Commentaria in Summam contra Gentiles, Liber II

The third conclusion is¹: The cause of the distinction of things is not the contrariety of agents. In proving this, Saint Thomas does two things: first, he proves absolutely that the contrariety of agents is not the cause of the distinction of things; second, he shows the same in particular concerning the contrariety of good and evil².

I. As to the first, it is argued first as follows. Either the diverse agents from which the diversity of things proceeds are ordered, or they are not. If the first, then there is one cause of that order, since many things are not united except through some one. Therefore there will be one cause of distinction. If the second, then the distinction of things will be casual, because their concurrence in acting will be accidental.

Note that, when it is said that something happens by chance which occurs beyond the intention of the agent, there will be a distinction by chance if it occurs beyond the intention of the agents. This will be the case, however, if diverse agents have no order among themselves. For one agent intends only its own effect; but that another agent produces another effect will be beyond the intention of this agent. And the same must be said of the other. And thus the distinction of things will be intended neither by one of them nor by both.

Second: and it is a confirmation of the preceding. Distinct things are found to have an order to one another not by chance, since in most cases one is moved by another³: namely, because chance occurs in fewer cases. But there are many distinct things one of which is moved by another in most cases: as these lower bodies are moved by the heavens. Therefore their distinction is not by chance. Therefore it does not come from diverse things that are not ordered.

Third. If several agents are taken as equal, they have a cause of their esse: as is clear from what precedes. Therefore they have a cause of their distinction. Therefore the diversity of such agents cannot be the first cause of the distinction of things.

II. As to the second⁴, it is proved, first, that the contrariety of good and evil is not the cause of the distinction of things, as if all goods proceeded from a good principle and all evils from an evil one; second, it is shown what is the first principle of evils⁵.

It is therefore argued first as follows. If this were so, the active principle of evils would have to be evil of itself and by its essence: for everything that is through another is reduced to what is through itself. But this is impossible. Therefore, etc. The falsity is proved. For everything that is, insofar as it is a being, is good. This is evident, * because each thing desires to preserve its esse; but good is that which all things desire.*

Note that Saint Thomas here speaks of evil not with respect to privation alone, but of what these authors say is a certain being in the nature of things, having its own nature and essence and esse as evil, and the principle of all evils.

Second. That which is evil in itself cannot be an agent. Therefore evil cannot be the first principle of evils. — The consequence is evident, because the first principle of evils is evil in itself. — The antecedent is proved as follows. Every agent, insofar as it is such, is in act. Therefore it is perfect. Therefore it is good. Therefore what is not good is not an agent. Therefore etc.

Third. Evil, insofar as it is evil, is not a being: for every being, insofar as it is a being, is good. Therefore evil, insofar as it is of this sort, has no efficient cause of itself. Therefore etc. The first consequence is proved. For every agent acts insofar as it is in act. And each thing acts so as to produce what is like itself. And thus it must be that what comes to be has esse in act.

Fourth. Evil in its effect cannot arise except apart from the intention of the agent, since every agent intends the good. Therefore evil does not have a cause per se. The consequence is evident. For what comes about apart from the intention of the agent does not have a cause per se, but per accidens.

Fifth⁶. Good and evil are produced by the same action. Therefore, etc. - The consequence is proved. Because things produced by the same action are not contrary principles, since agents that are contrary have contrary actions. - But the antecedent is proved by an example: for by the same action water is corrupted and air is generated.

III. Concerning this proposition, By one and the same action water is corrupted and air is generated, a doubt arises. For the action of an agent through motion or alteration is not materially and according to essence anything other than the very motion and alteration itself. But the corruption of water is not really identical with the generation of air, since they have distinct termini. Therefore it is not by one and the same action that one thing is generated and another corrupted.

2. For the evidence of this, it must be considered, from the doctrine of Saint Thomas in Verit., q. XXVIII, a. 1, that since motion is from an affirmed thing to an affirmed thing, and consequently it is the same motion by which one affirmative signified thing is acquired and the other cast off, there must be joined to the motion two changes, one of which is generation and the other corruption. On this account we can consider in such a passage from one affirmed thing to another either the character of motion or the character of change. If we consider the motion itself, then it is one and the same motion by which one of the opposites is cast off and by which the other is acquired: for motion takes its species and unity from the terminus to which, but not from the terminus from which. But if we consider the very character of change, then it is not one change, but several succeeding one another: because one is terminated at esse, while the other is terminated at non-esse. Nevertheless each change stands to the motion by way of concomitance, and both depend upon one motion.

To the doubt, then, it is said that by one action and one motion water is corrupted and air is generated, because these changes accompany one motion and one action. But when it is argued that the action of the agent, through motion or change, is really nothing other than the motion and the change: it is said that if each is taken per se and separately—that is, motion taken per se and change taken per se—then the action which acts through motion is the very motion itself, and the action which occurs with change is the very change itself. But if the change is taken as accompanying the motion, then the action is indeed the motion, but it is not the change that accompanies the motion, especially that change which terminates in the non-being of the terminus a quo; and yet to one action and to one motion, which is between contrary termini, both changes accompany—the one which is the generation of the one and the corruption of the other. And thus it is true that by one action water is corrupted and air is generated, through their accompaniment of the motion.

IV. Sixth. * Evil, insofar as it is evil, is not a being. But it is not altogether non-being:* for what altogether is not is neither good nor evil. * Therefore it is something insofar as it is not a being. Therefore evil, insofar as it is of this sort, is a privative being:* for non-being that is something is a privative being, and evil itself is the very privation. * Therefore it has no efficient cause per se. Therefore etc.* The antecedent is evident. * For everything that is, insofar as it is, is good; and thus, if evil, insofar as it is of this sort, were a being, then it itself, insofar as it is evil, would be good.*

2. Concerning this proposition, Evil, insofar as it is a non-being, is something, there is doubt: because it seems to involve a contradiction in the predicate. For "something" is convertible with "being," as is clear from De Veritate, q. XXI⁷. To say, therefore, that evil, insofar as it is a non-being, is something, is to say that insofar as it is a non-being, it is a being.

It is answered that ly inquantum can specify the formal ratio by which something is evil. And in this way the proposition is false: for the ratio of a non-being is not the cause why something is evil, as the objection rightly proceeds. - It can also make manifest the genus to whose species it is limited. And in this way ly inquantum is taken in this passage. For the sense is that there belongs to evil this species of non-being which is "something," that is, that it is a privative being insofar as it is contained under non-being. But there does not belong to it that it be that non-being which is altogether non-being. Just as if we were to say that man, insofar as he is contained under the genus animal, determines for himself the species of man, but not the species of horse.

It is further said that such a non-being is something, and is in some way a being, by reason of the substrate, namely because it signifies a negation in a subject.

V. In the second place,⁸ Saint Thomas concludes that the first principle of all evils is the one first good, in whose effects evil follows per accidens, since it has been shown that evil cannot have the character of a first principle. This is proved by the authority of Isaiah 45: I am the Lord, and there is none else etc.; Ecclesiasticus 11: Good things and evil etc.; and chapter 33: Against evil etc.

It should be noted, however, that what is said in God to do evils, or to create them is understood insofar as He creates things that are good in themselves and yet harmful to others, as the wolf to the sheep and fire to water. In this way God is the cause of the evils in men that are called punishments: according to Amos III, If there is evil etc.; and Gregory, Even evils. From these considerations is excluded the error of those who posited contrary first principles, namely efficient or formal ones: as Empedocles did first, then Pythagoras, and finally certain heretics, such as the Marcionites ⁹, Cerdonians, and Manichaeans, posited.

2. Concerning what was said above, namely that the First Good is the first principle of all things, in whose effects evil follows per accidens, a doubt arises. For that which follows per accidens upon the effect of some agent is outside its intention. But nothing is outside the intention in the effects of God, who is the First Good, since, according to the teaching of St. Thomas ¹⁰, nothing, by comparison with him, is fortuitous or accidental. Therefore nothing is per accidens in his effects.

It is answered that something can be said to be accidental in the effect of some cause in two ways: namely, either because it is entirely beyond the intention of the agent, or because it is beyond the agent's first intention. What is accidental in the first way is fortuitous or chance. And in this way no evil of nature is accidental in the effects of God. — But what is accidental only in the second way is not fortuitous and chance, if it occurs in most cases: for it is intended by a secondary intention, as following upon what is intended first and per se. And thus something can be accidental in the effects of God. For first and per se God intends some good in his works; but because sometimes the good intended is accompanied by some evil of nature in some thing, he also intends that evil secondarily, inasmuch as he wills rather that this evil occur than that the universe be deprived of that good to which such an evil is consequent.