Realism,Rational Action,and the Humean Theory of Motivation

Realists about practical reasons agree that judgments regarding reasons are beliefs. They disagree, however, over the question of how such beliefs motivate rational action. Some adopt a Humean conception of motivation, according to which beliefs about reasons must combine with independently existing desires in order to motivate rational action; others adopt an anti-Humean view, according to which beliefs can motivate rational action in their own right, either directly or by giving rise to a new desire that in turn motivates the action. I argue that the realist who adopts a Humean model for explaining rational action will have a difficult time giving a plausible account of the role that desire plays in this explanation. I explore four interpretations of this role and argue that none allows a Humean theory to explain rational action as convincingly as an anti-Humean theory does. The first two models, in different ways, make acting on a reason impossible. The third allows this possibility, but only by positing a reason-sensitive desire that itself demands an explanation. The fourth avoids this explanatory challenge only by retreating to an empty form of the Humean view. In contrast, an anti-Humean theory can provide an intuitively plausible explanation of rational action. I conclude that the realist about reasons should adopt an anti-Humean theory to explain rational action.

Melissa BarryEmail: