Category: epistemology
Type: thought experiment
Associated thinker(s): Edmund Gettier
Original publication or approximate period: “Is Justified True Belief Knowledge?” (1963)
Difficulty: Intermediate
Themes: knowledge, justification, epistemic luck
Related experiments: Fake-Barn Country; Russell’s Five-Minute World
Smith has strong evidence that Jones will get a job, and Smith has counted ten coins in Jones’s pocket. Smith therefore believes that the person who will get the job has ten coins. Unknown to Smith, the job goes to Smith instead; by coincidence, Smith also has ten coins.
Smith’s conclusion is true, and Smith reached it from evidence that seemed good. Yet the evidence connected the conclusion to Jones, whereas the truth depends on Smith. This is one of the structures used by Gettier to challenge an analysis of knowledge as justified true belief. The job and coins are stipulated details, not a report of an employment study.
Is justified true belief sufficient for knowledge when the route to truth involves epistemically troublesome luck?
The case shows how an account can include several attractive conditions and still admit counterexamples. It also distinguishes reasonable belief from knowing: Smith need not have been irresponsible or irrational for the knowledge attribution to seem doubtful. Improving a definition requires explaining what goes wrong, not simply adding the word “nonaccidental.”
Add a condition: proposals exclude false intermediate assumptions or require a suitable causal connection between the fact and the belief. Other cases test whether these repairs are broad enough.
Modal approaches: sensitivity and safety ask how the belief behaves in relevant nearby possibilities. Would Smith easily have believed falsely using the same method?
Virtue or knowledge-first approaches: some emphasize success attributable to cognitive ability; others question the project of reducing knowledge to an independent list of conditions. These approaches need not agree about every borderline example.
Gettier did not demonstrate that knowledge is impossible. His paper challenges a proposed sufficient condition. Avoid attributing a simple justified-true-belief formula uncritically to Plato: the historical relationship is more complicated. Also, a lucky event somewhere in the background does not necessarily eliminate knowledge; the kind and location of luck matter.
Stopped-clock and deceptive-environment stories broaden the family. Fake-barn country is especially useful because the subject may perceive a real object accurately without inferring through an explicitly false premise. Some theorists classify such cases separately, so the family resemblance should not erase the distinction.
Gettier’s 1963 article is the immediate modern source. The retrieved SEP analysis verifies its central challenge and surveys responses, including their limits. The narrative and questions are original explanatory prose; no single response is presented as a settled solution.
Research check: 2026-10-30. References above were retrieved for the support described; this is an original educational explanation, not a substitute for the primary texts. Additional speculative comparisons are teaching prompts, not established historical variations.