ack in the 1990s, I was an active participant in several e-mail forums devoted to theological discussion. I especially loved a couple of open forums where lay people, pastors, and seminary professors mingled—much like the combox of our blog. It was a helpful exercise in learning how to frame difficult concepts in simple terms. I loved the rookie participants, because they were full of good questions, eager to learn, and not afraid to challenge anything that seemed unclear or unbiblical.
But there were always a few lay participants who seemed to come to every discussion with the attitude that theology is (or ought to be) a dialectical exercise done mostly for recreation. They evidently thought the tools of the sport are nothing more than one's personal feelings, speculations, and inventiveness. Discussing doctrine was purely a diversion for them; nothing serious. But it seemed the more serious the topic under discussion, the more eagerly they jumped into the fray with their frivolous and half-baked ideas.
This was especially irritating when some difficult question about Christology, the Incarnation, or the two natures of Christ would come up. You could always count on several of the forum's theological tyros to crawl out of the woodwork and start shooting from the hip. "The hypostitic union? Get real. That doesn't mean anything. I think Jesus simply set aside His deity. How could he be human just like you and me if he retained the attributes of deity?" Or, "Well, I think He kept His deity and took on a human body. 'Two natures' is nonsense. He had a divine nature in a human body. And so on.
The Incarnation, of course, is one area of Christian theology where orthodoxy is meticulously defined and has been accepted by all major traditions without serious challenge since the fourth century. Why anyone (much less a total novice) would want to enter the fray now with a "Well, I think this: [your novel idea here]" kind of argument is mystifying.
The reason these issues were hashed out so carefully in the early church is that they are absolutely foundational. And on such matters it behooves us all to study not only Scripture, but also historical theology and the major creeds before launching into homebrew hypotheses or stupid speculations.
Here's a simplified synopsis of how the church grappled with and finally settled the major questions about Christ's two natures:
Several early heresies arose in the early centuries of the church. Among them all, they pretty much covered every possible heresy regarding the Person of Christ. You think you have a new way to explain the incarnation? It's no doubt already been done.
For example, the Ebionites insisted that Jesus was a mere manthe holiest of all men, but no more than that. The Apollinarians acknowledged His deity but denied that He had a human soul. The Nestorians made Him both God and man, but in doing so made Him two persons in one bodya man in whom the divine Logos dwelt rather than a single person who was both human and divine. The Eutichians, the monophysites, and the monothelites went to the opposite extreme, fusing the divine and human natures of Christ into one new nature. The Arians claimed He was not God, but the highest of all created beings. (That, of course is precisely what modern Jehovah's Witnesses believe.) And the Docetists denied that Christ was really human. Most docetists taught that Jesus' human body was only an illusion.
Several Church councils convened to examine Scripture and decide between these differing views. As soon as one issue was settled, however, another would surface and need to be dealt with. In 325, the council of Nicea condemned Arianism and proclaimed that Jesus is fully divine. But within 60 years, the Council of Constantinople had to deal with Apollinarianism, which went overboard on the side of Christ's deity and was not doing full justice to His humanity. In 381 the council of Constantinople condemned Apollinarianism as heresy.
This war against Christological heresies continued until the council of Chalcedon in 451 issued a statement about the Person of Christ that has stood as the definitive test of orthodoxy from that time until now. The statement is brief. It is all one very long sentence:
We, then, following the holy Fathers, all with one consent, teach men to confess one and the same Son, our Lord Jesus Christ, perfect in Godhead and also perfect in manhood; very God and very man, of a rational soul and body; coessential [homousios, identical in nature] with the Father according to the Godhead, and consubstantial [homousios, identical in nature] with us according to the Manhood; in all things like unto us, without sin; begotten before all ages of the Father according to the Godhead, and in these latter days, for us and for our salvation, born of the Virgin Mary, the God-bearer [Theotokos], according to the Manhood; one and the same Christ, Son, Lord, Only-begotten, to be acknowledged in two natures without confusion, without change, without division, and without separation; the distinction of natures being by no means taken away by the union, but rather the property of each nature being preserved, and concurring in one Person and one Subsistence, not parted or divided into two persons, but one and the same Son, and only begotten, God the Word, the Lord Jesus Christ, as the prophets from the beginning have spoken of him, and the Lord Jesus Christ himself has taught us, and the Creed of the holy Fathers has handed down to us.
The genius of that statement—the element that put an end to incessant heresies on the nature of Christ—is found in the phrase "two natures without confusion, without change, without division, and without separation." Those four negative statements forever defined and delimited how the person of Christ is to be understood. G. C. Berkhouwer called those four negatives "a double row of light-beacons which mark off the navigable water in between and warn against the dangers which threaten to the left and to the right."
Virtually every heresy that has ever surfaced with regard to the person of Christ either fuses or separates the deity and the humanity of Christ. Chalcedon declared that the two natures can be neither merged nor disconnected. Christ is both God and man. Truly God and truly man.
There is no terminology outside the Council of Chalcedon's statement that has ever been accepted as orthodox by any major branch of Christianity. So anyone who denies any element of that formulawhether it's the two natures, the union of the two natures, or whateveris unorthodox on the doctrine of the incarnation. It's as simple as that. And this is not something to treat lightly. The doctrine of Christ is not a theological sandbox for children to play in.
Incidentally, the technical term for the distinctive relationship between Christ's two natures is the hypostatic union. It's a doctine anyone who wants to discuss theology intelligently ought to be familiar with.