The first premise of this demonstration is really the...

The first premise of this demonstration is really the conclusion of the Demonstration of the Sincere, for from the above demonstration it was concluded that the chain of levels of existence must terminate in a level which is the highest and most perfect in which there is no weakness or imperfection, that is, it possesses infinite perfection.

With a bit of attention, the second premise becomes clear, for if it is assumed that such an existent is numerous, this would imply that each of them lacks entified perfections of the other, that is, the perfections of each of them would be limited and finite, while according to the first premise, the perfections of the Necessary Existent are infinite.

It might be imagined that the infinity of the perfections of the Necessary Existent implies that no other existent occurs at all, for the occurrence of any other existent would mean the possession of a part of the perfections of existence. The answer to this objection is that the perfections of other levels, all of which are created by the Necessary Existent, are the rays of His perfections and their existences do not interfere with the infinite perfections of the Necessary Existent.

However, if another Necessary Existent is assumed, the perfections of their existences would interfere with one another, because each of them possesses a perfection which is original and independent, and neither of them would be a radiance of or subordinate to the other. In other words, two objective perfections will interfere with one another when it is assumed that they are of the same level, but if one is vertically above another it will not interfere with it.

Therefore, the existence of creatures does not contradict the infinity of the perfections of the Creator. It is not the case that when a perfection is added to a creature, it is given up by the Creator and the Creator Himself comes to lack it. But the assumption of the existence of two Necessary Existents, or the infinity of their perfections are contradictory.

This point also can be made as follows: the assumption of two independent objective perfections is incompatible with the assumption that each of them is infinite. However, if one of them is the very dependency and relation to the other or is considered to be the radiance and manifestation of the other, there will be no contradiction with the infinity of the other that possesses independence and absolute needlessness.