Aristotle's Motionless Soul

Martin Tweedalea1

a1 University of Alberta

Whether or not we adopt some form of physicalism in our thinking about the psychology of humans and other organisms we all believe that a mind is something that comes into being, changes, develops and decays. The correlation of the development and then later the decay of our mental powers with changes in the brain post-dates our belief that the mental realm is as much an area where things ebb and flow, come to be and pass away, as is the physical. Even ancient authors who hold to the indestructibility of the soul allow that it changes in a host of ways. It is very odd, then, to discover that Aristotle appears to deny all this and feels impelled to treat the soul as unchanging and motionless. I propose to explore here exactly what Aristotle meant by saying the soul does not move and why he said it. In the end our investigation leads to some difficulties for Aristotle's psychological ontology which I am not able to resolve.