Gettierexempel

Gettierexempel refers to a class of thought experiments in epistemology that challenge the idea that knowledge is simply justified true belief. The term comes from Edmund Gettier, who in 1963 published counterexamples showing that a person can have a justified true belief without intuitively possessing knowledge. The central lesson is that justification, truth, and belief can align by luck, so they do not guarantee knowledge as a matter of that alignment alone.

The best-known Gettier example, often called the Smith–Jones case, proceeds as follows: Smith has strong justification for believing that Jones will get the job, and he also has justification for believing that Jones has ten coins in his pocket. From these, Smith infers that “the person who will get the job has ten coins in his pocket.” It turns out that Jones does indeed get the job and has ten coins, so the belief is true and justified, yet many readers feel it does not constitute knowledge because the truth of the belief rested on a lucky coincidence rather than on the reliability of the justification.

Another influential variant is the fake barn county case, where a person looks at a real barn among many fake barn facades and forms the true, justified belief that they are looking at a barn. Although the belief is true and supported by perception, the surrounding context makes it seem no more secure as knowledge than in the Smith–Jones example, since the justification would have supported the belief in many misleading scenarios.

Gettier problems have prompted extensive debate and a search for a more robust account of knowledge. Proposals include adding conditions such as no false lemmas, safety, or causal/reliabilist theories, and broader efforts to refine how justification relates to truth and belief.