Commentaria in Primam Partem Summae Theologiae

Concerning the order and title of the question, note that perfection does not signify any perfection whatsoever, such as goodness, life, wisdom, etc., nor does it signify all perfections in common (for in asking whether something is perfect, one is not asking whether it has all perfections, whether determinately or indeterminately); rather, it signifies the best mode of being according to whatever formal account; although, since the word has been extended by usage, perfection often stands for a thing or formal account actualizing something, as is clear when we say that wisdom is a perfection, and so on. Strictly speaking, therefore, "perfection," though first derived from total making, among philosophers signifies a mode of being—not any mode whatever, but the best: not of some determinate thing, but of whatever thing it is predicated of, whether substance or accident. For a thing can be understood and be under a manifold mode of being, one of which is better than another: just as the nature of plants and animals has a certain mode of being in the seed, and another mode of being in the generated individuals, and again another in the same when grown, etc.; and it is evident that the first is and is called imperfect, because the specific nature there is only in potency; the second, however, is perfect to some degree; the third, indeed, simply perfect, as is clear in Book IV of the Meteorology¹: for each thing is there said to be perfect when it can produce another such as itself; for then it has its nature in the best way. – Hence, just as to ask whether something is perfect according to this or that account, say science or nature, is not to ask whether it has some other perfection, but whether it has that one in the best way; so too to ask absolutely and without specification, as is done here, whether God is perfect, is not to ask whether God has some perfection, nor whether he has all of them, since this is reserved for the second article; rather, it is to ask whether God, that which is, is in the best way: for this is to be perfect.

II. But he testifies that this is the evident sense of the question by the cause of the response assigned in the body of the article. For it is said that God is perfect because He is not in potency but in act: for it is clear that being in act or in potency pertains to the mode of being. And therefore this question was ordered immediately after the question concerning the simplicity of the divine nature: for once the essence has been established, the question that at once presents itself concerns the intrinsic mode of being of that essence itself, such as the term perfect signifies: for it does not import the mode of being of a thing in respect to something surrounding it, or in any way extrinsic, but in itself. Hence Aristotle also, in I Caeli², treating of the nature of the universe, first determines whether it is perfect: since the questions whether it is, and whether it is simple or composite, which came before, were left as self-evident.

III. In the body there are two parts: first, the opinion of the Pythagoreans is reported; second, a reply is given to the question. – As to the first, there are two points. The opinion: that perfection does not befit a principle. The root: because they understood only material principles. The consequence is proved: because as such it is in potency; therefore.

IV. With respect to the second, likewise two points. The Conclusion, answering the question affirmatively: God is maximally perfect. The Root, opposed to the first: namely, because he is an active principle.

Proof. An agent must be in act; therefore the first agent is most of all in act; therefore it is most perfect. – All of this is evident. And the last inference is made clear from the meaning of the name "perfect," namely that to which nothing of what is required is lacking: for a being in potency lacks what it can be in act, whereas a being in act, as such, lacks nothing.

V. In response to the third, note two things. First, that the reply rests on this distinction: common in two ways, in the manner of act, and in the manner of potency. Commonness in the manner of act consists in being received; commonness in the manner of potency consists in receiving. Now esse is the most common of all in the manner of act: for it is related to all things as the received to the receptive, as is evident. – Second, that from this the defect of Scotus is clear, in Book IV Sent., dist. 1, qu. 1, against this position of St. Thomas, namely that esse, according to its formal ratio, is the most perfect of all perfections, which he argues from its commonness. For it is astonishing that he brings forward this argument in order to conclude it, when St. Thomas had answered it so expressly and so clearly.