Virtue epistemology construes intellectual virtue as a reliable ability to form true beliefs. Responsibilist versions seek to substitute for the passive, reliabilist model of the knower, that of an active subject who deliberately and purposefully exercises traits of character which tend to result in true beliefs. On these views, the disposition to exercise these epistemic virtues gives rise to notions of epistemic duty.In this paper, I propose a principle of doxastic rationality based on Bernard Williams’argument against doxastic voluntarism. This principle, (...) I go on to show, undermines a number of notions of epistemic duty which have been put forth within the framework of virtue theory. I then suggest an alternative formulation which remains within the bounds of rationality allowed for by my principle. In the end, I suggest that the failure of the earlier formulations and the adoption of the latter tend to vindicate the initial grounding of virtue epistemology in reliabilist intuitions. (shrink)