Raven paradox
= Raven paradox
{wiki}
“All ravens are black” is <logically equivalent> to “all nonblack things are nonravens”. An unrestricted rule that positive instances confirm universal generalizations would make a white shoe confirm the first statement. A <Bayesian confirmation> account instead conditions on background knowledge and the sampling procedure.<Studies in the Logic of Confirmation I by Carl Hempel>[section 5]{ref}