Consequently, it is impossible for His act to be eternal. Should someone contend that at least some of His effects could accompany Him, that would amount to positing a being who necessitates by His very essence—only now as a self-necessitating cause that also possesses will and power.

The point, then, is this: if the world were eternal, its maker would necessarily entail it; He could not be an agent whose effect is delayed. For every agent falls into one of three categories: (1) one whose effect must accompany him; (2) one whose effect must come after him; or (3) one for whom both alternatives are possible. Were the world eternal, its maker could not belong to the second category, for that would unite two mutually exclusive propositions—how can the effect be everlasting and yet occur later, coming into being after having been nonexistent?

Thus only two options remain: either the maker’s effect must accompany Him, or both accompaniment and non-accompaniment are possible. The second of these is likewise untenable. If the effect may or may not accompany the agent, its existence is merely possible, and a possibility cannot favor one side over the other without a determiner. The same reasoning applies to that determiner: if its agent necessitates it, the effect will accompany that agent, and hence will accompany the first agent as well. If its accompaniment is not necessary, it remains contingent and in need of yet another determiner, and so on ad infinitum. Therefore the sequence must terminate in a complete determiner that necessitates its effect.

It is thus clear that, were the universe eternal, its originator would have to be a complete determiner that necessitates its effect—whether one calls it the "complete cause" or any other name.