The Hypostatic Union: Patristic Formulas, Part II

“Distinguished in Thought Only”

A fourth formula expresses the truth that there is but one personality in Christ this way: “The two natures are distinguished by reason [i.e., in thought] alone.” Like the formulas before it, this one too was aimed at Nestorius’s dualism, so the Fathers who used it — Cyril among them — cannot fairly be suspected of Monophysite leanings on its account. The Fifth Ecumenical Council (A.D. 553) gave an authoritative reading of “by reason alone”: “If anyone … does not merely, in contemplation, accept the difference of the natures from which [Christ] is composed — the difference not being destroyed on account of the union, for the one [Christ] is from both, and through the one both [natures exist] — but instead uses the word ‘natures’ to argue for divided natures, subsisting separately and by themselves, let him be anathema.”¹ How foreign the idea of simply identifying the two natures was to the Fathers who used this formula appears clearly in Pope Agatho’s statement, read at the Sixth General Council of Constantinople (A.D. 680): “We recognize both natures of the one and the same incarnate — that is, made man — God the Word, without confusion, inseparably, unchangeably, distinguishing what is united by understanding alone… For we equally detest the error of division [Nestorius] and of commingling [Eutyches]."²

"The Word Assumed Flesh Through the Mediation of a Soul”

A fifth formula, aimed chiefly at Apollinaris, held: “The Word assumed flesh through the mediation of a soul.” This expresses the Hypostatic Union by describing the Logos as “assuming,” into the Divine Person, flesh already animated by a rational soul — that is, a true and complete human nature.³ The Athanasian Creed states the same truth in almost identical terms: Christ, “although He is God and man, yet He is not two, but one Christ. One, not by conversion of the Godhead into flesh, but by taking of the manhood into God; One altogether, not by confusion of substance, but by unity of Person.”

The Classical Formula: “Hypostatic Union”

The sixth formula is the classical one, generally received as the test and touchstone of Catholic belief since the Council of Chalcedon: “the union of the natures is hypostatic, or according to hypostasis.” It was framed against the errors of both Nestorianism and Monophysitism at once. Against Nestorianism, it upholds a physical and substantial union of the two natures in Christ, as against a merely moral or accidental one. Against Monophysitism, it denies any fusion or mixture of the natures. The union of Godhead and manhood in Christ, on this formula, is strictly personal or “hypostatic” — a physical union of person, not a moral one.

The Word’s Own History

Fixing “hypostasis” as the technical term for Christ’s Person, as against His twofold nature, was the fruit of a long development, in the course of which the word’s meaning shifted considerably. Originally hypostasis meant “substructure, foundation, sediment, broth.” In time it came to be used metaphorically for the “subject matter” of a speech, narrative, or poem, and eventually for “reality” as opposed to mere “semblance” or “appearance.”⁴ Simple as that transition might seem, there is no evidence of hypostasis being used in the sense of a first substance — an individual — before the controversies that forced the distinction. In St. Paul’s Epistles, hypostasis never occurs in the sense of “person” or “substance,” only in the sense of “foundation” or “basis,” or at most “essence.” Up to the Council of Nicaea, ecclesiastical usage treated hypostasis as a synonym for ousia (“essence”) — even St. Augustine confessed he saw no difference in meaning between the two.⁵

But the errors of the Trinitarian and Christological heretics made it necessary to draw a sharp line between “first substance” (an individual) and “second substance” (a nature or essence in the abstract). This led to the choice of hypostasis for the first sense, with special emphasis on self-subsistence and completeness in itself — and so the technical term “Hypostasis” was born, equivalent, when applied to rational beings, to “Person.”⁶ Nestorius plainly attached this same technical sense to hypostasis, or he would not have so stubbornly rejected the phrase “one hypostasis” while readily accepting “one prosopon [person].” St. Cyril, by contrast, was less consistent, repeatedly using hypostasis as a synonym for physis [nature] instead.⁷

For this reason, the phrase “union according to hypostasis” found in the decrees of the Council of Ephesus probably means “physical,” i.e., substantial, union rather than strictly “hypostatic” union — though objectively the phrase does express belief in Christ’s personal unity all the same. This ambiguity persisted up to the Council of Chalcedon (A.D. 451), which finally treated “hypostasis” and “prosopon” as synonyms, rendering Nestorius’s own distinction between “one hypostasis” and “one prosopon” meaningless. Finally, the Fifth Ecumenical Council of Constantinople (A.D. 553) rejected the phrase “two hypostases or two prosopa” outright, and expressly defined the union of the two natures in Christ as strictly hypostatic — a “union according to subsistence.”⁸

Further Reading

Garnerius, De Haeresi et Libris Nestorii (Migne, P.L., XLVIII) — J. Kopallik, Cyrillus von Alexandrien, Mainz 1881 — Funk-Cappadelta, A Manual of Church History, Vol. I, pp. 154 sqq., London 1910 — Bardenhewer-Shahan, Patrology, pp. 361 sq., 369, 641 — T. Gilmartin, A Manual of Church History, Vol. I, pp. 267 sqq., 3rd ed., Dublin 1909 — L. Fendt, Die Christologie des Nestorius, Munich 1910 — Bethune-Baker, Nestorius and His Teaching, London 1908 — F. Nau, Le Livre de Héraclide de Damas, Paris 1910 — Loofs, Nestoriana, Halle 1905 — Ph. Kuhn, Die Christologie Leos I. d. Gr., Würzburg 1894.

Notes