Academia.eduAcademia.edu

How Does Epistemic Rationality Constrain Practical Rationality?

Abstract

This article investigates the relation between epistemic and practical rationality. I defend the view that actions based on epistemically irrational beliefs are practically irrational. In section 1, I introduce an argument to the contrary by Derek Parfit. In section 2, I discuss how certain facts about ordinary language bear on Parfit’s argument. In section 3, I demonstrate that relying on irrational beliefs in practical reasoning leads to the violation of a principle of instrumental rationality and thus to irrational actions. In section 4, I distinguish between two readings of the view defended and argue that both are true.