Scotus on the Essence and Definition of Sensible Substances

In this paper I wish to present a textual and philosophical reconstruction of Scotus's sixteenth Question on Book VII of Aristotle's Metaphysics, i.e. the question as to whether matter is part of the essence and definition of sensible substances. As Scotus's arguments in favour and against a positive answer to the question clearly show, the problem is a genuinely Aristotelian one, which Aristotle himself discusses at some length in Chs. 10-11 of Book VII. Thus, in Section 1, 1 shall present the question of the essence and definition of sensible substances as it is outlined by Aristotle. In particular, I shall try to show how Aristotle's text contains two conflicting lines of thought (Account A and Account B), which are to some extent reflected in the Medieval debate as well. Most of what Aristotle says seems to indicate that the essence of sensible substances contains their form alone and so matter should be excluded from the definition of such sub-