Moral Rationalism and Moral Commitment

Abstract

Moral rationalism is identified as the view that moral constraints are rational constraints. This view seems implausible to many because it seems to involve belief in the fantastic-sounding possibility of egoist-conversion: that, in principle, an argument for moral constraints could be produced which would motivate a rational person who does not yet accept those constraints (i.e., an egoist) to observe them. Furthermore, the Humean want-belief model of motivation-the view that beliefs alone are incapable of motivating-seems to provide a good explanation for the impossibility of egoist-conversion. I argue that the moral rationalist is not in fact committed to the possibility of egoist-conversion, and that an explanation of its impossibility can be given which is compatible with rationalism; so this impossibility counts neither against rationalism nor for the want-belief model. I consider a number of apparent objections to my position and rebut them.