Aristotle's views on the fundamental nature of reality are usually taken to be inconsistent. Two sources for these views are Categories and the central books of Metaphysics. This text argues that he is engaged in different projects in these books.

Introduction; I. The Plan of the Categories; II. Nonsubstantial Individuals; III. Commitment and Configuration in the Categories; IV. Tales of the Two Treatises; V. The Structure and Substance of Substance; VI. Form as Essence; VII. Zeta 6 on the Immediacy of Form; VIII. The Purification of Form; IX. Generality and Compositionality; X. Form and Explanation; Bibliography; Indexes.

This book argues that according to Metaphysics Zeta, 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 the Categories, Physics, and De 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. .

Frank A. Lewis presents a closely argued exposition of Metaphysics Zeta—one of Aristotle's most dense and controversial texts. It is commonly understood to contain Aristotle's deepest thoughts on the definition of substance and surrounding metaphysical issues. But people have increasingly come to recognize how little Aristotle says in Zeta about his own theory of (Aristotelian) form and matter. Instead, he spends the bulk of the book examining 'received opinions', often as filtered through his own Organon, but including above all the views of Plato, who is at times friend, and at times foe. For much of the time, we are left to reconstruct Aristotle's finished views, subject to the constraint that they survive the critique he directs in Zeta at the philosophical tradition. In this book, Lewis argues that in giving his actual conclusion to Zeta in its final chapter, 17, Aristotle drops his earlier, largely critical engagement with received views, and turns approvingly to his own Posterior Analytics. The result is a causal view of (primary) substance, representing the property of being a (primary) substance (or the substance of a thing) as, in modern dress, the second-order functional property of (Aristotelian) forms, that they be the cause of being for different compound material substances. The property of being the cause of being for a thing is a role property, and it is realized in different forms and the sets of causal powers associated with them, matching the variety of things that have a form as their substance. Meanwhile, the failure of previous attempts at definition in earlier chapters leaves Aristotle's own definition standing as the 'best explanation' for the views proprietary to the theory of form and matter. The point that (Aristotelian) forms are the primary substances is not the main conclusion to Zeta, but rather a result his definition must give, if the definition is to be acceptable.

Aristotle responds in his metaphysics to a problem with Platonic theory: when a property belongs to a subject, is the property a feature of the subject or does it determine the nature of the subject? Furthermore, can the nature of a subject "belong to" the subject?

This book is a re-thinking of Aristotle's metaphysical theory of material substances. The view of the author is that the 'substances' are the living things, the organisms: chiefly, the animals. There are three main parts to the book: Part I, a treatment of the concepts of substance and nonsubstance in Aristotle's Categories; Part III, which discusses some important features of biological objects as Aristotelian substances, as analysed in Aristotle's biological treatises and the de Anima; and Part V, which attempts to relate the conception of substance as interpreted so far to that of the Metaphysics itself. The main aim of the study is to recreate in modern imagination a vivid, intuitive understanding of Aristotle's concept of material substance: a certain distinctive concept of what an individual material object is.

A new interpretation of Aristotle's metaphysics, a subject of considerable interest to all classical philosophers.

This book takes up the central themes of Aristotle's metaphysical theory and the various transformations they undergo prior to their full expresson in the Metaphysics.This book takes up the central themes of Aristotle's metaphysical theory and the various transformations they undergo prior to their full expresson in the Metaphysics.

Michael J. Loux here presents a fresh reading of two of the most important books of the Metaphysics, Books Z and H, in which Aristotle presents his mature theory of primary substances (ousiai). Focusing on the interplay of Aristotle's early and late views, Loux maintans that the later concept of ousia should be understood in terms of a theory of predication that carries interesting implications for contemporary metaphysics. Loux argues that in his first attempt in identifying ousiai in the Categories, Aristotle encountered a set of ontological problems which he wrestled with again in Metaphysics Z and H. In the Categories, where the primary realities are basic subjects of predication construed in essentialist terms as things falling under natural kinds, familiar particulars are the primary ousiai. In subsequent works, Aristotle holds that since familiar particulars come into being and pass away, they must be composites of matter and form; and in Metaphysics Z and H, he explores the implications of this insight for the search for ousia. Maintaining that the substantial forms of familiar particulars are the primary ousiai, the later Aristotle interprets forms as predicable universals rather than as particulars, each uniquely possessed by a single object.