  In this passage, Aquinas contrasts the relations involved in paradigmatic relational situations—namely, relations of the second type—with the relations involved in two sorts of non-paradigmatic relational situation. We are already familiar with relations of the third or ‘mixed’ type from our discussion of creation and intentional relations. Moreover, we can see that Aquinas follows the common medieval practice of connecting relations of this type with both Aristotle’s discussion in the Metaphysics and the Boethius-inspired example of the column. We have yet, however, to encounter relations of the first type. These are relations comprised by pairs of properties or accidents both of whose members are beings of reason. As an example of this type of relation, Aquinas gives self-identity. When we conceive of a situation involving this sort of relation, he says, we conceive of it as if it involved two things (“a relation requires two relata” and hence “reason apprehends the one thing twice”), and also as if the two things were ordered to each other by a pair of properties (or “[relative] dispositions”).  Obviously, however, there are not distinct things in extramental reality serving as the relata of the relation of self-identity, much less two properties by which such relata are related. Like many other medievals, therefore, Aquinas concludes that in this case the relations (or relative dispositions) are not real, but mere beings of  reason.[39]