Normative Source and Extensional Adequacy

Internalists about practical reasons maintain that all of an agent’s reasons for action derive their normative force via some relation in which they stand with that agent’s pro-attitudes, or the pro-attitudes that the agent would have in some idealized set of circumstances. One common complaint against internalism is that the view is extensionally inadequate – that it cannot render the correct verdicts about what reasons agents have in a range of important cases. In this paper, I examine that charge of extensional inadequacy, taking as my starting point an argument that Derek Parfit has recently leveled against internalism. Through a close evaluation of that argument and potential replies to it, I attempt to show that internalists cannot accommodate important pre-theoretical intuitions about what reasons we have. However, I also argue that Parfit’s case is importantly overstated; I set out to show that his argument cannot establish, as he thinks it does, that no reasons derive their normative force in the way that internalists believe that all do. In doing so, I draw attention to the possibility of a hybrid position about practical reasons that, surprisingly, receives little attention in the existing literature. If the arguments of the paper succeed, I will have established a modest theoretical advantage for hybridism over internalism – namely, that it is not vulnerable to the charge of extensional inadequacy. My hope is that this goes some way toward establishing hybridism’s credentials as a serious alternative to its “pure” competitors