The Gettier Problem Problem

Fifty years ago, in June 1963, Edmund Gettier published a very short paper in Analysis called “Is Justified True Belief Knowledge?”. Philosophical folklore has it that, before Gettier published this paper, most people were with Plato in thinking that justified true belief is both necessary and sufficient for knowledge.  If you know something, it has to be true, you have to believe it, and you have to have a justification for your belief.  In the original paper, Gettier gave some slightly complicated examples which appear to show that the conditions are not sufficient, not enough for knowledge:  a person might have a justified true belief in a proposition but still not know it. Since then, a very large number of more straightforward counterexamples to what’s now called the JTB conception of knowledge have been given.

Here’s an easy one (I think owed to Bertrand Russell).  Every day you walk past a church on your way to work and check the time.  You look up and see that it’s exactly 8 am.  You believe it’s exactly 8 am.  In fact, it is exactly 8 am.  You’ve got a justified true belief that it’s exactly 8 am.  But suppose the clock actually stopped twelve hours ago.  Many believe this is an instance of justified true belief, but not knowledge.  The JTB bit is in place, but that’s not enough, not sufficient for knowledge.

Some argue that there are examples that pull against necessity too, and it might be possible to imagine cases of knowledge even where one or another of the JTB components are missing.  Imagine a college student who’s been up all night cramming for a history exam.  She’s wired on caffeine, totally frazzled, and when asked “When was the Battle of Hastings?” she thinks she has no idea. 1066 comes to mind, but she has no confidence in the answer. She writes it down anyway.  Knowledge without belief?

For the last 50 years philosophers have tried to find answers to Gettier — by shoring up the definition of knowledge, finding ways to defuse the problem, even formulating new conceptions of knowledge.  In honour of this anniversary, The Philosophers’ Magazine asked Fred Dretske to tell us what he thinks we should have learned from 50 years of Gettier.  His answer appears in the current issue, and you can read it here: Fred Dretske, “Gettier and Justified True Belef:  Fifty Years On”

James Garvey

  1. Doris Wrench Eisler

    I’m not a philosopher so I’m probably missing something obvious here, but I believe that in spite of the fact “know” is incorporated in the word “knowledge” that word is not identical with “facts”. You can know many things that are neither true nor false: poetry, literature, art, etc. You also may ace a history test in which all the data is incorrect, but you covered and “know” the material.
    Concerning facts, true beliefs or any other kind have nothing to do with them.
    A fact or “knowing” is a tricky thing: something either is the case or it isn’t, and consensus is the definitive factor. So if a hundred people say there are cookies in the jar – that constitutes a fact – providing there isn’t some kind of trick or conspiracy – or they’re all nuts. A strong belief to that effect would justify further investigation. For the purpose of getting along in life though, that kind of certainty isn’t practical or necessary.
    So if I were Sue I’d check again in case my eyes were deceiving me. Maybe I’d be worried that my son was ill or something. Sam is justified in believing cookies exist in the jar, but he could be wrong. Life is like that. Very few things, if any, are absolutely certain. Check it out if it’s worth it let it go if not. Truth or fact is determined by consensus if important, and that’s why good science is subject to peer review.

  2. Hello Doris. Philosophers distinguish between several different sorts of knowledge, and I think they’re talking about propositional knowledge in Gettier cases, i.e. knowledge of propositions, for example, I know that 2 + 2 = 4, I know that I’m sitting at my desk, I know I have two hands, etc.

    In this sense, it’s not clear you can know things that are neither true nor false. When you mention knowing poetry, you might be using ‘know’ in a different sense — what philosophers call knowledge by acquaintance. I know Leaves of Grass, in that sense, I’m acquainted with it, I’ve read it, but that’s not propositional knowledge.

    Also probably propositional knowledge isn’t a matter of consensus in the sense you mean (I don’t think anyway). Either I’m sitting at my desk or I’m not. If I’m not, there’s no way I can know that I am. I might think I know, but I’d be wrong. People have thought they knew all sorts of false propositions, but in the sense philosophers mean when they talk about knowledge, it doesn’t make sense to say you know something that’s not true.

  3. Steve Merrick

    Doris, I think it’s the words that are causing at least part of your problem. I tend to use “know” for something approaching absolute knowledge, and “believe” for something more human, and less reliable. :wink: It’s not even the specific words/terms/labels that are important, it’s shared definitions for the words we agree to use.

  4. Dennis Sceviour

    Gettiers propositional examples seem twisted with casual inferences; whether 10 coins in a pocket cause another person to get a job, or whether Smiths Ford causes the existence of Boston. I see no causal connection. Nor is there any need to draw causal connections.

    Was it JS Mill who first popularized instrumental knowledge? Knowledge has an intrinsic purpose. I am not in Chicago and I have never been to Chicago. However, I know Chicago is there. If I set out on a quest to get to Chicago, I have knowledge of its existence without justification, and I am confident it will be there when I arrive. The point is that the knowledge and belief in the existence of Chicago is important as an intrinsic instrument for a quest.

    This seems a little different from Descartes Cogito. To Descartes, the existence of self depended on thought. However, the existence of Chicago does not depend on belief. Chicago would still be there even if the name was changed to Oz, and it would still be there even if someone were skeptical of its existence.

  5. The Gettier problem is just some intellectual sleight of hand that confuses received meaning with intended meaning. In that respect, it’s an interesting example of fallacious reasoning, but it’s simply embarrassing as an objection to JTB.

  6. Doris Wrench Eisler

    Should have said (this keyboard has a mind of its own) Sam is justified in believing there are no cookies in the jar, if he has no further knowledge of the situation, son is off his feed etc,. and he might be correct. Of course, if it is a given, there are cookies, he is wrong.

  7. Doris Wrench Eisler

    James Garvey and Steve Merrick – thank you for your input: I “know” words are the problem and what I’m trying to say is that something may be the fact or not, but the getting the knowledge of that is often problematical. For practical purposes most people can believe their eyes or others’ testimony, as in “Chicago exists,” but that isn’t the case with science. That’s why theories change: sometimes they are dead wrong, and we say “that wasn’t science in the first place,” and sometimes they are supplanted as Newton’s was with Einstein’s. And here you are dealing with so-called objective facts to which “know” applies. All knowledge other than mathematical concepts is relative and has meaning only in a specific context. Certainly, true, sincere, heartfelt belief has little relation to facts or is no proof anyway of truth, fact, knowledge. It just may be that 2 plus 2 equals four is utterly meaningless in some other universe.

  8. @Doris

    I pretty much agree with your main point. I’d say, though, that getting knowledge is always problematic.

    Really, the problem is with the idea of ‘knowledge’ itself as something completely certain. Complete certainty about anything is simply impossible–which is the actual problem with JTB; the T condition is unsatisfiable in every obtainable context for anything less than an omniscient observer.

    The only thing that makes sense is a JB model where ‘knowledge’ is belief that’s justified “enough”.

    Justification sufficient for knowledge, though, turns out to be just a way of saying that if P justifies belief in Q, then if not-Q then not-P.

    But, for any P, you can’t really establish that P, hence the trouble.

    You’re left with just a probabilistic notion where a belief is justified based on what other beliefs would have to be false in order for it to be false. For practical purposes, at some point you just say, “Okay, I’ll assume that this set beliefs is true, and count them and everything they entail as ‘knowledge’”.

  9. Hello James,
    Actually, the truth about Plato on knowledge is probably more interesting than the “philosophical folklore” to which you allude in your first sentence. Lloyd Gerson has recently argued in detail that Plato never intended to endorse the JTB account of knowledge. Rather, what Plato presented in the Theaetetus was a series of reductios, intended to show that common-sense conceptions of knowledge like JTB do not pick out our highest cognitive achievement, which Plato in the Republic and elsewhere calls “knowledge” (episteme). Rather, our highest cognitive achievement belongs to a natural kind that is not belief but entirely distinct from belief. This is widely acknowledged to be Plato’s apparent meaning in Republic book v (476-480), and Gerson argues forcefully that Plato never changed his mind about this. See his _Ancient Epistemology_ (Cambridge, 2009) and _Knowing Persons. A Study in Plato_ (Oxford, 2003). The former volume explores the contrast between this Platonic (and Aristotelian) conception of knowledge and the almost universal modern view that knowledge is a kind of belief. If you want to shake up the readers of The Philosophers’ Magazine about what “epistemology” really is (or could be), an interview with Gerson would surely do the job! Best, Bob Wallace

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