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...