For if the completion of the cause were itself contingent and occurred together with the event, it would follow that the completion of the cause for every event would likewise be a contingent occurrence accompanying it; in that case no event would possess an eternal, sufficient cause at all. Yet the very appearance of such completed causes is impossible on this hypothesis, for it would entail an infinite series of contingent happenings existing simultaneously without a producer, since the only supposed reality present would be an eternal, sufficient cause. This is something even the proponents of that view concede to be impossible, for it implies that events arise with no agent whatsoever.

Accordingly, the notion of an eternal, sufficient cause is false whether one claims that the condition for an event exists prior to it or exists alongside it, because in either case the coming-to-be of those conditions through an eternal, sufficient cause is impossible. Hence it is impossible for any event—or for the conditions required for its occurrence—to arise from an eternal, sufficient cause under any circumstance. Now the doctrine of the world’s eternity necessarily rests on the idea of such an eternal, sufficient cause, and whatever entails falsehood is itself false.

Moreover, every part of the universe is concomitant with some contingent event. Once it is shown that events cannot issue from an eternal, sufficient cause, it becomes clear that no part of the universe can be eternal, for each part exists only in conjunction with a contingent occurrence, and the existence of that occurrence through an eternal, sufficient cause is impossible. This is all the more evident when those philosophers themselves maintain that every event constitutes the completion of the cause of the event preceding it. Consequently, none of the events has a sufficient cause that coincides with it; what coincides is merely a part of the cause—namely, the abiding principle whose effusion is suspended until this particular event occurs, so that the second event does not come about until the first has ceased. Yet that abiding principle is not a sufficient cause for any of the events, not even when it produces the second while the first is still present, and at the occurrence of any event there is, in fact, no sufficient cause at all.

Thus it becomes evident that, in reality, these philosophers are saying that events occur without any sufficient cause—let alone one that is eternal.