The Lagoon: How Aristotle Invented Science

by Armand Marie Leroi

SOULS, THEN, BEAR a heavy burden. They embrace no fewer than three of Aristotle’s four explanatory causes – the formal, moving and final – leaving only the material cause for the stuff of which it is made. But for all their evident importance souls remain mysterious. What, after all, can move the stuff of which living things are made, contain its goals, yet be immaterial itself? Confronted with these demanding criteria, scholars have sometimes concluded that, when Aristotle speaks of the soul, he is invoking some sort of spiritual force. This ‘spiritual soul’ interpretation comes in different flavours that draw on two disparate intellectual traditions, biology and the philosophy of mind, though the end result is much the same – an unnecessary mystification of what Aristotle means. In the ‘philosophy of mind’ version Aristotle is a Cartesian mind–body dualist who believes that mental states are independent of the body; when he speaks of soul he is, in Gilbert Ryle’s phrase, invoking a ‘ghost in the machine’. Now, when Aristotle discusses the ‘active’ intellect, there are some passages that do, indeed, lend themselves to this interpretation, but they are the despair of scholars for they are so very inconsistent with everything else that he writes about the relationship of souls to mental states.