extending without end, or contingent beings extending without end, each of which has its existence determined by, or is an effect of, another,” the mind imagines that this entails positing things existing in external reality, each an effect of another existing thing, and that this continues without end.

For this reason, some have sought to refute this infinite regress by the same kind of argument they use to refute an endless succession of effects, such as motions continuing without end. This is mistaken. What is being posited consists of things none of which exists through itself; rather, each exists only through an existing cause distinct from it, and all are in this condition without end.

In reality, this amounts to positing nonexistent things, each a cause of another’s existence, without end, yet without any of them existing. Similarly, if a nonexistent thing has no reality, positing that it nevertheless exists amounts to combining two contradictories. And if positing a nonexistent effect through a nonexistent cause that necessitates its existence, while the effect does not exist, is self-evidently impossible to reason—both because the effect does not exist and because its cause does not exist—then a multiplicity of such causes is all the more impossible, and their succession without end is more impossible still. Likewise, if something is posited as a contingent effect that exists only through something that brings it into existence, and it is also posited that nothing exists to bring it into existence, then its existence is impossible. If it is nevertheless posited as existing, this would be