ABSTRACT
This chapter draws the abstract form of Simon Blackburn’s argument, and shows how it applies to morality. How does Blackburn’s problem arise specifically in moral philosophy? In order to set up Blackburn’s problem for moral realism, the chapter takes the liberty of speaking of conceptual modalities. The principle which Blackburn wields together with supervenience is the principle that there are no conceptual necessities tying moral and non-moral kinds. The principle is quite weak; it says that we cannot infer that something has a certain moral property from the fact that it has a natural property, even if it is a maximal or total relevant natural property. Supervenience ought to be seen as playing a twofold role in the debate over moral realism. On the one hand, if Blackburn is right, moral realism has to struggle to explain supervenience. But on the other hand, supervenience is one of the features of our moral thought which a projectivist must try to respect.
