This difficulty arises only when one assumes an essence that is idle, cut off from acting; if that premise is false, its negation must be true. The regress at issue here is a regress within the agent himself—within what completes his being an agent. Circularity likewise results, for he would not become an agent unless he had already become an agent. It is akin to saying that the maker of the world cannot have another maker, nor that maker yet another, and that he cannot be the maker of himself. Our discussion, however, concerns the element that perfects his agency.

Accordingly, if one claims that he was not a fully sufficient cause and then became one, either the completion of causation must itself have come into being, or we are left with a preference without a preferring cause. For if the sufficient cause was not established from pre-eternity, and the occurrence of events from him does not hinge on a new cause, an ungrounded preference follows. If it does depend on a new cause, the same difficulty reappears; and if that cause depends on yet another, an infinite regress ensues.

Thus the argument boils down to this: either the sufficient cause exists from eternity, or an ungrounded preference is unavoidable, or an impossible regress and circularity must be accepted—one of these three is inescapable. For this reason, many scholastic theologians opted for the ungrounded preference, contending that a willing, powerful agent chooses by virtue of His power alone, or by His power together with an incentive, or that the very act of will selects one of two equal alternatives. This was the answer adopted by the majority of the Muʿtazilites, the Ashʿarites, the Karrāmiyya, and those followers of the four legal schools who agreed with them.