This article considers whether and how there can be for Aristotle a genuine science of ‘pure’ psychology, of the soul as such, which amounts to considering whether Aristotle’s model of science in the Posterior Analytics is applicable to the de Anima.

What, for Galen, are powers, and how are they to be properly individuated? The notion of a power or capacity does a great deal of work in Galen. As in Aristotle, the concept of a dunamis is tightly linked with that of an energeia, but these are not simply logical abstractions. Rather the natural energeiai are the basic functional activities of the animal body and its parts, and just as health consists in proper functioning, so disease is defined as ‘damage (...) to one of the natural energeiai of the body’, and these activities are damaged when something interferes with its related dunamis. Here I try to make sense of the apparently very different things Galen says regarding dunameis. For example, he says that they do not inhabit our bodies as we do our houses; that is, presumably, they are not substantial or hypostasized; rather they are properties of us. Equally, he is perfectly clear that they are relational items: a power is a power for affecting something determinate in some determinate way. They. (shrink)