Another person could object, saying, “No—numericality is what is essential to the even and the odd, and color is what is essential to blackness; animality, by contrast, is not essential to man.” The purport of the whole discussion is that someone takes attributes that are identical in external reality and then claims that the quiddity he invents in his own mind is one of those attributes rather than the other. If he maintains that this accords with the way things truly are—as they do—his claim is invalid; but if he concedes, “It is only a convention I have adopted,” another convention can be set against it, and the exchange becomes pointless.
If it is said, “They mean only to rebut what Ibn Sīnā and others have asserted—that being even or odd is not a self-evident property of every number; sometimes its presence is known without a middle term, as one knows that two is half of four, while at other times it is not known save through a middle term, by which one learns that such-and-such is half of such-and-such, as when one discovers that 1,372 has a half—whereas animality is self-evident for the animal, for every animal is manifestly an animal,”
we reply: This is wrong on two counts.
First, the issue concerns a person’s knowledge—whether he knows that an attribute belongs to its subject without an intermediary, or whether his knowledge requires an intermediary. That distinction does not pertain to the things themselves, for the fact that a given number is even or odd is what it is, whether or not anyone knows it. The circumstance that one fact is grasped without proof while another requires proof does not create a real difference between the two.
Rather, the example merely exposes the essence of their doctrine, which we have explained elsewhere: for them, the quiddity is what a term denotes by direct reference (muṭābaqa); its internal part is what the term indicates by implication (taḍammun); and its external concomitant is what the term indicates by necessary entailment (iltizām). Thus quiddity, its internal constituent, and its external concomitant all return to what a word signifies by direct reference, implication, and entailment.
This whole matter follows the speaker’s intent and purpose; what his wording conveys is tied to that intent, not to the realities that exist in themselves, for the conception a speaker forms may correspond to reality—or it may not.