The leading representatives of rational inquiry—whether philosophers, scholastic theologians, or those who chose the exalted prophetic path—understood that unalloyed reason coincides with sound revelation. Accordingly, they spoke in the light of reason on both issues and affirmed what the messengers had affirmed: that the heavens and the earth were created in six days; that God alone is the Creator, Lord, and Sovereign of everything; and that nothing besides Him shares eternity with Him—for all else is originated, brought into being after previously not existing. At the same time, they held that preferring one of two identical alternatives cannot occur without a determining factor, making no distinction in this respect between one determiner and another. They further maintained that whatever God wills comes to pass and whatever He does not will never occurs.

By means of a clear, rational proof they established the origination of everything other than God without having to claim that, in pre-eternity, God was incapable of acting; without saying that an act was once impossible and then became possible without anything new arising; and without asserting that events occur with absolutely no cause. They also rejected the idea that the Maker of the world acts by sheer necessity as an eternal cause inseparable from its effect. They argued that every contingent entity that is not prior to temporal events is itself originated along with them, for an infinite succession of such events is impossible—and originated things cannot proceed from an agent whose action is necessitated by His very essence. Once the notion of a self-necessitating cause is dismissed, the temporal origination of every contingent being follows: if any contingent thing were eternal, it would require a complete, eternal determiner—but since the condition for eternity is impossible for anything contingent, no contingent being can be eternal. The details of this argument are elaborated elsewhere.

Our purpose here, however, is to note that many speculative thinkers and theologians—among them al-Ashʿarī and others—denied the existence of the causes, natures, and inherent powers that God has placed within His creation and command, and consequently they denied the divine wisdom intended through them.