its effect being capable of failing to occur, whether the cause acts voluntarily or by nature. If, then, we observe no cause in the world whose effect, distinct from it, must necessarily accompany it as a matter of rational necessity, how can it be known that a complete cause must be accompanied by its effect—let alone that this is known necessarily? This is a judgment without parallel, while the disputed case has not been established.

If he says, “By a complete cause I mean that upon whose existence the effect must exist,” the proposition would then be: “The cause whose effect cannot fail to occur either exists from eternity or does not.” The answer is that no such cause exists from eternity, nor is there among observed beings any cause whose effect cannot fail to occur.

To state this approach precisely: every observed cause that may be posited can rationally exist without its effect. There is no single cause in the world that necessitates an effect at all; rather, an effect follows upon two things, as explained above. Those causes can exist without that effect. Thus, if reason does not judge conclusively that the causes known to it necessitate their effects with an inseparable necessity, it has no basis whatsoever for judging that an effect must accompany its cause as a matter of rational necessity.

The argument then comes back to saying: “If the effect proceeds from Him at one time but not at another, this would be a determination without a determining factor.” This is what we discussed earlier, when we said that they affirmed this concerning Allah by analogy with His creation, despite the difference between them. This answer may be summarized by saying, in