 The earliest influential discussions of what we now call supervenience in ethics focused on its significance for substantive ethical investigation. Henry Sidgwick draws from it what he takes to be a “practical rule of some value” for such investigation (1907, 208–9). And G. E. Moore (1922) used the idea as part of his attempt to explain the idea of intrinsic value. Given that Moore and Sidgwick were both ethical realists, it is perhaps striking that the most influential philosophical use of ethical supervenience has been in arguments against ethical realism.