then one of His effects would have to accompany Him from all eternity. This alone refutes their claim and proves that nothing in the universe can be co-eternal with Him.
Moreover, if His act of bringing things into being were dependent on something other than Himself, that would entail either a vicious circle of antecedent causes or an infinite regress of efficient causes—both rejected by all rational people. For if that “other” were itself produced by Him, an anterior circle would arise; and if it were not produced by Him, an infinite regress would follow. In that case His causation would be contingent on that “other.” If that other is contingent, it too requires a Necessary Being, and the argument repeats itself. If, on the other hand, that other is necessary in and of itself, then the causal efficacy of each of the two Necessary Beings would depend on the efficacy of the other: neither would act until the other rendered it active, and vice-versa, so that neither of them would truly be an agent. The full treatment of this matter is set out elsewhere.
Our purpose here is simply to demonstrate that their view is even more erroneous than that of their opponents, and that the very principle on which they build their case—that a complete cause must be concomitant with its effect, and an effect must be concomitant with a complete cause—overturns their own argument and doctrine. For it implies that the complete cause did not stand as a complete cause for any contingent event until that event itself came to be.
Consequently, before that moment He was not a complete cause; then He became one, shifting from non-causation to actual causation without, according to them, any change occurring in Him or anything issuing from Him at all. When they say that the motions of the celestial spheres are the condition for His efficacy, or that the newly occurring conceptions and volitions of the celestial soul are the condition, or that every event is the condition for the one that follows it, their claim is invalid in two respects: