Gettier Problems
The Gettier Problem challenges the classical definition of knowledge as justified true belief.
In 1963, Edmund Gettier published a short paper ("Is Justified True Belief Knowledge?") presenting counterexamples where all three conditions are met, yet intuitively, the person would not be said to have knowledge.
The best example I know of a simple Gettier problem was formulated by Bertrand Russell in Human Knowledge: Its Scope and Limits (1948), predating Edmund Gettier’s 1963 paper.
Example
Suppose you glance at a clock that reads 4:20pm, and you form the belief that the time is 4:20pm. Coincidentally, it is 4:20pm — however, what you didn't know was that the clock was broken and always said 4:20pm.
- Your belief is true (it is 4:20pm).
- You are justified (you normally trust clocks).
- You believe it.
Russell’s case highlights the role of epistemic luck, a core concern in Gettier-style problems. While he did not frame it as a formal challenge to Justified True Belief, it foreshadowed Gettier's argument.
My own position sidesteps the problem rather than solving it: if the "true" condition can never be confirmed, the question of whether justified true belief is sufficient for knowledge never arises in practice. See Justified True Belief.