Edmund L. Gettier’s ‘Ist Justified True Belief Knowledge?’


This article will treat of Edmund L. Gettier’s paper ‘Ist Justified True Belief Knowledge?’.1 The paper, albeit very short, is so central because it is to the point and concise, and, most importantly, it tackles the long-held belief that justified true belief suffices for a proposition to qualify as knowledge. Although there have been many replies to Gettier’s challenge, I shall try a different approach, without, however, claiming total originality. The philosophical literature is growing too fast for one to make sure that no one else has come up with the same idea already.
I shall begin by summarizing Gettier’s most important points he sets out to prove (1). Then, I shall consider his examples, allegedly presenting cases of justified true belief which, nonetheless, fail to qualify as knowledge (2). Finally, I shall sum up my results (3).

1. The Analyses of Knowledge Gettier Considers

In his 1963 paper, Gettier considers the following three analyses of knowledge.

S knows that p if and only if

(i) p is true,
(ii) S believes that p,
(iii) S is justified in believing that p;

(i) S accepts that p,
(ii) S has adequate evidence for p,
(iii) p is true;2

(i) p is true,
(ii) S is sure that p is true,
(iii) S has the right to be sure that p is true.3,4

He explicitly assumes that both ‘has adequate evidence for’ and ‘has the right to be sure’ are substitutable by ‘ist justified in believing that’, such that if he can show a) to be false, the same argument will prove b) and c) to be false, too.5 Frankly spoken, I think this assumption of the legitimacy of the equation of the criteria, notwithstanding that Gettier formulates it as a conditional, presumptuous, in particular because he makes it without argument, even though the rest of his paper depends upon it. At best, the right to be sure depends upon having evidence, which, in turn, justifies a belief that p. Moreover, a) (ii) and b) (i) may be equivalent, but, as I demonstrated in ‘Defining Knowledge’6, both are not equivalent to c) (ii), since one can believe that p while not being sure that it be true, albeit p indeed is true and one has the right to be sure owing to justifying evidence e that p, without contradiction. Therefore, being sure and believing are not the same propositional attitudes, and thus ‘S is sure that p’ is an additional criterion of Ayer’s analysis which latter needs to entail ‘S believes that p’ in order to yield knowledge. Ayer himself does not state this explicitly, to be sure, yet on my reading he alludes to it. Whether he does so, howbeit, does nothing to the necessity of adding ‘S believes that p’ to his analysis.
There is, methinks, also something problematic about equating b) with a), because a) (iii) and b) (ii) are not necessarily the same. For, having appropriate evidence e for p internally justifies the belief that p if and only if (I) S realizes e and (II) S makes use of e to justify their belief that p. So, recalling the example from my last article, which I used to show why Ayer adds the condition that S be sure that p, if Sarah perceives a wasp crossing her visual field, believes that a wasp crossed her visual field, and a wasp in fact crossed her visual field, but is not sure whether it actually was a wasp that crossed her visual field, she is externally justified, though not internally, because on the one hand, she realizes that she could use her perception as evidence, but, on the other, does not make use of it, as she mistrusts it, that is, entertains the internal (logical) defeater that her perception may be wrong. If this is correct, it is not only of importance that S have adequate evidence e for p objectively, but at the same time deem e sufficient for justifying the belief that p subjectively. On this account, it seems there is an ambiguity in the expression ‘adequate evidence’, or a lack of detail in either Chisholm’s analysis or Gettier’s way of putting it. Regardless of how this may be, Gettier is mistaken in equating b) with a), so that, even if he be successful in arguing that a) be false, his contrived cases could not show b) and c) to be false, too.
I now turn to Gettier’s two contrived cases.

2. Gettier’s Two Cases

In the first, and by far better known, case Gettier contrives to prove that justified true belief may not always yield knowledge, he asks us to imagine two people, called Smith and Jones respectively, to apply for the same job.7 He asks us further to imagine that Smith have strong evidence—namely, that the company’s president have assured him that the company would eventually choose Jones, and, in addition, that Smith have counted the coins in Jone’s pocket ten minutes ago—for the conjunctive proposition

(d) Jones is the man who will get the job, and Jones has ten coins in his pocket.8

Gettier correctly goes on to say that (d) entails

(e) The man who will get the job has ten coins in his pocket.9

Therefore, Gettier contends, granted that Smith grasps the entailment of (e) by (d), he is justified in believing in the truth of (e). He then adds, however, the following stipulations:

But imagine, further, that unknown to Smith, he himself, not Jones, will get the job. And, also, unknown to Smith, he himself has ten coins in his pocket. Proposition (e) is then true, though proposition (d), from which Smith inferred (e), is false.10

His conclusion reads:

In our example, then, all of the following are true: (i) (e) is true, (ii) Smith believes that (e) is true, and (iii) Smith is justified in believing that (e) is true. But it is equally clear that Smith does not know that (e) is true; for (e) is true in virtue of the number of coins in Smith’s pocket, while Smith does not know how many coins are in Smith’s pocket, and bases his belief in (e) on a count of the coins in Jone’s pocket, whom he falsely believes to be the man who will get the job.11

This conclusion, in spite of its prima facie appeal, is faulty in several aspects, however, even granted that a lying company president is irrelevant for the presented case in sum. First, (e) is true only in a logical connection to (d) because Smith takes the whole proposition ‘The man who will get the job has ten coins in his pocket’ to be a(n epistemically) rigid designator in the actual world, that is to say, Smith additionally (or in fact) believes the equation

(j) The man who will get the job has ten coins in his pocket = Jones

or alternatively, the more exact conjunction

(j′) The man who will get the job has ten coins in his pocket, and there is one and only one man (in this place and time) who has ten coins in his pocket, and this man is Jones.

As it turns out, though, (e) is not a rigid but an ambiguous designator if only logically but not epistemically connected to (d). Thus, albeit Smith may be said to be subjectively (internally) justified, even so he is not justified objectively (externally), since his justification which he subjectively deems adequate evidence is objectively inadequate.12 Stated differently, false evidence is not evidence at all, so Smith is actually not justified in his belief, and therefore this is not a case of justified true belief.

Turning to Gettier’s second case, we are asked to conceive of Smith and Jones again. But this time Gettier wants us to imagine that Smith has strong evidence for the proposition

(f) Jowns owns a Ford.13

The evidence comprise that up to now, Jones have always owned a Ford, and just at this moment offer Smith a ride in a Ford he (Jones) is driving.14 Smith have, what is more, another friend named Brown, yet does not know where Brown be now. As a disjunction ‘p ∨ q’ is logically true if at least one of its arguments is true, that is to say, at least either p or q must be true in order to make the whole proposition true, Smith then forms three disjunctive propositions, each with (f) as its first argument and three respectively arbitrarily chosen places in the world as its second argument:

(g) Either Jowns owns a Ford, or Brown is in Boston;
(h) Either Jones owns a Ford, or Brown is in Barcelona;
(i) Either Jones owns a Ford, or Brown is in Brest-Litovsk.15

Here Gettier says that each proposition of (g) – (i) were entailed by (f).16 I feel uncomfortable about the term of entailment. Each of (g), (h), and (i) respectively entail (f), yet (f) does not entail (g) – (i), since this would empty and ridicule the concept of entailment. What is correct is that forming a disjunction out of a true proposition p and another proposition q, regardless of the latter’s truth value, neither alters p’s truth value nor makes the disjunction as a whole turn out false. But even if we took it that this alleged entailment held logically, it would not do so epistemically. The reason for this is that Smith’s manner of forming (g) – (i) (epistemically) renders all three propositions, by definition, mere guesswork. Guessing, however, can never count as knowledge.
But let us assume, for the sake of argument, that Gettier were right in that (f) entail (g) – (i). He extends the case by attaching the empirical, objective defeater that, unknown to Smith, Jones, as a matter of fact, does not own a Ford at present but is driving a rented car, while Brown coincidentally actually is in Barcelona, as (h) purports.17 According to Gettier, this case present a case of justified true belief, despite its not being knowledge.18
Again, as in the first case, the objection applies that, even given that Smith be logically and subjectively (internally) justified in believing that (h), he cannot be so epistemically and objectively (externally), since (f) in point of fact turns out false.

3. Conclusion

If my objections to Gettier’s cases hold, Gettier has failed to show how there could be cases of justified true belief in the sense of my analysis (which I attribute to Kant)19 which do not turn out as knowledge. It goes without saying that this does not rule out the possibility of cases of justified true belief which are not cases of knowledge simultaneously in principle. We shall see in articles to come whether there be any successful examples given in the philosophical literature.

1. Gettier, Edmund L.: ‘Is Justified True Belief Knowledge?’ in Analysis 23, pp. 121–123; Oxford: Blackwell Publishers, 1963, reprinted in Bernecker, Sven and Dretske, Fred (eds.): Knowledge. Readings in Contemporary Epistemology, pp. 13–15; Oxford: Oxford University Press, 2000, reprinted 2005. [All citations and references are from/to this edition, IJTBK, for short.]
2. via Chisholm in Chisholm, Roderick M.: Perceiving: a Philosophical Study; Ithaca, New York: Cornell University Press 1957, p. 16.
3. via Ayer in Ayer, A. J.: The Problem of Knowledge; London: Macmillan 1956, p. 34.
4. Confer: IJTBK, p. 13.
5. Op. cit.
6. Confer: ‘Defining Knowledge’, 3. A. J. Ayer: http://wp.me/p1QVNW-oD.
7. Confer: IJTBK, p. 14.
8. Op. cit.
9. Op. cit.
10. Op. cit.
11. Op. cit.
12. This is the point I hinted at in ‘Defining Knowledge’, 2. Immanuel Kant: http://wp.me/p1QVNW-oD.
13. Confer: IJTBK, p. 14.
14. Op. cit.
15. Op. cit.
16. Op. cit.
17. Op. cit., pp. 14-15.
18. Op. cit., p. 15.
19. Confer: Kant, Immanuel: Kritik der reinen Vernunft; Hamburg: Felix Meiner Verlag 1998, A 822/B 850 [The pagination follows the two original (German) editions from 1781 (A) and 1787 (B)] or Kant, Immanuel: Critique of Pure Reason; translated by Norman Kemp Smith; New York: Palgrave Mcmillan 1929; second edition published 1933, A 822/B 850 [The pagination follows the two original (German) editions from 1781 (A) and 1787 (B).].


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