Once the divinity of Christ had been established by the Church, as confessed in the Nicene Creed, questions arose concerning the relationship between his divine and human natures. If he is divine, was he really only an illusion of a human being? Did Christ have a soul? Two souls? Were there two Persons in one body, one divine and one human? How could that be? If Christ were not really human, then how could he be a suitable atonement for human sins? If he were fully human, did he commit sins? And most of all -- how could the eternal, uncreated Creator be united with the physical creature? Isn't this tantamount to pantheism?
Such questions began to trouble theologians in the early Church after Athanasius and Augustine in the 4th century. A variety of theories arose in an attempt to resolve this issue. Adding to the confusion were questions about ordinary human nature (now studies called psychology and anthropology): does our personhood rest on our soul, or spirit, or mind, or body? Is it possible for one body to possess two different souls or identities?
Here it is recognized that these questions regarding the Christ's nature are found to fit into the general trilogical pattern of Unity-Diversity-Equality, like many other aspects of theology. The Christological pattern shown here is an attempt to organize the basic positions in the controversy. More details on each position are given in each separate area (see the hyperlinks for each one).
These discussions eventually led to one of the major "ecumenical councils" or meetings with representatives from the whole Church, at Chalcedon (near Constantinople) in 451. Their statement, which henceforward has defined orthodoxy in the Church, reads in part as follows:
"We all with one voice confess our Lord Jesus Christ one and the same Son, at once complete in Godhead and complete in manhood, truly God and truly man, consisting of a reasonable soul and body; of one substance with the Father as regards his Godhead, of one substance with us as regards his manhood, like us in all things, apart from sin; begotten of the Father before the ages as regards his Godhead, the same in the last days, for us and for our salvation, born from the Virgin Mary, the God-bearer, as regards his manhood; one and the same Christ, Son, Lord, Only-begotten, to be acknowledged in two natures, without confusion, without change, without division, or without separation; the distinction of natures being in no way abolished because of the union, but rather the characteristic property of each nature being preserved, and coming together to form one person (prosopon) and one entity (upostasis), not as if Christ were parted or divided into two persons ...."
This carefully-worded statement of the Two Natures of Christ, the conclusion of over a century of controversy, illustrates the carefully-balanced qualifications that were stated in order to avoid a variety of unbiblical pitfalls. The process of development of this doctrine is a classic example of dilogical or complementary thought in Christianity. Dr. B. B. Warfield summarized this historical process in his book on Christology:
"To discover a one-natured Christ, we must turn to the outlawed sects of the Docetists on the one hand, and the Ebionites with their successors, the Dynamistic Montanists, on the other. Whatever else the church brought with it out of the apostolic age, it emerged from that, its formative, epoch with so firm a faith in the Two Natures of its Lord as to be incapable of wavering. 'Perfect man' [Ignatius,ad Symrn.iv. p. 2] it knew him to be. But the exhortation of Christians to one another ran in such strains as we find in the opening words of the earliest Christian homily that has come down to us: 'Brethren, thus ought we to think of Jesus Christ as of God, as of Judge of quick and dead;' [2 Clement Rom. I.1] 'and so exhorting one another, they naturally were known to their heathen observers precisely as worshippers of Christ.' [Pliny,Epistle x. p. 96: "carmenque Christo quasi deo dicere secum invicem."] So fixed in the Christian consciousness was the conception of the Two Natures of the Savior, that nothing could dislodge it. We shall have to come down to the radical outbreak which accompanied the Reformation Transcendental or Socinian for the first important defection from it after the early Dynamistic Monarchianism; and it was not until the rise in the eighteenth century of the naturalistic movement known as the Enlightenment that there was inaugurated any widespread revolt from it. It is under the influence of this revolt, which has not yet spent its force, that so many moderns have turned away from the doctrine as impossible."The constancy with which the church has confessed the doctrine of the Two Natures finds its explanation in the fact that this doctrine is intrenched in the teaching of the New Testament. The Chalcedonian Christology, indeed, in its complete development is only a very perfect synthesis of the biblical data. It takes its starting-point from the New Testament as a whole, thoroughly trusted in all its declarations, and seeks to find a comprehensive statement of the scriptural doctrine of the Person of Christ, which will do full justice to all the elements of its representation. The eminent success which it achieves in this difficult undertaking is due to the circumstance that it is not the product of a single mind working under a 'scientific' impulse, that is to say, with purely theoretical intent, but of the mind, or rather the heart, of the church at large searching for an adequate formulation of its vital faith, that is to say, of a large body of earnest men distributed through a long stretch of time, and living under very varied conditions, each passionately asserting, and seeking to have justice accorded to, elements of the biblical representation which particularly 'found' him. The final statement is not a product of the study, therefore, but of life; and was arrived at, externally considered, through protracted and violent controversies, during the course of which every conceivable construction of the biblical data had been exploited, weighed, and its elements of truth sifted out and preserved, while the elements of error which deformed were burned up as chaff in the fires of the strife.
"To the onlooker from this distance of time, the main line of the progress of the debate takes on an odd appearance of a steady zigzag advance. Arising out of the embers of the Arian controversy, there is first vigorously asserted, over against the reduction of our Lord to the dimensions of a creature, the pure deity of his spiritual nature (Apollinarianism); by this there is at once provoked, in the interests of the integrity of our Lord’s humanity, the equally vigorous assertion of the completeness of his human nature as the bearer of his deity (Nestorianism); this in turn provokes, in the interests of the oneness of his Person, an equally vigorous assertion of the conjunction of these two natures in a single individuum (Eutychianism): from all of which there gradually emerges at last, by a series of corrections, the balanced statement of Chalcedon, recognizing at once in its "without confusion, without conversion, eternally and inseparably" the union in the Person of Christ of a complete deity and a complete humanity, constituting a single person without prejudice to the continued integrity of either nature.
"The pendulum of thought had swung back and forth in ever-decreasing arcs, until at last it found rest along the line of action of the fundamental force. Out of the continuous controversy of a century there issued a balanced statement in which all the elements of the biblical representation were taken up and combined. Work so done is done for all time; and it is capable of ever-repeated demonstration that in the developed doctrine of the Two Natures (as it is worked out with marvelous insight and delicate precision in such a presentation of it as is given, say, in the Admonitio Christiana, 1581, written chiefly by Z. Ursinus and published in his works) and in it alone, all the biblical data are brought together in a harmonious statement, in which each receives full recognition, and out of which each may derive its sympathetic exposition. This key unlocks the treasures of the biblical instruction on the Person of Christ as none other can, and enables the reader as he currently scans the sacred pages to take up their declarations as they meet him, one after the other, into an intelligently consistent conception of his Lord.
"The key which unlocks so complicated a lock can scarcely fail to be its true key. And the argument may be turned around. That all the varied representations concerning our Lord’s Person contained in the New Testament fall into harmony under the ordering influence of so simple a hypothesis as that of the Two Natures, authenticates these varying representations as each a fragment of a real whole. It were inconceivable that so large a body of different and sometimes apparently divergent data could synthesize in so simple a unifying conception; were they not component elements of a unitary reality. And this consideration is greatly strengthened by the manner in which these differing or sometimes even apparently divergent data are distributed through the New Testament. They are not parceled out severally to the separate books, the composition of different writers, so that one set of them is peculiar to one writer or to one set of writers, and a set of different import peculiar to another writer or set of writers. They are, rather, pretty evenly distributed over the face of the New Testament, and the most different or apparently divergent data are found side by side in the writings of the same author or even in the same writing. The doctrine of the Two Natures is not merely a synthesis of all data concerning the Person of Christ found in the New Testament; it is the doctrine of each of the New Testament books in severalty. There is but one doctrine of the Person of Christ inculcated or presupposed by all the New Testament writers without exception. In this respect the New Testament is all of a piece."
-- Excerpt from ch. VII, "Recent Christological Speculation", in The Person and Work of Christ: Christological Studies by B. B. Warfield, Baker Book House, Grand Rapids (1970). [Emphasis mine.]
It should not be overlooked that objections to orthodox Christology also originate from Jewish and, especially, Muslim sources.