Abstract

ABSTRACT The target of John Broome’s critique is a certain kind of reductive project: that of reducing the property of rationality to that of normativity, or the property of being rational to that of being as we ought or have conclusive reason to be. Broome argues that this reductive project fails, because the identity claim on which it rests is false. Rationality, he argues, supervenes on the mind: two people who are mental duplicates are necessarily also rational duplicates. But normativity, or reasons-responsiveness, or being as we ought to be does not supervene on our minds: two people who are mental duplicates may not be normative duplicates. I am interested in the appeal of and prospects for the opposite reduction: of reasons, or normativity, understood as the property of being how one ought to be, to rationality. But because this reduction also entails the identity claim that Broome rejects, its success also depends on addressing Broome’s worries. This commentary has two aims: first, to motivate the project of reducing normativity or obligation or reasons to rationality, by bringing out what is attractive about it; and second, to argue that the project is not simply a non-starter, by taking up Broome’s challenge to the identity claim: like rationality, I argue, normativity, too—or at least the species of normativity that the reductive project targets—does supervene on the mind.