Those among the Muʿtazilah and others who dispute this, saying that it does not reach the level of necessity, but that reason favors existence over nonexistence, nevertheless do not dispute that a particular effect produced by an agent possessing power and choice cannot be beginningless and coexist with that agent. Indeed, neither they nor anyone else disputes this. It is therefore clear that, if anything other than Allah were beginningless, it would necessarily have a complete cause entailing its existence from all eternity—whether this is called a complete cause or a cause that necessitates by its very essence, or is conceived as an agent acting by will whose particular willed effect is beginningless and coexists with it.

That being so, we say:

The existence of a beginningless complete cause is impossible. A beginningless complete cause necessarily entails its effect; no part of its effect can fail to accompany it. If any part failed to accompany it, it would not be a complete cause of its effect. Thus, one and the same thing cannot necessitate an effect by its very essence while that effect, or any part of it, fails to accompany it. For whatever necessitates something by its very essence must coexist with the entirety of what it necessitates. A complete cause is one whose effect accompanies it, with no part of that effect coming later. If any part of its effect came later, it would not be a complete cause of that delayed part.

The philosophers concede that there is no complete cause from all eternity for all the events that arise one after another, for that would entail a contradiction. It is impossible for a beginningless complete cause to produce something that originates from it and is not itself beginningless.