A Probabilistic Theory of the Coherence of an Information Set

Bonjour (1985: 101 and 1999: 124) and other coherence theorists of justifi-cation before him (e.g. Ewing, 1934: 246) have complained that we do nothave a satisfactory analysis of the notion of coherence. The problem withexisting accounts of coherence is that they try to bring precision to our in-tuitive notion of coherence independently of the particular role that it ismeant to play within the coherence theory of justification (e.g Lewis, 1946:338). This is a mistake: it does not make any sense to ask what preciselymakes for a more coherent information set independently of the particularrole that coherence is supposed to play within the context in question. Whatis this context and what is this role? The coherence theory of justificationrides on a particular common sense intuition: when we gather informationfrom less than fully reliable sources, then the more coherent the story thatmaterializes is, the more confident we may be,