  Once it is established that there is a mover for each change, the finite causal  chains[44] can be followed up to the primary instance of motion, the celestial revolutions. In particular the Sun’s course along the  ecliptic is responsible for many sublunar changes, the rotating  seasons being foremost among them. Whether the cosmos has unmoved  or moved movers, moreover, whether the universe is causally closed  or needs some continuous external causal influence for its  preservation, depends ultimately, then, on the status of the  celestial motions.