Now, because a cause must be present together with its effect, one would have to posit an infinite number of simultaneous, contingent, originated causes—and that is impossible.

This objection stands whether one says that the cause of coming-into-being is also the cause of continuance, or that continuance has a cause distinct from origination. For the cause of origination must itself be originated; were it eternal, the temporal effect would proceed from an eternal cause, which is absurd. Such a cause would either be eternally producing the effect—so the effect would not be temporal at all, but everlasting—or it would only become a cause at some point. Yet that becoming-a-cause is itself an event, and the same argument applies to it: it too requires an originated cause. Thus we are faced with a plurality of events existing in the same moment, for causal efficacy must accompany the effect.

As for the answer he proposed, its purport is this: were it not for motion, the objection would indeed be decisive. Motion, however, either occurs without abiding or abides only through continuous origination and renewal; by virtue of that motion the originating and preserving causes terminate in other causes at later times.

In essence, the fact that a thing becomes a cause of another thing’s coming-to-be or persistence—even though that causality itself is an event—is rendered possible by uninterrupted motion. That continuous motion in turn produces further causes for those universals at subsequent moments, so that the causal nexus remains in existence on account of it.