In The Entangled Trinity, Ernest L. Simmons offers a profound reflection on the category of interrelationship and an exploration of the intriguing compatibility that exists between the contemporary scientific language of the quantum paradigm and the theological language of Christianity's foundational doctrine of the Trinity. It is a solidly constructed, creatively conceived project of great theological imagination and insight. The structure of the book is straightforward and balanced, consisting of three main parts, each containing three chapters. Simmons recognizes that the challenges and pitfalls implicit in every thoughtful exchange between science and religion are many and daunting, and thus a sturdy foundation is of the utmost importance. So, too, is a basic clarification of terms. Thus, the book's first part, “Foundational Concepts,” is a necessary point of departure. “Faith,” the first chapter, examines a dynamic “faith” arising from the age-old human quest for the ultimate, wherein reason, in Paul Tillich's words, “reaches ecstatically beyond itself.” The chapter “Knowledge” considers the dangers of intellectual reductionisms, as well as the significance of the passing from substance to relational ontologies, and advocates for a renewed appreciation of the power of metaphor, analogy, and symbol on their own terms. After connecting our contemporary spiritual crisis to the disastrous modern attempt to separate fact from value, the chapter “Theology” provides a helpful and comprehensive review of all the essentials: the definition, sources, ground rules, and methods of theologies that make a difference. Part 2, “Trinitarian Development,” offers an excellent review of the history of trinitarian thought in three chapters: “Bible to Nicaea,” “Constantinople to the Reformation,” and “Contemporary Trinitarian Development.” All the major players, the movers and shakers, as well as the decisive events, the councils and controversies, are accounted for and considered. Simmons writes clearly and well. He is, moreover, a teacher, and a gifted one at that.

The third and final part, “Science and the Trinity,” makes a bold contribution to contemporary trinitarian thought and validates as time well spent the previous foundational sections of the book, particularly those examining analogical function and the “is/is not” character of metaphor, relational ontology, and the appropriate ways of conceptualizing the proper roles that science can play for theology, addressed in the important seventh chapter “Theology, Science, and Quantum Theory.” The author makes clear that “no final or ultimate claims are being made here, only that this model has heuristic value in explicating for today the Christian experience of pluralistic monotheism” (165). That model is “perichoretic trinitarian panentheism.” Simmons employs metaphorically two key concepts from quantum physics—nonlocal relational holism called entanglement, and complementarity as understood through superposition of the wave function—to develop this model for conceiving of God's dynamic interrelatedness in history and sharing in the suffering of creation. The author explores the consonance between the Cappadocian language of God's perichoresis or mutual indwelling and quantum entanglement. Likewise, the author ponders how superposition and complementarity may allow for greater understanding of how the Trinity can be three distinct hypostases but one ousia, and why we address one person or another depending on the kind of theological question we are asking (our measuring position): “When we look for origins, we find Creator. But we are not always looking for origins. Sometimes we are looking for forgiveness and for hope. . . . If the divine is entangled, that is interrelated and interdependent with multiple potentials such as a wave function, then the same entangled divine relation can be experienced as incarnation, not just origination” (152).

This quantum-trinitarian model is breathtaking, especially when conceived in a panentheistic framework wherein God's love is depicted as truly kenotic, that is, self-limiting and making room for another—creation as relationship that affects Creator and creature alike.

In sum, The Entangled Trinity succeeds, admirably and creatively, in its stated intention “to allow contemporary scientific thinking to inform theological reflection” (51). The reality of interrelatedness points to our common responsibility to address all of our contemporary global crises as we become one greater global society. As such, the book is highly recommended not only to those engaged in the academic study of theology, but to all who are committed to the intellectual and practical task of building bridges across divides, and fostering respect for unity-in-diversity.