Imam Sadiq (peace be upon him): Hisham ibn al-Hakam said: One of the questions of a zindiq (heretic) was: "Why is it not permissible that the Creator of the universe be more than one?" He (peace be upon him) said: "Your statement is not free of several possibilities: either both are eternal and strong, or both are weak, or one is strong and the other weak. If both are strong, then why does one of them not repel the other, so that he alone might have lordship? And if you think one of them is strong and the other weak, it is established that the Creator is one, as we say, because the weakness of one of the two you supposed became evident. And when you say that Allah is two, then either they are in agreement in every respect, or they differ in every respect. But when we see creation ordered, the celestial spheres moving, the alternation of night and day and the sun and the moon, the soundness of the affair and its management and the harmony of the matter indicates that the Manager is one. Then it follows for you, if you claim two gods, that they would be three, because there is no escape from a gap between them so that they may be two; and this gap between them becomes a third which is eternal alongside these two gods, and it too must be a god. So it becomes necessary for you to profess three gods while you claim two. And if you claim three gods, what we said about two applies to you, and it is not established unless there are two gaps between them, and by means of the two gaps the three gods you claim become five. Thus the argument ends up at infinitely many gods."