Thus we say:

Granted that this is so, all he has thereby established is the final cause of motion.

It may then be asked: Where is the efficient cause of the celestial sphere’s motion? Although motion depends on an intended end, it must necessarily also depend on an efficient principle.

If they say, “Its soul moves it,” they are asked: What, then, brings about the causes of motion that arise in the soul, such as conceptions and volitions? These did not exist and then came into existence. What, then, is the efficient cause of this motion?

If they say that the soul itself produces this motion, they have made it move of its own accord, contrary to their own position.

If they say that something other than the soul produces it, they are told: The same argument applies to that thing as to the soul. If something arises in it that had not arisen before, the cause of that occurrence must be asked about.

If, instead, it is said that what brings about the soul’s motion remains in one and the same state throughout past and future eternity, they are told: Your position therefore entails that an event comes into existence without a cause. Moreover, if that mover of the soul was a cause from eternity, its effect must have existed from eternity. Thus, the conceptions and volitions that arose in the soul must have existed from eternity. This affirms two contradictories at once.