Abstract

I argue that rational support can be found for the essence of morality, which is conceived as impartially valuing the interests of others as being as weighty as one's own. That is, the question is what rational grounds can be given for moral intersubjectivity, where intersubjectivity is conceived as universal agreement determined by or turning on something universally shared or outside the self. Several reasons for skepticism are examined, including J. L. Mackie's argument from queerness. ;Mackie is answered by developing internalism, which explains intersubjective values not by means of a questionable metaphysics, but instead holds that they are complicated motivational dispositions shared by all rational beings. ;I examine and modify the rational foundation for ethics presented by Stephen Darwall in his 1983 Impartial Reason. After an initial, subjective, account of rational action is produced, Nagel's and Gauthier's approaches to grounding an intersubjective account are examined and rejected, though elements of Gauthier's approach are retained. I argue that only practical rationality can be the foundation for an acceptable morality, and then unpack and modify Darwall's concept of an intersubjective normative system, which we take practical nationality to be. I conclude that two of Darwall's principles capture an important part of the nature of practical rationality, although the remainder of his system does not. ;Building on these foundations, I develop and criticize a two stage view. On either view, I argue, vicious action is rationally proscribed, although neither view produces entirely intuitively satisfactory accounts of our duties of benevolence