Can a True Justified Belief Still Not Be Knowledge? A Three Page Paper Said Yes

The traditional account holds that a person knows something when three conditions are met together. The belief must be true, since nobody knows something false. The person must actually believe it, since knowing without believing makes no sense. And the belief must be justified, meaning held for good reasons rather than by luck or guesswork. Each condition is clearly necessary, and the account holds that together they are sufficient. That analysis appears in Plato and was treated as settled for a very long time, appearing in textbooks as the standard account of what knowledge is.

Edmund Gettier's 1963 paper produced cases with a consistent structure:

• •A person believes something on genuinely good evidence
• •That evidence is nonetheless mistaken about the particular case
• •The belief turns out to be true anyway, by coincidence
• •So all three conditions are satisfied
• •And yet calling it knowledge seems plainly wrong
• •So the three conditions are not sufficient after all

A worked example makes the structure concrete. Somebody looks at a field and sees what appears to be a sheep, and forms the belief that there is a sheep in the field, which is a perfectly reasonable thing to conclude from seeing one. What they are actually looking at is a large dog that resembles a sheep from a distance. However, there is in fact a sheep in the field, hidden behind a hill and entirely out of sight. The belief is true, it is believed, and it is justified by ordinary visual evidence, yet the person's reason for holding it has nothing to do with what makes it true, and almost nobody wants to call that knowledge.

The whole argument rests on the reader agreeing that the case is not knowledge, and whether that agreement is universal became an empirical question. Experimental philosophy has put these cases to people who have never studied the subject and measured their responses, and the early results suggested that the judgement varied by cultural background, which would have been a serious problem for an argument built on a shared intuition. Later and larger studies have generally found the judgement more robust than that across groups, while confirming that details of how the case is presented shift responses substantially. The method itself remains contested within philosophy.

Attempts to repair the definition have been numerous and none has been generally accepted, which is the durable result. Adding a fourth condition requiring that the belief not rest on any false premise handles some cases and fails against others constructed specifically to avoid false premises. Requiring that the belief be produced by a reliable process shifts the problem to specifying reliability. Requiring that the person would not hold the belief if it were false runs into difficulties with necessary truths. A substantial minority position holds that knowledge cannot be analysed into simpler conditions at all and should be treated as basic.

Knowledge was defined as belief that is true and justified, and a 1963 paper showed that all three can hold while the belief is true only by coincidence, so the justification has nothing to do with what makes it true. The field with a dog that looks like a sheep and a hidden real sheep is the standard illustration. No repair to the definition has been generally accepted since.