Simplicius

Aristotle argues in <i>On the Heavens</i> 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 English) 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.