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:
“If all mankind minus one, were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person, than he, if he had the power, would be justified in silencing mankind.”
—John Stuart Mill (1806–1873)
“Earth in beauty dressed
Awaits returning spring.
All true love must die,
Alter at the best
Into some lesser thing.
Prove that I lie.”
—William Butler Yeats (1865–1939)
“They have their belief, these poor Tibet people, that Providence sends down always an Incarnation of Himself into every generation. At bottom some belief in a kind of pope! At bottom still better, a belief that there is a Greatest Man; that he is discoverable; that, once discovered, we ought to treat him with an obedience which knows no bounds. This is the truth of Grand Lamaism; the “discoverability” is the only error here.”
—Thomas Carlyle (1795–1881)