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)
“Did my heart love till now? Forswear it, sight,
For I ne’er saw true beauty till this night.”
—William Shakespeare (1564–1616)
“My belief is that science is to wreck us, and that we are like monkeys monkeying with a loaded shell; we don’t in the least know or care where our practically infinite energies come from or will bring us to.”
—Henry Brooks Adams (1838–1918)