Moral realists often disagree about the nature of moral properties. These properties can be natural (as per naturalistic moral realism) or non-natural. But it is unclear how we should understand the notion of naturalness employed in these discussions. In this paper I propose a novel account of moral naturalness. I suggest that a property F is natural iff F falls within the scope of a natural law. In turn, a law is natural when it figures in a nomic nexus involving (...) the laws of physics. (shrink)

Part I of this trilogy, Historical and Scientific Setting, set out a general context for selecting a certain subclass of inter-theoretic relations as achieving appropriate explanatory and ontological unification – hence for properly being labelled reductive. Something of the complexity of these relations in real science was explored. The present article concentrates on the role which identity plays in structuring the reduction relation and so in achieving ontological and explanatory unification.