Thomas Aquinas’s “Summa Theologiae”: A Guide and Commentary by Brian Davies (review)

The purpose of this book is to provide guidance to a nonspecialist reader of Aquinas’s Summa theologiae. It is not meant as a substitute for the text itself, but rather as a companion for a reader in order to offer explication for the most important arguments, a sense of the context of the whole, a quick survey of the terrain of a treatise, some historical context when necessary, and a prod to critical thinking. Davies’s ambition is daunting. As the subtitle indicates, he intends the book to be both a guide and a commentary. If it were only a guide, it would focus on the truly critical themes in some depth in order to aid the reader through the various parts without commenting on everything. If it were only a commentary, its purpose would be largely expository and exegetical. It is hard to do both functions well on a work as large and complex as the Summa theologiae.

After a brief overview of Aquinas’s life and a short commentary on the meaning of sacra doctrina, Davies turns to the topic of God. Given his previous work on Aquinas, it is not surprising that the strongest and longest section of his book concerns the Prima pars. Davies does a nice job of parsing the existence of God and mapping out the Five Ways in a manner suitable to his audience. He then turns to the question of how God does not exist, and makes it plain that the main thrust of Aquinas’s treatment is apophatic, or negative. It is surprising that Davies never mentions the influence of Pseudo-Dionysius on Aquinas and generally downplays the Neoplatonic strains in Aquinas’s theology. I would have thought that divine simplicity and goodness deserve more consideration, and I would have liked to see Davies give more insight for the reader on how to parse some of Aquinas’s metaphysical terms (especially the real distinction in created beings and how this is the main marker of the ontological gap between God and creation). When Davies turns to how we name or use language about God, he signals to his readers that he is entering into an area that has been much debated. Not surprisingly, while he does a reasonable job of trying to explain how analogical predication works to a nonspecialist reader, specialists will have much to quibble about. At the heart of his explanation of analogy is the claim that analogy is primarily “a linguistic phenomenon in which one and the same word is used to speak of different things with connections of meaning that can be traced in each use of the word” (69). Analogy in Aquinas is more than a theory about language; it is embedded in a metaphysics of participation and creation that needs to be adumbrated to understand how analogy works. The subsequent treatment of God’s knowing and willing is reliable, though more attention might have been paid to the practical model of divine knowing. When it comes to the Trinity, Davies does a solid job of trying to explain that most complicated doctrine of Aquinas to a nonspecialist.

Davies misses the opportunity to explore the fundamental contrast that Aquinas draws between God’s causal immanence in all things as Creator and his special, interpersonal, Trinitarian indwelling through grace, as the treatise on the Trinity segues into the treatise on creation. When turning to creation, Davies notes that the fundamental metaphysical principle behind Aquinas’s account is that “the existence of something that does not exist by nature has to be caused” (110), although he seems diffident about its validity (“like it or not”) and never mentions participation. Sometimes he speaks about God’s causality in creation as “causally accounting for their esse” (ibid.) even as he notes that God...