By illustrating hypothetical cases in which a person has a justified true belief, and yet still does not have knowledge, Edmund Gettier's famous counterexamples (see footnote 1) certainly complicate, if not invalidate altogether, the definition of knowledge as justified true belief.
In Gettier's first counterexample, Smith "has strong evidence" (i.e., justification) for two propositions: "Jones is the man who will get the job," and "Jones has ten coins in his pocket." His evidence is "that the president of the company assured him that Jones would in the end be selected, and that he, Smith, had counted the coins in Jones's pocket ten minutes ago." From the two propositions, Jones reasonably infers a third: "[t]he man who will get the job has ten coins in his pocket." As it turns out, it is actually Smith and not Jones who gets the job. And Smith, by sheer coincidence, also happens to have ten coins in his pocket. Gettier's conclusion is that Smith did not really know that "[t]he man who will get the job has ten coins in his pocket," even though his belief in this proposition was justified and true.
In Gettier's second counterexample, Smith has "strong evidence" for the proposition, "Jones owns a Ford." His evidence is that "Jones has at all times in the past within Smith's memory owned a car, and always a Ford, and that Jones has just offered Smith a ride while driving a Ford." Smith also has a friend named Brown, "of whose whereabouts he is totally ignorant." Choosing three locations "quite at random," Smith "constructs" three disjunctive propositions:
1. Either Jones owns a Ford, or Brown is in Boston.
2. Either Jones owns a Ford, or Brown is in Barcelona.
3. Either Jones owns a Ford, or Brown is in Brest-Litovsk.
Smith is aware that each of these propositions is entailed by the original proposition, "Jones owns a Ford," and he accepts them "on the basis" of his justified belief that the original proposition is true: he is "therefore completely justified in believing each of" them. However, what Smith does not know is that Jones has recently gotten rid of his Ford and is now driving a rental car. What he also
does not know is that Brown, by some bizarre coincidence, is actually in Barcelona. Thus, Smith's belief that "either Jones owns a Ford, or Brown is in Barcelona" (proposition #2) is not only justified, but also true. And yet it can hardly be considered knowledge.
After illustrating these two cases, Gettier leaves us with a seemingly inevitable conclusion: the definition of knowledge as merely justified true belief-which he attributes to Plato, among others-does not "state a sufficient condition for someone's knowing a given proposition." In other words, it is not enough simply to have a justified true belief-one must have something more
in order to possess knowledge.
Although the logic behind Gettier's counterexamples is as close to being flawless as any logic can be-perhaps even as flawless as Descartes' cogito ergo sum-his overall argument is not without its weaknesses. Two unfounded assumptions tarnish the otherwise brilliant luster of his reasoning, leading us to question his method and doubt his conclusions. Let's have a look at them.
ASSUMPTION #1: Plato defines knowledge simply as "justified true belief."
In making this assumption, Gettier seems to suggest that Plato would consider any kind of evidence or reasoning (including Smith's) to be legitimate justification. This is by no means obvious. In the Meno
, Plato's persona, Socrates, speaks of justification as the "tie of the cause" that fastens true beliefs to their rightful origin in the soul (201); and in the Theaetetus
, Socrates refers to justification as "an account" or λογοs (98). While it is tempting to read "tie of the cause" to mean any
kind of causal connection, or to construe "account" to mean any
kind of account, nothing about these descriptions indicates that they should be interpreted so broadly. In fact, in the Theaetetus
, Plato (via Socrates) examines no fewer than three different explanations of justification, and every one of them he rejects. This alone should prove that Plato did not regard every kind of "account" or "tie" as a genuine form of justification; for if he did, he would have accepted every explanation.
The truth of the matter is that Plato never did decide exactly what justification is, nor did he ever settle upon a definition of knowledge that he felt was final or perfect. The Theaetetus
, which is his last major attempt to tackle the issue of knowledge, ends famously in aporia: neither justification nor knowledge is fully elucidated.
Thus, when Gettier suggests that his counterexamples prove Plato's definition of knowledge to be "false," he betrays an unfamiliarity with Plato's writings. For if Plato never explained justification to his own satisfaction-at least not in any of his extant dialogues-then it is reasonable to assume that he himself must already
have been aware that his definition of knowledge was incomplete, tentative, and imperfect. Gettier's counterexamples therefore do not tell us anything new-and they certainly do not
refute Plato. At most, they merely remind us that the question of knowledge has not yet been answered.
ASSUMPTION #2: Smith does not have knowledge.
In order to make the judgment that Smith does not have knowledge, Gettier must appeal to some prior standard, or idea, of what knowledge is: he must have before his mind an ideal conception of Knowledge, and then he must compare this conception to his perception of Smith's belief, to see whether the two are identical. If they are not identical, then Smith's belief (or at least Gettier's perception of it) falls short of the ideal conception, thus provoking Gettier to deliver his negative judgment.
Gettier's conception, if expressed in language, would most likely assume the form of a definition-e.g., "Knowledge is X." This definition would be (or rather, would express
) Gettier's own theory of knowledge, his own epistemology. One has to wonder, however, what would happen if Gettier were to put forth and defend his theory before the eyes of the world. Would the theory be universally excepted? or would it be contested by other brilliant philosophers with counterexamples similar to his? Seeing that even Plato's putative theory has been called into question, it is hard to imagine that Gettier's theory would be immune to any criticism-or any defects.
Yet even if Gettier's theory were
somehow immune, and therefore were the closest human approximation to the one correct conception of knowledge, this would not necessarily mean that Gettier knows
it to be such. For Gettier's belief in his conception may be no different than Smith's belief that the man who gets the job will have ten coins in his pocket-it may be justified and true, and yet still
not constitute knowledge.
Gettier's judgment that Smith does not have knowledge is an assumption because the conception that provoked it is-in the end-also an assumption. If Gettier's readers did not already have a roughly similar conception in mind-if they did not already share a somewhat related epistemic "worldview"-then they would not so readily assent to his judgment; they would not so easily be persuaded by his argument. A recent study (see footnote 2) published in Philosophical Topics
, in which individuals from both Western and non-Western cultures were asked to respond to several Gettier-style counterexamples, shows this to be the case. While Westerners were far more likely to say that the hypothetical subject (i.e., Gettier's "Smith") does not have knowledge, non-Westerners were far more likely to say that he does
. This raises a mischievous question: Are non-Westerners epistemically deficient, or are Westerners-and hence Gettier himself-simply wrong about knowledge?
If Gettier knows that he is not wrong, and if he can somehow get me to know
that he knows, then I will retract my claim that his judgment is based on an assumption.
1 Is Justified True Belief Knowledge?
2 Normativity and Epistemic Intuitions