The first and principal law may be enunciated as follows: No other distinction can be predicated of the infinite, but that arising from the relative opposition of origin between the terms. [Footnote 288]
[Footnote 288: Realis distinctio inter relationes divinas non est nisi ratione oppositionis relativae. S. Th., S. T.; qu. 30, art. ad.]
We have already demonstrated that the life of the infinite is terminated by three distinct personalities, which establish a multiplicity in its bosom. A distinction, therefore, must be predicated of the infinite. But of what sort?
This distinction, in the first place, could not fall upon the essence, without breaking its absolute simplicity. It must, consequently, be found among the terminations of the essence, or personalities. But, again, these three persons being possessed of the same identical essence, and thus participating in all its perfections, how can they be distinguished, one from the other? By a real opposition of origin. One person originates; the other is originated; as principle and term they are necessarily opposed to each other, and consequently distinct.
This law maintains both the unity and the multiplicity in the infinite. It maintains the unity; for the law does not require any real distinction between the persons and the essence, but only a distinction made by our reason to facilitate our apprehension; hence the three divine persons are truly and essentially the infinite. It maintains multiplicity, because the three divine persons are opposed on the ground of opposition of origin, and are consequently distinct. Here lies the whole difficulty, the reader will say; three things opposed one to another, and thus distinct from each other, how are they one in essence?
We might reply, in the first place, that the possibility of this is grounded on a psychological fact, which every one accustomed to reflection may easily ascertain. Take the operation of the human spirit. Man knows himself; in this fact the me enters twice; because the me is the subject which knows, and at the same time the object known. The me knowing is the being in the subjective form; the me known is the being in the objective form. Again, man loves himself through the idea of himself: the me here enters three times—the me under the subjective form of knowing and of loving; the me under the objective form of known; the me under the objective form of being loved. Nevertheless, all three are one and the same being: the me under the subjective form knows and loves the me under the objective form; a multiplicity and a unity which cannot be disputed; not only because of the testimony of consciousness, which avers to the fact, but because on this multiplicity and unity are founded two distinct sciences, psychology and ideology; psychology, which treats of the me as subject, of its nature and properties; ideology, which treats of the product of the me, or ideas.
This operation of man is an image of the genesis of God's life. The infinite knows and loves himself. Into this fact of his eternal life he enters three times; the infinite, so to speak, as subject knowing and loving himself; the infinite as object known; the infinite as object loved. The infinite knowing himself is necessarily opposed to the infinite known, because it originates him by an intellectual operation; the infinite known is necessarily opposed to the infinite knowing, because originated by him. Again, the infinite loving himself and the infinite known (because the infinite cannot love himself except through the infinite known) are necessarily opposed to the infinite loved, because they originate him; the infinite loved is necessarily opposed to the infinite loving and known, because emanating from both. This relative opposition of origin causes a real distinction among the terms without breaking the unity of the essence.
But, the better to illustrate this law, and to show how well it maintains unity and multiplicity in the infinite, we shall here investigate the metaphysical law of the fact; that is, why and how things which are opposed to each other can harmonize and be brought into unity, in a third thing.
We have given an example of the fact in the operation of man; but let us give a few more instances to generalize it more and more. This fact is observed in both the ideological and ontological orders. First, as to the order of ideas. Two ideas, which in their own order are opposed to each other, harmonize and are brought together in a third idea. Take, for instance, the idea of substance and modification; substance conveys the idea of something subsisting by itself, that which requires no being to lean on in order to subsist. It means something standing permanent. The idea of modification is that of something which is not permanent in itself, but requires another being to lean on, to cling to, in order to subsist. The two ideas, as it appears, are directly opposed to each other, since their notions are contradictory; yet both ideas, contradictory one to the other in their own order, agree and are brought into companionship in the common idea of existence, one existing permanently, the other existing by leaning on another.
Moreover, take the transcendental idea of unity, truth, and goodness. Unity implies a negation of multiplicity, something undivided in itself and distinct from others. Truth implies a multiplicity, because it is essentially a relation of an object to an intelligence; aequatio rei et intellectus, as St. Thomas defines it. Goodness also implies a multiplicity, because it is essentially a relation of a being to a tendency or faculty.