In 1971, Simon Blackburn worked out an argument against moral realism appealing to the supervenience of the moral realm on the natural realm.1 He has since revised the argument, in part to take account of objections,2 but the basic structure remains intact. While commentators3 seem to agree that the argument is not successful, they have not agreed upon what goes wrong. I believe this is because no attempt has been made to see what happens when Blackburn's argument is addressed to (...) particular varieties of moral realism. As I see it, we must look to these various brands if we want to understand just where the concept of supervenience can be usefully employed. (shrink)

David Brink has recently argued for the “parity” of ethics and the sciences. While the parity claim alone might be metaphysically neutral, Brink favours a form of ethical naturalism on which moral properties “are” natural properties, just as non-moral macrophysical properties “are” the microphysical states that compose them. Brink supports this claim by showing that both types of properties share certain important features: specifically, that both may be constituted, supervening and synthetically necessitated. I shall argue that notwithstanding these common features, (...) there remain significant modal differences in the way the two types of properties are assigned to the world. These differences represent an important respect in which moral properties are not on par with their scientific counterparts. (shrink)