BonJour presents a coherence theory of justification for empirical knowledge. What justifies our empirical beliefs is their coherence with our other beliefs, which is more than mere consistency between beliefs. Coherence involves various relations, including inferential and explanatory relations. Explaining justification in terms of coherence is also different from offering a coherence theory of truth, which he rejects in favor of the correspondence theory. BonJour also strongly argues in favor of an internalist view of justification as opposed to an externalist view.

He argues that foundationalist theories cannot explain empirical justification, which leaves coherence theories as the best alternative. However, by insisting that a coherence theory has to allow for observational input (the “Observation Requirement”), he ends up with a theory that seems almost as foundationalist as coherentist. He recognizes this fact and concedes that a “pure” coherence theory will not work. In fact, in later years, BonJour abandoned the coherence theory of justification he defended in this book. (10/10/10)