Akrasia and Epistemic Impurism

This essay provides a novel argument for impurism, the view that certain non-truth-relevant factors can make a difference to a belief's epistemic standing. I argue that purists, unlike impurists, are forced to claim that certain ‘high-stakes’ cases rationally require agents to be akratic. Akrasia is one of the paradigmatic forms of irrationality. So purists, in virtue of calling akrasia rationally mandatory in a range of cases with no obvious precedent, take on a serious theoretical cost. By focusing on akrasia, and on the nature of the normative judgments involved therein, impurists gain a powerful new way to frame a core challenge for purism. They also gain insight about the way in which impurism is true: my argument motivates the claim that there is moral encroachment in epistemology.