The Christological heresies and the Chalcedonian solution to them focus on the problem of their being two natures and one Person in Christ. “First, Jesus Christ is only one person, the divine Person, or the Hypostasis of the Son of God or of the Word. Second, this one divine Person subsists or exists in two natures, the Divine nature and the human nature, each of which is perfect as a nature, lacking no perfection of the nature. Thus His human nature has a human soul as well as a human body.”1
“The reason pagans could not conceive of anything like the incarnation is that their gods are part of this world, and the union of any two natures in this world is bound to be unnatural, because of the otherness that lets one thing be itself only by not being the other…The Christological heresies are a reflection of tendencies to make pagan the Christian sense of the divine.”2 Here, however, we are not dealing with pagans, but with Christians who are trying to understand the same problem. Nowhere in the world of our experience is there anything like one existent with two different natures. Likewise, within the world of created things, for a thing to be one thing necessarily entails it not being another. Part of the definition (if singulars could have definitions) of Matt, for example, would be that Matt is not John, or a rock, etc.
The problem, then, is how to understand Jesus Incarnate. Is He man with God related to Him in a close way, such as that of the saints? Are there actually two persons here, a human person and a divine person? Does the divinity of Christ replace the rational soul of the otherwise fully human man Jesus? Or are the two natures, somehow beyond our understanding, somehow mixed? All of these solutions and more have been proposed by men of faith seeking to understand the great mystery of the Incarnation of the Son of God.
In 431 A.D., the Council of Ephesus decreed that the Virgin Mary is Theotokos, the God bearer, for her son Jesus is one person who is both God and man, divine and human. “Now, it was proved that the body of that man is the body of the natural Son of God, that is, of the Word of God. So it becomes us to say that the Blessed Virgin is ‘the Mother of the Word of God,’ and even ‘of God’.”3 Objection to the title “Mother of God” arose, due to confusion concerning the mystery of the incarnation. Nestorius stated that Mary gave birth to Jesus Christ, a regular human person. As such, Mary is not “Mother of God,” but simply the “Mother of Christ” or even the “Mother of Christ’s humanity.”
Another position, also heretical and indeed contrary to even reason alone, that was taken in opposition to the previous heresy of Nestorius is that of Eutyches. “Eutyches…says there is one nature, also. He says that, although before the union there were two distinct natures, the divine and human, they came together, nevertheless, in the union into one nature.”4 St. Thomas, among others, would demonstrate that this is both repugnant to Scripture and to reason.
“If…the human nature and the divine were two before the union, but from those in the union one nature was breathed together, this should take place in one of the ways in which it is natural that one comes to be from many.”5 In the next few articles, Thomas goes through the various ways this can be said to take place in nature, and demonstrates that all are untenable. The most important of these is the idea of a “mixture,” which can result in a single nature only through the destruction of both of the joined natures.
These two primary position, one of the Incarnate Christ being on person and one nature, and the other of Him being two distinct persons, one divine and one human, reflected the tendencies and arguments of the two primary “schools” of thought at Alexandria and Antioch.
With the 4th century debates between the Arians and the orthodox, especially Athanasius, we have “the emergence and development of two main types of Christology…: the so-called ‘Word-Flesh type, with its concentration on the Word as subject in the God-man and its lack of interest in the human soul, and the ‘Word-man’ type, alive to the reality and completeness of the humanity, but more hesitant about the position of the Word as a metaphysical subject…as it turned out, it was their head-on collision in these critical decades which precipitated the required synthesis.”6
Although most of the debate came in the East, primarily from the leading proponents of the Antiochene and Alexandrian schools, a key factor in the final confession was the Tome of Pope Leo. At the Council of Chalcedon, in which more than 500 bishops took part, with the Pope represented by his legates, the Nicene Creed was upheld, and a formal confession of the doctrine of Christ’s two natures and one Person followed. It can be summarized as follows:
“Jesus Christ is one and the same Son, the same perfect in Godhead and the same perfect in manhood…consubstantial with the Father in Godhead, and the same consubstantial with us in manhood..; begotten from the Father before the ages as regards His Godhead, and in the last days, the same, because of us and because of our salvation begotten from the Virgin Mary, the Theotokos, as regards His manhood;…in two natures without confusion, without change, without division, without separation, the difference in the natures being by no means removed because of the union,…coalescing in one prosopon and one hypostasis…”