Sect. 106Complete Unity of the Produced Persons with Their Principle, Resulting from Their Immanent Origin: Similarity, Equality, Identity, Inseparability and Coinherence (ΠΕΡΙΧΏΡΗΣΙΣ)Complete Unity of the Produced Persons with Their Principle, Resulting from Their Immanent Origin: Similarity, Equality, Identity, Inseparability and Coinherence (ΠΕΡΙΧΏΡΗΣΙΣ)

I. The intellectual origin of the Divine Persons accounts not only for their personal characters but also for their perfect unity, which is commonly considered under the five different forms mentioned in the title of this section, and comprehends their Essence, Life and external operations their Dignity, Power, and Perfection. The unity of identity in Essence—that is, the absolutely simple unity of the Divine Essence itself—contains the germ of the other forms, and gives to these other forms of unity in God a perfection which they have nowhere else. Similarity and equality, inseparability and interpenetration, are but so many inadequate conceptions of one and the same essential identity. The several forms of unity express certain relations between the Divine Persons. But these relations are of a different kind from the relations of origin, of which they result. Theologians term them relationes rationis, in contradistinction to the relationes reales,—that is, the relation of origin.

II. In detail the several forms of unity of the Divine Persons are originated and formed as follows:—

1. From the fact that in God the produced Persons are the innermost manifestation of His Nature and Life, there follows, first of all, a similarity entailing more than a mere agreement of qualities, viz. a similarity extending to the very Essence; and, as there are no accidents in the Divine Nature, but all perfections are contained in its Essence, the similarity is perfect in all and excludes all dissimilarity (ὁμοιότης κατὰ οὐσίαν ἀπαράλλακτος. Cf. Card. Newman, Athan., ii. 370).

2. As the produced Persons are, further, an exhaustive manifestation of their Principle, which completely expresses and diffuses Itself in Them, we have as a consequence the equality (identity of quantity) between the Divine Persons. Quantity in God is not a material quantitative greatness, but the virtual internal greatness of perfection and power, which is infinite (cf. § 64).

3. Similarity in kind, combined with equality of quantity, or, generally speaking, intrinsic and universal agreement, is sufficient, even in creatures, to justify the expression, “The one is what the other is,” viz. they are something more than similar and equal. In this sense the Greeks apply to creatures the term ταυτότης, which, in etymology, though not quite in sense, is equivalent to identity. The identity, however, of creatures, e.g. of the members of the same family, is but partial and very imperfect. In God, on the contrary, the identity of the Three Persons is absolutely perfect. For the internal and exhaustive manifestation of the Divine Nature is not a multiplication but a communication of It to the produced Persons, and is therefore present in all and is identical with each of Them; consequently, as to what They are, the Persons are not only similar, equal, and related, but are purely and simply the same. The notion of identity, without destroying the distinction of the Persons, completes the notions of similarity and equality, at the same time presenting them under a form peculiar to God. The Divine Persons are similar and equal, not by reason of like qualities and quantities possessed by Them, but by reason of the possession—in all alike essential, perfect, eternal, and legitimate—of the quality and quantity of one Substance. On the other hand, the identity of Essence adds to simple similarity, which may exist between separate things, the notion of intimate connection; and to simple equality in quantity, the notion of intrinsic penetration. Further, it completes the notion of this connection and penetration by representing them as effected, not by some combination or union, but by the Essence of the Three Persons being one and undivided.

4. The inseparable connection of the Divine Persons with one another is brought about in the most perfect manner by Their relations of origin. The produced Persons cannot even be conceived otherwise than in connection with their Principle, and, being the immanent manifestation of a substantial cognition and volition, They remain within the Divine Substance and are one with It. The producing Principle, likewise, cannot be conceived as such, and as a distinct Person, except inasmuch as He produces the other Persons; and These, being the immanent Product of His Life, are as inseparable from their Principle as His life itself.

5. The intimate unity of the Divine Persons appears at its highest perfection when conceived as interpenetration and mutual comprehension. The Greek περιχώρησις, and the Latin circuminsessio (better circumincessio), are the technical terms for the Divine interpenetration. Περιχωρεῖν has a fourfold construction: περιχωρεῖν εἰς ἄλληλα, ἐν ἀλλήλοις, διʼ ἀλλήλων, and ἄλληλα; the first three correspond with the meanings “invade,” “pervade,” of χωρεῖν, the last with its meaning of “hold” or “comprehend.” The circumincession, or comprehensive interpenetration, implies the following notions. Each Person penetrates and pervades each other Person inasmuch as each Person is in each other Person with His whole Essence, and possesses the Essence of each other Person as His own; and again, inasmuch as each Person comprehends each other Person in the most intimate and adequate manner by knowledge and love, and as each Person finds in each other Person His own Essence, it follows that it is one and the same act of knowledge and love by which one Divine Person comprehends and embraces the other Persons. “Each of the Three Who speak to us from heaven is simply, and in the full sense of the word, God, yet there is but one God; this truth, as a statement, is enunciated most intelligibly when we say Father, Son, and Holy Ghost, being one and the same Spirit and Being, are in each other, which is the doctrine of the περιχώρησις” (Card. Newman, Athan., ii., p. 72; cf. Franzelin, th. xiv.).

By reason of these several forms of unity arising from the unity of Essence, the Divine Persons constitute a society unique in its kind: a society whose Members are in the most perfect manner equal, related, and connected, and which, therefore, is the unattainable, eternal, and essential ideal of all other societies.

III. The unity of the Divine Persons, in all its forms, embraces as subject-matter Their inner Being and Life, and also Their operations ad extra. As regards the power necessary to these operations, and the various elements concurring in its exercise (viz. idea, decree, execution), the activity of each Person is in the most perfect manner similar, equal, and identical with that of the other Persons, and consequently is exercised so that all the Persons operate together, inseparately and inseparably, not only in external union, but intrinsically, in each other, so as to be but one absolutely simple activity.

The absolute simplicity of the Divine activity is not impaired by the scriptural and traditional expression “that the Divine operation proceeds from the Father through the Son in the Holy Ghost.” This expression is intended to convey the meaning that the Divine operation or activity is perfectly common to the Three Persons, but is possessed by each of Them in a particular manner, viz. in the same manner in which they possess the principium quo of action—that is, the Divine Nature. Another signification of the same formula will be explained in the following section.