This is made clear by the fact that motion is of three kinds: natural, forced, and voluntary.

Forced motion depends on an external mover, while natural motion occurs only when a body leaves its proper centre and naturally inclines to return to it. Both are therefore incidental; voluntary motion alone is primary.

If that is so, an effect produced by an agent needs the agent’s will far more than it needs will of its own. For if all motions ultimately depend on will, then clearly their dependence on the agent’s will is greater than their dependence on the will of the thing acted upon.

If they say, “In our view, the celestial sphere is not an effect produced by a necessarily existent originator; rather, it is eternal and necessarily existent in itself,” this supposition would commit them to consequences far more serious than what they sought to avoid: making that which is necessarily existent in itself a body occupying space, subject to temporal occurrences, and dependent on a cause that it seeks to imitate, along with all the other consequences.

[Seventh Argument]

It may be said: A contingent being cannot exist without an agent, yet it can exist without possessing longing. Its existence is therefore conditional upon the agent that produces it, not upon its possessing longing. How, then, can you affirm that which a contingent being does not need in order to exist, while dispensing with that without which it cannot exist?

[Eighth Argument]

It may be said: Your statement, “The First Cause would thus be a natural cause of the world and that which completes it. The analogy here would be with what the celestial sphere does and brings about by its nature, or with the existence of this alongside the existence of the substance of the celestial sphere, especially since