77-78 The Platonists hold as a fundamental postulate that every created thing has three kinds of being. The three are given different names by different Platonists, but they all mean the same thing. For present purposes we can use the following terms for them: causal being, formal being, and participated being.
...This distinction among three kinds of being should be noted carefully, for it sheds much light on the understanding of Platonic philosophy, and we shall refer to it often.
77 Of these three kinds of being, the highest and most perfect causal being. Accordingly the Platonists believe that all of the powers which are commonly attributed to God exist in Him only in the causal mode of being. Thus they say that God is not Himself being but the cause of all being, and similarly that God is not Himself intellect. Statements such as these can give a modern Platonist a good deal of trouble if he does not understand the principle behind them. I remember that a great Platonist once told me that he was amazed by a passage in which Plotinus says that God understands nothing and knows nothing. It is perhaps even more amazing that my Platonist did not understand in what sense Plotinus means that God does not understand: Plotinus simply means that the attribute of understanding exists in God in its causal being rather than in its formal being. Plotinus is not denying that God understands; he is only attributing to him understanding of a higher and more perfect kind. That this is the case can be clearly understood from the following. Dionysius the Areopagite, the prince of the Christian theologians, says in one place that God knows not only Himself but also every smallest particular thing; but elsewhere Dionysius uses the same manner of speaking that Plotinus uses, saying that God is not an intellectual or intelligent creature, but is ineffably exalted above all intellect and cognition.
108 the ancients called the Angelic Mind, adorned with the Ideas, paradise… they referred to people as being “in Paradise” if they lived a completely non-physical intellectual life, and, having already risen above human nature and become like angels, lived in contemplation alone.
Above these three hypostases is God Himself, the author and cause of every creature. The Attribute of divinity has its causal being in God, its original source. Proceeding directly from Him, divinity has its second or formal being in the Angelic hypostasis
81 The Platonists and the ancient philosophers Hermes Trismegistus and Zoroaster call this first creature sometimes “son of God,” sometimes “Wisdom,” sometimes “Mind,” and sometimes “Divine Reason,” which some even interpret as “the word.” But everyone should be careful not to suppose that this “word” is the “Word” that our theologians call the “Son of God.” For what we mean by “the Son” is of one and the same essence as the Father, is equal to him in everything, and, lastly, is a creator and a creature; whereas what the Platonists call “the son of God” must be identified with the first and noblest angel created by God.
107 God alone, who is derived from nothing and from whom all things are derived, is a wholly simple and individual essence… Therefore an angel is not unity itself, or else he would be God, or there would be many gods, which cannot even be conceived. For what will be one if not a unity? It is left for an angel to be a number. But if it is, it is a number in one aspect and a multiplicity in another. Every number, however, is imperfect insofar as it is a multiplicity, but perfect so far as it is one. Therefore, whatever is imperfect in an angel let us ascribe to the angels’ multiplicity, which it has from being a number, that is, a creature; and whatever is perfect to its participation in unity, which it has from being associated with God.
In an angel we find a double imperfection: the one, that it is not being itself but only an essence to which being comes by participation, so that it may be; the other, that it is not intelligence itself but only happens to understand, since by its nature it is an intellect capable of understanding. The second imperfection, however, depends on the first, since what does not exist of itself, certainly does not understand by itself, since there can be nothing where being itself is not. Therefore both of these imperfections befall an angel insofar as it is a multiplicity. It remains for its perfection and completion to be produced by unity coming from above. God is the unity from which angels draw their being, their life, and all their perfection.
Any number, after unity, is perfected and completed by unity. Unity along, completely simple, perfected by itself, does not go beyond itself but in its individual and solitary simplicity is composed of itself, since it is self-sufficient, in want of nothing, and full of its own riches. Since number by its nature is manifold, it is simple--so for as it is capable of simplicity--only by virtue of unity; and although every number falls into ever greater multiplicity the further it is removed from unity, and the more diversity, the more parts, and the more compoundness there is in it; nevertheless, none is so close to unity as not to be a multiple, having only an accidental unity and being one not by nature but by composition.
Let us apply these notions to divine things, after the Pythagorean custom. God alone, who is derived from nothing and from whom all things are derived, is a wholly simple and individual essence. Whatever he has, he has from himself. For the same reason that he exists, he knows, wills, and is good and just. We cannot understand any reason why he exists except that he is being itself. Other things are not being itself, but exist by means of it.
109 An angel, from what we have said, has perfectly realized his own nature and intellectual qualities. Nevertheless, he does not have a way to fulfill his functions of understanding and contemplation unless he is first surrounded by God with intelligible forms. For this reason the darkness has hitherto been upon the face of the deep.