Abstract

In his paper, "Explanations of Irrelevance" (1983), Paul Horwich proposes an amended version of hypothetico-deductivism, (H-D * ). In this discussion note it is shown that (H-D * ) has the consequence that "A is a non-black raven" confirms "All ravens are black" relative to any tautology! It is noted that Horwich's (H-D * ) bears a strong resemblance to Hempel's prediction criterion of confirmation and that the prediction criterion faces the same obstacle. A related problem for hypothetico-deductivism in its simplest form--that is, E confirms H iff E is an (observational) consequence of H--is displayed. The discussion concludes with a suggestion about how (H-D * ) and simple hypothetico-deductivism might be amended in order to avoid these results