Since, on this assumption, each event had previously been nonexistent, their claim that the universe is eternal collapses. It is therefore evident that, so long as events are continually arising, there cannot have been a fully sufficient cause in pre-eternity. If they object that His originating the second event is conditioned by the first, and so on ad infinitum, we reply: At the very moment any single event comes to be, He is not yet a fully sufficient cause; rather, at every instant some event must exist by virtue of which His sufficiency is completed. If at no moment is He a fully sufficient cause, then the existence of a fully sufficient cause whose efficacy is independent of any event is impossible. Once that notion is negated, the thesis of the world’s eternity falls with it.

To make this clearer in their own terms, they say: “Why may we not posit that the Necessary Existent is perpetually bestowing effusion, except that the emergence of an effect from Him depends on the preparedness of the recipients, and that these various preparednesses depend on celestial motions and planetary conjunctions, each of which is preceded by another without a first? It is for this reason,” they continue, “that change occurs in the universe.” We answer: If the arising of an effect on His part is contingent upon the preparedness of the receptacles, and that preparedness in turn depends on those motions and conjunctions, then those motions and conjunctions are themselves contingent events, just as the preparednesses are contingent events. The argument that proves the contingency of what overflows to the lower receptacles proves equally the contingency of those motions and conjunctions—for all of them are events that begin to exist. Their own reasoning, therefore, entails that nothing should ever come to be, because a fully sufficient cause, being eternal without beginning, would have produced its effects from all eternity.