Justified true belief is a definition of knowledge that is most frequently credited to Plato and his dialogues. The concept of justified true belief states that in order to know that a given proposition is true, one must not only believe the relevant true proposition, but one must also have justification for doing so. In more formal terms, a subject S knows that a proposition P is true if and only if:
- P is true
- S believes that P is true, and
- S is justified in believing that P is true
This theory of knowledge suffered a significant setback with the discovery of Gettier problems, situations in which the above conditions were seemingly met but that many philosophers disagree that anything is known. Robert Nozick suggested a clarification of "justification" which he believed eliminates the problem: the justification has to be such that were the justification false, the knowledge would be false.
Famous quotes containing the words justified, true and/or belief:
“Oppression has no logic—just a self-fulfilling prophecy, justified by a self-perpetuating system.”
—Gloria Steinem (b. 1934)
“His true Penelope was Flaubert,”
—Ezra Pound (1885–1972)
“The belief that there are final and immutable answers, and that the professional expert has them, is one that mothers and professionals tend to reinforce in each other. They both have a need to believe it. They both seem to agree, too, that if the professional’s prescription doesn’t work it is probably because of the mother’s inadequacy.”
—Elaine Heffner (20th century)