In "On the Soul" 3.1-5, Aristotle goes beyond the five senses to the general functions of sense perception, the imagination and the so-called active intellect, whose identity was still a matter of controversy in the time of Thomas Aquinas. In his commentary on Aristotle's text, Simplicius insists that the intellect in question is not something transcendental, but the human rational soul. He denies both Plotinus' view that a part of our soul has never descended from uninterrupted contemplation of the Platonic forms, and Proclus' view that our soul cannot be changed in its substance through embodiment. Continuing the debate in Carlos Steel's earlier volume in this series, Henry Blumenthal assesses the authorship of the commentary. He concludes against it being by Simplicius, but not for its being by Priscian. In a novel interpretation, he suggests that if Priscian had any hand in it at all, it might have been as editor of notes from Simplicius' lectures.

In chapter 1 of "On the Heavens" Aristotle defines body, and then notoriously ruptures dynamics by introducing a fifth element, beyond Plato's four, to explain the rotation of the heavens, which, like nearly all Greeks, Aristotle took to be real, not apparent. Even a member of his school, Xenarchus, we are told, rejected his fifth element. The Neoplatonist Simplicius seeks to harmonise Plato and Aristotle. Plato, he says, thought that the heavens were composed of all four elements but with the purest kind of fire, namely light, predominating. That Plato would not mind this being called a fifth element is shown by his associating with the heavens the fifth of the five convex regular solids recognised by geometry. Simplicius follows Aristotle's view that one of the lower elements, fire, also rotates, as shown by the behaviour of comets. But such motion, though natural for the fifth element, is super-natural for fire. Simplicius reveals that the Aristotelian Alexander of Aphrodisias recognised the need to supplement Aristotle and account for the annual approach and retreat of planets by means of Ptolemy's epicycles or eccentrics. Aristotle's philosopher-god is turned by Simplicius, following his teacher Ammonius, into a creator-god, like Plato's. But the creation is beginningless, as shown by the argument that, if you try to imagine a time when it began, you cannot answer the question, 'Why not sooner?' In explaining the creation, Simplicius follows the Neoplatonist expansion of Aristotle's four 'causes' to six. The final result gives us a cosmology very considerably removed from Aristotle's. This text is a transation of Simplicius' commentary on Aristotle's "On the Heaven 1.1-4".

The "Enchiridion" or "Handbook" of the first-century AD Stoic Epictetus was used as an ethical treatise both in Christian monasteries and by the sixth-century pagan Neoplatonist Simplicius. Simplicius chose it for beginners, rather than Aristotle's "Ethics", because it presupposed no knowledge of logic. We thus get a fascinating chance to see how a pagan Neoplatonist transformed Stoic ideas. The text was relevant to Simplicius because he too, like Epictetus, was teaching beginners how to take the first steps towards eradicating emotion, although he is unlike Epictetus in thinking that they should give up public life rather than acquiesce, if public office is denied them. Simplicius starts from a Platonic definition of the person as rational soul, not body, ignoring Epictetus' further whittling down of himself to just his will or policy decisions. He selects certain topics for special attention in chapters 1, 8, 27 and 31. Things are up to us, despite Fate. Our sufferings are not evil, but providential attempts to turn us from the body. Evil is found only in the human soul. But evil is parasitic (Proclus' term) on good. The gods exist, are provident, and cannot be bought off. With nearly all of this the Stoics would agree, but for quite different reasons, and their own distinctions and definitions are to a large extent ignored. This translation of the "Handbook" is published in two volumes. This is the second volume, covering chapters 27-53; the first covers chapters 1-26.

The "Enchiridion" or "Handbook" of the first-century AD Stoic Epictetus was used as an ethical treatise both in Christian monasteries and by the sixth-century pagan Neoplatonist Simplicius. Simplicius chose it for beginners, rather than Aristotle's "Ethics", because it presupposed no knowledge of logic. We thus get a fascinating chance to see how a pagan Neoplatonist transformed Stoic ideas. The text was relevant to Simplicius because he too, like Epictetus, was teaching beginners how to take the first steps towards eradicating emotion, although he is unlike Epictetus in thinking that they should give up public life rather than acquiesce, if public office is denied them. Simplicius starts from a Platonic definition of the person as rational soul, not body, ignoring Epictetus' further whittling down of himself to just his will or policy decisions. He selects certain topics for special attention in chapters 1, 8, 27 and 31. Things are up to us, despite Fate. Our sufferings are not evil, but providential attempts to turn us from the body. Evil is found only in the human soul. But evil is parasitic (Proclus' term) on good. The gods exist, are provident, and cannot be bought off. With nearly all of this the Stoics would agree, but for quite different reasons, and their own distinctions and definitions are to a large extent ignored. This translation of the "Handbook" is published in two volumes. This is the first, covering chapters 1-26; the second covers chapters 27-53.

Aristotle's "Physics Book 3" covers two subjects: the definition of change and the finitude of the universe. Change enters into the very definition of nature as an internal source of change. Change receives two definitions in chapters 1 and 2, as involving the actualisation of the potential or of the changeable. Alexander of Aphrodisias is reported as thinking that the second version is designed to show that Book 3, like Book 5, means to disqualify change in relations from being genuine change. Aristotle's successor Theophrastus, we are told, and Simplicius himself, prefer to admit relational change. Chapter 3 introduces a general causal principle that the activity of the agent causing change is in the patient undergoing change, and that the causing and undergoing are to be counted as only one activity, however different in definition. Simplicius points out that this paves the way for Aristotle's God who moves the heavens, while admitting no motion in himself. It is also the basis of Aristotle's doctrine, central to Neoplatonism, that intellect is one with the objects it contemplates. In defending Aristotle's claim that the universe is spatially finite, Simplicius has to meet Archytas' question, "What happens at the edge?". He replies that, given Aristotle's definition of place, there is nothing, rather than an empty place, beyond the furthest stars, and one cannot stretch one's hand into nothing, nor be prevented by nothing. But why is Aristotle's beginningless universe not temporally infinite? Simplicius answers that the past years no longer exist, so one never has in infinite collection.

In the sixth century AD Simplicius produced detailed commentaries on several of the works of Aristotle, which help in our understanding of the "Physics", and of its interpretation in the ancient world. This is Urmson's translation of Simplicius' commentaries on "Physics 5" in which Aristotle lays down some of the principles of his dynamics and theory of change. What does not count as a change: change of relation?; the flux of time? There is no change of change, yet acceleration is recognized. Aristotle defines "continuous", "contact" and "next", and uses these definitions in discussing when we can claim that the same change or event is still going on.

Is there such a thing as three-dimensional space? Is space inert or dynamic? Is the division of time into past, present and future real? Does the whole of time exist all at once? Does it progress smoothly or by discontinuous leaps? Simplicius surveys ideas about place and time from the preceding thousand years of Greek Philosophy and reveals the extraordinary ingenuity of the late Neoplatonist theories, which he regards as marking a substantial advance on all previous ideas.

In "Categories" chapters 7 and 8 Aristotle considers his third and fourth categories - those of Relative and Quality. Critics of Aristotle had suggested for each of the non-substance categories that they could really be reduced to relatives, so it is important how the category of Relative is defined. Arisotle offers two definitons, and the second, stricter, one is often cited by his defenders in order to rule out objections. The second definition of relative involves the idea of something changing its relationship through a change undergone by its correlate, not by itself. There were disagreements as to whether this was genuine change, and Plotinus discussed whether relatives exist only in the mind, without being real. The terms used by Aristotle for such relationships was 'being disposed relatively to something', a term later borrowed by the Stoics for their fourth category, and perhaps originating in Plato's Academy. In his discussion of Quality, Aristotle reports a debate on whether justice admits of degrees, or whether only the possession of justice does so. Simplicius reports the further development of this controversy in terms of whether justice admits a range or latitude (platos). This debate helped to inspire the medieval idea of latitude of forms, which goes back much further than is commonly recognised - at least to Plato and Aristotle.

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.

Aristotle argues in "On the Heavens" 1.5-7 that there can be no infinitely large body, and in 1.8-9 that there cannot be more than one physical world. As a corollary in 1.9, he infers that there is no place, vacuum or time beyond the outermost stars. As one argument in favour of a single world, he argues that his four elements, earth, air, fire and water, have only one natural destination apiece. Moreover they accelerate as they approach it and acceleration cannot be unlimited. However, the Neoplatonist Simplicius, who wrote the commentary translated here in the sixth century AD, tells us that this whole world view was to be rejected by Strato, the third head of Aristotle's school. At the same time, he tells us the different theories of acceleration in Greek philosophy.

Book two of Aristotle's "Physics" is thought by some to be the most interesting and representative book in the whole of his corpus. It explains his conception of nature, of physics as opposed to mathematics, of causation and explanation, of chance and of purpose in nature. Simplicius, writing in the 6th century AD, is the most comprehensive of all the commentators. He reports interpretations of Aristotle from the preceding 800 years by Eudemus, Posidonius, Porphyry and Syranius. His accounts of the various definitions of nature and of chance are highly useful, are as his analyses of Aristotle's technical terms, per accidens and privation. He often carries out the project, which Aristotle himself proposed but never undertook, of putting Aristotle's scientific explanations into syllogistic form.

This is the commentary attributed to Simplicius on Aristotle's "On the Soul". It is intended to provide a wider readership with the opportunity to assess the disputed question of authorship. Is the work by Simplicius, or by his colleague Priscian, or by another commentator? The commentary is a source for late Neoplatonist theories of thought and sense perception and provides insight into this area of Aristotle's thought. In this volume the Neoplatonist commentator covers the first half of Aristotle's "On the Soul", comprising Aristotle's survey of his predecessors and his own rival account of the nature of the soul.

There has recently been considerable renewed interest in Book 7 of the Physics of Aristotle, once regarded as merely an undeveloped forerunner to Book 8. The debate surrounding the importance of the text is not new to modern scholarship: for example, in the fourth century BC Eudemus, the Peripatetic philosopher associate of Aristotle, left it out of his treatment of the Physics. Now, for the first time, Charles Hagen's lucid translation gives the English reader access to Simplicius' commentary on Book 7, an indispensable tool for the understanding of the text. Its particular interest lies in its explanation of how the chapters of Book 7 fit together and its reference to a more extensive second version of Aristotle's text than the one which survives today.

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 partly in its preserving 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.

Simplicius' commentary on Aristotle's "Categories" falls into two parts. First, it examines the six categories dealt with in chapter 9 of "Categories", namely acting, undergoing, being in a position, when, where, and having. Secondly, it examines the so-called "Postpraedicamenta" consisting of chapter 10-15, which treat four kinds of opposition (relatives, contraries, possession, and privation, affirmation and negation), along with priority, simultaneity, movement and (again) having.