Abstrakt
The article discusses two issues implied by the structure of De caelo I.9: Aristotle’s further defence of the uniqueness of the universe and, in more detail, the general question of whether the cosmology of De caelo overlaps, or is even compatible, with Aristotle’s theology including the notion of the Prime Mover. It offers an analysis of several long-standing difficulties including the question of whether the lines 279a18–22 imply an external mover of the heavens.
The negative answer that the article defends does however not solve the problem of how Aristotle conceives the source of natural cosmic motion. In this respect, the article pays close attention to the peculiar conception of the animate supralunary matter and to De caelo II.3, 286a7–21 as a text that complements I.9 by relying on the holistic self-motion that implies no Prime Mover, but requires the separation of the supralunary and the sublunary spheres.