The Thrice-Holy God: A Review of Katherine Sonderegger's Second Volume

Perhaps the most enigmatic inquiry of any Christian theology is that of the Trinity. This enigma has lead to so many struggles and fears, so many divisions and splinters in the Church, so much head spinning and hand-wringing, that many within Protestantism, particularly progressive Protestantism, have looked for ways to dispense with the whole pesky concept. Many in my own denomination have marginalized the inquiry altogether leading to the much dismayed, but somewhat too accurate to be said in full-throated jest, quip: "Unitarians Considering Christ" rather than "United Church of Christ." It's a joke, of course, and not a really good one at that. But if we're honest, don't many of us just want to put Trinity on the sideline and see if we can't run our playbook without it? Some will cite historical problems in the very construction of trinitarian theology, imperial and imperialist impulses in the origination of trinitarian controversies that lead to Nicea and Chalcedon. Some will hide behind their biblicism and "biblical scholarship" to avoid giving account of the thrice-Holy God. But Trinity is not a modern construction or merely a tool of the coercive powers of Religious zealots. It is the confession of the God revealed in Scripture and the proper way, if somewhat seemingly impossible way, of talking about the God of Israel. 

Katherine Sonderegger’s Systematic Theology, Volume 2: The Doctrine of the Holy Trinity: Processions and Persons is, without question, one of the most demanding theological works I have read in recent years. So it may be closer to being up to the task of trinitarian theology than many of its predecessors. There were many moments in reading this book—long stretches, really—when I found myself wondering whether I actually understood what she was trying to convey at all. And yet, insofar as I did understand her, I take this volume to be one of the great works of systematic theology written in our time. It is difficult, often frustrating, occasionally exasperating—but also daring, generative, poetic, and theologically consequential in ways that few contemporary trinitarian projects manage to be.

Part of the difficulty is stylistic and methodological. Sonderegger does not write in the idiom of much modern Protestant theology. She is unapologetically metaphysical, realist, and dogmatic in a register that many contemporary theologians—myself included—approach with considerable suspicion. Her prose is dense, her arguments recursive, and her conceptual architecture demands sustained attention. This is not a book that yields itself easily or quickly. And yet, the difficulty is also inseparable from its ambition. Sonderegger is not offering a revision or modest correction of modern trinitarian theology; she is attempting a fundamental reorientation of how trinitarian doctrine is conceived, structured, and ordered.

At times, her tone is polemical, and I am not always convinced that this is necessary or helpful. Her critiques of modern trinitarian theology—particularly of person-centered, relational, and hyper-Christological accounts—can feel overstated, even dismissive. This is especially true in her engagements with figures such as Moltmann, Barth, and Rahner. With demonstrable sympathy and appreciation, she identifies real dangers in their theologies: the risk of collapsing divine unity into sociality, of privileging event over being, of allowing the incarnation to redefine God’s eternal life in ways that threaten divine freedom. These are not trivial concerns, and Sonderegger is right to press them with seriousness.

Still, I sometimes suspect that she does not quite do justice to the extent to which these theologians themselves were aware of, and resistant to, precisely these dangers. Barth’s relentless insistence on God’s freedom, Rahner’s anxiety about tritheism, and Moltmann’s own warnings about projecting human sociality onto God suggest a more self-critical posture than Sonderegger’s polemic occasionally allows. Her critiques are sharp, but they can feel one-sided, as though modern trinitarian theology is more naïve or reckless than it actually is.

As far as I can tell, what Sonderegger is attempting to do is to recover a trinitarian theology that begins decisively with God’s oneness—not as a preliminary abstraction, but as a realist and metaphysical claim about God’s being. This alone sets her apart from much contemporary Protestant theology, which often treats divine unity as either a problem to be solved or a conclusion reached only after narrating God’s triune relations. Sonderegger reverses that order. God is One—ontologically, fully, and eternally—and only from within that unity can the doctrine of the Trinity be rightly articulated.

I am, by temperament and training, far more post-structuralist—or at best, a critical realist—than Sonderegger wants me to be. I remain wary of strong metaphysical claims and suspicious of theological systems that seem "speculative" and too confident in their apprehension of divine reality. And yet, I find myself deeply sympathetic to her motives. She is not attempting to domesticate God or render divine mystery manageable. Far from it! On the contrary, she wants to protect God’s freedom, fullness, and integrity against the subtle ways modern theology can make God dependent upon history, revelation, or human categories of relation. Her doctrine of God is one of an unyielding and relentless God who is "Holy Fire" and yet, her's is a God that is rational, even intellectual. 

This concern is especially evident in her treatment of incarnation and procession. Sonderegger is intent on affirming the eventfulness of God without suggesting a kind of supersessionist novelty in the incarnation—as though God becomes something God was not, or as thought the One God became triune. The persons of the Trinity, she argues, emerge from and consummate the eternal processions; they do not generate them. God’s triune life is not constituted by historical events, even as it is truly revealed within them. This allows her to affirm divine action and self-giving without collapsing God’s eternal being into temporal becoming.

What Sonderegger achieves, delicately and often eloquently, is a trinitarian theology that holds together two claims that are frequently placed in tension: the ontological completeness and oneness of God, and the dynamic movement and eventfulness of God’s inner life. She insists that God has an inner life not defined by frenetic activity or restless motion, but by Sabbath rest—and yet, this rest is not inert or static. God is eternal procession, eternal action, eternal life. Divine stillness and divine movement are not opposites but mutually informing realities.

In this way, Sonderegger affirms both the subjectivity and the objectivity of God without sacrificing one for the other. She upholds perichoresis without reducing the divine persons to discrete, individual “knowing subjects.” And most importantly, she holds the Trinity without dividing God—a task that remains the central and abiding challenge of trinitarian theology. Even where I resist her metaphysical confidence or question her polemical edges, I cannot escape the sense that Sonderegger has done something rare: she has re-opened the doctrine of the Trinity as a live, unsettling, and profoundly theological problem, and she has done so through careful attention to the whole of the Bible, natably through careful attention to Exodus and Leviticus, places that few trinitarian theologians even tread, let alone begin. Her's is a trinitarian theology built up from the logic of the Hebrew Bible. That alone makes this volume indispensable.