November 28, 2012 by mattwilcoxen
On my trip home from Chicago to Sydney last week, I slowly and carefully read St. Cyril of Alexandria’s On the Unity of Christ. It’s an exacting expression of the Christological logic which held sway at the First Council of Ephesus (431) and which is also embedded in the Christological statement developed by the Council of Chalcedon (451). Simplistically speaking, the former combatted the idea that there were two persons in Christ, the latter contended against the idea that there was only one nature in Christ.
Cyril’s explicit opponents are the followers of Nestorius. These (mostly Syrian) ministers had a particular way of interpreting the incarnation, one which Cyril saw as entirely undercutting salvation. When they read the all-important verse that “The Word became flesh” (John 1:14), they interpreted this word “became” in the same way that they interpreted the “became” in places like 2 Cor 5:21 (“God made him who knew no sin to become sin for us”). Taken this way, they could say that the Word became flesh in the sense that the divine Word was “associated with” a man, but that it was wrong to say of that man that he is God.
Nestorius believed that the Spirit formed a perfect human being in the virgin’s womb, and that the divine Word, the second person of the Trinity, was “conjoined” to this human being. When Christians worship the human Christ, Nestorius would say, they are making an “intellectual reference” to God, because God has chosen to act in the man Jesus. Cyril objects to this Christology, in part, because it does not make the action of God in Christ qualitatively different than God’s action in the prophets, or in our lives through the Holy Spirit. There is a difference in degree, but not a difference in kind. If we follow Nestorius we can speak of God’s action upon the man Jesus, but we cannot speak of God’s action as the action of the man Jesus.
If we cannot speak of the man Jesus Christ as the divine subject, then we are denying “the economy” of salvation, as Cyril puts it time and again. This use of theological language precludes us from making the essential soteriological statement that the Son entered the realm of sin and death, taking it upon himself and obliterating it through his perfect life, his death, and his resurrection. A Nestorian understanding of Christology might provide us with a supreme source of information about God, but it would not declare that life has conquered death. The life of Jesus Christ would be like the glass at an aquarium: the transparent dividing line between two worlds that can never become one.
Cyril rejects Nestorian logic simply because his reading of the Bible declares that God has really entered into communion with us; God is not the aquarium visitor merely tapping on the glass. Life has come into the realm of sin and death, vanquishing it, and giving our humanity the new possibility of life in God. Cyril does not pretend to know how it is possible that God has done this, but revelation tells him that it is actual. This is the “mystery of Christ”–a wonderful paradox.
And so Cyril describes Jesus Christ as a “union”. There is one subject and always one subject here. The 2nd person of the Trinity, possessing the divine nature in fullness, takes on a human nature. Cyril is clear that the unity is not a mixture, and it does not entail change in God. It seems to me (although I’m admittedly extending the logic here), that Cyril can speak of unity in the strong way he does, and yet make these two caveats (no mixture, no change in God) for two reasons. First, the union is a hypostatic union. Though we distinguish nature and person in God, we cannot ground one on the other. Assuming Cyril has even the weakest form of divine simplicity (no composition in God), we must conclude that nature and hypostasis coincide in God. In humanity, things are different. Nature and person are separable. Nature is a sort of potentiality for personal expression. What this means is that the divine person (and thus the divine nature!) can be expressed as a human nature. Second, there is no change in God in the incarnation because (a) the incarnation is freely-willed and not imposed on God from without, and (b) God’s self-expression in the incarnation is true to his eternal self. So we can (indeed, must) venture statements like “Mary was the mother of God”, or “God suffered, or “God died”, or “God was raised from the dead”. The predication of suffering to God does not endanger the divine essence because in the very act of suffering and dying for us in the flesh, God triumphed over all suffering and death. It was never a fair ontological fight.