Basil of Caesarea, Gregory of Nyssa, and the Transformation of Divine Simplicity (review)

Andrew Radde-Gallwitz has written an incisive study of one of the central points at stake in the debates between Eunomius of Cyzicus and the Cappadocian brothers Basil of Caesarea and Gregory of Nyssa. This book is a must-read for anyone interested in Cappadocian doctrines of God or in the subject of divine simplicity in general. It is thoroughly researched, full of new insights, and clearly and economically written, and it justly deserves the Templeton Award for Theological Promise that it has recently won. The author wisely limits his study to Basil and Gregory, noting that, for all their similarities, their work is noticeably different from that of the third "Cappadocian," Gregory of Nazianzus, on topics such as this.

In its most technical terms, Radde-Gallwitz's argument is that Basil and Gregory effected a crucial transformation of the notion of divine simplicity by crafting a theological epistemology that dissociates the knowledge of God from the epistemological priority of definition—the principle derived from Plato's dialogues that to know something means to be able to explain or define it, i.e. to know its essence. Against the subordinationist position of Eunomius, they crafted this new notion of divine simplicity in order to defend the dual claim that Christians really do know God through the myriad statements about God contained (primarily) in Scripture, and yet the knowledge of God is nevertheless limited. By contrast, Eunomius's position is based on a modified form of the priority of definition: he famously claimed to have comprehended the divine essence and to be able to define it as unbegottenness/agennesia.

The problem at hand is how to maintain the traditional view that God is simple while at the same time giving a plausible account of how God is known. One of the book's many assets is its clear explanation of what divine simplicity entails and what it does not, together with a robust response to modern critics of the notion, from Karl Barth to Christopher Stead (on whom Radde-Gallwitz is a little too hard). The author rightly notes that in patristic literature divine simplicity is (a), to borrow David Burrell's terms, a formal principle or a second-order rule of theological language more than that it is a proper subject of discussion like divine ineffability, and (b) a principle that is normally applied to the revealed language of Scripture and the church's language of prayer and worship, as opposed to indicating some other, philosophical source of knowledge. To say that God is simple means in theological terms that God is not made up of separable parts and in hermeneutical terms that the many and various statements about God in the Bible do not contradict each other, despite appearances if we were to apply such statements to creatures.

Of particular value is Radde-Gallwitz's account of the range of options on divine simplicity that existed in late ancient Christianity, including the crucial idea, advanced by Origen, of epinoiai, which supplies Basil with a key tool for articulating a positive doctrine of divine knowledge. The author also accounts for the history of the Eunomian term agennetos as well as Athanasius's understanding to divine simplicity, which approaches the "identity thesis." This last point should land like a bomb in the midst of contemporary (and much western historical) discussion of divine simplicity, where the identity thesis is the reigning notion. On this view all predicates about God are statements about God's essence, so that the divine essence and properties are identical, as Augustine (and more obliquely Gregory of Nazianzus) also hold. But the identity thesis is one of the key notions that Basil and Gregory of Nyssa oppose in Eunomius.

In his analysis of the use of epinoiai, Basil denies the identity thesis, and he further distinguishes epinoiai, which are human concepts, from the reality of the divine being. Gregory of Nyssa further analyzes how the terms that do...