a producer, and that is impossible. Should someone claim an infinite regress, an endless chain of efficient causes would follow, which is likewise impossible; therefore we must finally arrive at the Creator.

This is a truth the philosophers themselves concede and use against the Muʿtazilah, and it is evidence against them here. One states: the very fact that the celestial sphere is in motion demands an originator of that motion, for merely resembling the sphere does not generate movement. Hence the agent in question must itself be the one that produces the motion, and it is impossible for an agent to bring something into being before it exists. Consequently, it must be producing every single segment of the motion at the instant that segment occurs. Because the sphere is inseparable from successive contingencies, at every moment there must be someone who brings the newly arising event into existence within it. But for what is alleged to be eternal, producing a contingent event within it is impossible; therefore its supposed eternality is impossible. Eternity precludes the occurrence of any particular contingent or of a series of contingents; rather, eternity means perpetual existence in tandem with its necessitating cause. That would require the necessitating cause to be producing its contingents one after another, whereas an agent that acts by its very essence and whose effect is necessary cannot produce things sequentially—its effect must accompany it perpetually. Moreover, this would entail the presence of a changing entity, which would mean that what changes must be inseparably bound to what does not change, rendering the unchanging entity an effect of the changing one—an absurdity.

Furthermore, if the motions of the heavenly spheres are voluntary, and no contingencies occur except through them, it would follow that the world is governed by multiple lords, each living, powerful, and willing. The early philosophers even called them gods and lords. Yet this is impossible, for if two such agents are posited, then either their agreement is necessary or their divergence possible. If their agreement is necessary—so that neither can will anything but what the other wills, and neither can will or act except what the other wills and acts—then their power must come either from something other than themselves or from the two of them together