13. It cannot reasonably be thought that the notion of unity is derived from the object since this is physical- man, animal, even stone, a presentation of that order is something very different from unity [which must be a thing of the Intellectual]; if that presentation were unity, the mind could never affirm unity unless of that given thing, man, for example.
Then again, just as in the case of "On the right" or other such affirmation of relation, the mind does not affirm in some caprice but from observation of contrasted position, so here it affirms unity in virtue of perceiving something real; assuredly the assertion of unity is not a bare attitude towards something non-existent. It is not enough that a thing be alone and be itself and not something else: and that very "something else" tells of another unity. Besides Otherness and Difference are later; unless the mind has first rested upon unity it cannot affirm Otherness or Difference; when it affirms Aloneness it affirms unity-with-aloneness; thus unity is presupposed in Aloneness.
Besides, that in us which asserts unity of some object is first a unity, itself; and the object is a unity before any outside affirmation or conception.
A thing must be either one thing or more than one, manifold: and if there is to be a manifold there must be a precedent unity. To talk of a manifold is to talk of what has something added to unity; to think of an army is to think of a multitude under arms and brought to unity. In refusing to allow the manifold to remain manifold, the mind makes the truth clear; it draws a separate many into one, either supplying a unity not present or keen to perceive the unity brought about by the ordering of the parts; in an army, even, the unity is not a fiction but as real as that of a building erected from many stones, though of course the unity of the house is more compact.
If, then, unity is more pronounced in the continuous, and more again where there is no separation by part, this is clearly because there exists, in real existence, something which is a Nature or Principle of Unity. There cannot be a greater and less in the non-existent: as we predicate Substance of everything in sense, but predicate it also of the Intellectual order and more strictly there- since we hold that the greater and more sovereign substantiality belongs to the Real Beings and that Being is more marked in Substance, even sensible Substance, than in the other Kinds- so, finding unity to exhibit degree of more and less, differing in sense-things as well as in the Intellectual, we must similarly admit that Unity exists under all forms though still by reference, only, to that primal Unity.
As Substance and Real Being, despite the participation of the sensible, are still of the Intellectual and not the sensible order, so too the unity observed present in things of sense by participation remains still an Intellectual and to be grasped by an Intellectual Act. The mind, from a thing present to it, comes to knowledge of something else, a thing not presented; that is, it has a prior knowledge. By this prior knowledge it recognises Being in a particular being; similarly when a thing is one it can affirm unity as it can affirm also duality and multiplicity.
It is impossible to name or conceive anything not making one or two or some number; equally impossible that the thing should not exist without which nothing can possibly be named or conceived; impossible to deny the reality of that whose existence is a necessary condition of naming or affirming anything; what is a first need, universally, to the formation of every concept and every proposition must exist before reasoning and thinking; only as an existent can it be cited to account for the stirring of thought. If Unity is necessary to the substantial existence of all that really is- and nothing exists which is not one- Unity must precede Reality and be its author. It is therefore, an existent Unity, not an existent that develops Unity; considered as Being-with-Unity it would be a manifold, whereas in the pure Unity there is no Being save in so far as Unity attends to producing it. As regards the word "This," it is nat a bare word; it affirms an indicated existence without using the name, it tells of a certain presence, whether a substance or some other existent; any This must be significant; it is no attitude of the mind applying itself to a non-existent; the This shows a thing present, as much as if we used the strict name of the object.