PHIL2606: Knowledge, Reason and Action
Week 3: Gettier Cases

    The JTB account

  1. We are considering the JTB account of knowing, according to which:

    JTB: To know a proposition is to have a justified true belief in it.

  2. Recall that this is an identity claim - it is the claim that one relation (the relation of knowing) is identical to another relation (the relation of having a justified true belief in).
  3. Note: the claim is that these two relations are actually identical. The claim is not that they are necessarily identical. But most philosophers think that if two things are actually identical then they are necessarily identical (i.e. that identity is necessary).
  4. Assuming that identity is necessary, JTB has the following consequences (we can prove each from JTB by a simple argument):
    1. Truth is necessary for knowing
      (Necessarily: for all s and p: if s knows p then p is true)
      (It is not possible that: for some s and p: s knows p but p is not true)
    2. Belief is necessary for knowing
      (Necessarily: for all s and p: if s knows p then s believes p)
      (It is not possible that: for some s and p: s knows p but s does not believe p)
    3. Justification is necessary for knowing
      (Necessarily: for all s and p: if s knows p then s is justified in believing p)
      (It is not possible that: for some s and p: s knows p but s is not justified in believing p)
    4. Truth, belief, and justification are jointly sufficient for knowing
      (Necessarily: for all s and p: if s has a justified true belief in p then s knows p)
      (It is not possible that: for some s and p: s has a justified true belief in p but s does not know p)
  5. Being consequences of JTB, if any of these four things is false then JTB is false.
  6. We can show that one of these four things is false by coming up with a counterexample to it. A counterexample to, say, the truth condition would a possible situation in which someone knows some proposition that is false.

    Note that it only needs to be a possible situation - it need not be an actual situation. Any possible such situation will do, no matter how strange or unlikely. But it does need to be possible.

  7. Last week we looked at some potential counterexamples to the first three - the truth condition, the belief condition, and the justification condition (but weren't convinced that they actually are counterexamples. This week we look at some potential counterexamples to the fourth consequence - that having a justifed true belief is sufficient for knowing. We will find them more convincing.
  8. What do we need for a counterexample to the claim that having a justified true belief is sufficient for knowing? A possible situation in which someone has a justified true belief in a proposition, but does not know that proposition.
  9. Gettier's paper

  10. In 1963, Edmund Gettier published a paper in which he proposed two counterexamples to the claim that having a justified true belief is sufficient for knowing. (Gettier, E. L. (1963), ‘Is Justified True Belief Knowledge?’, Analysis 23, pp. 121-3.)
  11. Here is the first of his two cases:

    The ten coins case
    Smith and Jones have applied for the same job. Smith has good evidence that Jones will get the job, and that Jones has ten coins in his pocket. From this Smith deduces that the man who will get the job has ten coins in his pocket. As it turns out, and unknown to Smith, it is Smith who will get the job, but he also has ten coins in his pocket. So: (a) It is true that the man who will get the job has ten coins in his pocket, (b) Smith believes that the man who will get the job has ten coins in his pocket, and (c) Smith is justified in believing that the man who will get the job has ten coins in his pocket; but (d) Smith does not know that the man who will get the job has ten coins in his pocket. We thus have a counterexample to the claim that having a justified true belief in a proposition is sufficient for knowing it.

  12. Reject the case?

  13. Is this actually a counterexample?
  14. We might try rejecting it by claiming that there is no such possible situation - at least one of (a) - (d) is not true of the situation described.
  15. But wait, can we do that? Hasn't Gettier just stipulated that these are all true of the situation?
  16. No - coming up with a counterexample is much harder than that. For consider the claim: Necessarily, anyone who is a bachelor is a male. Suppose I say: "Consider a case in which someone is a bachelor but not a male - such a case shows us that the claim is false!" But just because I stipulate that the case is to be one in which someone is a bachelor but not a male, that doesn't mean that such a case is possible.
  17. What Gettier is doing is something like the following. He has a certain kind of situation in mind, and he tell us which. It is one in which: the man who will get the job has ten coins in his pocket, Smith believes this, and Smith has a certain reason for believing this. We are in no position to deny that these things are true of the situation Gettier has in mind. It is up to him which one he has in mind. We might object that he has failed to describe a possible situation, but the kind of case he has described does indeed seem to be possible.

    Gettier then makes two claims about this situation, which are indeed assessible by us for truth or falsity: that Smith is justified in believing that the man who will get the job has ten coins in his pocket, and that Smith does not know that the man who will get the job has ten coins in his pocket. As it turns out, these are claims that most of us tend to judge as being true.

  18. So there are two ways in which we can reject the proposed counterexample:
  19. The most promising of these seems to be to deny that Smith is justified in believing what he does.

    But this seems like a pretty clear case in which Smith is justified. If Smith is not justified, then is anyone ever justified? If we try to defend JTB by biting the bullet and claiming that justification is much harder than we all think, then we have to thereby claim that knowledge also is much harder than we all think. That seems like a pretty big cost. It seems much cheaper to accept that we have a genuine counterexample here, and a problem for JTB.

  20. What if we accept the case?

  21. Suppose we accept that we do indeed have a genuine counterexample here, so that JTB is false. What should we do?
  22. We could throw our hands in the air and give up on the project of finding an account of knowing.

    But that would be premature at this stage. That is better seen as a last resort, after many different accounts have been tried and found to fail. We will come back to that later.

  23. Most epistemologists have reacted by trying to find a better account of knowing. Some have looked for an additional condition, X, to add to the truth, belief and justification conditions, such that having a justified, true, and X belief is sufficient for knowing. This is called de-Gettierizing the JTB account, and the problem of trying to find such a condition is sometimes called the Gettier problem. Others have tried taking a different approach. We will consider some attempts of both kinds. For a comprehensive survey, see Shope, R. K. (1983), The Analysis of Knowing: A Decade of Research (Princeton, NJ: Princeton University Press).
  24. Whichever we do, from the Gettier cases we should learn more than just that the JTB account is false - we should and think about what has gone wrong – why does Smith lack knowledge in the case described?
  25. Unger's proposal

  26. What has gone wrong in the ten coins case - why does Smith not know that the man who will get the job has ten coins in his pocket?
  27. One natural idea is this: because it was just a matter of luck that his reasoning led to a true belief.
  28. Drawing on this idea, here is a proposal from Peter Unger (Unger, P. (1968), ‘An Analysis of Factual Knowledge’, Journal of Philosophy 65, pp. 157-70):

    Unger: Necessarily: for all s and p: s knows p iff it is not at all accidental that s is right about p being true.

    (Note the form of this account: it is not an identity claim, but a claim of necessary coextensivity.)

  29. But we can modify the ten coins case to get what is very plausibly a counterexample to this new proposal:

    The ten coins without luck case
    Let's add to the original ten coins case that there is someone on standby to make sure that the man who gets the job, whoever he is, has ten coins in his pocket, to make sure that Smith's belief is true. Then it is not at all accidental that Smith is right about the man who will get the job having ten coins in his pocket, but Smith still does not know that the man who will get the job has ten coins in his pocket.

  30. Unger might reply: it is at least to some extent accidental that Smith is right - it is accidental that someone decided to stick around and ensure that Smith's belief is true. So there is no problem here for the proposed account.
  31. But if Unger says this, then he gets himself onto a slippery slope towards saying that no one knows anything, or at least that much of what we take ourselves to know we don't actually know. Why? Because whenever we form a belief that is true, there will always be some extent to which it is lucky or accidental that we formed a true belief rather than a false one. Can you think of any cases in which it is not?
  32. Of course, Unger could bite the bullet on this, and accept it as a consequence of his account. But it seems like a very costly way of fixing the problem with the JTB account.
  33. The no false lemmas proposal

  34. Here is another natural thought about why, in the ten coins case, Smith does not know that the man who will get the job has ten coins in his pocket: his justification appeals to something false. He is justified in believing that the man who will get the job has ten coins in his pocket, but this justification is not sufficient to yield knowledge, because it appeals to something false.
  35. The idea is that there is an additional condition on knowing, to go with the truth, belief, and justification conditions. Call it the no false lemmas condition:

    Necessarily: for all s and p: if s knows p then s's justification for p does not appeal to any falsehoods.

  36. So we might try extending the JTB account by adding in this extra condition:

    NFL: To know a proposition is to have a justified true belief in it, such that the justification does not appeal to any falsehoods.

  37. Note again: the claim is not that one is not justified if one appeals to any falsehoods; it is the claim that any justification that appeals to a falsehood is not sufficient justification to yield knowledge.
  38. It seems that the ten coins case is not a counterexample to this account. And nor is the ten coins without luck case.
  39. But it is not too hard to come up with a Gettier-style counterexample to this new proposal. It turns out that there are Gettier-style cases in which the protagonist's justification appeals only to things that are true, but still she does not know (and perhaps even cases in which the protagonist's justification does not appeal to any propositions at all (and thus to no false propositions)).
  40. Here is a case of the first kind, taken from Feldman, R. (1974), 'An Alleged Defect in Gettier Counter-examples', Australasian Journal of Philosophy 52, pp. 68-9. (Note, Feldman was using this case for a different purpose.)

    The Nogot case
    Smith is justified in believing p: that Mr Nogot in his office has always been reliable and honest and has just announced that he owns a Ford. From p, Smith deduces q: that someone in his office has always been reliable and honest and has just announced that he owns a Ford. From q, Smith deduces r: that someone in his office owns a Ford. On this occasion Mr Nogot was lying, but someone else in the office owns a Ford. So r is true, Smith believes r, Smith is justified in believing r, and Smith's justification for believing r does not appeal to any falsehoods (p and q are both true). But Smith does not know r. So NFL is false.

  41. Here is a second case, a nice simple one:

    The stopped clock case
    Jane looks at a clock and sees that it shows 1pm. She forms the believe that it is 1pm. The clock is actually broken and stuck on 1pm, but, by chance it is 1pm. So it is true that it is 1pm, Jane believes that it is 1pm, Jane is justified in believing that it is 1pm (the clock says so), and her justification does not appeal to any falsehoods (it is true that the clock says so). But Jane does not know that it is 1pm. So NFL is false.

Exercise

Read:

Come up with your own Gettier case. Is it a problem for Unger's account? Is it a problem for the no false lemmas account? If not, modify your case so that it is a problem for both of these accounts as well.