insufficient reason

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The principle introduced by the English mathematician and Presbyterian clergyman Thomas Bayes (1702–61), and championed by the French mathematician Pierre Simon Laplace (1749–1827), according to which we are entitled to consider two events as equally probable if we have no reason to consider one more probable than the other. It enables uncertainty (2) to be transformed into risk (2) and provides a justification for prior probabilities (2) in Bayesian inference in the absence of other grounds for estimating them. Its critics have shown that it leads to contradictions, and they deny that anything can be inferred from ignorance. Also called the principle of indifference.

Subjects: Psychology.

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