Mark,55 Wigner,EugeneP.,53,3,3o Williams,GeorgeC., 347 Williams,ThomasRhp, 339 Wilson,Edmund(literarycritic), 2)4-r, )44 Wilson,EdwardO.,publicationreferences,332,735-40,743-4,147-5o, 3r2 Witham,I^tty,l+8 Wolf,ArthurP.,ryo-5,74r Wollstonecraft, Mary 268,348 wolves, socialbehavior, 283 Wong,Yuwa,34r Wordswo*h, William,38 WorldEconomicForum,jr8 WorldWarII.6z Worldwatch Institute,35r Wrangham, RichardW., 336 Wright, Robert,347 xenophobia,27fi Yukawa,Hideki, z3g-4o,145

Grateful acknowledgmentis made to the followingfor permispublishedmaterial: sionto reprintpreviously GEO Extra Nr. r: "Quo Vadis,Homo Sapiens"by EdwardO. Wilson, reprinted courtesyof GEO Extra Nr. r, Hamburg, Germany. Excerptshom Biophilia;The Diversity HamardIJ niversityPress: Fire by Edof Lrfe; Genes,Mind, and Culture; andPromethean ward O. Wilson, reprintedcourtesyof HarvardUniversityPress. The NewYorkTimesCompany:Excerptfrom "Is HumanitySuicidal?" by Edward O. Wilson (The New YorkTimesMagazine, May zo,1993),copyright@ 1993by The New YorkTimesCompany,reprintedcourtesyof The New YorkTimesCompany. David Philip Publishers(Pty) Ltd.: Excerpts from The Art of Tracking:The Origin of Scienceby louis Liebenberg.Reprinted (Pty)Ltd., Claremont, by permissionof David Philip.,Publishers \ SouthAfrica. Time Intemational:Excerpbfrom "l,egionsof the Doomed"by Edward O. Wilson (Time Intemational, October 7o, rg95). Adaptedby permissionaf Timelntemational. Viking Penguia and Elizabeth Spires:Excerpt from "Falling Away"from Annonciadeby ElizabethSpires,copyright@ 1985, 1986,1987,1988,1989by ElizabethSpires.Reprintedby permission of Viking Penguin,a divisionof PenguinBooksUSA Inc., and of ElizabethSpires.