Should Motivational Humeans be Humeans About Rationality

Abstract

For many years, the received view was that the Humean Theory of Motivation. concisely captured in the slogan that reason alone cannot motivate actions, is inconsistent with any very robust non-instrumental theory of rationality. This in turn meant that the Humean Theory was also incompatible with robust versions of moral rationalism." Recently various authors have advocated positions which challenge the prevailing orthodoxy in various ways. Michael Smith, for example, advocates both the Humean Theory of Motivation and an Anti-Humean theory of rationality.' And Christine Korsgaard, herself a rationalist, in at least one paper has seemed to argue that robust rationalism about moral judgements is compatible with Bernard Williams, Humean motivational assumptions in his well-known paper, "Internal and External Reasons." The trick, she suggests, is to think of rationality as requiring a certain sort of disposition, broadly classifiable as a desire whose content is such that rational individuals will always possess the desire that the Humean Theory requires for motivation." In this paper I will argue that the orthodox view has a lot going for it. Its strength can be easy to miss if we focus on idealized, fully rational and fully informed agents. The availability of information or the lack thereof can influence what we have reason to do, and I will argue that certain versions of rationalism have trouble taking account of this if they also want to remain consistent with a Humean theory of motivation. Furthermore, such rationalists often are not able to say what they should want to say about the reasons had by those who are somewhat irrational. My exposition will be somewhat dialectical. I begin by sketching some of the motivations for the orthodox position resting on motivational internalism about reasons for action. I will then outline a tempting strategy for making the Humean Theory of Motivation compatible with an anti-Humean theory of rationality. Mark van Roojen