Originally published in 1991. Philoponus’ long commentary on Aristotle’s definition of light sets up the major concerns, both in optics and theory of light, that are discussed here. Light was of special interest in Neoplatonism because of its being something incorporeal in the world of natural bodies. Light therefore had a special role in the philosophical analysis of the interpenetration of bodies and was also a paradigm for the soul-body problem. The book contains much about the physiology of vision as well as the propagation of light. Several chapters investigate the philosophical theory behind what came to be known as ‘multiplication of species’ in medieval light theory. These issues in the history of science are placed within an analysis of Neoplatonic development of the distinction between Aristotle’s kinesis and energeia. The book treats Philoponus’ philosophy of mathematical science from the point of view of matter, quantity, and three-dimensionality.

The Posterior Analytics contains Aristotle's philosophy of science. In Book 2, Aristotle asks how the scientist discovers what sort of loss of light constitutes lunar eclipse. The scientist has to discover that the moon's darkening is due to the earth's shadow. Once that defining explanation is known the scientist possesses the full scientific concept of lunar eclipse and can use it to explain other necessary features of the phenomenon. The present commentary, arguably ascribed to Philoponus incorrectly, offers some interpretations of Aristotle that are unfamiliar nowadays. For example, the scientific concept of a human is acquired from observing particular humans and repeatedly receiving impressions in the sense image or percept and later in the imagination. The impressions received are not only of particular distinctive characteristics, like paleness, but also of universal human characteristics, like rationality. Perception can thus in a sense apprehend universal qualities in the individual as well as particular ones. This volume contains an English translation of the commentary, accompanied by extensive commentary notes, an introduction and a bibliography.

In this, one of the most original ancient texts on sense perception, Philoponus, the sixth century AD commentator on Aristotle, considers how far perceptual processes are incorporeal. Colour affects us in the same way as light which, passing through a stained glass window, affects the air, but colours only the masonry beyond. Sounds and smells are somewhat more physical, travelling most of the way to us with a moving block of air, but not quite all the way. Only the organ of touch takes on the tangible qualities perceived, because reception of sensible qualities in perception is cognitive, not physical. Neither light nor the action of colour involves the travel of bodies. Our capacities for psychological activity do not follow, nor result from, the chemistry of our bodies, but merely supervene on that. On the other hand, Philoponus shows knowledge of the sensory nerves, and he believes that thought and anger both warm us. This argument is used elsewhere to show how we can tell someone else's state of mind.

This study provides the first full discussion of Philoponus' excursus on matter in contra Proclum XI. 1-8 which sets out the innovative definition of prime matter as three-dimensional extension. The author argues that Philoponus' definition was motivated primarily by philosophical problems in Neoplatonism. Philoponus employs the explanation of growth, the interpretation of Aristotle's category theory and the notions of formlessness and potentiality to substantiate his definition. To conclude, the book offers an assessment of the significance of Philoponus' innovation. It is demonstrated for the first time that Plotinus' view of matter exerted considerable influence on both Philoponus and Simplicius. Moreover, the structure of Syrianus' and Proclus' metaphysics prepared the way for Philoponus' account of prime matter.

Aristotle's account of place, in which he defined a thing's place as the inner surface of its nearest immobile container, was supported by the Latin Middle Ages, even 1600 years after his death, though it had not convinced many ancient Greek philosophers. The sixth century commentator Philoponus took a more common-sense view. For him, place was an immobile three-dimensional extension, whose essence did not preclude its being empty, even if for other reasons it had always to be filled with body. However, Philoponus reserved his own definition for an excursus, already translated in this series, The Corollary on Place. In the text translated here he wanted instead to explain Aristotle's view to elementary students. The recent conjecture that he wished to attract young fellow Christians away from the official pagan professor of philosophy in Alexandria has the merit of explaining why he expounds Aristotle here, rather than attacking him. But he still puts the students through their paces, for example when discussing Aristotle's claim that place cannot be a body, or two bodies would coincide. This volume contains an English translation of Philoponus' commentary, as well as a detailed introduction, extensive explanatory notes and a bibliography.

Aristotle described the scientific explanation of universal or general facts as deducing them through scientific demonstrations, that is, through syllogisms that met requirements of logical validity and explanatoriness which he first formulated. In Chapters 19-23, he adds arguments for the further logical restrictions that scientific demonstrations can neither be indefinitely long nor infinitely extendible through the interposition of new middle terms. Chapters 24-26 argue for the superiority of universal over particular demonstration, of affirmative over negative demonstration, and of direct negative demonstration over demonstration to the impossible. Chapters 27-34 discuss different aspects of sciences and scientific understanding, allowing us to distinguish between sciences, and between scientific understanding and other kinds of cognition, especially opinion. Philoponus' comments on these chapters are interesting especially because of his metaphysical analysis of universal predication and his understanding of the notion of subordinate sciences. We learn from his commentary that Philoponus believed in Platonic Forms as inherent in, and posterior to, the Divine Intellect, but ascribed to Aristotle an interpretation of Plato's Forms as independent substances, prior to the Demiurgic Intellect. A very important notion from Aristotle's Posterior Analytics is that of the 'subordination' of sciences, i.e. the idea that some sciences depend on 'higher' ones for some of their principles. Philoponus goes beyond Aristotle in suggesting a taxonomy of sciences, in which the subordinate science concerns the same scientific genus as the superordinate, but a different species. This volume contains the first English translation of Philoponus' commentary, as well as a detailed introduction, extensive explanatory notes and a bibliography.

A substantially revised and supplemented edition of the collected volume originally published, by Duckworth, in 1987.

In On the Soul 3.1-8, Aristotle first discusses the functions common to all five senses, such as self-awareness, and then moves on to Imagination and Intellect. This commentary on Aristotle's text has traditionally been ascribed to Philoponus, but William Charlton argues here that it should be ascribed to a later commentator, Stephanus. (The quotation marks used around his name indicate this disputed authorship.) 'Philoponus' reports the postulation of a special faculty for self-awareness, intended to preserve the unity of the person. He disagrees with 'Simplicius', the author of another commentary on On the Soul (also available in this series), by insisting that Imagination can apprehend things as true or false, and he disagrees with Aristotle by saying that we are not always free to imagine them otherwise than as they are. On Aristotle's Active Intellect. 'Philoponus' surveys different interpretations, but ascribes to Plutarch of Athens, and rejects, the view adopted by the real Philoponus in his commentary on Aristotle's On Intellect that we have innate intellectual knowledge from a previous existence. Instead he takes the view that the Active Intellect enables us to form concepts by abstraction through serving as a model of something already separate from matter. Our commentator further disagrees with the real Philoponus by denying the Idealistic view that Platonic forms are intellects. Charlton sees 'Philoponus' as the excellent teacher and expositor that Stephanus was said to be.