 The second step of the argument is the claim that necessarily coextensive properties are identical. Brown offers a nice motivation for this thesis: we should commit ourselves to the existence of a property only insofar as it can do explanatory work, and the only way for a property to do explanatory work is for it to distinguish metaphysical possibilities (2011, 213). If we assume that identity is sufficient for reduction, these two steps together entail the reduction of the ethical.