पुष्टि पर

परिचय

Hosiasson-Lindenbaum’s paper appeared in 1940 in the “Journal of Symbolic Logic”, when she was already living as a refugee in Vilnius. It sets out axioms for a degree of confirmation, understood as the probability of a hypothesis on the evidence, and applies them to the puzzle Carl Gustav Hempel had formulated shortly before: since “all ravens are black” is logically equivalent to “all non-black things are non-ravens”, a white shoe seems to confirm the hypothesis about ravens. Her answer: since non-black things far outnumber ravens, a black raven raises the probability of the hypothesis much more than a white shoe. Hempel discussed the solution in 1945 and Carnap built on her axioms in 1950; refined, it remains the standard Bayesian reply, though I. J. Good and others showed how much it depends on background assumptions.