Others, however, held that an endless series of occurrences is inadmissible both in the past and in the future; this is the view of Jahm ibn Ṣafwān and Abū al-Hudhayl al-ʿAllāf. Still others allow such perpetuity in the future but not in the past; this is the position adopted by most of the adherents of Jahm and Abū al-Hudhayl—namely the Jahmites, Muʿtazilites, Ashʿarites, Karrāmites, and whoever agrees with them.

As for an infinite regress of causes, agents, or anything that forms part of the very notion of an agent or efficient cause, it is impossible by the consensus of rational people. To say, for example, that the Maker of the universe has a maker, and that maker has another maker, and so on without end—such a regress is unanimously judged impossible, and we have set forth the rational proofs for its impossibility elsewhere.

Likewise, when one claims, “A contingent event must have a contingent cause, and that cause must in turn have a contingent cause,” then, if what is intended is a particular contingent event, this entails an infinite regress within the very notion of agency; and if what is meant is the entire class of contingent events, it leads to a vicious circle, which is itself impossible.