This special issue of Harvard Theological Review is devoted to a critical discussion of fourth-century Christian trinitarian theology, a topic that is now in a significant new phase of scholarly debate amongst both historical and systematic theologians. The papers and conversation published here arose from a day-conference on 5 May 2006 at Harvard Divinity School, when a number of invited scholars and doctoral students from Yale, Chicago, Emory, Fordham, Weston Jesuit School of Theology, and St. Vladimir's Orthodox Theological Seminary, joined the students of the Harvard conference course, “Trinitarianism and Anti-trinitarianism: The Christian God in Dispute” (Spring 2006), for a day of shared papers and public debate. The immediate focus of the event was a roundtable on Lewis Ayres's important new book, Nicaea and Its Legacy (Oxford: Oxford University Press, 2004), and that discussion—in extended format—now makes up the first part of this issue. Other papers from students then followed, supplemented by comments from senior members from the floor. In the second part of this issue, two of those original papers, along with two other specially commissioned pieces—on Gregory of Nazianzus and Augustine, respectively—extend and refine the debate outlined in the first part. This brief introduction will explain the wider significance of this ongoing debate about patristic trinitarianism, both East and West, and outline what this issue of HTR contributes to it.

It is a privilege to have the opportunity for such extended reflection on my book Nicaea and Its Legacy. No doubt some authors feel that their manuscripts are truly finished before they are published: I am one of those who merely abandons a manuscript to the copy editors when other pressures demand an end to hostilities. It should be no surprise, then, that I have always envisaged Nicaea as a snapshot of a moving landscape, not just in the ever-growing body of scholarship on the fourth century, but also in my own thinking. Accordingly I will begin here as I was invited to do in our discussion at Harvard, by offering an account of what I think Nicaea accomplishes and of some areas in which the book needs further work.

In his work, Nicaea and Its Legacy, Lewis Ayres raises a number of issues important to the discipline of theology. The first is simply the difficulty of studying the past, especially the fourth century, one of the key periods in the formation of Christian theology. Reading texts from fifteen hundred years ago is sufficiently challenging, but these texts are set in a very complex history (or histories) of theological, social and imperial controversies and transitions. Then there is the task of relating the study of historical theology to modern systematic theology, knowing that simply retelling the history more thoroughly will not solve or resolve modern issues, for they have their own complicated genealogy. There is also the need to be aware of the involvement of different exegetical practices and presuppositions—then and now—in all of this. Finally, and most broadly or ecumenically, there are the implications that such work now has for dialogue between “Western” and “Eastern” trinitarian theology, and the questionable usefulness of such categories. That Ayres has remained sensitive to these, and other, dimensions of difficulty, while also engaging with a substantial body of literature, numerous primary texts, and diverse secondary texts (if that is still a useful distinction) makes his work both challenging and significant.

Lewis Ayres's Nicaea and its Legacy has created a stir among historians of Christian doctrine since its publication. Its relation to the previously existing body of scholarship on fourth-century trinitarian theology is one of both consolidation and provocation. Ayres accomplishes a prodigious work of consolidation by synthesizing much of the groundbreaking scholarship that has lately transpired in the study of fourth-century trinitarian debates, while simultaneously making his own contributions toward retelling the narrative of these debates. Following Hanson, Simonetti, Barnes, and others, Ayres rejects a simplistic division between more or less uniform camps of Nicene and “Arian” theologies. Somewhat paradoxically, however, his distinctive contribution to this retelling is to insist on a fundamental unity between pro-Nicene camps in both the Greek and Latin traditions. While Ayres makes this point with forceful persuasion, the point itself is not controversial among patristic scholars. The assertion of a substantive rift between Eastern and Western trinitarian theologies has not held much sway within this milieu; it is not found in either Hanson or Simonetti, for instance, and its genealogy, traced back to the figure of de Régnon, has been famously exposed by Michel Barnes. What is provocative, however, is Ayres's insistence that there existed a geographically consistent “pro-Nicene” culture in both East and West that was also internally consistent as a superior construal of the “plain sense” of canonical Scripture. More provocative still is Ayres's polemical engagement, in the concluding chapter of his work, with modern systematic theology. Here, Ayres offers a sweeping dismissal of modern trinitarian theology as wallowing in a Hegelian wasteland, in bondage to methodological commitments that are antithetical to “pro-Nicene culture,” with no hope of a redeeming synthesis in sight. The only way forward is first to return to an integration of historical and systematic theology, based on a reappropriation of the basic tenets of pro-Nicene culture.

Let me turn in this “Response” to the concerns of those who have been unhappy with particular features of Nicaea and Its Legacy. Although the bulk of my discussion will be taken up with the responses of Khaled Anatolios and John Behr, I want also to range a little more widely. For the most part, criticisms of my book Nicaea have stemmed as much from opposition to my overall attitude towards the task of historical theology as from opposition to my interpretation of particular episodes of the fourth century. A range of related questions focuses on the relationship between the good practice of theology and the implications of the forms of modern historical consciousness that I have clearly found persuasive. The three critics that I engage here all seem to me to be pushing in directions that (consciously or unconsciously) inappropriately restrict the scope and character of theological—and particularly of historical theological—investigation. I must confess at the beginning of this discussion that I assumed the majority of negative responses to my project as a whole (as opposed to negative responses to particular sections of the argument) would come from what might be termed the theological “left”: those who are convinced by some of the fundamental lines of post-Enlightenment and recent liberal critique of classical Christian tradition. It has, however, been fascinating to see other critics emerge from what might perhaps be termed the theological “right”: those sympathetic to modern attempts to retrieve the centrality of classical Christian texts, theologians, and exegetical methods. Both forms of critique demand a response.

As a concluding comment, I should like to return to the point raised by Ayres, that it is not enough simply to tell a better version of the fourth-century history in the expectation that modern theologians will finally get it straight! This is a valid point: if we want to have Christianity's fourth-century heritage taken seriously, we need to be in dialogue with modern writers. But, if there is to be a dialogue, both sides must be allowed to speak, and so we are also responsible for expounding the historical material on its own terms. As Heidegger put it, “[O]nly when we think through what has been thought will we be of any use for what must still be thought.” Perhaps studying the figures from a distant era will open up for us possibilities we would never have dreamed of within our own modern presuppositions, so that we can recognize differences even beyond those which lie within our own horizon or tradition. If I am right in affirming that there is a different style of doing theology prior to Augustine and after him in the East than that which we find in the theological and scholarly tradition in which Ayres's book stands, then we must ask whether we need to address the question of the legitimacy of each (and ponder how one might even answer that) or whether a plurality of approaches is possible without reducing one to the other. In a way, this would be a further step toward deconstructing monolithic notions of “Orthodoxy” in recognition of genuine and legitimate diversity within early Christianity and among modern Christians. Might it be better not to speak of Nicaea and its legacy, but of the legacies of Nicaea—or better—“Christ and him crucified” (2 Cor 2:2) and the ways in which Nicaea and its interpreters affirm the true divinity of this one?

The publication of this work in 1892 made de Régnon the most influential and yet least known of Catholic historians of doctrine.

Gregory Nazianzen's doctrine of the Trinity has had a most unusual reception in modern times. Since the Council of Chalcedon in 451 Gregory has been honored with the title “the Theologian” for his definitive teaching on the Trinity in the late-fourth century. His influence was then strongly felt in the christological developments that continued through the eighth century, and his stature in Greek Christian tradition is comparable only to that of Augustine in the West, although his influence is felt there as well. Yet despite his acknowledged ecumenical significance, Gregory's theological achievement has often eluded modern patristic scholars and systematic theologians. Even the most recent wave of specialized work on Gregory and the current synoptic studies of patristic doctrine have tended to overlook major aspects of his work. One of the most acute points of confusion in current scholarship—and a matter of no little significance for Nicene theology—is Gregory's doctrine of divine causality and the monarchy of God the Father within the Trinity. The recent debate over this topic, I would suggest, reflects the extent to which Gregory's doctrine has yet to be assimilated in contemporary historical and systematic theology. In this article I will seek to clarify Gregory's doctrine of divine causality in light of its current reception and to give some indication of its wider significance.

It is generally held by systematic theologians that Augustine more or less radically shifts the understanding of the doctrine of the Trinity found in his Greek sources, and that, at least in part, this shift is a consequence of his failure fully to understand these sources. His own testimony of puzzlement provides some strong prima facie evidence in favor of such readings.

What is often termed the modern crisis of the Western self—the problems associated with the proto-Cartesian and proto-Kantian conceptions of the self—has given rise to attempts not only to confront the crisis constructively, but also to trace its origin. In one philosophical reading of the development of the crisis in the Western self, Augustine stands as one of its forefathers. In this reading, Augustine's anthropology is anchored firmly within Platonism and is viewed as a key precursor of the tradition leading to the modern, autonomous self of Descartes and Kant. Such a reading often focuses on Augustine's somewhat idiosyncratic self-analysis in Confessionum libri [Conf.] XIII, and points to his so-called psychological model of the Trinity found in De Trinitate [Trin.]. It is argued that his method of inward movement, which involves the utilization of the structures of individual consciousness as an analogy to the immanent Trinity, in conjunction with his analysis of the individual self in Conf., becomes a basic foundation for the modern private, autonomous self.