(ز)
(The second argument)

It may be said: This classification contains overlapping categories. Privation and possession fall under negation and affirmation and are, at most, a subtype of that opposition. Correlatives likewise fall under contraries and are merely a subtype of them.

If he says, “By negation and affirmation I mean what does not fall under privation and possession—namely, denying of a thing what it is incapable of possessing. This is why one of its distinctive properties is held to be that neither of its two terms undergoes transformation,” and so forth, he may be answered in two ways.

The first is that this amounts only to dividing negation into two kinds: first, denying what a thing can possess; and second, denying what it cannot possess.

It may then be said: The first is the affirmation of what a thing can, but need not, possess; the second is the affirmation of what it must possess. Thus, what is meant is the negation of what is impossible and the affirmation of what is necessary. For example, “Zayd is an animal” is a necessary affirmation, while “Zayd is not a stone” negates what is impossible.

On this understanding, contingent things capable of existence and nonexistence—as when we say, “A triangle is either existent or nonexistent”—would fall under the category of privation and possession. Yet this is not so. For