  As we have seen, Aristotle begins his discussion of relations in the Categories with the assumption that relations are a certain type of accident, and then inquires after their proper characterization, eventually arriving at the view that they are a proper subset of the entities signified by relative terms—namely, all and only those that actually serve to relate two or more things.  Medieval philosophers tend to reverse Aristotle’s approach, beginning where he ends. That is to say, they tend to start their discussion with the view that relations are entities that are both signified by relative terms and play a certain metaphysical role, and then proceed to ask about the precise nature and ontological status of these entities—in particular whether they must, in every case, be identified with Aristotelian accidents. There are at least two reasons for this reversal. First, the medievals see nothing in Aristotle’s preferred characterization of relations that requires relations to be accidents (or indeed, entities of any ontological type). Second, and perhaps more importantly, the medievals think that there are certain situations that require relations to be something other than accidents (more on this in Section 5 below).