METAPHYSICS ‘Necessary’ is not a term that applies to every being: but the disjunction ‘necessary or contingent’ does apply, right across the board (Ord 207) Not only did Scotus lay a new emphasis on the necessary–contingent disjunction, he introduced a fundamentally new notion of contingency It was generally believed by scholastics that many matters of fact were contingent It is contingent that I am sitting down, because it is possible for me to stand up—a possibility that I can exemplify by standing up at the very next moment Scotus, like other scholastics, accepted such a possibility: but he went further and claimed that at the very moment when I am sitting down there exists a possibility of my standing up at that same moment This involves a new, more radical, form of contingency, which has been aptly named ‘synchronic contingency’ (Lect 17 496–7) Of course, Scotus is not claiming that at one and the same moment I can be both sitting down and standing up But he makes a distinction between ‘moments of time’ and ‘moments of nature’ At a single moment of time there can be more than one moment of nature At this moment of time I am sitting down: but at this same moment of time there is another moment of nature in which I am standing up Moments of nature are synchronic possibilities Scotus is not talking about mere logical possibility: an instant of nature is a real possibility that is distinct from mere logical coherence It is something that could be possible while the nature of the physical world remains the same Synchronic possibilities need not be compatible with each other, as in the case just discussed; they are possible, a modern philosopher might say, in diVerent possible worlds, not in the same possible world Scotus’ instants of nature are indeed the ancestor of the contemporary philosophical concept of a possible world His own account of the origin of the world sees God as choosing to actualize one among an inWnite number of possible universes Later philosophers separated the notion of possible worlds from the notion of creation, and began to take the word ‘world’ in a more abstract way, so that any totality of compossible situations constitutes a possible world This abstract notion then came to be used as a means of explicating every kind of power and possibility Credit for the introduction of the notion is often given to Leibniz, but, for better or worse, it belongs to Scotus The introduction of the notion of synchronic contingency involves a radical refashioning of the Aristotelian concepts of potentiality and actual202