Aristotle on Matter, Form, and Moving Causes: The Hylomorphic Theory of Substantial Generation by Devin Henry

Reviewed by: Aristotle on Matter, Form, and Moving Causes: The Hylomorphic Theory of Substantial Generation by Devin Henry Samuel Meister Devin Henry. Aristotle on Matter, Form, and Moving Causes: The Hylomorphic Theory of Substantial Generation. New York: Cambridge University Press, 2019. Pp. xiii + 236. Cloth, $99.99. Hylomorphism has been widely discussed as a mereological account that distinguishes the material from the formal parts of an entity. But for Aristotle, hylomorphism serves a second purpose, namely, to explain the generation of substances. In this book, Devin Henry offers a comprehensive study of Aristotle’s hylomorphic account of substantial generation. In particular, he argues that, in Generation of Animals, Aristotle defends a view that Henry calls “reproductive hylomorphism” (16, 105): an application of the hylomorphic model of substantial generation to the central case of the generation of animals. Henry’s book has many virtues. The integration of hylomorphism with Aristotle’s treatment of the generation of animals illuminates both the general framework and its applications. Moreover, Henry clearly formulates bold exegetical claims that he defends in a similarly lucid fashion. Regardless, then, of whether one agrees with Henry on any given claim, this study will be a rich resource for further work on the relevance of hylomorphism for Aristotle’s account of substantial generation. According to Henry, the hylomorphic model of substantial generation, as developed in the Physics and On Generation and Corruption, involves three principles: matter, form, and the moving cause (103). Henry sets out that model in the first four chapters and then applies it to the Generation of Animals: chapters 5 to 6 are dedicated to matter and form, whereas chapters 7 and 8 discuss the moving cause. (The final chapter 9 connects Aristotle’s account of generation with his cosmology.) Roughly, then, reproductive hylomorphism is the view that the generation of animals is to be explained in terms of matter, form, and the moving cause. At first sight, it may not seem controversial to attribute reproductive hylomorphism to Aristotle. After all, Aristotle holds that, in the generation of offspring, “the male provides the form and starting point [archē] of motion, while the female provides the body and the matter” (GA I.20, 729a9–11/Henry 118). Hence, the generation of animals involves matter, which is contributed by the mother, and form, which is contributed by the father. Moreover, the form plays the role of the moving cause. Thus, it is hard to deny that Aristotle is committed to some version of reproductive hylomorphism. However, as Henry understands it, reproductive hylomorphism is a more specific view. In chapters 5 and 6, he draws a distinction between two stages of generation that is not explicit in Aristotle: embryogenesis and morphogenesis. Embryogenesis begins from menstrual blood that is transformed into “an embryo endowed with a primitive heart and rudimentary nutritive capacities” (129). Morphogenesis proceeds from that embryo that is transformed into “an organism with the same shape and form as its generating parents” (129). Crucially, Henry argues that, at both stages, there is a process of what we might call “hylomorphic composition,” and at both stages, the mother contributes the matter, while the father contributes the form. In embryogenesis, the form is imposed by the male semen onto the mother’s menstrual blood. According to Henry, this is a mechanical process to be understood in terms of Aristotle’s analogy with fig juice and milk (GA I.20, 729a9–11): just as fig juice makes milk coagulate, menstrual blood coagulates upon contact with the semen. The early embryo produced in that way is like a curd, and its form is nothing “as sophisticated as capacities of soul” (120). By contrast, in morphogenesis, the mother contributes the body and nutritive soul, and the father contributes the substantial form, which, according to Henry, is not the entire soul of the resulting organism but only its sensory capacities (133). A first query about this two-stage version of reproductive hylomorphism concerns the product of embryogenesis. On the one hand, the embryo produced in embryogenesis is meant to be curd-like and not to have any soul capacities. On the other hand, the product of embryogenesis is an embryo with “rudimentary nutritive capacities” (129...