The existence of an action is necessarily positive evidence of the existence of an agens, but does not prove the existence of more than one agens. There is no difference whether the existence of one God be assumed or the existence of two, or three, or twenty, or any number. This is plain and clear. But the argument does not seem to prove the non-existence of a multitude of deities; it only shows that their number is unknown; the deity may be one sole being, but may also include several divine beings. The following supplemental argument has therefore been advanced: possibility is inapplicable to the existence of God, which is absolute; the possibility of the existence of more than one God must therefore be denied. This is the whole essence of the proof, and its fallacy is self-evident; for although the notion of possibility cannot be applied to the existence of God, it can be applied to our knowledge of God: for an alternative in our knowledge of a thing does not involve an alternative in the actual existence of the thing, and perhaps there is neither a tripartite deity as the Christians believe, nor an undivided Unity as we believe. This is clear to those who have been taught to notice the conclusions implied in given premises. Fifth Argument. One of the modern Mutakallemim thought that he found a proof of the Unity of God in the idea of requisiteness. Suppose there were two divine beings; if one of them were able to create the universe, the second God would be superfluous, and there would be no need for his existence. If, on the other hand, the entire universe could not be created or governed except by both of them, each of them would be imperfect in so far as he would require the co-operation of another being, and would thus be limited in power. This argument is, in fact, only a variation of “the mutual neutralization of two deities.” There is this difficulty in such proofs, that a certain degree of imperfection is ascribed to a Being which does not accomplish tasks beyond its sphere. We do not call a person weak because he cannot move a thousand hundredweights, and we do not say that God is imperfect because He cannot transform Himself into a body, or cannot create another being like Himself, or make a square whose diagonal should be equal to one of its sides. In the same manner we should not consider it an imperfection in God, if He were not the only Creator, and if it were absolutely necessary that there should be two Creators; not because the one God required the assistance of the other, but because the existence of both of them was equally necessary, and because it was impossible that it should be otherwise. Further we do not say that the Almighty is imperfect, because He does not, according to the opinion of the Mutakallemim, produce a body otherwise than by the creation of atoms, and by their combination with accidents created in them. That inability is not called want or imperfection, since another process is impossible.