The issue of the definition of sensible substances plays a pivotal role in Aquinas’s metaphysical theory of essence. According to Aquinas, a real definition is the correct and complete account that signifies a real essence of a sensible substance. Moreover, from Aquinas’s perspective, the question of the definition of sensible substances is deeply related to the notions of matter and form: for sensible essences cannot be properly understood without reference to the hylomorphic composition of a sensible substance. In my paper, I will try to show how the logical ‘starting point’ of the definition can shed light on Aquinas’s hylomorphic analysis of material essences, that is his conception of the relationship between form, matter and essence in material objects.
I will mainly rely on Aquinas’s commentary on Aristotle’s Metaphysics Z 10-1 that deal specifically with the problem of the proper object and parts of the definition of a sensible substance.
In his Commentary (c.1270- 1272), Aquinas develops his own interpretation of Aristotle’s theory of definition, an interpretation in total agreement with the rest of his writings: in particular, the same position was already stated in his early work De Ente et Essentia (c.1252-1256).
Since Aquinas’s theory of definition and essence is fundamentally an interpretation of Aristotle’s own position, I will firstly briefly look at Aristotle’s book Z 10-11 itself. I will then turn to Aquinas’s own interpretative and theoretical position, trying to elucidate what I consider to be his peculiar view.
See the DPhil Seminar website for details.
DPhil Seminar Convenor: Lewis Williams
