- Aquinas's Ontology of the Material World: Change, Hylomorphism, and Material Objects by Jeffrey E. Brower
Brower sets out, and I think quite successfully, "(a) to offer a precise reconstruction of the essential elements of Aquinas's ontology of the material world; (b) to locate these same elements within the context of Aquinas's thought more generally (and in particular, within the context of his views on [End Page 277] natural philosophy, metaphysics, and theology); and finally (c) to highlight the historical and philosophical significance of Aquinas's views, especially from the perspective of contemporary metaphysical debates" (vii). This book is one of the clearest, most carefully argued reconstructions and defenses of Aquinas's work on hylomorphism and material objects I have encountered. It is an excellent resource for philosophers both classical and contemporary, and a model for those interested in bringing the two into dialogue with each other.
Not only is this book filled with boxes containing clear definitions of key concepts and reconstructions of arguments, but it is also full of useful figures and tables that help represent Aquinas's rather subtle distinctions. Being finely attuned to these subtleties, Brower has included what he describes as "a catalog of the most important terms for which we have had to distinguish more than one sense" (311) within his "Glossary of Technical Terms" found at the end of the book.
I cannot do justice to each part of this wonderful book in such a short review. Therefore, I will provide a brief overview of what I take to be the main points of interest. Aquinas's Ontology of the Material World is divided into five parts: "Introduction" (chaps. 1 and 2), "Change" (chaps. 3 and 4), "Hylomorphism" (chaps. 5-7), "Material Objects" (chaps. 8-10), and "Complications" (chaps. 11-13). Part 1 provides "a systematic introduction to Aquinas's complete ontology" (3). According to Brower, "there are four main ontological types [of beings] in terms of which the world as a whole can be understood: (1) Prime Matter, (2) Form, (3) Substance, (4) Accidental Unity" (18). Part 1 is largely concerned with providing an explanation of what these ontological types are as well as their relationship to the ten Aristotelian categories and Aquinas's discussion of modes of being. Chapter 2 focuses on a more detailed analysis of these issues. Of particular interest (especially to the analytic philosopher) is Brower's discussion of how recent literature on ontological pluralism can shed light on Aquinas's talk about modes of being.
According to Brower, Aquinas's material ontology is rooted in his hylomorphism, which itself stems from his general analysis of change. For that reason, he next turns—parts 2 and 3—to Aquinas's analysis of change. Chapter 3, "Change in General," provides Aquinas's general analysis of change in terms of generation and corruption. It is in his general analysis of change that we are introduced to the basic elements of his hylomorphism, namely, matter, form, and hylomorphic compound. According to Brower, "change is to be analyzed in terms of generation and corruption, where this is to be understood in terms of the temporal succession of distinct states of affairs that overlap, and hence share a common constituent that endures the change itself" (62). For Aquinas, change is not merely the coming to be of something that was not, nor the passing away of something that was, but rather the coming to be of something from something and the passing away of something into something. If Y comes to be from X (rather than X merely 'popping' out of existence, which is succeeded by Y 'popping' into existence), [End Page 278] then there must be something from X that endures the change into Y. This enduring subject allows Aquinas to "distinguish instances of change from instances of creation" (61). As noted above, a proper analysis of change provides the basis on which his hylomorphism is developed. Brower writes: