A paradox of induction (1). Suppose a researcher wishes to confirm the hypothesis that all ravens are black, using the logic of induction. The more black ravens that are observed, the more probable the hypothesis becomes. But instead of going outside and examining ravens, the researcher may just as well stay indoors and observe a green carpet, a blue skirt, a brown egg, a grey telephone, and so on, because each of these is also a confirming instance of the hypothesis. The reason is that the propositions All ravens are black and All non-black objects are not ravens are logically equivalent: they are identical in meaning, different merely in wording. Logicians agree that there is no flaw in this reasoning; the difficulty is a purely psychological one arising from misguided intuition. Also called the confirmation paradox or the raven paradox. See also confirmation bias. Compare Goodman's paradox. [Named after the German-born US philosopher Carl (Gustav) Hempel (1905–97) who first expounded it in 1937 in the Swedish journal Theoria]
Subjects: Psychology — Philosophy.