Aquinas on Nature, Hypostasis, and the Metaphysics of the Incarnation

AQUINAS ON NATURE, HYPOSTASIS, AND THE METAPHYSICS OF THE INCARNATION RICHARD CROSS Oriel College, University ofOxford Oxford, England ACCORDING TO Christian orthodoxy, Jesus Christ is one person-the second person of the Trinity-who has both divine and human natures. As the Council of Chalcedon (451) puts the matter, the two natures are united in one person. The claim that the two natures are united in one person is contrasted, in the creed of the Council, with something like the claim that the two natures are mixed together into one new nature. Thus the creed clearly presupposes some kind of distinction between the senses of "person" and "nature."1 I think that it is fairly clear that the distinction that the Council of Chalcedon presupposes must be something like the distinction between an individual, on the one hand, and its kind-nature and non-essential properties on the other. The position would then be that the second person of the Trinity began to instantiate some kindnature (viz., human nature) which he did not previously instantiate , without this entailing that the person ceased being divine. The human nature, on this view, would be a non-essential property -or a non-essential kind-nature-of the second person of the Trinity. As Thomas Morris points out, this will mean that the orthodox Christian 1 "We teach the confession of ... one and the same Christ, Son, Lord, only-begotten, acknowledged in two natures which undergo no confusion, no change, no division, no separation. At no point was the difference in natures taken away through the union, but rather the property of both natures is preserved and comes together into a single person and a single subsistent being": thus the creed of the Council of Chalcedon, in Decrees of the Ecumenical Councils, ed. Norman J. Tanner (London: Sheed and Ward; Washington, D.C.: Georgetown University Press, 1990), 1:86. I have used Tanner's translation , making slight alterations in the punctuation. 171 172 RICHARD CROSS will reject the view that every nature [i.e., kind-nature] is an essential property of every individual who exists in that nature.2 Since the second person of the Trinity did not cease being divine, the Chalcedonian account will also entail acceptance of the possibility of some individual having more than one kind-nature. But, as Morris again points out, this does not seem to be necessarily inconsistent-it might be the case that, for some sets of kind-natures, such a state of affairs is indeed possible.3 In this paper, I want to look in some detail at Aquinas's account of the distinction between person and nature. In so doing, I hope to get a fairly clear grasp of Aquinas's account(s) of the .metaphysics of the incarnation. I shall argue that the accounts which Aquinas gives of the metaphysics of the incarnation other than in De Unione Verbi Incarnati fail to be coherent and that the somewhat different account in De Unione Verbi 2 Thomas V. Morris, The Logic of God Incarnate (Ithaca and London: Cornell University Press, 1986), 41. 3 Morris, 40. It is worth noting that this interpretation of Chalcedon is not found unanimously in the literature. For example, Bernard Lonergan claims: "The distinction between persons and nature [in the decree of Chalcedon] is added to state what is one and the same and what are not one and the same. The person is one and the same; the natures are not one and the same. While later developments put persons and natures in many further contexts, the context of Chalcedon needs no more than heuristic concepts" (Bernard Lonergan, "The Origins of Christian Realism," in A Second Collection, ed. William F. J. Ryan and Bernard J. Tyrrell [London: Darton, Longman and Todd, 1974], 259: my italics). Kenneth Surin makes a similar point: "The 'classical' christological formulations function-'negatively'-as 'meta-linguistic' or 'grammatical' principles, and not as ontological 'descriptions' of the 'mind' or 'will' of Christ" (review of Morris in Theology 90 (1987]: 55). By way of external support for the interpretation suggested here, however, I would cite a recent attempt to show that Cyril of Alexandria-whose work was of...