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.