Ideal rationality and the relation between propositional and doxastic justification

Abstract

In this paper, I explore how the ideal rationality-based account of propositional justification impacts our understanding of the relation between propositional and doxastic justification. The ideal rationality-based account sits uncomfortably with the widely accepted claim that propositional justification is necessary for doxastic justification. In particular, the combination of the necessity claim and the ideal rationality-based account of propositional justification entails that some plausible doxastic attitudes are doxastically unjustified and thereby severs epistemic justification from connections with epistemic responsibility and the competent formation of beliefs. Thus, those who endorse both the necessity claim and the ideal rationality-based account of propositional justification will be forced to give up either their account of propositional justification or the necessity claim. I argue that there is good reason to give up the ideal rationality-based account of propositional justification instead of the necessity claim. This result indicates that an adequate account of propositional justification should be sensitive to the agent’s cognitive capacities. If propositional justification should be understood in this way, then the widely accepted explanation of doxastic justification in terms of propositional justification is not promising either. This is because an agent’s cognitive capacities and limitations play a prominent role in understanding propositional justification. Instead, I argue that, at the explanatory level, propositional justification relies on doxastic justification.