Abstract

While all complete ethical theories need a plausible conception of their morally significant units , that conception is rarely explained or argued for by ethical theorists. Rather, it is usually either simply presupposed or derived from the particular ethical theory, i.e., once the theory has been outlined, a certain conception of the morally significant unit can be seen as simply following from that system. I argue in a different direction. ;Taking Derek Parfit's work in Reasons & Persons as an initial model, I begin with a metaphysical exploration of persons and personal identity, and then I discuss the relationship between the metaphysics of personhood and various ethical theories. Parfit's own view is that the most plausible account of persons and personal identity renders utilitarianism more plausible than it would have been if a form of Non-Reductionism were true. While I agree with much of Parfit's metaphysical analysis of personal identity, I nonetheless show that utilitarianism is actually incompatible with a more coherent and specific Reductionist account. I arrive at this conclusion by first showing how the self, an enduring entity unified by psychological connectedness, ought to be considered as the morally significant unit, and I defend this view from two objections stemming from ethical theory. Second, I show how this analysis of the self allows for such key non-utilitarian concepts as compensation and equitable distribution of benefits to continue to play an important role in ethical theory . Third, I show that all forms of utilitarianism purporting to be able to assess utility in every significant moral context actually presuppose a highly implausible and problematic metaphysics of the person. Finally, I show how my version of Reductionism can lend plausible metaphysical support to a version of contractualism