The Hypostatic Union: The Dogma in Its Relation to Reason

The Hypostatic Union of the two natures in our Lord Jesus Christ is a theological mystery, and as such absolutely indemonstrable. But it is not, as the Rationalists allege, repugnant to reason.

A Genuine Mystery

A theological mystery is one whose very existence unaided human reason cannot discover, and which, in the language of the Vatican Council, so transcends created intelligence by its own nature that even when revealed and received by faith it remains shrouded in a degree of darkness so long as we remain wayfarers on earth.¹

That the Hypostatic Union is a mystery in this strict sense follows from the fact that, unlike the Trinity, it does not belong to the inner life of the Godhead but is the result of a free divine decree. Whatever God has freely decreed to bring about in time can be known only through the manifestation of the divine will itself — either as accomplished fact (Creation) or through revelation (the end of the world). The whole question, then, is whether reason can, after the fact, perceive the Hypostatic Union’s intrinsic possibility, or demonstrate it by strict argument. Fathers and theologians answer uniformly in the negative. St. Cyril of Alexandria calls “the mystery of Christ” something so ineffably profound as to be altogether incomprehensible.² Leo the Great confesses: “Unless faith believes it, no speech can explain how the two substances came together in one Person.”³ Suarez, in full agreement with St. Thomas,⁴ voices the common judgment of the Schoolmen: “It is the common opinion of theologians that neither human nor angelic natural knowledge can evidently know or demonstrate that the Incarnation is possible.”⁵ Whether the angels might at least conjecture the Incarnation’s possibility by their natural powers is disputed among theologians; some deny it outright, while others hold the angelic intellect capable of grasping its abstract possibility — though Cardinal De Lugo, who favors this second view, concedes that any such angelic knowledge would be mixed with so much doubt as to amount, practically, to ignorance.⁶

Scripture itself points the same way. Defining the existence of absolute mysteries of faith, the Vatican Council quotes St. Paul’s words about “a wisdom which is hidden in a mystery, which none of the princes of this world knew” (1 Corinthians 2:7), set against the wisdom “the Greeks seek after.” These two wisdoms differ in both object and source: the wisdom of God is the supernatural spirit of Christ, which raises man above himself, while the wisdom of “the disputer of this world” never rises above the level of the flesh. Their sources differ correspondingly — worldly wisdom from unaided reason, the wisdom of God from the Holy Spirit, who through revelation and inward enlightenment unfolds “the deep things of God” and reveals what has “never entered into the heart of man” (1 Corinthians 2:9-10). Paul is explicit that this hiddenness is not merely a fact but a matter of principle: “the things that are of God no man knoweth but the Spirit of God” (1 Corinthians 2:11) — the mysteries of the Godhead simply transcend human understanding as such. The Incarnation is a mystery, in the first place, precisely because it belongs to the free decrees of God, which lie beyond all created foreknowledge;⁷ and the same Pauline texts imply, further, that the inner life of God, and in particular the existence of the Divine Logos, is a supernatural mystery beyond the reach even of the angelic intellect.

Beyond All Analogy

The human mind can no more comprehend the Hypostatic Union than it can fathom the Trinity; every attempt to do so has only underscored how thoroughly indemonstrable the mystery is.

Nature does offer certain analogies — substantial unions that help us visualize the mystery once revealed, such as the union of body and soul in man. But even a cursory look shows there is no real parity between any natural union and the Hypostatic Union; whatever similarities exist are outweighed by more numerous and more important differences.⁸ Those who have spun such analogies into full arguments have, notoriously, always ended in heresy — Anton Günther and his followers Baltzer and Knoodt are the standing nineteenth-century example.⁹ Günther’s Christology tends toward Nestorianism, and his Trinitarian teaching toward a thinly veiled Tritheism,¹⁰ both rooted in his mistaken definition of “person” as “a self-conscious substance.” Since Christ possessed both a divine and a human consciousness, Günther was led to ascribe to Him two physical persons, united only by a “dynamic and formal union” into a “relational person” — which is exactly the error of Nestorius under another name: fusing two hypostases into “one person” while conceiving the union of natures as merely relational rather than truly hypostatic.

Answering the Objections

Though reason cannot form an adequate notion of the Hypostatic Union’s inner nature, it has no difficulty refuting the objections various skeptics, from Celsus to Pierre Bayle, have raised against its bare possibility.¹¹

Bayle argued that if the Divine Logos supplies the human person in Christ, then no man could be certain of his own personhood. The conclusion is simply absurd — does this make every human being a potential Christ? Manifestly not; there is but one Christ.

A subtler objection, from Celsus, holds that a Hypostatic Union of Divinity with humanity would involve change in the eternal Godhead. The dogma actually contains two distinct claims: that the Logos began to be what He had not been before (true man), and that He continued to be what He had always been (true God). Does this amount to a change? The objection, in fact, cuts deeper than the Incarnation alone — it touches God’s whole relation to the universe, in Creation, providence, and concursus generally. God creates the world in time without Himself passing from potency to act, since He is immutable; the Incarnation only sharpens the difficulty because of the permanent, intrinsic relation the Logos bears to the humanity He hypostatically assumes. But the underlying principle is unchanged. A real change in the Godhead would occur only on the Monophysite hypothesis — if the two natures combined substantially into one nature, i.e., if the union were a natural synthesis rather than a hypostatic one. That is not the Catholic teaching. A Divine Hypostasis must be conceived as actually infinite in exactly the way the Divine Nature is infinite; and reason can therefore grasp that a Divine Hypostasis’s “power of termination” must likewise be infinite, capable of terminating not only in its own Divine Nature but in some created nature besides. Celsus’s argument, taken rightly, proves only that Hypostatic Union is the sole possible kind of union between Godhead and manhood — not that the Incarnation is impossible, since the Divine Hypostasis possesses infinite capacity precisely by virtue of what it is to be a Hypostasis. On this footing the objection dissolves: in the Incarnation, God was not drawn down to the level of a mutable creature; rather, created manhood was elevated into the infinite Hypostasis of the immutable Logos. Whatever change is involved falls entirely on Christ’s assumed humanity, which received through this union a superior dignity and a divine consecration — not on the unincarnate Logos Himself. As St. Augustine puts it: “Man did not change God; rather, he was so assumed that he himself was changed for the better, and formed by Him ineffably more excellently.”¹²

A related objection asks whether the Divine Logos gained any increase of intrinsic perfection by hypostatically assuming a created nature. The question answers itself once we recall that the Logos, as a Divine Person, is the possessor of the Divine Nature, which by definition cannot be perfected further. The Incarnate Logos cannot be more perfect than the unincarnate Logos, since the Second Person’s identity was in no way altered by assuming human flesh — God remains unchangeably the same forever. As Maxentius writes: “The human nature assumed for our salvation neither added to nor subtracted from Him; rather He glorified it by His own union with it. Nor is God the Word less than Christ, since He Himself is Christ, nor can He be less than Himself; and having assumed flesh, He remained, without any doubt, the same perfect God.”¹³

A further objection holds that the Logos must at least have gained an increase of extrinsic perfection by assuming manhood — a variant of the Pantheistic error, already refuted elsewhere, that “God plus the universe” must add up to more perfection than “God minus the universe.”¹⁴ But adding divine and created perfections together yields nothing new: Christ’s humanity added to the Logos’s Divinity no more produces a higher sum of perfection than the universe added to God does, since any created perfection, however exalted, is already virtually and eminently contained within the perfection of God, and can add nothing to it. St. Thomas puts the point memorably: “In the composite person [i.e., Christ], although there are more goods than in the simple person [i.e., the Word alone], since there is both an uncreated good and a created good, the composite person is still not a greater good than the simple one — because created good stands to uncreated good as a point stands to a line, there being no proportion between the two. Just as adding a point to a line does not make it longer, so adding a created good to an uncreated good in a person does not make that person better.”¹⁵

Notes