One Hypostasis and the Communication of Idioms

The same sentence that confesses two natures confesses one Person and one Hypostasis — and the one hypostasis is not a new subject produced by the union but the eternal hypostasis of the Word, who assumed a human nature that has its concrete existence in him. From that single subject follows the communication of idioms, by which what belongs to either nature may be said of the one Christ: God was born of the Virgin, one of the Holy Trinity suffered in the flesh. This file expounds the second half of the Chalcedonian formula and what hangs on it.

Tradition: Pan-Orthodox

One Person and One Hypostasis

The Definition confesses the one Christ “in two natures… the peculiar property of each nature being preserved and being united in one Person and subsistence, not separated or divided into two persons” — in Greek, εἰς ἓν πρόσωπον καὶ μίαν ὑπόστασιν (Council of Chalcedon, Definition of Faith; trans. Percival, NPNF, Second Series, vol. 14; Greek in Acta Conciliorum Oecumenicorum II.1.2, ed. Schwartz).

Two things are done in that clause. First, prosōpon and hypostasis are treated as equivalent and both attributed to Christ in the singular — closing the Nestorian escape route, since Nestorius could confess one prosōpon of union while allowing two hypostases. Second, the whole weight of the unity is placed on who Christ is rather than on what he is: the unity is hypostatic, personal, at the level of the subject, and precisely not at the level of nature. This is why the two natures can be affirmed without dividing him. Duality of nature and unity of person are not competitors; they answer different questions.

The confession is exactly St. Cyril’s “hypostatic union” (henōsis kath’ hypostasin) of the Second Letter to Nestorius, restated with the Cappadocian vocabulary (Cyril, Ep. 4, PG 77:44–49; McGuckin, St. Cyril of Alexandria and the Christological Controversy, Leiden: Brill, 1994). It is what Ephesus won, carried forward intact.

The Hypostasis of the Union Is the Word Himself

Chalcedon says “one hypostasis” but does not say which hypostasis, and in the century that followed some read the council as though the union produced a new, composite subject constituted out of two — a reading that would make the incarnate Christ a different subject from the eternal Son, and so would break the identity on which the Gospel depends.

The Church answered this conciliarly. The Fifth Ecumenical Council (Constantinople II, 553) defined that the hypostasis of the union is none other than the pre-existent hypostasis of the Word: the Word did not acquire a person by becoming man but assumed human nature into the person he eternally is. It endorsed the theopaschite confession that the one crucified in the flesh is “true God and Lord of glory and one of the Holy Trinity,” and it condemned the doctrine of a hypostasis newly constituted by the union (Council of Constantinople II, Anathemas; trans. Percival, NPNF, Second Series, vol. 14; Tanner, ed., Decrees of the Ecumenical Councils, vol. 1; Price, The Acts of the Council of Constantinople of 553, Liverpool: Liverpool University Press, 2009; see The Three Chapters and Constantinople II).

The identity claim is the whole point. The one who lay in the manger is the one who made the worlds; the one who died on the Cross is the one who was eternally begotten of the Father. If the incarnate subject were a new composite, then the Word did not become man — something else became a God-man — and we are not saved.

Enhypostasia: How a Nature Can Be Real Without Being a Person

Chalcedon’s formula raises an immediate question: if Christ’s human nature is complete, why is it not a human person? Every human nature we know of is somebody’s.

The answer developed in the sixth and seventh centuries, associated above all with Leontius of Byzantium and Leontius of Jerusalem and given its classical form by St. John of Damascus, is the doctrine of enhypostasia. A nature never exists in the abstract; it exists in a hypostasis. Christ’s human nature has no hypostasis of its own and never had one — there was no man who was then joined to the Word — but neither is it anhypostatic, a nature without any subject, which would be an abstraction and not a reality. It is enhypostatic: it has its concrete personal existence in the hypostasis of the Word, who from the moment of conception is the subject of it (John of Damascus, An Exact Exposition of the Orthodox Faith III.9; Meyendorff, Christ in Eastern Christian Thought, Crestwood, NY: SVS Press, 1975, on Leontius and the enhypostaton; Grillmeier, Christ in Christian Tradition, vol. 2 pt. 2, London: Mowbray, 1995).

[Disputed: the precise history of the term *enhypostatos* and how much of the classical doctrine belongs to Leontius of Byzantium. Older scholarship credited Leontius of Byzantium with coining the doctrine as a solution to the Chalcedonian problem; more recent study argues that his usage is narrower than that account allows and that the developed doctrine is better located in Leontius of Jerusalem and in John of Damascus (Meyendorff, *Christ in Eastern Christian Thought*, 1975, on the Leontii; Grillmeier, *Christ in Christian Tradition*, vol. 2 pt. 2, 1995). The dogmatic content — that Christ's humanity subsists in the hypostasis of the Word — is not in dispute among Orthodox theologians; the terminological genealogy is.]

Enhypostasia is not a technicality. It is the reason Christ’s humanity is ours and not another individual’s private property: the human nature he assumed is not the nature of a particular man alongside us but human nature itself, taken up into the divine hypostasis, so that what happens to it happens for us. On this hangs the whole doctrine of deification (see Theological Anthropology).

The Communication of Idioms

Because one and the same hypostasis is the subject of both natures, the properties and acts of either nature may be predicated of the one Person. This is the communicatio idiomatum (Greek antidosis idiōmatōn, “exchange of properties”):

It is right to say “God was born of the Virgin Mary” — because the one born is the Word, who is God. This is why the title Theotokos is not a Marian courtesy but a christological necessity (see Theotokos).
It is right to say “God suffered and died on the Cross” — because the one who suffered is the Word; he suffered in his human nature, and the Godhead remained impassible, but the sufferer is God. This is the theopaschite formula “one of the Holy Trinity suffered in the flesh,” dogmatized at Constantinople II.
It is right to say “the Son of Mary created the world” — because the Person of the Word, who created all things, is the same Person born of Mary.

The rules that govern this exchange are exact, and St. John of Damascus states them. The properties are exchanged at the level of the person, not at the level of the natures: “We do not attribute the properties of the humanity to the Godhead, nor the properties of the Godhead to the humanity… But we attribute both to the one Christ, for he is both God and man” (John of Damascus, An Exact Exposition of the Orthodox Faith III.4). One may not say “the divine nature suffered” or “the human nature is uncreated”; one says “the Son of God suffered” and “the Son of Mary is uncreated in his Godhead.” The Damascene puts the union itself in the same terms: the natures “are united to each other in the one hypostasis of the Logos without confusion, without change, and without division” (Exact Exposition III.3).

The communication of idioms is therefore not a rhetorical trope but the direct grammatical consequence of the hypostatic union — and it is the point at which Chalcedon’s supposed coldness is answered. A Definition that seems to the ear to be about metaphysical distinctions turns out to license the boldest sentences Christianity utters: God was born; God died; God was buried; God rose.

What Hangs on It

The Chalcedonian formula is often heard as an exercise in Greek philosophical precision. It is in fact a soteriological instrument at every point.

Because Christ is one hypostasis, his human acts are the acts of God and therefore have infinite saving weight: the obedience is God’s obedience in our nature, the death is God’s death in our flesh.

Because he is in two natures without confusion, our nature is genuinely healed rather than replaced. He assumed what we are, and what he assumed he deified — his humanity is the first-fruits of ours, “deified by its union with the Logos… not by conversion into divinity but by being permeated with divine energy and glory” (John of Damascus, Exact Exposition III.17). Chalcedon’s unconfused duality is the dogmatic guarantee of theosis: if the humanity were absorbed, deification would mean annihilation, and there would be nothing left of us to be saved.

Because he is in two natures without separation, the deified humanity is not a second thing beside him but his own; and therefore ours can be joined to his in the Church, in the Mysteries, and at the resurrection.

This is why the Church treats the four adverbs as boundary-stones rather than as speculation. They are the shape of salvation stated negatively — and the Fathers who defended them, from Cyril to Maximus to the Damascene, defended them as men defending the Gospel, not a formula.

References

Council of Chalcedon (451). Definition of Faith. Trans. Percival, ed., NPNF, Second Series, vol. 14; Greek in Acta Conciliorum Oecumenicorum II.1.2, ed. Eduard Schwartz.
Council of Constantinople II (553). Anathemas. In Percival, ed., NPNF, Second Series, vol. 14; Tanner, ed., Decrees of the Ecumenical Councils, vol. 1.
Cyril of Alexandria. Second Letter to Nestorius (Ep. 4), PG 77:44–49.
John of Damascus. An Exact Exposition of the Orthodox Faith III.3, III.4, III.9, III.17. Trans. NPNF, Second Series, vol. 9.
Price, Richard. The Acts of the Council of Constantinople of 553. 2 vols. Liverpool: Liverpool University Press, 2009.
Meyendorff, John. Christ in Eastern Christian Thought. Crestwood, NY: St. Vladimir’s Seminary Press, 1975.
Grillmeier, Aloys, with Theresia Hainthaler. Christ in Christian Tradition. Vol. 2 pt. 2. Trans. Pauline Allen and John Cawte. London: Mowbray, 1995.
McGuckin, John A. St. Cyril of Alexandria and the Christological Controversy. Leiden: Brill, 1994.
Tanner, Norman P., ed. Decrees of the Ecumenical Councils. 2 vols. Washington, DC: Georgetown University Press, 1990.