Why Believability Cannot Explain Belief Revision

A common view in epistemology is that some beliefs are more entrenched than others. This view is plausible, but we show that it fails to explain which statements individuals tend to doubt when an incontrovertible fact is inconsistent with the relevant set of statements. We report three studies that each show that the believability of statements is influenced by context. Given a conditional of the form If P then Q and a categorical statement P, individuals tend to judge the categorical as more believable than the conditional. But, when the same statements are followed by an incontrovertible fact, not-Q, that is inconsistent with them, individuals tend to judge the conditional as more believable than the categorical. The theory of mental models accounts in part for these and other results of the experiments, including a study of the believability of exclusive disjunctions and categoricals.