The Gettier Problem

Traditionally, knowledge has been taken to yield a reductive analysis in terms of (conceptually primitive) necessary and jointly sufficient conditions—most commonly, justified (or warranted) true belief. In 1963, however, Edmund Gettier’s “Is Knowledge Justified True Belief?” challenged the reductive model of knowledge by producing a series of counterexamples where, intuitively, a justified true belief fails to be knowledge. Since Gettier’s original challenge, the philosophical literature has been replete with attempts to defend the reductive analysis against Gettier counterexamples (now generalized well beyond the cases posed in 1963) and those claiming that such defenses fail.