 If the Medieval Derivational Approach is correct, Aristotle’s categories ultimately trace to the ways in which form, matter, and perhaps motion relate to substances and the predicates that apply to them. Whether the derivations can withstand philosophical scrutiny is of course an important question, one that I will not pursue here, though I will say that Brentano was probably a bit too enthusiastic about the prospects for an entirely satisfactory a priori proof of the completeness of Aristotle’s categories. Moreover, the Medieval interpretations face the charge that they are an over-interpretation of Aristotle. Aristotle simply does not provide in his surviving writings the sort of conceptual connections that underlie the Medieval derivations. So perhaps the Medievals have succumbed to the temptation to read into Aristotle’s system connections that Aristotle did not accept. Indeed, from a twentieth-century perspective, the Medieval derivations look very strange. It is commonplace in contemporary Aristotle scholarship to view the Categories as an early work and to think that Aristotle had not developed his theory of form and matter until later in his career. If this general approach is correct, the claim that the categorial scheme can somehow be derived at least in part from form and matter appears implausible.