Summing up what we have discovered about the nature of Essence, we find first three genera. Then, these three, Essence, Movement and Stability were contemplated respectively by the essence, movement and stability within ourselves, which we also harmonized with those intelligibles. Then again we lost the power of distinguishing them by uniting, confusing, and blending these three genera. But a little later we divided, extricated and distinguished them so as again to see essence, movement and stability; three things, of which each exists apart. The result of this process then is that they are regarded as different, discerning them by their differences, and recognizing difference in essence by positing three things each of which exists apart. On the other hand, if they be considered in their relation with unity and in unity, if they be all reduced to being something single and identical, one may see the arising, or rather the existing of identity. To the three genera already recognized, therefore, we shall have to add identity or difference, or (in Platonic language[308]), "sameness and other-ness." These two classifications added to the three others, will in all make five genera for all things. Identity and difference (are genuine genera, indeed, because they) also communicate their characteristics to inferior (beings), each of which manifests some such element.
THESE FIVE GENERA ARE PRIMARY BECAUSE NOTHING CAN BE AFFIRMED OF THEM.
These five genera that we thus recognize are primary, because nothing can be predicated of them in the category of existence (being). No doubt, because they are essences, essence might be predicated of them; but essence would not be predicated of them because "being" is not a particular essence. Neither is essence to be predicated of movement or stability, for these are species of essence. Neither does essence participate in these four genera as if they were superior genera under which essence itself would be subsumed; for stability, movement, identity and difference do not protrude beyond the sphere of essence, and are not anterior thereto.
WHY NOT ADD OTHERS SUCH AS UNITY, QUANTITY, QUALITY, OR RELATION?
9. These and similar (Platonic) arguments demonstrate that those are genuinely primary genera; but how are we to prove they are exclusive? Why, for example, should not unity, quantity, quality, relation, and further (Aristotelian) categories, be added thereto?
NEITHER ABSOLUTE NOR RELATIVE UNITY CAN BE A CATEGORY.
Unity (may mean two things). The absolute Unity, to which nothing may be added, neither Soul, nor Intelligence, nor anything else, cannot be predicated as attribute of anything, and therefore cannot be a genus. But if we are referring to the unity which we attribute to essence, when we say that essence is one, it is no longer the original Unity. Besides, how could the absolute One, which within itself admits of no difference, beget species? If it cannot do this, it cannot be a genus. How indeed could you divide unity? By dividing it, you would multiply it; and thus Unity-in-itself would be manifold, and in aspiring to become a genus it would annihilate itself. Besides, in order to divide this unity into species, you would have to add something to unity, because it does not contain differences such as exist in being. Intelligence might well admit differences between essences, but this could not possibly be the case with unity. The moment you add a single difference, you posit duality, and consequently destroy unity; for everywhere the addition of a single unity causes any previously posited number to disappear.
UNITY IS NOT SYNONYMOUS WITH ESSENCE.
It may be objected that the unity which is in essence, in movement, and the remainder of the genera, is common to all of them, and that one might therefore identify unity with essence.[309] It must then be answered that, just as essence was not made a genus of other things because they were not what was essence, but that they were called essences in another sense, here likewise unity could not be a common attribute of other things, because there must be a primary Unity, and a unity taken in a secondary sense. If, on the other hand, it be said that unity should not be made a genus of all things, but something which exists in itself like the others, if afterwards unity be identified with essence, then, as essence has already been listed as one of the genera, we would be merely uselessly introducing a superfluous name.[310] Distinguishing between unity and essence is an avowal that each has its separate nature; the addition of "something" to "one" makes a "certain one"; addition of nothing, on the other hand, allows unity to remain absolute, which cannot be predicated of anything. But why could this unity not be the First Unity, ignoring the absolute Unity? For we use "first Unity" as a designation of the essence which is beneath the "absolute Unity." Because the Principle anterior to the first Essence (that is, the first and absolute Unity) is not essence; otherwise, the essence below Him would no longer be the first Essence; here, on the contrary, the unity which is above this unity is the absolute Unity. Besides, this unity which would be separated from essence only in thought, would not admit of any differences.
Besides, there are three alternatives. Either this unity alleged to inhere in essence will be, just like all other essences, a consequence of the existence of essence; and consequently, would be posterior to it. Or, it will be contemporaneous with essence and the other (categories); but a genus cannot be contemporaneous with the things of which it is the genus. The third possibility is that it may be anterior to essence; in which case its relation to Essence will be that of a principle, and no longer a genus containing it. If then unity be not a genus in respect to essence, neither can it be a genus in respect of other things; otherwise, we would have to say of essence also that it was a genus embracing everything else.