Credence, Conditionals, Knowledge and Truth

Abstract

Epistemology, strictly speaking, is the theory of knowledge: what it is, when we have it, why it is valuable, what we can do with it. But the term has come to be used more widely, to include the theory of reasonable belief, rational belief change, non-conclusive inference, etc., in cases where knowledge may not be obtainable. Especially under the heading ‘formal epistemology’, probability theory typically plays a prominent role here, while it typically does not play much of a role in traditional, knowledge-centred epistemology, because, it is natural to think, probability theory typically governs something weaker than knowledge. It is about the management of uncertainty. Sarah Moss’s book Probabilistic Knowledge is revolutionary. It shares with traditional epistemology the claim that knowledge is the central concept. On the other hand, it is probabilistic through and through. In short, our ordinary probability judgements can be knowledge. There are different kinds of probability. Maybe we can know objective chances, but that is not Moss’s target. Maybe we can know that a certain body of evidence renders probable a conclusion, but that is not the target either. Our ordinary probability judgements are not statements about their relation to a body of evidence. The subject may not be capable of such second-order judgements. ‘Fido can believe that you are probably about to take him outside without being capable of any second-order belief about what is consistent with his evidence’ (23).1 The target is our ordinary credences – degrees of closeness to certainty, expressed by ‘probably’, ‘more likely than not’, etc. Recurrent examples are ‘Jones probably smokes’ and ‘it is 0.6 likely that Jones smokes’.