It is well known that events belong to different kinds and follow one another in existence. If the agent of these different kinds of events is assumed to have always remained in one and the same state, with neither an act nor an attribute subsisting in Him, but to be one and simple, then it is impossible for His manner of bringing things into being to vary, or for Him to bring something into being that He had not previously brought into being. This is what they themselves maintain and make the mainstay of their argument for the world’s having no beginning. How, then, could the different kinds of events arise from Him, one after another, while there is nothing new in Him—no state, act, determination, attribute, or anything whatsoever?

They objected to the theologians who deny that voluntary acts subsist in Him, for holding that something could arise from Him without a newly occurring cause. They said:

This contradicts plain reason.

They may be told:

That falsehood is part of your own position. If even some events cannot arise from such an agent, then the perpetual occurrence of different events from a complete cause, in which and from which nothing new has occurred, is even more impossible than what those theologians maintain.

Furthermore, an event cannot occur until the complete act that brings it into being takes place, and a contingent thing cannot exist until there exists a complete necessitating cause that determines its existence. A complete necessitating cause necessarily entails what it necessitates and produces. Thus, no contingent event occurs and comes into existence until its complete necessitating cause exists. That complete necessitating cause must, in turn, have a complete necessitating cause, and so on.

It follows that each event must have an infinite number of complete necessitating causes existing simultaneously.

This is an infinite regress of causes and causal agents, which all rational people agree is invalid.