Jaap Mansfeld and Frans de Haas bring together in this volume a distinguished international team of ancient philosophers, presenting a systematic, chapter-by-chapter study of one of the key texts in Aristotle's science and metaphysics: the first book of On Generation and Corruption. In GC I Aristotle provides a general outline of physical processes such as generation and corruption, alteration, and growth, and inquires into their differences. He also discusses physical notions such as contact, action and passion, and mixture. These notions are fundamental to Aristotle's physics and cosmology, and more specifically to his theory of the four elements and their transformations. Moreover, references to GC elsewhere in the Aristotelian corpus show that in GC I Aristotle is doing heavy conceptual groundwork for more refined applications of these notions in, for example, the psychology of perception and thought, and the study of animal generation and corruption. Ultimately, biology is the goal of the series of enquiries in which GC I demands a position of its own immediately after the Physics. The contributors deal with questions of structure and text constitution and provide thought-provoking discussions of each chapter of GC I. New approaches to the issues of how to understand first matter, and how to evaluate Aristotle's notion of mixture are given ample space. Throughout, Aristotle's views of the theories of the Presocratics and Plato are shown to be crucial in understanding his argument.

Chapters 5 and 6 of Aristotle's "Categories" describe his first two categories, Substance and Quantity. It is usually taken that Plotinus attacked Aristotle's "Categories", but that Porphyry and Iamblichus restored it to the curriculum once and for all. Nonetheless, the introduction to this text stresses how much of the defence of Aristotle Porphyry was able to draw out of Plotinus' critical discussion. Simplicius' commentary is our most comprehensive account of the debate on the validity of Aristotle's "Categories". One subject discussed by Simplicius in these chapters is where the differentia of a species (eg the rationality of humans) fits into the scheme of categories. Another is why Aristotle elevates the category of Quantity to second place, above the category of Quality. Further, de Haas shows how Simplicius distinguishes different kinds of universal order to solve some of the problems.

Chapters 5 and 6 of Aristotle's Categories describe his first two categories, Substance and Quantity. It is usually taken that Plotinus attacked Aristotle's Categories, but that Porphyry and Iamblichus restored it to the curriculum once and for all. Nonetheless, the introduction to this text stresses how much of the defence of Aristotle Porphyry was able to draw out of Plotinus' critical discussion. Simplicius' commentary is our most comprehensive account of the debate on the validity of Aristotle's Categories. One subject discussed by Simplicius in these chapters is where the differentia of a species (eg the rationality of humans) fits into the scheme of categories. Another is why Aristotle elevates the category of Quantity to second place, above the category of Quality. Further, de Haas shows how Simplicius distinguishes different kinds of universal order to solve some of the problems.