CHAPTER III: THE UNITY OF MUTUAL INEXISTENCE, OR PERICHORESIS

1. Definition of Perichoresis

By the Perichoresis of the Three Divine Persons we mean their mutual Interpenetration and Inexistence by virtue of their Consubstantiality, their immanent Processions, and the divine Relations.

In Greek the technical term for this mutual Inexistence is περιχώρησις, or, still more emphatically, συμπεριχώρησις. The Latins call it circumincessio, or, as the later Scholastics wrote it, circuminsessio. Both the Greek and the Latin terms designate exactly the same thing, but they reflect somewhat different conceptions thereof. “While the Greeks conceived the [Divine] Processions more after the manner of a temporal succession along a straight line,” says Oswald,¹ “the [later] Latins pictured it to themselves after the manner of juxtaposition in space, as extension in a plain… . This is why the Latins derived their technical term from circuminsidere, i. e., to sit or dwell in one another, while the Greeks got theirs from περιχωρεῖν, which means to go or move within one another.” We have already called attention to a similar divergency in the formulas expressing the Procession of the Holy Ghost, with regard to which the Latins commonly say, ex Patre Filioque, while the Greeks prefer ex Patre per Filium. Petavius was probably mistaken when he preferred the Greek and the early Scholastic modes of expression to that of the later Schoolmen. The Greek Fathers, besides περιχωρεῖν εἰς ἀλλήλους, also employed the locution ἐν ἀλλήλαις αἱ ὑποστάσεις εἰσίν.²

Suarez³ and Ruiz⁴ preferred to base Perichoresis on the attribute of immensity rather than upon the unity of the Divine Nature. Each of the Three Divine Persons, argued these eminent theologians, must be where the other Two are. It is true that the Three Divine Persons together indwell in creatures not only by virtue of Perichoresis, but likewise by omnipresence. But omnipresence is so far from constituting the formal essence of Perichoresis, that even a Tritheist could without inconsistency teach the simultaneous presence and indwelling of three Gods in a creature. Christ clearly affirms the divine Perichoresis when He says: “I am in the Father, and the Father is in me.”⁵ On the other hand, St. Paul’s famous dictum: “In him we live, and move, and are,”⁶ merely asserts the immensity of God, not the Trinitarian Perichoresis. For, as Petavius rightly observes,⁷ “though the mind abstract entirely from the notion of place and location in space, and regard solely the Divine Hypostases considered in themselves and absolutely, Perichoresis and the mutual inexistence of Person in Person will still be there; because if one be posited it will be necessary to posit the other; they cannot be separated from one another, but each will remain intimately united with each and all three will mutually inexist.” Hence the Perichoresis of the Blessed Trinity cannot be adequately explained by the divine attribute of immensity.

If we compare Perichoresis with Consubstantiality (ὁμοουσία, or better ταὐτουσία), we find that the two notions are related to each other as effect is related to cause. The ontological reason for the mutual Inexistence or Indwelling of the Three Divine Persons is primarily their possession of one and the same Divine Nature or Essence. “Perichoresis in the Godhead originates in the unity of the Divine Essence,” says Petavius, ”… and it consists in this, that one Person cannot be divided or separated from another, but they mutually exist in one another without confusion and without detriment to the distinction between them.”⁸ This does not, of course, preclude the existence of other secondary sources of Perichoresis, such as the Divine Processions and Relations.

2. The Proof of Perichoresis

The Decretum pro Iacobitis (A. D. 1439) expressly bases the Perichoresis of the Three Divine Persons on identity of Essence. “Omnia [in Deo] sunt unum, ubi non obviat relationis oppositio. Propter hanc unitatem Pater est totus in Filio, totus in Spiritu Sancto; Filius totus est in Patre, totus in Spiritu Sancto; Spiritus Sanctus totus est in Patre, totus in Filio — All things in God are one, except where there is opposition of Relation. Because of this unity, the Father is wholly in the Son, and wholly in the Holy Ghost; the Son is wholly in the Father, and wholly in the Holy Ghost; and the Holy Ghost is wholly in the Father, and wholly in the Son.”⁹ This doctrine undoubtedly forms part of the deposit of faith. St. Thomas demonstrates it by three arguments, of which one is based on the divine ταὐτουσία, another on the origins, and a third on the mutual Relations of the Divine Persons.

a) The first and main source of the Trinitarian Perichoresis is the Consubstantiality of the Three Persons, or their identity of Essence. Sufficient Scriptural proof for this proposition, at least in so far as it regards the First and Second Persons of the Blessed Trinity, was adduced by St. Athanasius, who from a well-known sermon of Jesus¹⁰ argues as follows: “For whereas the countenance and Godhead of the Father is the Being of the Son, it follows that the Son is in the Father and the Father in the Son. On this account and reasonably, having said before, ‘I and the Father are one,’ He added, ‘I in the Father and the Father in me,’ by way of showing the identity of Godhead and the unity of substance.”¹¹ That the Holy Ghost is included in this Divine Company we know from 1 Cor. II, 11: “Quis enim hominum scit, quae sunt hominis, nisi spiritus hominis, qui in ipso est? Ita et quae Dei sunt, nemo cognovit, nisi Spiritus Dei (supply: qui in ipso est) — For what man knoweth the things of a man, but the spirit of a man that is in him? So the things also that are of God no man knoweth but the Spirit of God [that is in Him].” St. Athanasius probably found the bracketed clause, “qui in ipso est,” in his Bible, for he treats it like a verbal quotation.¹²

The intrinsic connexion between Trinitarian Perichoresis and the Consubstantiality of the Three Divine Persons is perhaps most effectively brought out by those of the Fathers who employed Perichoresis as a popular and intelligible middle term to demonstrate the essential identity of Father and Son against the Arians.¹³

b) A secondary source of this mutual Immanence, according to many Fathers, is the origin of the Three Divine Persons from one another, i. e., the divine Processions by mode of Generation and Spiration. For inasmuch as the Logos is begotten as the “Divine Word” of the Father by the Father’s notional understanding, He is necessarily immanent in the Father, as the internal word or concept is immanent in the human intellect. “Ex mente enim et in mentem,”¹⁴ says St. Cyril of Alexandria,¹⁵ “verbum est semper, ideoque mens in verbo.¹⁶ … Verbum manet in mente generante et mentem generantem habet totaliter in se … et oportet simul existere cum Patre Filium et vicissim Patrem cum Filio — For the word is always of the mind and in the mind, and therefore the mind is in the word… . The word remains in the mind in which it is conceived, and contains that mind entirely within itself… . So it behooves the Son to exist simultaneously with the Father, and the Father to exist simultaneously with the Son.” St. Hilary expresses this truth more concisely thus: “Deus in Deo, quia ex Deo Deus est — God is in God, because God is from God.”¹⁷ The Holy Ghost, too, in consequence of His Procession by way of mutual love, reposes deep down in the Principle which produces Him, as love reposes in the heart of a lover. St. Ambrose aptly observes: “Sicut Pater in Filio et Filius in Patre, ita Dei Spiritus et Spiritus Christi et in Patre et in Filio, quia oris [=halitus] est spiritus — As the Father is in the Son, and the Son is in the Father, so the Spirit of God and the Spirit of Christ is both in the Father and the Son, because He is the spirit [a breath] of the mouth.”¹⁸ There is Scriptural warrant for this mode of conceiving the divine Perichoresis. Cfr. John I, 18: “Unigenitus, qui est in sinu Patris — The only begotten Son who is in the bosom of the Father.” The Greek original of this passage implies a movement ad intra, which is not fully brought out by either the Vulgate or the vernacular version: “Ὁ μονογενὴς υἱὸς ὁ ὢν (= περιχωρῶν) εἰς τὸν κόλπον τοῦ πατρός.”

c) The third and last source of Perichoresis are the Divine Relations, that is, the relative opposition of the Three Divine Persons to one another. The Father cannot be conceived without His Son, nor can the Son be conceived without the Father, and the Holy Ghost is altogether unthinkable without His common Spirators, the Father and the Son. St. Basil, and especially the Eleventh Council of Toledo (A. D. 675), particularly emphasized this logical aspect of the divine Perichoresis. “Nec enim Pater absque Filio cognoscitur,” we read in its decrees, “nec sine Patre Filius invenitur; relatio quippe ipsa vocabuli personalis personas separari vetat, quas etiam, dum non simul nominat, simul insinuat. Nemo autem audire potest unumquodque istorum nominum, in quo non intelligere cogatur et alterum — For neither can the Father be known without the Son, nor the Son be found without the Father; for the relation indicated by the name of a person forbids us to separate the persons who are intimated, though not expressly named. And nobody can hear any one of these names without perceiving therein one of the others.”¹⁹ Perhaps our Lord’s saying: “He that seeth me seeth the Father also… . Do you not believe that I am in the Father, and the Father in me?”²⁰ — which Sabellius so egregiously misunderstood — must be interpreted in the light of these considerations, though both the context and the construction put upon it by the Fathers make it more advisable to base the Perichoresis here expressed by Jesus, upon the notion of Tautousia rather than upon the divine Relations.²¹

3. Dogmatic Importance of the Doctrine of the Perichoresis

The doctrine of the Trinitarian Perichoresis is of considerable dogmatic importance, because it tersely and luminously expresses the two salient aspects of the dogma of the Blessed Trinity, viz.: Trinitas in Unitate and Unitas in Trinitate, thus equally discountenancing the heresy of Monarchianism on the one hand, and that of Tritheism on the other. In matter of fact Perichoresis involves two important truths: (1) that there is a real distinction between the Three Divine Persons, and (2) that the Divine Nature, or Essence, in spite of the Hypostatic distinctions, is absolutely one. Sabellius, by welding the Three Persons into One, practically denied the dogma of mutual Inexistence, while the Tritheists, who imagined the Divine Essence to consist of three Gods, found themselves unable to admit a real indwelling of the One in the Other.²²

We shall meet with a similar phenomenon in Christology, though the order is there reversed. The Perichoresis of the two Natures in Christ can be conceived only in virtue of the Hypostatic Union from which it springs. It postulates a perfect and unalloyed duality together with absolute oneness of Person and an indivisible unity in spite of the Saviour’s twofold Nature. For this very reason the doctrine of Perichoresis furnishes a powerful weapon for the defence of the faith against such extreme Christological heresies as Nestorianism and Adoptianism on the one hand, and Monophysitism and Monotheletism on the other.

The doctrine of the Perichoresis fittingly concludes the treatise on the Trinity, because it represents the final upshot of the whole discussion and clearly and luminously brings out both aspects of the dogma, viz.: the Trinitas in Unitate and the Unitas in Trinitate. At the same time it forms an invincible bulwark against all Antitrinitarian heresies, guarding as it does the Trinity of the Divine Persons against the Monarchians and Unitarians, and the unity of the Divine Nature against the various Tritheistic sects.

Readings

Scheeben, Dogmatik, Vol. I, § 123, Freiburg 1873. — Oswald, Trinitätslehre, § 14, Paderborn 1888. — Franzelin, De Deo Trino, thes. 14, Romae 1881. — Kleutgen, De Ipso Deo, pp. 694 sqq., Ratisbonae 1881. — Chr. Pesch, Praelect. Dogmat., Vol. II, ed. 3a, pp. 330–343, Friburgi 1906. — St. Thomas, S. Theol., Ia, qu. 42, art. 5. — Petavius, De Trinit., IV, 16.

On the practical and devotional value of the dogma of the Divine Trinity cfr. F. J. Hall, The Trinity, pp. 289 sqq.; Wilhelm-Scannell, A Manual of Catholic Theology, Vol. I, pp. 351 sqq.; H. P. Liddon, The Divinity of Our Lord, pp. 659 sqq.