Gettier problem

The Gettier problem, in the field of epistemology, is a landmark philosophical problem with our understanding of knowledge. Attributed to American philosopher Edmund Gettier, Gettier-type counterexamples (called "Gettier-cases") challenged the long-held justified true belief (or JTB) account of knowledge. On the JTB account, knowledge is equivalent to justified true belief, and if all three conditions (justification, truth, and belief) are met of a given claim, then we have knowledge of that proposition. In his three-page 1963 paper, titled Is Justified True Belief Knowledge?, Gettier showed, by means of two counterexamples, that there were cases where individuals had justified true belief of a claim, but still failed to know it. Thus, Gettier showed that the JTB account was inadequate—it could not account for all of knowledge. The JTB account was first credited to Plato, though Plato argued against this very account of knowledge in the Theaetetus (210a).

The term "Gettier problem", or "Gettier case", or even the adjective "Gettiered", is sometimes used to describe any case in epistemology that purports to repudiate the JTB account.

Responses to Gettier's paper have been numerous. Some rejected Gettier's examples, while others sought to adjust the JTB account to blunt the force of counterexamples. Gettier problems have even found their way into experiments, where the intuitive responses of people of varying demographics to Gettier cases have been studied.

The question of what constitutes "knowledge" is as old as philosophy itself. Its earliest instances are found in Plato's dialogues, notably Meno (97a–98b) and Theaetetus. Gettier himself was not even the first to raise the problem named after him; its existence is known to have been acknowledged by both Alexius Meinong and Bertrand Russell. The latter discussed it in his book Human knowledge: Its scope and limits.

Russell's case, called the stopped clock case, goes as follows: Alice sees a clock that reads two o’clock, and believes that the time is two o’clock. It is in fact two o'clock. There's a problem, however: unknown to Alice, the clock she’s looking at stopped twelve hours ago. Alice thus has an accidentally true, justified belief. Russell provides an answer of his own to the problem. Edmund Gettier's formulation of the problem was important as it coincided with the rise of the sort of philosophical naturalism promoted by W.V.O. Quine and others, and was used as a justification for a shift towards externalist theories of justification. John L. Pollock and Joseph Cruz have stated that the Gettier problem has "fundamentally altered the character of contemporary epistemology" and has become "a central problem of epistemology since it poses a clear barrier to analyzing knowledge".

...
Wikipedia