ABSTRACT
This chapter provides an overview of some key arguments on behalf of internalism and externalism, respectively. It looks at how the debate over internalism interacts with the debate over moral rationalism. Moral rationalism, is the view that morality necessarily provides normative reasons. The chapter also provides the discussion of moral rationalism as a general frame to discuss some of the major versions of internalism. Much of the critical discussion of internalism has revolved around extensional objections. These objections attempt to show that internalism predicts either that there are too few normative reasons or too many normative reasons. Given very plausible assumptions about the distribution of desires, Simplest Internalism cannot vindicate any of the rationalist theses. Simplest Internalism requires one to desire to perform a specific action in order for there to be a normative reason to perform that action. Full Information Idealized Internalism also has problems with the rationalist theses.
