It is said: The issue of how the full complement of those effects comes into existence is exactly the same as the issue concerning any one of these accidents. If what necessitates its origination is itself originated, an infinite regress of causes follows; and if it is eternal, this entails the emergence of events from an eternal being. If one says that the necessitating factor is the Eternal, but only on condition of a contingent event, the reply is that this, together with your claim that the Eternal is a complete cause, is untenable—for a complete cause cannot have anything newly arise from it, and therefore none of the conditions can originate from it either.

Furthermore, in your view the cause must be concomitant with its effect—neither preceding it nor following it. Thus, if the Eternal is said to cause the second event on the condition that the first has occurred, the cause would then precede its effect. This is precisely the argument advanced by al-Rāzī, for he said: “Every originated thing must have its complete cause present when it exists, even if some of the cause’s components precede it.” Therefore, if you regard every accident as a component of, or a condition for, the cause of the next one—and that component or condition is part of the complete cause—those originated conditions would have to be present whenever any event occurs. This would entail that successive events exist simultaneously, which is impossible.

In sum, their assertion that the complete cause is accompanied by its effect and that the First Being is such a complete cause entails that nothing can originate from the First. It also entails that the full cause of every event is realized only when the event itself occurs, so its complete cause is not prior to it. This contradicts their claim that the first event is a condition for the complete cause of the second, for the first precedes the second, and what precedes something cannot be part of its complete cause.