Full Idea
Epistemologists have noted that logical entailments do not always constitute reasons. P may entail Q without the connection between P and Q being at all obvious.
Gist of Idea
Logical entailments are not always reasons for beliefs, because they may be irrelevant
Source
John L. Pollock (Epistemic Norms [1986], 'Ref.of Extern')
Book Reference
'Epistemology - An Anthology', ed/tr. Sosa,E. /Kim,J. [Blackwell 2000], p.204
A Reaction
Graham Priest and others try to develop 'relevance logic' to deal with this. This would deny the peculiar classical claim that everything is entailed by a falsehood. A belief looks promising if it entails lots of truths about the world.