Abstract

In this paper, I present a puzzle about the connection between an agent’s knowledge and her rationality and a way to solve it. The puzzle is that, intuitively, many of us want to accept both that it is rational for an agent to act on what she knows and that it is irrational for an agent to take what she knows for granting in her practical reasoning. These two claims about rationality present us with a puzzle because, holding fixed our interpretation of rationality, we cannot accept them both. According to my view, the most compelling way of solving this puzzle is to distinguish between our primary and dispositional evaluations of actions. By making this distinction, we not only gain a unique perspective on the relationship between knowledge and rationality, we also see how doing what we know is best might still manifest an undesirable habit.