The aim is to clarify this point. They may be told:

The existence we witness is beyond doubt, and it entails the existence of an eternal, necessary being. For existence itself entails a being that is eternal and necessary in itself, since whatever exists must either be eternal and necessary, or originated, or contingent. Whatever is originated must have an originator, and whatever is contingent requires a necessary being. No human being disputes this.

The eternalists merely say, “This world is eternal and necessary in itself,” or, “It is the effect of an eternal cause that is necessary in itself.”

They may therefore be told: If you maintain that this world is eternal and necessarily existent in itself, these impossibilities—and many more besides—follow from your position. For you may be asked: Why did the outermost celestial sphere and the other spheres move, and why did these transformations occur? These are events that came to be after not existing, and they are certainly contingent. Thus, whatever brought them about—whether a celestial sphere or something else—which you have assumed to be eternal and necessarily existent in itself, must, if it brought them about for a purpose, attain perfection through them. Yet the assumption is that it is eternal and necessarily existent in itself. Your position therefore entails that what is eternal and necessarily existent in itself attains perfection through something other than itself. This is precisely the impossibility you sought to escape, yet you have fallen into it, along with the other impossibilities necessarily entailed by this assumption, such as the impossibility of the outermost sphere being the originator of all motions, and others. Even if each moving celestial sphere were assumed to be eternal and necessarily existent