Sizeless Stretchable Souls

Substantial Form as Nature in Thomas Aquinas

Abstract

Aquinas follows Aristotle in defining nature, taken strictly, as a thing’s primary intrinsic principle of motion and rest. He also identifies nature, so defined, with the essential makeup of its bearer, and chiefly with the substantial form. I sketch a rationale for this identification. A subtle but key thesis of Thomas’s regards the indivisibility of substantial form. He does not get the thesis from Aristotle. Its wording is Augustine’s, and its thought is largely Albert’s. But it seems to help clinch the aforesaid identification. I suggest that the history of the topic gives indirect support to this judgment.