A Cognitive Cul-de-Sac Fred I. Dretske Mind, New Series, Vol. 91, No. 361. (Jan., 1982), pp. 109-111. Stable URL: http://links.jstor.org/sici?sici=0026-4423%28198201%292%3A91%3A361%3C109%3AACC%3E2.0.CO%3B2-W Mind is currently published by Oxford University Press.
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Mind (1982) Vol. XCI, 109-1 I I
A Cognitive Cul-de-sac FRED I . DRETSKE
There aren't many navigational aids in epistemology these days, but the following two reference points seem durable enough. (A) If S knows that P , and knows that P implies Q, then (assuming S accepts Q as a result of this knowledge) S knows that Q. (B) If S knows that P, then (given the satisfaction of certain conditions relating to S's sincerity, the willingness of S's audience to accept what S says as an honest expression of what he knows, etc.) S can bring his listeners to know that P (can inform them of P) by telling them that P. Principle (A) is a cousin of the one used by Edmund Gettier to construct his well-known counterexamoles. It has received its share of abuse. but no one seems prepared to abandon it.' Indeed, its poorer (I would say bankrupt) relatives (e.g., S knows everything implied by what he knowswhether or not he knows it is implied) have sometimes been taken as axiomatic in systems of epistemic logic. T h e second principle, though less precise, and more difficult to state in any crisp way, is taken for granted by all of us who believe that knowledee is transmissible. It is hard to see how something like this principle could fail to be true if communication is possible and education occurs. For the way we know much of what we know is by hearing it from others who know. The following example convinces me that both principles are false.z This is not to say that they do not hold in special circumstances, only that to' regain their status as principles their scope must be restricted. George loves Bordeaux wines and he is especially fond of those from the Medoc region of Bordeaux. He has quite a remarkable palate and unerringly identifies a genuine Medoc as a Bordeaux, and specifically as a Medoc, when he tastes one. Strangely enough, though, given his general knowledgeability about wines, George is confused about Chianti. He has
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I took a swipe at this principle in 'Epistemic Operators,' The Journal of Philosophy, lxvii, 24 (24 December 1970). I leave it to others to judge how crippling the blow was. Gail Stine, for one, was not particularly impressed; see her 'Skepticism, Relevant Alternatives, and Deductive Closure,' Philosophical Studies, 29 ( I 976). There is a structural resemblance between this example, at least the first part of it, and Alvin Goldman's dauchshund example in 'Discrimination and Perceptual Knowledge,' The Journal of Philosophy4 lxxiii, 20 (1976) The resemblance is not coincidental although Goldman uses his example for a different purpose.
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no trouble distinguishing a Chianti from a Medoc, of course, or in identifying a Chianti as a Chianti, but he thinks Chianti is a Bordeaux wine. He has never studied the labels very carefully, but he has the vague idea that 'Tuscany' is the name of a wine-growing region in southern Bordeaux. George's friends are unaware of this lacuna in his otherwise extraordinary viticultural expertise. A dinner party is given at which George is a guest. A rather ordinary Medoc is served, a wine that George finds pleasant but wholly unremarkable. T h e following day the following piece of conversation occurs : Michael: What kind of wine did they serve at dinner last night? George: It was a Bordeaux, but a rather undistinguished one. Does Michael now know that they served a Bordeaux wine at the dinner party? According to any reasonable application of principle (B), he does. After all, George knows that they served a Bordeaux. He sincerely and honestly tells Michael what he knows to be the case. Michael accepts George's word on these matters (George's reputation as a wine connoisseur is widely known), and believes what he is told. According to (B), then, Michael should know that they served a Bordeaux. But he doesn't. For all he has been told, it might well have been a Chianti. George, in fact, would have said precisely the same thing had it been a Chianti. He often has. Therefore, (B) is false. This is not to say that George could not tell Michael something that would be informative. George could have said that it was a pleasant Medoc, one of his favorite Bordeaux wines. This communication would have told Michael that they had a Bordeaux since it would have revealed something that George knew (it was a Medoc) that eliminated the possibility of its being a Chianti. But George didn't say this. All he said was that it was a Bordeaux. And this, though an honest expression of what George knows, is not something from which Michael can learn the kind of wine they had. You cannot learn that P from someone who tells you that P if they would say that P whether or not P, and this holds even if the person happens to know that P. Suppose, now, that several weeks pass and George is once again questioned about the dinner party. Susan: What kind of wine did they serve? George: Well, I distinctly remember that it was a Bordeaux, but I cannot remember what kind. It was, at any rate, nothing to get excited about. Susan (naively): Oh, it was a French wine then? George (haughtily): Of course. Bordeaux, as everyone knows, is France's most famous wine-growing region. Since George remembers that they served a Bordeaux, he (now) knows that they served a Bordeaux. He also knows that Bordeaux wines are French wines-knows, if you will, that 'Xis a Bordeaux wine' implies 'X is a French wine.' And George believes, as a result of what he knows, that they served a French wine. Therefore, according to (A), he should (now)
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know that they served a French wine. But he does not know this. Notice, George is in precisely the same position that Michael was earlier. From all that George's memory 'tells' him, the wine they served could have been a Chianti. And if it was a Chianti, it was Italian, not French. If all George remembers is that it was a Bordeaux (does not, in particular, remember that it was a Medoc), George does not know that it was French despite knowing (remembering) that it, was a Bordeaux and knowing that all Bordeaux wines are French. Note that Susan has learned very little from this exchange. She may have learned, say, that George did not have a sherry for dinner,' but she certainly did not learn (come to know) what kind of wine it was or whether it was French-the two things she explicitly asked about. Of course, she now has true beliefs about these matters, but that is something else. As long as George cannot remember what kind of wine it was (a Medoc), he cannot tell her what she wants to know in a way that will let her know it. George has an incommunicable piece of knowledge, something he cannot pass on (as knowledge) to anyone else. It stops with George. It is, moreover, a piece of knowledge from which he cannot come to know some of its most salient consequences (e.g., that it was a French wine). This, surely, qualifies as a cognitive cul-de-sac. Some may object to my description of the example. They may argue that if George does not remember that it was a Medoc (nor any of its distinctive qualities), then he does not now know it was a Bordeaux. His knowing it was a Bordeaux is a piece of knowledge that in this unusual case (because of his confusion about Chianti) depends, critically, on his retention of the . ~depends, in particular, evidence he had for thinking it was a B ~ r d e a u x It on his remembering that it was a Medoc or, at least, something about the wine that serves to distinguish it from a Chianti. Since he has, through forgetfulness, lost this crucial piece of auxiliary information, he no longer knows that it was a Bordeaux he drank. If one chooses to describe the situation in this way, one should be aware of the price. One salvages principle (A) but only by sacrificing at least one of the following platitudes :
(C) If S knew that P, and has not forgotten that P, then he remembers that P. (D) If S remembers that P, then S knows that P. I'm not sure (A) is worth the price. UNIVERSITY OF WISCONSIN I
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She may have learned something of this sort. It depends on whether we can assume that something like (A), appropriately qualified, can be used to go from: ( I ) George believes he had a Bordeaux, and (2) George would never believe he had a Bordeaux if, in fact, he had a sherry, to the conclusion that George did not have a Sherry. Ordinarily we don't have to remember what justified us in believing in order to retain a knowledge of what we thereby came to believe (see George Pappas, 'Lost Justification,' Midwest Studies in Philosophy, vol. V , French, Uehling and Wettstein (eds.), Minneapolis, 1980),but this case, it may be argued, is different.
