Journal of the History of Philosophy

The author’s purpose is to understand the role divine ideas play as causal principles in Aquinas’s philosophy. His contention is that, although Thomas’s doctrine of ideas is perhaps not the key to an understanding of his metaphysics, it is certainly “a key to such an understanding” (xiv).

The book is divided into six chapters. The first chapter seeks to provide a general definition of divine ideas according to Aquinas. Divine ideas are exemplar causes in the likeness of which God produces creatures. Ideas in the strict sense belong to God’s practical or actually practical knowledge. The causality exercised by exemplars is that of formal causality, but because they are productive of things, they entail efficient and final causality, as well. In chapter 2, Doolan examines Thomas’s arguments in favor of the existence of divine ideas. Chapter 3 deals with the question of the multiplicity of divine ideas. Doolan first establishes, against Gilson and others, that Aquinas did indeed hold that there was a multiplicity of divine ideas. He then shows how Aquinas was able to reconcile the diversity of ideas with God’s simplicity. The gist of the solution involves viewing ideas as nonbeings relative to God, who is, of course, ipsum esse. Now the only way non-beings can enter into God is in the form of entia rationis. “It is for this reason,” Doolan concludes, “that the ideas exist simply as known beings rather than as real ones and, moreover, that there can be many of them” (110). Chapter 4 is devoted to identifying the divine ideas. Although Aquinas does hold that God has the ideas of matter, possibles, and evil, Doolan argues that “according to the strictest meaning of the term ‘exemplar’ as Thomas comes to employ it, only those divine ideas that are of individual things made by God at some point in time can truly be called exemplars” (155). Doolan then turns, in chapter 5, to an examination of the manner in which divine ideas exercise their causality. He considers two questions in this regard: first, whether the causality of divine ideas is limited to the production of form, and second, whether exemplar causality, to the extent that it is productive of the forms of creatures, leaves any room for the causality of creatures. Doolan examines the well known passages in Thomas’s works relating to the articulation of divine and secondary causes in the production of effects, and concludes that “it is through the combined agencies of God and the natural agent that a natural effect comes to be” (189). Finally, because the resemblance things have with their exemplars has often been accounted for by Platonically-minded philosophers by saying that the former participate in the latter, Doolan devotes the last chapter to clarifying the relation between exemplarity and participation in Aquinas. After examining several central texts as well as the most influential interpretations of the doctrine, he concludes that individuals do not participate in their exemplars, according to Aquinas.

The author’s ultimate conclusion is that the doctrine of divine ideas is essential to Thomas’s philosophy for two reasons. First, it plays an important epistemological role by providing a theoretical expression for a central tenet of theism, namely that God must possess a proper knowledge of the beings he creates. Second, it provides an ontological foundation for the directedness of nature and the determinacy of form, showing that creation results from the divine intellect and will.

While Doolan does a convincing job of arguing for the importance of divine ideas in Aquinas’s philosophy, his interpretation of specific texts is sometimes a little strained. For [End Page 624] instance, he argues in chapter 4 that divine ideas for Thomas are properly only of individuals, but the only evidence he can muster for this view in the text that he sees as most clearly supporting it—De ver., q. 3, a. 8—is a sed contra!

At a more...