Abstract

A number of philosophers have recently claimed that unjustified beliefs can be defeaters. However these claims have been made in passing, occurring in the context of defenses of other theses. As a result, the claim that unjustified beliefs can be defeaters has been neither vigorously defended nor thoroughly explained. This paper fills that gap. It begins by identifying problems with the two most in-depth accounts of the possibility of unjustified defeaters due to Bergmann and Pryor. It then offers a revised version of Pryor’s account. On this proposal, an unjustified belief can be a defeater if it is rational, all things considered. If a belief is rational, all things considered, it can require one to abandon other beliefs with which it conflicts—even if it is unjustified. Finally, this paper shows that the proposed account of unjustified defeaters is one that can and should be embraced by leading accounts of justified belief as diverse as reliabilism and evidentialism.