Edmund Gettier
1927 CE – 2021 CE · Contemporary Era
“The philosopher who destroyed a 2,400-year-old theory of knowledge in three pages.”
Biography
An American epistemologist at Wayne State University and later the University of Massachusetts Amherst. In 1963, Gettier published 'Is Justified True Belief Knowledge?', a three-page paper containing two counterexamples to the analysis of knowledge that had been accepted, in various forms, since Plato. The paper generated one of the largest literatures in the history of philosophy: thousands of articles, dozens of books, and an entirely new subfield. Gettier himself published almost nothing else in his career, reportedly finding the attention bewildering.
Major Works
Key Arguments
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The Gettier Cases
Since Plato, philosophers had generally accepted that knowledge is justified true belief (JTB): you know something when you believe it, your belief is true, and you have good reasons for believing it. Gettier constructed two devastatingly simple counterexamples. In one: Smith has strong evidence that Jones will get the job and that Jones has ten coins in his pocket. Smith forms the justified belief that 'the man who will get the job has ten coins in his pocket.' But unbeknownst to Smith, he himself will get the job, and he also happens to have ten coins in his pocket. His belief is justified and true, but it is clearly not knowledge, because it is true for the wrong reasons. His justification points to Jones, but the truth-maker is Smith himself.
Why it matters: Overturned the JTB analysis that had stood since antiquity. The Gettier cases revealed that justification and truth can come apart, a belief can be justified and true without the justification having anything to do with why the belief is true. This three-page paper generated more philosophical literature than works a hundred times its length.
The Problem of Epistemic Luck
What the Gettier cases reveal is a deeper problem: knowledge seems incompatible with a certain kind of luck. In Gettier scenarios, the believer arrives at a true belief through reasoning that is perfectly sound but that only happens to connect to the truth by accident. Smith's belief is true by sheer coincidence, his good reasoning and the fact that makes his belief true are entirely disconnected. This suggests that knowledge requires not just justified true belief but some appropriate connection between the justification and the truth. But specifying that connection has proved extraordinarily difficult. Every proposed analysis has faced its own counterexamples.
Why it matters: Revealed that the problem of knowledge is far deeper than philosophers had assumed. The concept of epistemic luck, being right for the wrong reasons, has become central to contemporary epistemology. It connects to questions about reliability, safety, sensitivity, and what distinguishes genuine cognitive achievement from fortunate guessing.
The Fourth Condition Problem
After Gettier, epistemologists spent decades trying to repair the JTB analysis by adding a fourth condition, some additional requirement that would rule out Gettier cases while preserving genuine knowledge. Proposed fixes included: the belief must not depend on any false assumptions (the 'no false lemmas' condition), the belief must be produced by a reliable cognitive process (reliabilism), the belief must be such that it would not be held if it were false (the sensitivity condition), and the belief must be safe, true in all nearby possible worlds where it is held (the safety condition). Each proposal faced devastating counterexamples of its own. Some philosophers concluded that knowledge simply cannot be analyzed into necessary and sufficient conditions, that it is a primitive concept, not reducible to belief plus additional ingredients.
Why it matters: The failure to solve the Gettier problem after sixty years of concentrated effort is itself philosophically significant. It suggests either that knowledge is more complex than any simple analysis can capture, or that the entire project of conceptual analysis, breaking concepts into necessary and sufficient conditions, has fundamental limitations. The Gettier problem thus became a test case for the methodology of analytic philosophy itself.
Lasting Influence
Destroyed the classical analysis of knowledge with the shortest landmark paper in philosophical history and generated an entire subfield of epistemology.
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The Companion Guide
Seven eras of philosophy in one volume — reading lists, key terms, journal prompts · $19.99