Aristotle's Physics is about the causes of motion and culminates in a proof that God is needed as the ultimate cause of motion. Aristotle argues that things in motion need to be moved by something other than themselves - he rejects Plato's self-movers. On pain of regress, there must be an unmoved mover. If this unmoved mover is to cause motion eternally, it needs infinite power. It cannot, then, be a body, since bodies, being of finite size, cannot house infinite power. The unmoved mover is therefore an incorporeal God.

Simplicius' commentary on Aristotle's Categories is the most comprehensive philosophical critique of the work ever written, representing 600 years of criticism. In his Categories, Aristotle divides what exists in the sensible world into ten categories of Substance, Quantity, Relative, Quality and so on.. Simplicius starts with a survey of previous commentators, and an introductory set of questions about Aristotle's philosophy and about the Categories in particular. The commentator, he says, needs to present Plato and Aristotle as in harmony on most things. Why are precisely ten categories...

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...

Aristotle classified the things in the world into ten categories: substance, quantity, quality, relative, etc. Plotinus, the founder of Neoplatonism, attacked the classification, accepting only these first four categories, rejecting the other six, and adding one of this own: change. He preferred Plato's classification into five kinds which included change.
In this part of his commentary, Simplicius records the controversy on the six categories which Plotinus rejected: acting, being acted upon, being in a position, when, where, and having on. Plotinus' pupil and editor, Porphyry, defended...

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...

The commentary attributed to Simplicius on Aristotle's On the Soul appears in this series in three volumes, of which this is the first. The translation provides the first opportunity for a wider readership to assess the disputed question of authorship. Is the work by Simplicius, or by his colleague Priscian, or by another commentator? In the second volume, Priscian's Paraphrase of Theophrastus on Sense Perception, which covers the same subject, will also be translated for comparison.
Whatever its authorship, the commentary is a major source for late Neoplatonist theories of...

Book 2 of the Physics is arguably the best introduction to Aristotle's ideas, as well as being the most interesting and representative book in the whole of his corpus. It defines nature and distinguishes natural science from mathematics. It introduces the seminal idea of four causes, or four modes of explanation. It defines chance, but rejects a theory of chance and natural selection in favour of purpose in nature.
Simplicius, writing in the sixth century AD, adds his own considerable contribution to this work. Seeing Aristotle's God as a Creator, he discusses how nature relates...

Simplicius, the greatest surviving ancient authority on Aristotle's Physics, lived in the sixth century A. D. He produced detailed commentaries on several of Aristotle's works. Those on the Physics, which alone come to over 1,300 pages in the original Greek, preserve a centuries-old tradition of ancient scholarship on Aristotle.
In Physics Book 5 Aristotle lays down some of the principles of his dynamics and theory of change. What does not count as change: change of relation? The flux of time? There is no change of change, yet acceleration is recognised. Aristotle...

In On the Soul 3.1-5, Aristotle goes beyond the five sense to the general functions of sense perception, the imagination and the so-called active intellect, the of which 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 the soul has never descended from uninterrupted contemplation of the Platonic Forms, and Proclus' view that the soul cannot be changed in its substance...