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...

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 in the sixth century AD (here translated into...

Aristotle's Meteorology influenced generations of speculation about the earth sciences, ranging from atmospheric phenomena to earthquakes. The commentary of John Philoponus (6th century AD) on the opening three chapters of Meteorology is here translated for the first time into English by Dr Inna Kupreeva, building on the work of L.G. Westerink. Philoponus, who today is increasingly respected as a philosopher in his own right, here engages critically with Aristotle's views about the building-blocks of our world, its size and relationship to other heavenly bodies, and reception of...