  As the above remarks suggest, the fourteenth century marks an important turning point in the medieval discussion of relations. After this point, there is a noticeable shift away from the Categories paradigm, with the result that many philosophers come to regard those situations in which substances are related by virtue of their accidents as the exception rather than the rule. Part of the explanation is due, perhaps, to a gradual waning of Aristotle’s influence, but part of it is also due to substantive doctrinal changes. By the fourteenth century, it is common to deny the existence of any real distinction between substances and most of their accidents, and hence philosophers are increasingly willing to say that substances themselves provide the ontological grounding for relational situations. Again, due to important semantic innovations around the same time, and the subsequent emergence of late-medieval nominalism, philosophers also begin to depart from the traditional Aristotelian characterization of relations. Thus, instead of thinking of relations as the items responsible for relating two or more substances, they now begin to think of them as items existing only in the mind—that is, as mere beings of reason or concepts. With respect to both of these developments, as we shall see, Ockham is an important transitional figure.