  The discussion of motion, which focuses on its ontological status, is placed in the larger context of a discussion of quantity. The reason is, that motion is one particular type of quantity, namely successive quantity (as distinct from permanent quantity). Autrecourt argues that material substance and its quantity are not distinct. The same holds true for other characteristic properties of a substance, the sensible qualities: they are not distinct from their substance. Autrecourt claims, for instance, that fire and its heat and water and its coldness are not distinct. At the background of this section is the late-medieval debate about the basic ontological categories, induced by Aristotle’s Categories and Metaphysics. Given these preliminaries, it comes as no surprise that Autrecourt also defends the thesis that motion is not distinct from the mobile object.