Powers and Essence
I have written that the essence of a thing is constituted by its powers. Suppose that A subsists in itself, and B, in A. Then B is an accident of A. Thus, my skin has the power to appear white to observers. But this property, having white skin, is not essential to me. Does this contradict my claim that essences are sets of powers or causal dispositions? Not at all. The key here is “its own” powers. Appearing white in normal light is an essential property of whiteness. This disposition, therefore, makes up the essence of whiteness. I have whiteness accidentally, and whatever can be said of my own kind-nature (though not, of course, individual-nature) will exclude any reference to white skin.