 Inspecting all of Aquinas’s derivation to determine its cogency is far too large a project to undertake here. I have quoted the portion above to show the way in which the Medieval derivational approach augments in an interesting way Moravscik’s Modal Approach. The Modal Approach, I argued, would gain some plausibility if there were some way of seeing Aristotle’s own attitudes about the modal structures in the material world somehow determining the generation of the categories. By invoking a combination of a priori sounding semantic principles and theses about the relationship between form and quality and matter and quantity, Aquinas has gone some way toward doing this. Aristotle is certainly committed to the claim that form and matter are two of the absolutely fundamental aspects of the material world. Indeed, he argues in the Physics that form and matter are necessary for the existence of motion, which, he thinks, essentially characterizes bodies.