Aristotle believed that the outermost stars are carried round us on a transparent sphere. There are directions in the universe and a preferred direction of rotation. The sun moon and planets are carried on different revolving spheres. The spheres and celestial bodies are composed of an everlasting fifth element, which has none of the ordinary contrary properties like heat and cold which could destroy it, but only the facility for uniform rotation. But this creates problems as to how the heavenly bodies create light, and, in the case of the sun, heat. The value of Simplicius' commentary on On the Heavens 2,1-9 lies both in its preservation of the lost comments of Alexander and in Simplicius' controversy with him. The two of them discuss not only the problem mentioned, but also whether soul and nature move the spheres as two distinct forces or as one. Alexander appears to have simplified Aristotle's system of 55 spheres down to seven, and some hints may be gleaned as to whether, simplifying further, he thinks there are seven ultimate movers, or only one.

In the second half of book 1 of the "Prior Analytics," Aristotle reflects on the application of the formalized logic he has developed in the first half, focusing particularly on the non-modal or assertoric syllogistic developed in the first seven chapters. These reflections lead Alexander of Aphrodisias, the great late second-century AD exponent of Aristotelianism, to explain and sometimes argue against subsequent developments of Aristotle's logic and alternatives and objections to it, ideas associated mainly with his colleague Theophrastus and with the Stoics. The other main topic of this part of the "Prior Analytics" is the specification of a method for discovering true premises needed to prove a given proposition. Aristotle's presentation is sometimes difficult to follow, and Alexander's discussion is extremely helpful to the uninitiated reader. In his commentary on the final chapter translated in this volume, Alexander provides an insightful account of Aristotle's criticism of Plato's method of division.

The last 14 chapters of book 1 of Aristotle's "Prior Analytics" are concerned with the representation in the formal language of syllogistic of propositions and arguments expressed in more or less everyday Greek. In his commentary on those chapters, "Alexander of Aphrodisias" explains some of Aristotle's more opaque assertions and discusses post-Aristotelian ideas in semantics and the philosophy of language. In doing so he provides an unusual insight into the way in which these disciplines developed in the Hellenistic era. He also shows a more sophisticated understanding of these fields than Aristotle himself, while remaining a staunch defender of Aristotle's emphasis on meaning as opposed to Stoics concern with verbal formulation. In his commentary on the final chapter of book 1 Alexander offers a thorough discussion of Aristotle's distinction between denying that something is, for example, white and asserting that it is non-white.

Commenting on the end of Aristotle's On the Heavens Book 3, Simplicius examines Aristotle's criticisms of Plato's theory of elemental chemistry in the Timaeus. Plato makes the characteristics of the four elements depend on the shapes of component corpuscles and ultimately on the arrangement of the triangles which compose them. Simplicius preserves and criticizes the contributions made to the debate in lost works by two other major commentators, Alexander the Aristotelian, and Proclus the Platonist. In Book 4, Simplicius identifies fifteen objections by Aristotle to Plato's views on weight in the four elements. He finishes Book 4 by elaborating Aristotle's criticisms of Democritus' theory of weight in the atoms, including Democritus' suggestions about the influence of atomic shape on certain atomic motions. This volume includes an English translation of Simplicius' commentary, a detailed introduction, extensive commentary notes and a bibliography.

One of the arguments in Aristotle's "On the Heavens "propounds that the world neither came to be nor will perish. This volume contains the pagan Neoplatonist Simplicius of Cilicia's commentary on the first part of this this important work. The commentary is notable and unusual because Simplicius includes in his discussion lengthy representations of the Christian John Philoponus' criticisms of Aristotle along with his own, frequently sarcastic, responses.This is the first complete translation into a modern language of Simplicius' commentary, and is accompanied by a detailed introduction, extensive explanatory notes and a bibliography.

This is the first English translation of Simplicius' responses to Philoponus' "Against Aristotle on the Eternity of the World." The commentary is published in two volumes: Ian Mueller's previous book in the series, " Simplicius: On Aristotle On the Heavens 1.2-3," and this book on 1.3-4. Philoponus, the Christian, had argued that Aristotle's arguments do not succeed. For all they show to the contrary, Christianity may be right that the heavens were brought into existence by the only divine being and one moment in time, and will cease to exist at some future moment. Simplicius upholds the pagan view that the heavens are eternal and divine, and argues that their eternity is shown by their astronomical movements coupled with certain principles of Aristotle.The English translation in this volume is accompanied by a detailed introduction, extensive commentary notes and a bibliography.

Aristotle believed that the outermost stars are carried round us on a transparent sphere. There are directions in the universe and a preferred direction of rotation. The sun, moon and planets are carried on different revolving spheres. The spheres and celestial bodies are composed of an everlasting fifth element, which has none of the ordinary contrary properties like heat and cold which could destroy it, but only the facility for uniform rotation. But this creates problems as to how the heavenly bodies create light, and, in the case of the sun, heat. The topics covered in this part of Simplicius' commentary are: the speeds and distances of the stars; that the stars are spherical; why the sun and moon have fewer motions than the other five planets; why the sphere of the fixed stars contains so many stars whereas the other heavenly spheres contain no more than one (Simplicius has a long excursus on planetary theory in his commentary on this chapter); discussion of people's views on the position, motion or rest, shape, and size of the earth; that the earth is a relatively small sphere at rest in the centre of the cosmos.

The commentary of Alexander of Aphrodisias on Aristotle's "Prior Analytics" 1.8-22 is a very important text, being the main ancient commentary with chapters in which Aristotle invented modal logic - the logic of propositions about what is necessary or contingent (possible). The first volume of Ian Mueller's translation covered chapters 1.8-13, and reached as far as the chapter in which Aristotle discussed the notion of contingency. In this, the second volume, the 'greatest' commentator, Alexander, concludes his discussion of Aristotle's modal logic. Aristotle also invented the syllogism, a style of argument involving two premises and a conclusion. Modal propositions can be deployed in syllogisms, and in the chapters included in this volume Aristotle discusses all the syllogisms containing at least one contingent premiss. In each volume, Ian Mueller provides a comprehensive explanation of Alexander's commentary on modal logic as a whole.

The subject of Aristotle's On the Heavens, Books 3-4, is the four elements of earth, air, fire and water, which exist below the heavens. Book 3, in chapters 1 to 7, frequently criticizes the Presocratic philosophers. Because of this, Simplicius' commentary is one of our main sources of quotations of the Presocratics. Ian Mueller's translation of this commentary gains added importance by enabling us to see the context which guided Simplicius' selection of Presocratic texts to quote. Simplicius also criticizes the lost commentary of the leading Aristotelian commentator, Alexander, and thereby gives us important information about that work. The English translation in this volume is accompanied by a detailed introduction, extensive commentary notes and a bibliography.

In the chapters of his 'Physics' commented on here, Aristotle disagrees with Pre-Socratic philosophers about the basic principles that explain natural changes. But he finds some agreement among them that at least two contrary properties must be involved, for example hot and cold. His own view is that there are two contrary principles at a more abstract level: the form possessed at the end of a change and the privation of that form at the beginning. But there is also a third principle needed to supply continuity - the matter to which first privation and later form belong. Despite the apparent disagreements, Simplicius, the Neoplatonist commentator, wants to emphasise the harmony of all pagan Greek thinkers, as opposed to Christians, on such a basic matter as first principles. He therefore presents not only the Pre-Socratics and Aristotle, but also himself and earlier commentators of different schools as all in basic agreement.

This is the first complete translation into a modern language of the first part of the pagan Neoplatonist Simplicius of Cilicia's commentary on Aristotle's argument that the world neither came to be nor will perish. It is notable and unusual among the commentaries because Simplicius includes in his discussion lengthy representations of the Christian John Philoponus' criticisms of Aristotle along with his own, frequently heavily sarcastic, responses.

Commenting on the end of Aristotle On the" Heavens" Book 3, Simplicius examines Aristotle's criticisms of Plato's theory of elemental chemistry in the "Timaeus." Plato makes the characteristics of the four elements depend on the shapes of component corpuscles and ultimately on the arrangement of the triangles which compose them. Simplicius preserves and criticizes the contributions made to the debate in lost works by two other major commentators, Alexander the Aristotelian, and Proclus the Platonist. In Book 4, Simplicius identifies fifteen objections by Aristotle to Plato's views on weight in the four elements. He finishes Book 4 by elaborating Aristotle's criticisms of Democritus' theory of weight in the atoms, including Democritus' suggestions about the influence of atomic shape on certain atomic motions.

The subject of Aristotle's "On the Heavens," Books 3-4, is the four elements of earth, air, fire and water, which exist below the heavens. Book 3, in chapters 1 to 7, frequently criticizes the Presocratic philosophers. Because of this Simplicius' commentary is one of our main sources of quotations of the Presocratics. Mueller's translation gains added importance from its enabling us to see the context which guided Simplicius' selection of Presocratic texts to quote. Simplicius also criticizes the lost commentary of the leading Aristotelian commentator, Alexander, and thereby gives us important information about that work.

Simplicius' greatest contribution in his commentary on Aristotle on Physics 1.5-9 lies in his treatment of matter. The sixth-century philosopher starts with a valuable elucidation of what Aristotle means by 'principle' and 'element' in Physics. Simplicius' own conception of matter is of a quantity that is utterly diffuse because of its extreme distance from its source, the Neoplatonic One, and he tries to find this conception both in Plato's account of space and in a stray remark of Aristotle's. Finally, Simplicius rejects the Manichaean view that matter is evil and answers a Christian objection that to make matter imperishable is to put it on a level with God. This is the first translation of Simplicius' important work into English.

This is the first English translation of Simplicius' responses to Philoponus' "Against Aristotle on the Eternity of the World." The commentary is published in two volumes: Ian Mueller's previous book in the series, " Simplicius: On Aristotle On the Heavens 1.2-3," and this book on 1.3-4. Philoponus, the Christian, had argued that Aristotle's arguments do not succeed. For all they show to the contrary, Christianity may be right that the heavens were brought into existence by the only divine being and one moment in time, and will cease to exist at some future moment. Simplicius upholds the pagan view that the heavens are eternal and divine, and argues that their eternity is shown by their astronomical movements coupled with certain principles of Aristotle.Until the launch of this series, the 15,000 volumes of the ancient Greek commentators on Aristotle constituted the largest corpus of Greek philosophical writings which had not been translated into English or other European languages. There are now over 100 volumes in the series.