  [2] Now there are other relations that are real as regards both relata, namely, whenever there is a [relative] disposition between two things in virtue of something really belonging to each of them—as is clear from all relations that follow on quantity, such as large and small, double and half, and things of this sort. For there is a quantity in both relata. And the same is true of relations that follow on action and passion, such as mover and movable, father and son, and the like.