T is book argues that according toMetaphysicsZeta, substantial forms constitute substantial being in the sensible world, and individual composites make up the basic constituents that possess this kind of being. The study explains why Aristotle provides a reexamination of substance after theCategories,Physi s, andDe Anima, and highlights the contribution Z is meant to make to the science of being. Norman O. Dahl argues that Z.1-11 leaves both substantial forms and individual composites as candidates for basic constituents, with Z.12 being something that can be set aside. He explains that although the main focus of Z.13-16 is to argue against a Platonic view that takes universals to be basic constituents, some of its arguments commit Aristotle to individual composites as basic constituents, with Z.17's taking substantial form to constitute substantial being is compatible with that commitment.

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Norman O. Dahl is Emeritus Professor of Philosophy at the University of Minnesota.  His main interests are moral philosophy and ancient philosophy.  In the latter area he is the author ofPractical Reason, Aristotle, and Weakness of the Will(1984),article on MetaphysicsZeta, and publications on Aristotle's ethics and Plato's ethics.