For the first person, whom we have said to be subsisting by himself, being intelligent activity, necessarily intelligences himself. He is the God-head intelligencing himself.
Now, an object understood, inasmuch as it is understood, exists in the understanding in an intelligible state; for to understand means just to apprehend, to grasp intelligibly that which is understood.
The Godhead, therefore, is in himself as the Godhead understood is in the Godhead understanding. Now, the object understood existing in the intelligence, is what is called mental word, intellectual conception, and by the Greeks, logos.
Hence in the Godhead exists the Godhead as mental word or logos. St. John, with a sublime expression, which electrified all the Platonic philosophers, began his Gospel thus: "In the beginning (the Father) was the Word."
This Word of the Godhead being conceived by an immanent act, an act which has neither beginning nor end, which is not power before it is act, is conceived therefore eternally, and consequently is coeternal with the conceiver. It is God or the infinite; because the first person, or intelligent activity, begets him by an operation which terminates inside himself, by the law of immanence; consequently the Word is identical with his essence, and is, therefore, the infinite.
Yet is he a distinct person from the first as Word.
For although the intelligent activity and the Word are both God, yet are they distinct from each other by the law of opposition of origin, which implies that a term proceeding from a principle is necessarily opposed to it, and consequently distinct from it. Thus the intelligent activity, as principle, is necessarily opposed to the Word as term; and, vice versa, the Word as term is necessarily opposed to the intelligent activity as principle. In other words, the intelligent activity could not be what it is, unless it were the opposite of the Word, and this could not be the Word unless it were the very opposite of intelligent activity. Hence, to be intelligent, activity belongs so exclusively to the First, as to exclude any other from partaking in that distinctive constituent; and to be Word is claimed so exclusively by the Second, as to be attributed to no other. The result is a duality of terminations, possessed of the same infinite nature and its essential attributes, each having a constituent so exclusively its own as to be altogether incommunicable. Now, two terminations, possessed of the same infinite nature and its essential attributes, with a constituent so exclusively their own as to be attributed to no other, convey the idea of two persons. For what is a person? A spiritual being with a termination of his own, which makes him distinct from any other, gives him the ownership of himself and renders him solidary of his action.
Now, the intelligent activity is a spiritual being, since he is the Godhead; is possessed of a constituent of his own, intelligent activity; has the ownership of himself; for, as intelligent activity, he is himself and no other, and cannot communicate himself; and is solidary of his notional action, that is, the action which constitutes him what he is: he is, therefore, a person.
Likewise the Word is a spiritual nature; for he is the same Godhead as to substance; as a relation or Word, he is the owner of himself, incommunicable, and solidary of his notional action; hence, he is also a person.
In other words, the Godhead is an infinite spirit; all that constitutes him, both substance and terms of relation, is spirit. Consequently, each term of the divine relation, as such term, has an individuality of his own and, as infinite spirit, has knowledge and intelligence of himself; he beholds himself distinct from the other as term of relation, one with the other as substance. His distinction causes his relative individuality; consciousness and intelligence of this relative individuality make him a person.