 The first is a simplified version of arguments due to Frank Jackson (1998, Ch. 5; see also related arguments by Brown 2011 and Streumer 2017, Ch.s 2–3). The argument has two steps. The first step is an argument that if the ethical properties strongly (or globally) metaphysically supervene on the base properties, then there is no metaphysically possible ethical difference between states that does not have a correlated base difference between the same states. If we make some liberal assumptions about property types, this entails in turn that there is a base property that is necessarily coextensive with every ethical property.