Is it possible to predicate non substance of other non substance in Aristotle's categories?
For example is predicating a quality of a quantity, or quality of an action valid in Aristotle's philosophy?
1 Answer
I think there are only two cases that it is possible: (1) If we predicate a specific difference of that non-substance, and that specific difference belongs to another category: for instance, three is odd. Suppose that odd is a quality, three is a quantity, then we can predicate odd of three. (2) If we don not predicate a specific difference, but an accident of that non-substance, such as "this action is just". In this case, the predication is only a predication accidentally, not a real predication. For Aristotle, "just" is predicated of "this action" not because justice is present in this action, but because justice is present in the person who acts. In summary, in real predications, non-substance can only be subject of essential predication (where the predicate is either genus, specific difference, definition). Non-substance can be subject of accidental predications, but such predications are pseudo-predications and do not reveal the real "belonging to" or "present in" relation among entities. For references, see Posterior Analytics I 22, 83aff, Metaphysics V 7, 1017a, Topics I 9.
