The Theology of Thomas Aquinas

Chapter Ten: Hypostatic Union

  Ten Hypostatic Union   Aquinas offers sustained meditations on Jesus Christ in many of his writings.1 In terms of content, there is a remarkable consistency to Aquinas’ teaching about Christ over the course of his theological career . He returns repeatedly to the same fundamental claims about Jesus: Jesus’ centrality in the salvific process; the divine identity of Jesus from the outset of his story; and Jesus’ genuine and full humanity, not simply divinity, on account of hypostatic union. Equally remarkable, however, is the diversity in presentation in Aquinas’ various writings about Jesus. While he remains true to his central insights about Jesus, Aquinas taught Christ differently in his different writings. He can include diverse topics to promote the analysis of Jesus; alter the order of presentation; and pursue different tasks in proclaiming Christ in these various works. One will learn much about Aquinas’ skill as a writer and teacher, as well as his intentions as a theologian, by paying close attention to the shape of the Christology in the major writings. In this essay, I will focus on Aquinas’ discussions of a key aspect of any incarnational Christology, hypostatic union, as found in three of his more important writings: the early Scriptum on the Sentences of Peter Lombard; the Summa contra Gentiles (also known as the Liber de veritate catholicae fidei contra errores infidelium); and, the Summa Theologiae. In each of these works, spanning his whole theological career, Aquinas insists that the two natures, the divine and the human, have been united precisely in the second Person of God. From eternity, the second Per-  son is fully God, one and the same God as the Father and the Holy Spirit; the second Person is also a distinct Person in the Godhead, different from the other two Persons. Without loss to itself as Word, the second divine Person has taken up a second nature, and come to express human nature as well.The divine Word, because of incarnation, is also fully and truly human.Thus, in retelling the story of Jesus, one must attend to the divine and to the human dimensions. And yet the Christology of each of these writings has its proper feel. Aquinas proceeds differently in the contra Gentiles than he does in either the earlier Scriptum or the later Summa: while there is some overlap in theological tasks and ambition, in these writings he tries to do different things in subjecting Christ to close analysis . In developing his theology, Aquinas typically draws on a range of resources.2 In these writings on Christ, he can deploy these resources in varying ways, in accordance with his ambitions in a given work. In this essay, I will highlight these formal features of Aquinas’ Christological writings, as a way of displaying crucial aspects of his work as a theologian. Especially important for this essay are what I will call “alternative Christologies .” In teaching Christ, Aquinas does more than simply present his main claims. He relates his own position, worked out in conscious conformity to the tradition, that is, to other teachings about Christ, in order to show the advantages of what he takes to be orthodox proclamation about Jesus.These alternative Christologies can take two main forms: the Christologies advanced by historical figures, both orthodox and heterodox; and more speculative Christologies, which posit scenarios that differ from the revealed order. Aquinas plays off of these alternative Christologies in stating in his own writings his version of orthodox truth about Christ and in exploring its ramifications. The value of attending to the rhetoric of his Christology, including such use of authoritative texts, is significant.3 It allows me to suggest the extent of Aquinas’ debt to earlier traditions about Christ while making patent how at times he goes beyond them in his own constructive reflections about Jesus. I begin with the Summa contra Gentiles, then turn to the Summa Theologiae, and finally to the Scriptum on the Sentences. As is apparent, I am proceeding out of chronological order, beginning with the middle work and ending up with what chronologically is the earliest of Aquinas’ theological writings.4 There is a twofold warrant for this order. First, the teaching of the contra Gentiles in my opinion is the most accessible of Aquinas’ writings on Christ for a modern audience, which may be less versed in the intricacies of hypostatic union. Second, by leaving the Scriptum for last, it will be easier to make clear...