10. In what sense is the particular manifestation of Being a unity? Clearly, in so far as it is one thing, it forfeits its unity; with "one" and "thing" we have already plurality. No species can be a unity in more than an equivocal sense: a species is a plurality, so that the "unity" here is that of an army or a chorus. The unity of the higher order does not belong to species; unity is, thus, ambiguous, not taking the same form in Being and in particular beings.
It follows that unity is not a genus. For a genus is such that wherever it is affirmed its opposites cannot also be affirmed; anything of which unity and its opposites are alike affirmed- and this implies the whole of Being- cannot have unity as a genus. Consequently unity can be affirmed as a genus neither of the primary genera- since the unity of Being is as much a plurality as a unity, and none of the other [primary] genera is a unity to the entire exclusion of plurality- nor of things posterior to Being, for these most certainly are a plurality. In fact, no genus with all its items can be a unity; so that unity to become a genus must forfeit its unity. The unit is prior to number; yet number it must be, if it is to be a genus.
Again, the unit is a unit from the point of view of number: if it is a unit generically, it will not be a unit in the strict sense.
Again, just as the unit, appearing in numbers, not regarded as a genus predicated of them, but is thought of as inherent in them, so also unity, though present in Being, cannot stand as genus to Being or to the other genera or to anything whatever.
Further, as the simplex must be the principle of the non-simplex, though not its genus- for then the non-simplex too would be simplex,- so it stands with unity; if unity is a Principle; it cannot be a genus to its subsequents, and therefore cannot be a genus of Being or of other things. If it is nevertheless to be a genus, everything of which it is a genus must be taken as a unit- a notion which implies the separation of unity from substance: it will not, therefore, be all-embracing. just as Being is not a genus of everything but only of species each of which is a being, so too unity will be a genus of species each of which is a unity. But that raises the question of what difference there is between one thing and another in so far as they are both units, corresponding to the difference between one being and another.
Unity, it may be suggested, is divided in its conjunction with Being and Substance; Being because it is so divided is considered a genus- the one genus manifested in many particulars; why then should not unity be similarly a genus, inasmuch as its manifestations are as many as those of Substance and it is divided into as many particulars?
In the first place, the mere fact that an entity inheres in many things is not enough to make it a genus of those things or of anything else: in a word, a common property need not be a genus. The point inherent in a line is not a genus of lines, or a genus at all; nor again, as we have observed, is the unity latent in numbers a genus either of the numbers or of anything else: genus demands that the common property of diverse objects involve also differences arising out of its own character, that it form species, and that it belong to the essence of the objects. But what differences can there be in unity? What species does it engender? If it produces the same species as we find in connection with Being, it must be identical with Being: only the name will differ, and the term Being may well suffice.