On the Relation Between Psychological and Physical Concepts

READINGS IN

PHILOSOPHICAL AI{ALYSIS SE LI 1CTED

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On the Reletion Betu'een Psychologicaland

PhysicalConcepts* MORTTZ SCHLICK

I in ettempts co frcc the Cartesian lacking has not been philosophy Recent

problemof the relationbetu'eennrind and body frorn its mctaphysical ical subsub. obscurities,by refusingto poseit in terrnsof mentaland physical the harntlcss the in gcnwith tne wltn harntlcss natllllcssquestlon to horv. norvrIn instead.with lnstead, scnstances: besinnins. euesrionaslo beginning, beglnnng,instead, stances; stances; concepts. That tlris eral,u'e havecomeby our physicalandpsychological is acruallythe correctrvry to approachthe solutionof thc problcm,I havc no doubr. Indeed,I am convinced tlrat the problcrn will alrcady bc solvcd rhe momcnt s'e becorne conrpletely clear as to the rulcs in eccordance wich rvhich we employ thc rvords "mental" and "physical." For wc shall then grasp the proper mcening of all physicdl and psychologicalpropositions, and in doing so *'ill know in rvhat relation thc propositions of physics stend to tlrose of psychology. When Descartcssought to dcfinc his "corporcal substance"bv spccifying the anribute "extensiot' as its characteristic mark, hc took thc fimt srep in a direction s'hich must be follos,ed to thc cnd beforc onc can hope to form a clear idca of the propertieswhich bclong to all "physicirl" concepts, ancl to thesc alone. "Dxtensio" rcfers, of coursc, to sptrtigl cxtcnsion; and it is indeed possiblcconfidcntly to assertthat an analvsis yiclds rvithout furthcr ado a dcfinidon of the concept of spatialercrension of the concept"phvsical." The problern,hon ev€r, is by no mcansso simple that it sufficcsto sav "whatever is spadallv extended is physical," for thcre arc rvords which rnoke senseu'hen conrb,incdn'ith thc prcdicatc "spatiallv cxtcndcd," and r*'hich neverthelessrefer to "mcntal" statcs;such words, for exanrple,as t'tactual scrlsation,ttt'pain,t' etc, Consequently,the diftcr"visual irnage,t' cnce \\-e are scckingcan bc found along the ntrcvc lincs only if thc u'ord anclphvsicnl usrlgcs. "cxtcntlcrl" hasclificrcrrtnrconingsin its ps.r'chological Is this rhc cnsci l)o I hrrvcthe snutcthirrgin urind.or sontcrltingtlillcr'cnt. rvhcn Isrrv of a plrin tlrirt it sprcirdsot'cr il cct't,tirlil'cl. rls('rlrrl):rt'('(l i t p l rl si t' :rlol ri ct' t,fot' t' x Io rr lr c r rI as c r ilr cn t' c ft:ti ns p :tti i rlc x tc rt:;i t.t' to ' l rrrrsl rtr.rl l rr' \1 ', S- r n' l tl.tr lir tr ,l r r itlr tln. l.ir r ,l tu t r tr t,,.i ,r tr of l l tr t l r . r ' . l r t.r..,,l A 'ri ti r,',/,'Sr r r l/,,:,,' I lr c,qls,i11.1l r r lr lr r tlr lr r ltr',1 i r t r ,115-

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DATA, REALITY, AND qU! M!ND-B0DY PRoBLEM 39+ ample my hand? Is the visual imag€ of the moon "cxrcndcd" in the samc senseas the moon itselfl Do my visual imprcssionson looking at a book have extensionin the samesenseasthe tactual imprcssionsI obrain by holding it in my handi The answeringof thesequestionsis the first step in the processof clari fying our concepts,nay the second,-for rhe lirsr and more difficult stcp is to ask tlresequestionsat all. This step \r'ns not taken by Descartesnor by thoseu'ho follow him,-the possibilitynot cvcn occurring to them that the word "etctefllio" is usedin more than one sense.lt would therefore not be correct to describetheir use of this rlord bv saying that rhev took it to have rhe sdntemeaning in significrntl.v different cases.'fhey didn't evcn sce that there u'ere differcnt cases,Belkeley alone u'as a famo[s exception. He posed rhe third of our three questions.The 6rst trvo couldn't be raisedin his system,since a by no meansinconsiderablepart of his philosophyconsistccl€.\acdyin a proof thar thesequestionsdo not exist, For hirn therc is no otlrcr kind of extensionthan that rvhich can of sight and touch; indeed. in Berke"bc nttriburcclto thc rcprcscntariorls lcy's philosophy it is ilrcady a uristakeio speakof theseas "represenratiurtg" sirrccthcre is notlring rrhiclr is copicd by them and is their original. Kant, u'ho plrikrsoplriz.cd so rrruch latcr than Berkeley, believed he had nothing to lclrn frorrr hirrr, nrrd didn't succeedin raising our questions. He invarinbly spcaks,ns did L)cscartes before hirn, of extension,of Space, and omits anv invcstigationas to s'hether it may not be necessaryto discinguishbcni'een sevEralspice-concepts;first, l,ecrn'een the phyiical and the psychological,and under the latter, benreen visual-space,tactualspace,etc. This ncglect had unfortunate consequences for Kant's phiklsophy of geometry,and, through this, for his s,r'stem asa whole, Physical sPsce,the spnceof nature,is for him alsopsychologicalspace,sincenature is for him "rnere appearance,"that is, mere "idea," and this is a psychoIogical term. It is possiblcto regard Kant's distinction between "outer" and "inncr" senseas an attempt to drarv a boundary betn'een the physical and thc mental. His doctrine that Space,the form of intuition for outcr scrrsc,is lacking in the caseof inner senseis indeed reniniscent of Dcscartcs,rrs wcll as a forerunner of recent a$emDts to characterizethe nrcntnl rrs sirrrply ttrc non-spatial.It is said that even therc tlre nrcntal hns to rlo uitlr tlrc sprtill (in idcasnnd pcrccption),it is itsclf notr-spiltiirl.'l'lrc irlcrr of rt rrrl tt'i:rrglcis itsclf ncitlrcr rctl nor trirutgul,rr,nor is thc pcrcclttiorr o l ' :rr rt ' r t t . nt lt . tolr l icc ti ts c l f c x rc rtrl c rl . 'Ilr is : r ' . ' , t ' r t iororr r ' (' si l s l rp p c l rl l rrrt'o cf p l :rrrs i l ri l i tl ' totl tc l ' :rt' ttl r:rttl rt. tto tr ls " 1x r c r ' pt ion " :rttrl" i .l c l t" :trr' ;rtrrl ' i !l rro rrs. l !1' l l tcrtr orrt' (' ;ul t' (' l (' t' t if lt c t' f r r

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k' :ttc tnrrisc,l tlre r;rr t ' , , t i, ritr r\ t o t lr c ir r s t ili: r lllir l r r l ll r i s r l i r t i r t c t i o n l r r 't r r l t 'r r (' rrn t('rtl;rrrrl:rt't, u nr l lir r r it ( , ur s c luc st o y r ir r t int l o u t t h i l t s u f c l y i l l i r s l ocr'ru'rcrl ro us t():\lx'Jli {,f nrl nct ()f pcr('cl)tion-nntl, lirtcr, of irrr;rgirrg ' r'nlv irftcr \re h:rtl g:rincd thc knoslctlgc that thc occurrcncc of "contclrts" is sr,nlcho\r, dc;lcndcnt on proccsscs in thc scnsc orgurs, arrd,

frrrtlrcnrrorctlmt thcsc proccsscsarc physical.) One can certairily not say of thc contcnts of pcrception-at least in thc casesof sight and touch -thrt thcv are "non+patial"; rather they are beyond doubt cxtcnded.Indcctl it is from them that rve first derive this concept, Neverthclcsstrve do not meenthe sanreby "extension"in psychological :rnd ph'r'sic:rlcontexts.In order to make the difference clear it is bcst to cxanrineexactly thosecaseswherc it is nrostdiffcult to distinguishpsychokrgical from phvsical space.We askcd above if, for exanrplc.a pain is crtcnded in the samesens€as is a physical obiect, sey, my hand. llut what about the caservherc the pains arc in mv hand itsclf, rvhcrc my rvholc hand aches?Do u'e not have here a mental datum the spadalcxtcnsionof which is identical rvith that of the phvsical object u'hich is "my hand"l The ansrver is, "absolutely not!" Pain has its ou'n space iust as visunl scrtsationshave theirs and as do serx;ationsof touch. Thc fact that scvcral sensationsof pain can occur sirmtltaneously is sufficient ro require us to spcak of a "pain-space."Every arrangementof simultaneousitcms is a sidc-by+ide (as opposedto e sequcncc)end it is customary to cell such facts "spatial." It is experiencervhich first brings about the coiirdinatiorr of the sevcrnlspccesof vizual and tactual sensations, feclingnof pain, etc. This can bc rrrafeto standout nlost clearlv by conceivingof a man who livesin comptetciarkness anclcomplete abienie of motioi. Hc rvould bc acquainteds'ith neitlrcr visual nor tactual sensations,but he could very rvell have "pain thr
396

DAT.\

REALTTY, AND THE I\flND-BODY

PROBLEM

akin to the kineesthcticscnsation cendlestickmove,perceivede sensarion the movementof his hand,suchcxpcricnce which normatlyaccompanies could leadhim to coiirdinatetfie spaceof the "handache"with that of thc candlestick(and if, for example,the candlesrickhad five branches,its extensionwould correspondto that of the 6ve 6ngers).Hc could thus meaningfullysay, "I havea prin in the candlcstick."(Similar and as yct hayebeenadvancedby Ludwig Wiagenstein unpublishedconsiderations in anotherconnection.)Thus, it is possibleto conceiveof expcricnccs n'hich would result in the localizationof the samehandachesin quitc It follou'sthat mentalpain-space diferent physicalspaces. and physical spaceare entirely differentthings, The difierenceis obviousin extrcmecases.Let us comparc,rcferring back to our secondexample,the extcnsionof the moon with that of the visualimageof themoon.J'hediameterof the moon,a physicalmagnitudc, can be givenin milcs;thc dilrnetcr of the vizualimage,on thc other hand, is not evenI "siz.e,"(Necdlessto sny,thc visualimagcmust not be confuscdwith the rctinal inrage,rvhich hasphysicalmagnitudc,and, conscquently,a dirmetcr s'hich cln be specifiedin units of mcasurc.)Thc extensityof the visualirrmgeis frequentlyassigned an angularmcasure. The latter is, indeetl,a phvsicrlmagnitude, but it doesnot makeonc of thevisualinngeitsclf.Rather,sucha mcthodof assigning a mcasure canbc justifiedonlv by meausof a definitionalco
n ln rvhat, then, doesthe differenceconsistwhich is to lead us to a definition of the "physical"? Herc we shall apply thc method which seemsto me the sole mcrlrod of ule philosophy:lVe shdl turn our ett€ntionto the rvay in rvhich prolxr sitions about physical objects are aerifed. That rvhich is conrrrronto nll thc nrcthodsby which such propositionsare verificd, nrust thcrr bc tlr:rt rvlrich is clraractcristicof the phvsical. All propositions:rrc tcstc(l \rirlr ncspcctto thcir truth or falsity bv thc perfornrnnceof t'crtnin opcr:rtions, nrtrl to tTivcatr accolrntof tlre meaningof tlte prolx'sitiortscorrsislsirr spcciflirrlTtlrcscr4rcrarirrns. Of s'hnt sott, thcrt,arc thcscopcrrrlionsirr tlrc c:tscof propositionsin rvhiclrplr|sic.rltcrnrsrl'rl)cnr?In orlrcr rlor',|s,irr rult;trrlrx'sllrt' 1tt'occss of rlctcrtttinitrgplrysit'rlpr,rllertics<'orrsist? f t lr r s ir ' : rlrf r opt rl i t' s' .u ' t'tttt.ttu t,tl ,l ' p r' o l l (' l ' ti ( ' hc-V s.' l l rl c rl cl i l tcrll rv tl rc

PSYCHOLOGICAL AND PHYSICAL CONCEPTS

397

methodsof measurerncnt(Bridgman'sbook, The Logic af Modent Physics,carricsthisthoughtthroughfor phvsicsasa whole.) It will suffice of thesemethodsto the scientificmethodsof if wc fimit our discussion Thcre are,of coursc,pre-scientificu'avs of noting the prescnce phrvsics. of physicalpropertieswhich continuero play a dominatingrdle in everyday life, but there is no dilfercnccin principlc bctn'ccnthe procedures of cvcrydav lifc and thoseof rescarch,Sincc,horvcvcr,thc methodsof scicnccstandout moreclearly,wc shalllimit oursclvcsto these.In cvcryof one day lifc, also,physicalconccptsariseonly u'hcrc nreasurcmcnts kind or anothcrhavctakenplace(evcnif by thc thoroughlvcrudcmcthodsof pacing,tonch,visualcstimation,ctc.), that is,qunntitdtiaedctcrnrinaspringsfrom a counting,and tionshavebccnachieved.Evcry measurcment canin the lastanalysisalu'aysbe tracedto a numberingof "coincidcnces," 'whercby a coincidenceis to be understoodthe spatialcomingtogethcrof two prcr.iouslyseparated singulariticsof thc visualor tactualficlds(marks, whereby spatialexpointerq ctc.). This characteristicof meazurenrent tensionis, as it were, mascered by divisioninto discrctcparts hesofrcn beenpointed out. It is this way of dctcrminingthc spatialwhich is thc physicdl. I Why cxactlv do we makc useof this procedure? The only corr€ct an$veris, bccauscof its obiectivity, that is, bccausc and inter-subjcctivevalidity. What this meanscan be of its inter-sensual easilyclarfficd by an cxample.If I movc the tips of my indcx fingers torvard onc anothcr,thcrc occurs in the visualficld an evenrwhich is callEd"mcetingof the finger tips," and anothcrcvcnt in thc uctual ficld rvhichI call "contactof thc fingcr tips." 'L-hese two evJnts,eachof which is a discreteand distinguishable elemcntin its fielcl,alrvaysoccur simultancously. cmpiricalrclationbctweenthcm.Every This is a fundamcntal time that a coincidcnccoccursin the field of touch,one alsooccursin thc visual6eld (at leastunder favoroblecircumstances of an exactly spccifiable sort,for examplgillumination,positionof the cyes,etc.).This rclationship is indcpcndcnt of the particularsensein quesdon;it is inter'I'hat is sensual. We alsolearnfrom experience lhat it is inter-subjective. to sey,ail otherpeoplewho arepresentaffirm(againundergiven,rerdily that the samenumber of homologouscoincispecifiablecircumstances) dcnccsoccur in their visualand tactualfields.Thus, not only the different scvcralscnscs, but alsothe differentsubjectsagreein their testimonv l.'he order of the.se coinciconcerningthc occurrenceof coincidences. (properly,space-tirrrcdcncesis nothingothcr than physicalspace-order rrrrlcr);it is an ohjectiecorder (for bv this u'ord n'e bring togetlrertlrc of intcr-scrtsrral lnd irttcr-subicctive). trro itlcrrs ln gcncrnl, obicctivity olrtlins onlv for tlrcsc plrl,sicll propositions oI t'oirrcirk'rtccs,iltt{l not for llroPositiortsrr'lrit lr s'lriclr:rrc rcsle(l lrv nrcrrrrs irr' ('( rln ('('rn('rls itlr r lr : r lit ic s of c olnt or s oulr l, [ cc l i r r l l ss r r c l r : r s s ; t r l r t r " , . ,

398

DATA, REALITY, AND l'HE MI:{D-BODY PROBLET!

propositions. or ioy, u'ith memoriesand the like, in short ^"psychological" consistsin the fact rhat The meaning of all physical propositio$thus they formulate either coincidencesor larvs relating to coincidences; and theseare spatio-temporel deterrninetions.One may be tempted rc sav thet this makes senseonly if the coinciding itcms are specified, and that the proposirions are incomplete rvithout this addition. But closer examination shorvs that such specifications(rvhich indccd nrust be made) refer us back to propositions concerning other coincidences. (Here rse find thc iustification for the theses,elaborated particularly by A, S. Eddington, that physics as a whole is to be understood as geometry. "GeometIy" in this connection clearly refers to an enrpirical scicnce, rather thln a purely formal mathematicaldiscipline.) Even explication by menns of ostensiveg€snrres,rvhich along in the last analysis,relates our concepts to the world, and makesthem signs of obiecrc in nature, is readily seen to consist in the bringing about of coincidences ({or example, of a pointing finger *'ith the object singled out). 'fhe fact tfrat the spatial description of atomic processesdocs not occur in modern quantum theorv does not I alter the fact thrt all phlsicnl lrru'srre verified by the occurrenceof coincidences;for dris holtls slso of thc lau's in *,hich magnitudesrelatirrg to atonlsappear.'l'he;c nr:rgrrituclcs also have meaningonly by their rclation to physicalspaccdctcrruinations. According to u'lrnt s'c lravcsaid above,rhe essentialfcature of phvsical conceptsis thlt tlrcy are arrived at by selectingout of the infinite vrriety of eventsa specialclass,namely these"coincidences,"and describingtheir inter-reladonshipss'ith the help of numbers. Physical nragnitudcsarc idenrical with tlre number-combinationsrvhich are thus arrived at. The questionu'hich u'e are seekingto answer (in principle) can thcrcfore be put as follows: What is the relation of these coincitlcncesto all other events,for exarnpleto the occurrenceof a pain, to the changeof a color, to a feeling of pleasure,to the emergenceof e mernofy, and so forthl Iil It is u.suallyclaimed that the phvsicist simply and dclibcratcly avoids referenccto s'hlrever is not a mattcr of space-tinrcdctcmrinations,He ignores, it is said, the "qualitativc" and limis hinrself to dcscribing the to bc found in the rrorld. This usuallv dcvelops quantitativerelationship's into the charge that physics is "onc-sided"; that it plavs a narrorvlv circulrrscrihcdrrilc in our Lnorvlcdgcof realitv; that it givcs us only a fragnrcnt \\ hich nrust be supplemented,an cmpty spacc-tinrc hull s'lriclr nrustbc lillcrl u ith content.This conrcrtt.it is urgcd,is tlrc psvchologictl. tliscil)svclroLrgl rr,,rrld thcrcforc confrtrnr Ph|sics :ls atl tut(rr't(rttuttts tltrtt ttot cvclt pltvsicsrtrrtlpst'plirrc.lrrrk't'tl.rrc oftcn hclrrthc opirti
PSYCTTOLOGTC.{L AND PnYSICAL CONCDPTS

lgg

there remainsa place where metaphysicsis privilegcd to lay down thc larv. To the asscrtion of thc onc-sidcdncssand limitatiorrs of the rncthods of phl'sics,thcre stnndsin sherp opposition the chim that an absolutely complete dcscription of the world is possibleby the use of physical methods; that evcrv cvent in the world can be dcscribed in the language of physics. and thcrefore specifically, that evcry psvchological proposition eanbe translnredinto an expresion in rvhich phvsicnlconceptsaloneoccur. This clairn-rvhich is referred to (in somervhatinelegant terminology) as the thcsis of "ph1'5lsdism"-is correct, if the phvsicnl languageis not only otrlective,rvhich wc have alreadv se€n,trut is in adclition the only objective language;or, more accurately,if translatatrilityinto the physical languagcis a necessarycondition of obiectiviry. This sccrusindeed to be the case.All experienceup to norv points to the conclusion that only physicnl concepts and concepts v'hich are reducible to physical concepts fulfill thc rpquirement of obiectivity, which is, of courser essendalro e language,frir s'ithour it the languagecould not serve es a meansby which different subjccts could arrive at an understanding. I therefore hold the thesis of phvsicalism to be correct (compare my Allgancine Erkennnisleltre, :nd ed., p, z7r), but-and this can hardly be ovcremphasized-it is correct only on the basisof specific cxperiencet, The thesis is therefore a factual onei an cmpirical proposition, as is, say, thc proposition that England is an island, or the asseftion rhat conservation of energy obtains in narure. 'llhe thesisis thereforc not a philosophical discovery.the philosopherassuch is not interesredin facrs of experience as such, for each fact is only one of indefinitely manv possible facts. Rather he is interestedin the possibility of facts.Since,in nry opinion, his task is that of determiningthe meaningof propositions.and sirrcca proposition hes meaning only u'hen ir fornruhtes t possible state of afTairs (whether or not the state of affairs actually existsis irrelevant). it is one and the samething to sav that thc philosopheris concernedrvith the meaning of proposicions,and to say that he dealsrvith the possibitityof facts. That thc rvorld is exactly asit is, that mattcrs stand cxactly as cxperience shorvs they do, is-in a rcadily intelligible serlse-a contingent fact; ond it is in cxactlv thc samcscnsca contingcnt fact that the physical language is an inter-subiectivcunivcrsal languagc.(Even one of the most ardent cxponcnts of "ph1'sicalism," Carnap, explains it as e stroke of good ltrck. Cf , Erkcnntnis :, p. 4+S.) As far as u'e are concerned,it follorvs directly f ronr this that the rvord "physicalism"in no u'av designates a "philosophicnl nl()vcnlcnt."This is an adnronitionto us to cYaluateand nrakeuse of thc f,r<'rsrr'lrichtlrc tcrnr brings to mind no differently than any otlrcr crrrpir it';rlnr:rttcrof firct; to trcnt tlrcrrr,nrrnrcll'.ns r pnradigrnrns orlc lxrstl,rc rs .l r i s c x i rc tl vl )y l )i (' trrri tl gotl rcr possi bl (' st:l tcs of s il, ilit r ' r 111nror !' st:tttrlottl s rl s:tr:' ti rt',t;t :r ll' . r irJi r , ' r r r r lr i,l r tl rc o ttc tl tl t i s l rc trr:rl lrt' v :rU zerl

4OO

DATA, REALITY, AND THE IIIIND-BODY PROBLE:\!

background, that n'e shall first come to understand the latter correctlyr and to grasp the rdle actually played by physical conc€pts,as rvell es their relarion to psychological concepts. ry What, dren, are the data of expericnceon rvhich the objeetiviw and universaiityoi the physical langua'gerests?They consistin the facl that hetn'eenthe "coincidencest'anclall othcr cvcnts,rhcre can be found systematic relationshipssuch rhat to evcrv diffcrcnce in an1' of the other sl'cnts,therc correspondsa deternrin:rrcclilTcrenccin thc coincidencesso that, in principle, tlre rvorld contrins rxr variarion nor constnncy s'hich does not go hand in hand u'ith a vrrintion or constancv in thc clorrrain of coincid-enccs. If this is the cnsc.thcn clcarly ttre entire rvorlctJlf experienceis uniquel.vdetcrmincdby thcsccoincidenccsirvhcn theseare knou'n. so is it. It is from this that stcmsthc univcrsalcharacrerof thc rrhysicnl tanguage.Tu'o examplcsrna.ysrrfliceto illustrate.For the first rvi "irnnrt thc relationshipthat cxists bct\r'cen the psychologicaland the phvsical is of n color dcfined by a frequcrrcv, nunrbcr conc€pts color, Phvsicnllv, a of vibrations pcr sccorrd.J'his numtrr, as is rvell knorvn, is arrived at bv thc fanriliar pruccdrrrc of counting thc interfercncc fringcs of thc light or measuringa spcctrrrnl,and from the rcsulting figurcs along rvith other mcasurcmcntsrcad off thc apparatus,calculatingthc t'frcquency." That is to my, one obscrvcsthc coincidcnceof a spectralline or of an intcrfcrence fringe u'ith certain marks on tbc mcasurjng apparatus.No*' expcricncc shon's that thcse coincidenccs als'ays occur at thc same places,and in accordanccrvith thc samegencral lals, n'henevcrthc light has visuallv thc samccolnr. For n:onochromaticlight of an absoh::clvspecific shade of rcd, I all'ays gct cxactl,vthe samcfrcquency. Consccluentlv,if I kno'u' that a source of light is unitting ravs of this frequenct, then I knos' rvhat color I rvill seeu'hcn it mccts my eye. Thus, to designatetlre color. it is sufficientto give the frcqucncy. Indeed, this phvsical dcsigration is actually far more accuratethan thc corrcspondingcolor rvord (for exanrple,"Bordeaus-red") usedbv the pvchologist. But is thc corrcspondcnceof thc frcqucncy rvith thc color as sccntrulv runnmlliguousiDo I aln'ays see tl're samecolor u'hcrr I look nt r solrrcc crnitting the sanrefrequencvi Obviously n()t. f()r if nrt' clc is tircd. or lus prctiouslt'trcenaffectedbv light of ntrotltcrcolrr, ol'if rttv ttcrvous sysr c nlis r r nr lert he i n fl u c n c eo f s i rn to n i ntl, rt' rrI l r:rvcrl i ffcrcntcol or i rtrp rr's s i, , r:rrslt lr or r glorl ri c c ti v c l vtl tc rrrtl i :tti o ittr tl tc s:true.l )ocsrr' toi pcri No, l'or cspelicncctclrchcstlr:rt t'lrt'crr'frrtctlrc "thcsiso[ plrlsit':rlisrtr"? s l r rh i c h ,i n s p i tco [ tl rc i rl o tti t' 1 'o[thc frctprcrtcr'I , st' c i rr rr llt lr t ' r cr ' : r r c ir :tt'r'rlt'lt't't;tlrlc,tr:trttclytlxrst' :r rlilli'rcrrt r.l'r. r,r1/.r1'7 pln'sit'nl<'lt:rtt11.', rrlrirl r r o l r ( r t i l l l r r ' ' , t,r tr ' ,,f ilt\' o tti;tttt' ,til, ilr Itttr ( lr l:r t rr\ n('rrou:i s\'sl ('i l 1 I lt t ' t t t t . ' . , 1 1 ' , , r l r r ' n , ' l r r r Y r r cr t' o t1 1 ' ,\,,lcn t, \1 ltr , lt r r r r:rtttr;rl l t :r 1rl rf,'i ,';rl i n

PSYCHOLOGICAL AND PHYSTCALCoNCEPTS

+Ol vestigation, making usc of thc mcthod of coincidences,shou's (as far as our expericncc gocs) that evcry diffcrence in color qualiry goes hand in hand with a diffcrcnce in thc optical segurentof che nervous system. But rvidrout conccrning ourselves as to whethcr a physiologicel in..-vestigation of thc ncrvous system will be carried m completion, or is a technical possibility, u'c find other physically describebleprocesses ';lleven which can be tued in place of neural cvcnts to achieve an unambiguous correspondcnce between serucnualiqy and coincidence system, namely the physicalbehaviorof the individual-in particular thc reacrions(speech, writing, ctc.) by which he rcports on his scnsationsrvhen he is askedabout their qualities.It will bc supposedthat the reasonthese reafiions are $ satisfacrory.for the purposc as thc abovc-mentioned ncural processesis bccausethcy in their turn can bc unambiguously correlatcd with these processcs(by virnre of the causalconncction between them). But this is irrclevanc to our purposc. What conccrns us is solely the frcr rhar it is possibleunambiguouslyto coiirdinatc Auelity of sensadonwirh coincidence systems. Every change of color quelrty thus corrcsponds to a change in the system of coincidenccs;but this is a mattcr not of those coincidencesalone which are involved in the mcasuringof thc frequency of the light, but also of other coincidcnccs,observablcon the body of the perceiver, the belonging of rvhich to the sum-total of coincidenccs is a matter of em' pirical fact. With the taking into account of all relevant coincidences,the coOrdination of phvsical conccpts with the qualities becomescompletely unambiguous,as "physicalism" asserts. One cannot reproachthe physicist r*'ith the inrentionaloverlooking of all qualities,for it is iust not true thrt hc ovcrlooksthcru. On rhe conrrarl', even'differcnce is for hirn an occasionand a lrint to serrch for a differcnce of coincidences.If, for examplc,I l'crc to say tlut I sce blue undcr circumstancesin rvhich one is expcctedto have a sensati()nof vcllol, (sry, at the place of the sodium linc of the spcctrunr), the plrlsicist rvotrld not rest until he had "explained" this unexpcctedfact, tlrat is, undl he had discoveredphysical peculiariticsin my bodv, in other u'ords, rbnornral nleasurements shorvn by cerrain coincidcnces,rvhich appear in this case and in no other. The world of qualitics is thus of highcst importance for him. He in no rvay forgea it, but on the contrarv only regarclshis quanritative svstemas a satisfactorydescriptionof nature if the uranifold of the rvorld of qualitiesis represehtedin it by a correspondingnrultipliciry of ntrnrtrcrs, For otrr secondexanrple,let us take tlrc
'it?

4o2

DATA, REALITY, AND THE IUIND-BODY PROBLEM

bv evens s'hich occur outside the body of the griever, and s'hich can

bl describeclin plrl'sicalterms (for .*orpl*. sorneJne'sdeath,or the news of a denth). But the differcnce bets'ccn tlris cascand rhe precedingconsistsin the fact that no one bclievesthat thcre existsa one-to-onecorrespondencebetrveenthe qualitv of the feelirrgof grief and theseexternd events.Rather, the dependenceof the fcclinq on the state of the subiect is so oby'iousthat everybodv looks to thc lrodv of the griever hirnselffor the coincidencesq'hich are herc principrllv in qncsrion.Once again we do not need to considerthe eventsiu the rrcn'oussvstenr-which are for the most part unknown-for it is sufficicnt t,, pai' attcntion to his expression,his utterances,his whole dcportnrcnt.In thcsc processes-rvhich are describablein terms of coincidcnccs-\r'e haveth? facts by which feclings are expressiblein the phvsicnl language. Let it not be thought that thc phvsicistnrust leavesomethingout of his description,that there is sonrethings'hich he cannot formulate, rvhich it remains,sa5 for the poet to exprcss.For even the poct can only perceive someone'sgrief in tcrnrs of bodily behnvior,and only in terms of bodily behavior can he mnlic it intuitive for the listcner. Indeed, the berye.ra prsychologisthe is, drc nrorc hc is a masterof poetic language,the lesshe will make trseof psvchokrgicalternrsto describethe grief. Insteadhc rvill attempt to achicvc his purposc in an apparentlvindirect rvay b"v describing horv the grievcr rvrlks, his expression,horv he holds his head, the rveary movenrentsof his hand, or by repeatinghis broken words,-occurrences,in short, *{rich can also be describedby the physicist, although he would make use of other svnrbols.

v How exactly do rve build our "psychological" concepts?lVhereas the physical language gives formularion to events in their extensive spttialtemporal reladonships,the psychologistbrings rhem together from guite a dilferenr point of vierv, namely,in accordanceu'ith their "intensivesirni: .larity." Thus, each of a large number of different but resemblingpropertiess'hich occur in expcrience,is called by the comtnon nanle "grcen". snother manifold is called "yellol", and so on. Both of thesemanifolds to one anorherasrvell asro ccrtein other qualiexhibit such a resernblance ties, thrt they are grouped under the common term "color". ln addition, rlrcre are orher elementsrvhich differ from thesc,but resembleeach otlrcr antl rlrt'rcforc rcceivee common nanle,as for cxaruple,"sotrnd", "plcnsrrrcfcclirrq",":lnqcr", "odortt, t'pltin", "trncnsincss", etc. Fnrtltcrtttorc.thctr: :rl r.f;rrr r ilicol' s c v c nt sr r L ri c hl re c rrl l c rl" c h rrrrqoc f c o l rl r,"" i ntcrrsi l i crti on "(l('('r'(':rs('in "tlf irtq:rrt':t1. oI sorrrrrl." briglrrrtcss," oI n fcclinq.""r'isu:rlrrtoti rrrr,""t : r r ' t r r :r rl r or ir r l ," :trrtl s rl o rt. \\' i tl r tl rc s cl l rc rqrtrl rrr:tl l ybcLxrgtl rc ol ('\('nts,"virttul coittt'itlcttcc:" urtrl"tltt'tu:rlcnincirlt'n<'c." t'l:rsscs \\'c r nr r sllr t r r r ' lot cirtr' l rrtk ' th (' l :rttr' rrtt tl u ' l i s t r' 1 " l r ,,rrl rrrLrl ,l l ' 11" 1' ,r' 1-

PSYCHOLOGICAL AND PHYSICAT, CONCEPTS

+o3

c€pts.tf this strilics one as paradoxicalor seernsto contradict our earlier statementstthclr hc is far rcmoved frorn an understandingof the relation betn'ccn ph.r'sicaland psvchologicalconccpts.It w'ouid be clearlv r mistaketo silv: "-l'hc coincidencesare of a rnuch nrore complicnredneture." If, for'cxlrnple, I dream that I am plaving billirrcls, I iee the balts come togcthcr irr snch a $'ay that at certain points on their surfacesthere occur coinciclcnccss'hich cannot, hou'evcr (in rlris cme), be used to cnn.t,L.t a phvsical or objcctivc spacc,For they :rrc onlv drsam-evenqs. Onc clnnot fit thcm into the samestructure rvith the crlrrcspondingevents of an actual garne.1'hcy obey diltcrent laus. The "plrvsic:rl space" that onc nright construct s'ith thcir aid, rvould bc nn rrrrrculphvsical sp:rce, u'hcrcasthc visualcoincidcnccsof a dreanras mental evcrrtslrnvenaturally thc samerealitv asthe fact of waking lifc. But they do not hrvc rhc inrersubiectivity rvhich distinguishesthe coincidcncesobserved in rcnl life. Indeed, the difference from an actual billiard game consistscxactly in rhe frrct that the coincidencesof thc drcam arc not suited to the construction of an inter-subjectivespace,rvhereasthc coincidcncesof nornml lifc fit in a direct and easyrvav inro Ehcsystemof phvsicalspacearrdnntural law. 'I'hus. it is not the coincidencesas such. u'hich constitute the "physical world", rather it is their incorporation into a certain systcrn (the svstem of obiective space) u'hich makespossiblcthc founation of physical concepts.The adjectives"ph1'sicd" and "mcntal" formulatc only nvo different representationalmodes by which thc data of expericnceare ordcred; they are diferent \r'avs of describingreality. Thar in rvhich one coun$ ordercd coincidcncesin inter-subjectivcspace,is rhc physical; rvhcreas that rvhich operatcs by the groupirrg of intensive propcftics is a psvchological description. The so-called"psvcho-phvsicnlproblcnt" ariscsfrorn the rnired enrploynrenr of both modesof rcprescntationin one and the sanlesclttcn(:e. Words are put side bv side u'hich, u'hen correctly used,rcall.vllclorrg to This gives rise to no difficultics in evcrr-dnr' life, difrerent langua-ees. becausethere languageisn't pushcd to the critical point. This occurs first in philosophicalreflection on the propositionsof scicnce.Herc the ph.vsicistmusr needs assureus that, for example, the sentcnce. "Tlre lcaf is green" merely meansthat a certain spatialobjcct reflccts ravs of a ccrtain frequency only: rvhile the psychologist nrust necds insist thrt the sentencesays somethingabout the qualiqy of a pcrceptual contcnt. The different "mind-bodv theories"are
ilo l ilr:t(l ('<':r.,\' tl x.i l i l {l ('r.,t,i l trl

4o4

DATA, REALTTY, AND THF, rtr',:\D-BODY PROBLET\!

ing of thetrue situadon,but hasfavoredthe growth of a matcrialisticmeaphysics,u'hich is asmuch a hindranceto rhc clarificationof thc problem as any other metaphysics. VI In our world, the physical language has the characrcr of obiectiviw and universaliw. rvhich the psychologicallnngu:rgcsecnrsto lack. It is possibleto conceivethat matterswerc turned arotrnd-tlrat thc formation of psychologicalconceptsrvasinter-scnsurland intcr-sublcctive.while no runiversalagreem€ntcould be achievedin the cnscof assertionsconccrning coincidences.Such a rvorld rvould bear no rescrnblauccto the actual rvorld, but one could nevertheless picturc it to oncself-as consisting,for example,of a finite number of discrete qualities (classifiablcin various resemblsncc-clases)the sinrultancousor successivcoccurrcnce of rvhich n'as shown by exp'erienceto bc governed by certain larvs,but rvhich q'cre ;.never clearly distinguishedfrour one anothcr by clear-cur boundaries. 'Naturally, in this rvrirta, tlre nrcansof comrnunicaiion,thc linguistic svmbols, would be constnrctcd of endrely difierent matcrial than our words, and the individuals rvlxr speaku'irh one enothcr would not possessspatial . bodiesof the sort to rvhiclr \r'e are accustomed,L-butall this is not im'possible. The reasonfor the fact that exectly the physicallanguage,the language of spatial coincidences,is for us an inter-subicctive meansof communication, lies naturally in the fact rhat it is by spatial rclationshiprsthat individuals are both distinguished from and yet bound up rvith on€ another. Putting it somervhat differently: Tlre external rvorld is a spatial u'orld. lndeed, the rvord "eriternal" servesto dcsignatca spatiel reladon; and it is easy to see that the opposition bets'een "I" and "extcmal rvorld" is as a matter of fact only the differenceb€twe€n "one's orvn" body and other physical obiects. But the clarification of such complicated concepts as

Iiesbeyondthc scopeof this paper.lVe con"I" or even"consciousness" tent ourselveshere rvith the examinationof the employmentof certain simplepsvchologicatand physicaltcrms. It is a preliminary task rvhich revents the emergenceof those difficultics which hide behind thc words

'psycho-physical problem." vTt \\'c hrrteernphlsized that the circumstances on which reststhe unitrs;rlrtvof tlrc plrvsicrrlInngungc,rhlt is to sry, the "tltcsisof phvsicalrntltcl rhltt a lrrgicnlclr:rrrctcr.-l'hcv nrc, hrlrvinr,":ur.,,l ;rrrt'rrrpirir':tl \' t'r'..l r.rrclr:r Pt r r ' : r s iv cs r r r r , ' . t nr lr v c : u' c s r ) t h( ) r o t t g l r l y r t c c r t s t o n t c t tl o Irt'tn .tlr;rt rt r', lr1 ' n{ r nl( ' : t ns( ' : t s v lo f or nr : ut i. l c a : r s t o h o t t 't l t c r v o r l t l , ,'rr l1' t lr c r c r lt ' , ' ir iv t ' r c l: r t ior t s lr ilxr l i r l l t o l o l r t e i t t , t l t o t r g h ' ,lrl,l 1,,,,1 rl

PSYCHOLOGICAL AND PHYSICAL @NCEPTS

405

cvcqrthing clsc remainedthe samc.It would be a world enormously dilfcrent from the actual rvorld. In it there s'ould be no uniform one-to-one correspondencebetwccn coincidcucesand qualities.Perhapsrve can imagine this most easily if we consider feclings. I can, for example, integinc thrrt rny feeling of grief in no rvay to anv bodily condidon. If, for exanrple,I laughcd, corresponclcd skipped ar
+06

DATA, REALITY, AND THE I\r$rD-BoDl

PRoBLEII

4. If I feel \rarrl. rhc color qunlitics changein one direccion of the spccrrum, if I fcel cotd, in thc othcr-hcic as rvcll, nicdlcss ro say, warmrh and'coldness must be indcpcnclcnrof coincirlcnces.-erc., etc. In circunrstalrccs such as tll()se described, and in a thousand orhers more

or lcss plrurtastic,therc urluld be no possibiliry of assigniugn.ords for the color
uu trVhat could be said about such a non-phvsicalisticworld as s'e havc pictrrrcrl in scvcral examplesi First of nll pcrhaps this, thtt s'c shorrkl hnrrllv slr':rliof it ns anc u'orld llrrt rntlrcr ns trro diffcrcnt clrurrrilrs, onc ntt
PSrCttoLoclCAL ANIJ PII\ SIC.{L Co}-CEP't's

+o7 lr'ould not be lacking in all connection. There u'ould be certein relarions bcnveen the spatid characteristicsof the ts'o, for the coincidenceswould in any casemrrk the boundariesof the qualiries. By merrrs of a comparison of the consrructed exarnplewith the acual rrorld u'e first learn ro understand and evalurte the structur€ of the latter, It is, as far as experiencetells us, so constructcd that it is fully describablcby nreansof the spatio-tcmporalconceptuirlappararusof Physics; this implics tlre existencein the rvodd of a certrin dcrerurinaremode of intcrconnccrion The instant rve think a*'ay this pr()perry of rhe world, reality frrlls apart into scveral domains; it ceasestr.rbc a tutiau'se. \['e hrve therefore to do u'ith an empirical frct of frr-renching significance.But only with an empirical fact. lVe can bc savcdfrom attaching too nruch rveight to this fact by noting that $'e can conceivcof differcnt degrccsof the separationof the domain of qualitiesfrour that of the coincidences,so that a gradual transition from the lcrual u'orld ro our so completely different imaginary rvorld is conceivable. For exanrple,qualities in general might be suictly bound up u'ith coincidences,wirh the cxccption, for example, of a limited domain of colors, let us say, shadcs of green,for rvhich all our earlierassumptionsrvould be uue. In this case, the private donrain excludcd from physics rvould be of extremelv limited scope. 14/ecan, however, think of it as broadened to any desired degree, first to include all visual, then all acoustic qualities,erc., so rhar rhe validiry of the ph;-sicalistic assertionrvould be ever more restricted. lloreover, lve can think of the rvorlds of sight, sound, smell, etc., as related to one another in certain uniform \r'eys or notr as rve choose. In thc latter casc\1'eare led to conceiveof asnrany mutually independentdonrainsas there are kincls of quality. Needlcss to say thcre is here no question of nretaphvsicrrl pluralisnrany more than it t'ould be a metaphysical tlualisnrto conrrastthe rvorld of qualitiesuniformly inrerrelatedin accordrrnccu'ith empiricallas's rvith the rvorld of coincidences.Rrrher rve u,ould hrtvet
r t l r t r l r lr ' tt' c ,,r r o l' lcn lr ir r r lcr t' tl llr t, u r trl ctst:rrrtl i rrg of tl rr: rtl ;r | l r 1 1 tr .r l r ltr l Pr lr ' lr r r lr r llit' r l lr o g r o siti orts.

I rr, r r l r r t r r r r 1 r