Book 4
8
Again, it must be that which is that changes, for change is from something into something. And further, neither is it true that all things are at rest or in motion sometimes, but nothing continuously; for there is something The sphere of the fixed stars; cf. Aristot. Met. 12.6, 12.7.1, 12.8.18. which always moves that which is moved, and the prime mover is itself unmoved.Cf. Aristot. Met. 12.7.
