1. The Council of Chalcedon, which provides the most precise formulation of Christian faith in the Word Incarnate, uses the words “person” and “nature” to set aside certain errors. It does not define what a nature is but takes it for granted that when two subjects can truly be said to be the same kind of something, they are of one nature.
2. With respect to the two natures in Jesus, the Council insists that he is in them “without any commingling or change or division or separation; that the distinction between the natures is in no way removed by their union but rather the specific character of each nature is preserved and they are united in one person and one hypostasis” (DS 302/148).14 In excluding commingling, Chalcedon denies that Jesus’ divinity and humanity are mingled with each other or mixed together. If they were, something of the reality and integrity of either or both natures would be lost. Thus, the definition protects the truth that Jesus is both God and man, and excludes the idea that he is a hybrid, partly human and partly divine but not entirely either.
3. The Second Council of Constantinople later makes it clear that the two natures are united in the hypostasis (the person), and that the person is the divine Word (see DS 424–30/216–20). In affirming that the Word is God from God and that the Incarnate Word is one person, we must deny that Jesus is a human person. Yet in denying this we do not say that Jesus lacks anything which belongs to the positive reality and perfection of a human person. Rather, we say that Jesus’ human, creaturely reality and perfection are not primary in him as our human, creaturely reality and perfection are primary in us.15
4. In our experience, any entity which is of a certain nature by that very fact cannot possibly be an entity of any other nature. This is how finite natures are: They exclude one another. Thus one tends to suppose that Jesus, if he is truly human, cannot be divine, and vice versa. But this assumption is false. Divine nature is not exclusive, though the fact of the Incarnation of the Word is the only evidence we have for this. And this fact is a datum of faith, which remains a mystery to us. We do not understand what God is in himself.
Great difficulties arise if one forgets that language used with respect to God is relational. This point was treated in chapter two, appendix three.
“Nature” said of the divinity of Jesus cannot be used in the same sense as “nature” said of his humanity. For his human nature is the same as ours, and one of the essential characteristics of our nature is that it excludes our being anything of another nature—“nature” said again in the same sense. For example, one could not be human and a horse, since to be either excludes being the other and likewise excludes being any other kind of thing we understand. Clearly, whatever divinity is, the same does not hold true of “nature” said of God.
Similarly with “person” (see S.t., 1, q. 29, aa. 3–4). There is a vast literature about the consciousness of Jesus. It usually takes for granted a remarkable familiarity with God, as if we knew what divine knowing is and as if God were a conscious self much like ourselves. In sober fact, we do not know what the inner life of God is like and have absolutely no reason to make the assumptions required for these arguments to get under way.
Moreover, even with respect to ourselves the concept of person has much that is mysterious about it. Our person includes not only our conscious subjectivity, but our bodiliness as well (see S.t., 1, q. 75, a. 4; sup., q. 75, a. 1). “Me” serves better than “I” to indicate what belongs to our person, for someone who is careless bumps me, thoughts occur to me, my conscience bothers me, and people who disapprove what I write criticize me. “Me” somehow unites all these. There seems to be no particular difficulty in supposing that Jesus’ subjectivity has the same general character of mysterious inclusiveness, with the difference that he also somehow knows: The Father begets me.16
5. Keeping in mind that we do not and cannot understand what God is in himself, we shall avoid the mistake of thinking we understand God’s nature or, in particular, the divinity of Jesus. Avoiding this mistake is also important to understand the relationship between the goods proper to Jesus according to his two natures, for these goods are nothing but his full being.
6. If this mistake is avoided, we shall not think we understand what divine goodness and love are in themselves, nor imagine some conflict between them and human goodness and love. The Incarnation of the Word is our assurance that it is not necessary to choose between the human and the divine, for the human nature the Word assumed was not thereby annulled (see GS 22).
7. If a choice between loving God and loving human goods were necessary, it is evident that the Lord Jesus, being God, could not have made the wrong choice, would have chosen loving God, and thus could not have loved human goods. But anyone who could not naturally and spontaneously love all the basic human goods would not have an intact human nature, for love of these goods is nothing but human nature’s built-in disposition toward its own fulfillment. Jesus, however, has an intact human nature and so loves human goods. Therefore Jesus, though a divine person, did not have to prefer—or, more accurately, could not prefer—the love of God to the love of basic human goods.
In his Incarnation, the Word as man accepts the conditions of human coming to be and human life. The Incarnation does not take place all at once—not that at any moment the Word is incompletely united with his humanity, but that this humanity, like our own, comes to be only gradually, and so, if one may speak thus, cannot be assumed faster than it becomes. Moreover, the Word becomes flesh not in an ideal humanity, in which his divinity would at once demand his human fulfillment, but in flesh like our own sinful flesh (see Rom 8.3). In this sense, in becoming man, Jesus “emptied himself, taking the form of a servant, being born in the likeness of men” (Phil 2.7; cf. Rom 8.3).17
14. For the significance of Chalcedon in its historical context, see Aloys Grillmeier, S.J., Christ in Christian Tradition, vol. 1, From the Apostolic Age to Chalcedon (451), 2d ed. (Atlanta: John Knox Press, 1975). For a summary of current erroneous accounts of Christ, see Jean Galot, Le Christ, Foi, et Contestation (Chambray: C.L.D., 1981), 9–88; critique, 141–83. These errors have been specified and condemned by the Congregation for the Doctrine of the Faith: Declaratio ad fidem tuendam in mysteria Incarnationis et Sanctissimae Trinitatis a quibusdam recentibus erroribus, 64 AAS (1972) 237–41; Origins, 1 (23 March 1972), 666–68. Moreover, the validity and possible authentic development of traditional Christology has been reaffirmed by leading theologians: International Theological Commission, Select Questions on Christology (Washington, D.C.: United States Catholic Conference, 1980).
15. For a sound, systematic treatment of the Incarnation, with a good review of scriptural data and brief history of the development of the doctrine in the Church: Jean Galot, S.J., Who Is Christ? A Theology of Incarnation, trans. M. Angeline Bouchard (Chicago: Franciscan Herald Press, 1981), 41–313.
16. A theological development consonant with my view: Walter Kasper, Jesus the Christ (London: Burns and Oates, 1976), 163–96. A philosophical treatment of person: Germain Grisez, Beyond the New Theism: A Philosophy of Religion (Notre Dame and London: University of Notre Dame Press, 1975), 343–53 and 365–69.
17. See J. Schneider, “omoíōma,” Theological Dictionary of the New Testament, 5:195–97, for a clarification of the meaning of “in the likeness of” in Phil 2.7 and Rom 8.3.