Dominic Cassella

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Matter and Mathematics: An Essentialist Account of the Laws of Nature by Andrew YOUNANDominic V. CassellaYOUNAN, Andrew. Matter and Mathematics: An Essentialist Account of the Laws of Nature. Washington, D.C.: The Catholic University of America Press, 2023. xii + 228 pp. Cloth, $75.00Andrew Younan’s work situates itself between two opposing philosophical accounts of the laws of nature. In one corner, there are the Humeans (or Nominalists); in the other, the Anti-Humeans (or Platonists). The goal of the book is to find an explanation for the orderliness of the natural world that avoids falling into the difficulties of the two opposing philosophies. For example, the Humeans treat “events” as fundamental, and the laws of nature follow from these “events.” For the Humeans, reality is essentially random, with any order being something of our own contrivance. Whereas for the Anti-Humeans, the laws of nature are fundamental and are treated as causing events, turning the effect of necessity into the cause of material [End Page 166] characteristics. Looking to Aristotle and Thomas Aquinas, Younan proposes the recovery of a third option, the Essentialist position. This Essentialist position understands substances, that is, individual beings, as fundamental and all else (for example, events and laws of nature) follow from these individual beings. The thesis of the book, generally understood, is that Essentialism evades the critiques that the Humeans and Anti-Humeans put against one another while retaining what is right in each approach.The book is divided into two parts. The book’s first part deals with general objections and replies and is divided into three chapters. Chapters 1 and 2 address the two opposing accounts of nature mentioned, while chapter 3 argues for the benefits of recovering an Essentialist position. Chapter 1 examines the objection that Aristotelian natural philosophy is incompatible with modern science, an objection raised by Descartes. Chapter 2 addresses the objections of the Humeans, namely, that natural philosophy and, with it, causality and induction have been debunked. Chapter 3 looks at the fathers of quantum theory, specifically Heisenberg, and argues that a return to Aristotle’s understanding of nature would benefit the modern scientific project. The book’s second part is an argument for the Essentialist position and is divided into three chapters. Chapters 4 and 5 are the foundation for chapter 6. Chapter 4 is an abstractive account of mathematics, differing from Descartes and his conceptions, which draws on the texts of Aristotle and Aquinas’s Division and Methods. Chapter 5 situates necessity and its role in Aristotelian natural philosophy. Chapter 6 is the author’s attempt at defining what it is to be a law of nature.Younan argues that adopting an essentialist understanding of nature in a system where all knowledge begins in the senses has three significant “payoffs.” The first is that it avoids governance language, that is, it avoids making laws themselves causes of necessity; the second is that it avoids the assertion of a priori knowledge; the third is that it understands individual things as the fundamental primitives in nature, restoring the substance to its proper place as the thing that “stands under” accidental being.The book is concluded with an appendix that explores and rearticulates Thomas Aquinas’s fifth way under the consideration of everything the author had argued for in the book’s main text. Taking as established by the rest of the book that necessity and teleology go hand in hand, Younan argues for a creator God who establishes a universe freely but within certain parameters that follow upon being itself. Younan concludes, with Thomas Aquinas, that laws of nature are “ordinances of reason” that must come from a rational mind. To be as consistent as they are, the laws of nature must be promulgated by God, and they are discoverable within the nature of matter itself.Younan’s book often engages its interlocutors on the big-picture scale, frequently giving generalizations and not going into details to avoid getting bogged down in the weeds. The author is very aware of what he is doing. [End Page 167] It is appropriate since engaging the multiheaded hydra of the schools of thought that Younan...