De Anima's lead idea is that the soul is the form of the body.' Implicitly, its functions and states depend in some systematic way on functions and states of the body. So Aristotelian psychology is a department of physics. This works well enough for nutrition, locomotion, and perception. Unfortunately, as Aristotle is quick to confess, it is considerably less clear how theoretical thought, particularly, fits the lead idea. Lacking a dedicated organ, the mind (voDc,) cannot be the form of any determinate, localizable bunch of matter. So noetic2 functions will have to depend in some weaker way on the body. I have in mind the following, fairly basic, idea: SUP. A family Y of properties supervenes on a family @ of properties 5 necessarily, for any property r in Y, if x has y~, then there is a property cp in such that x has cp and, necessarily, whatever has cp has