Some people have supposed that investigating whether the chain of efficient causes must come to an end is no different from investigating whether the chain of effects must come to an end. A group of dialectical theologians adopted this notion, and some of them argued, “If no conclusive proof shows that a finite series of effects is untenable, then by the same reasoning a finite series of causes is likewise tenable.”

This is the line Abu Ḥāmid al-Ghazālī follows in his refutation of the philosophers in The Incoherence of the Philosophers, where he maintains that their admission of the possibility of events with no first beginning logically entails the possibility of an endless succession of causes.

Many mutakallimūn among the Muʿtazilah, together with some Ashʿarīs, Karrāmīs, and a number of jurists from the Ḥanafī, Mālikī, Shāfiʿī, and Ḥanbalī schools, having equated the two questions, relied—concerning the regress of causes and effects—on certain well-known arguments. Yet many of them then proceeded to invalidate those very arguments, to the extent that one and the same scholar will present a particular proof in one work and dismantle it in another, as Abū ʿAbd Allāh ibn al-Khaṭīb and others do, affirming it in one book