METAPHYSICS ity For Scotus, unlike Aristotle or Aquinas, but like Avicenna, non-existent items can possess a potentiality to exist: a potentiality that Scotus calls objective potentiality, to contrast it with the Aristotelian potentiality, which he calls subjective potentiality There are two ways in which something can be called a being in potentiality In one way it is the terminus of a power, that to which the power is directed—and this is called being in potentiality objectively Thus Antichrist is now said to be in potentiality, and other things can be said to be in potentiality such as a whiteness that is to be brought into existence In the other way something is said to be in potentiality as the subject of the power, or that in which the power inheres In that way something is said to be in potentiality subjectively, because it is in potentiality to something but is not yet perfected by it (like a surface that is about to be whitened) (Lect 19 80) Non-existent items, Scotus explains, are individuated by their objective potentiality: non-existent A diVers from non-existent B because if and when they exist A and B diVer from each other Other terms of the Aristotelian metaphysical arsenal are likewise reinterpreted The relationship between matter and form, for instance, is expounded by Scotus in a novel way For Aristotle, matter was a fundamental item in the analysis of substantial change Substantial change is the kind of change exempliWed when one element changes into another— e.g water into steam (air)—or a living being comes into or goes out of existence—e.g when a dog dies and its corpse decays When a substance of one kind changes into one or more substances of another kind, there is, for Aristotle, a form that determines the nature of the substance that precedes the change, and a diVerent form or forms determining the nature of the substance(s) subsequent to the change The element that remains constant throughout the change is matter: matter, as such, is not one kind of substance rather than another, and has, as such, no properties While form determines what kind of thing a substance is, it is matter that determines which thing of that kind a substance is Matter is the principle of individuation, and form, we might say, is the principle of speciWcation Scotus rejects both the notion of matter lacking properties and the thesis that matter is the principle of individuation Matter, according to him, has properties such as quantity, and further, prior to such properties, it has an essence of its own, even if it is virtually impossible for human 203