THIRD ARTICLE: WHETHER THERE IS ONE SUPREME EVIL WHICH IS THE CAUSE OF ALL EVIL

State of the question. This article is in direct opposition to the Manichaeans, Albigenses, and other heretics who taught a system of dualism. The title inquires directly about the efficient cause of evil. It was in the thirteenth century that the Albigenses were spreading their doctrines in southern France. In the beginning of his article St. Thomas collected the arguments that might be proposed in support of dualism.

First objection. In things we almost everywhere find contrariety; for example, life and death, good and evil, true and false, noble and base. Therefore two contrary principles must be postulated. The reply will be that contraries agree in being.

Second objection. If one of the contraries is in the nature of things, so also is the opposite. But the supreme good exists. Therefore supreme evil also exists. Reply: evil opposes that good which it negates, not that good in which it is.

Third objection. Grades of perfection are judged according as they approach the best or that which is good by essence. So also it should be with grades of evil with regard to the supreme evil. The reply will be that bad and worse are judged according as they recede from good, not as they approach the supreme evil.

Fourth objection. Evil by participation must eventually lead to evil by essence. Reply: there is no evil by participation, but beings that are deprived of some due good.

Fifth objection. Everything that is "per accidens" is ultimately reduced to that which is "per se", and since evil exists in many instances, it must have a cause "per se", namely, the supreme evil. The reply will be that, although evil occurs in many instances in the human race, it is not intended "per se".

Sixth objection. The evil of an effect is traced to the evil in the cause, namely, a deficient cause. But there cannot be an infinite process, and we must eventually come to the first evil cause. The reply will be that evil is traced to some good cause from which the evil ensues "per accidens".

Conclusion: there is not nor can there be a first principle of evil.

This proposition is of faith. (cf. Denz., nos. 234 ff.) St. Thomas' argument "sed contra" refers to the dogma of the creation, according to which God is the cause of all being.

The body of the article contains two parts: the first is strictly theological and proves the conclusion; the second is historical, explaining why the Manichaeans postulated two principles.

The conclusion is proved in three ways:

1. from the notion of good;

2. from the notion of evil;

3. from the notion of the first principle.

1. From the notion of good. Good and being are convertible. But the first evil principle would be evil in essence and in no way good. Therefore this first principle of evil would not be being and would not exist.

The proof of the major was given above.[1141] Every being as being in act is a certain perfection and a good desirable to itself, and thus every being strives to preserve its being. As matter is being in potency, so it is good in potency. Hence no being is said to be being inasmuch as it is evil but inasmuch as it lacks some being. And therefore evil exists only in the good as in a subject.[1142]

2. From the notion of good. If evil were integral being, or if it completely corrupted the good in which it is, it would destroy itself, as Aristotle pointed out, for evil cannot be except in a subject.[1143] But the supreme evil would be integral being.

3. From the notion of first principle. A first principle cannot be caused "per accidens" by another, nor can it be a mere accidental cause. But evil is caused "per accidens" by good, that is, by a defective agent or by a contrary agent, and evil can be a cause only "per accidens", that is, by reason of an annexed good. Therefore the notion of evil is repugnant to the notion of a first principle. And therefore the dualistic position of Manichaeism involves contradictions on all sides.

In the second, historical part of the article St. Thomas explains how the Manichaeans arrived at this solution of this problem of evil. These heretics failed to consider the most universal cause of being as being, that is, the creative cause, and only considered particular efficient and final causes. They did not understand that what is harmful with regard to some particular being, as a viper with regard to man, may be useful with regard to the universal good of the entire universe. Nor were they able to rise above mutually contrary causes to the most universal cause.

In his reply to the fifth difficulty St. Thomas says that the corruptible beings in which there is an evil of nature are a small part of the universe. He reasoned in this way because he thought that the heavenly bodies were incorruptible, but today spectral analysis has shown the opposite to be true. At any rate, after the resurrection of the dead there will be no more corruption.[1144] In this reply he affirms that only in men does evil seem to be in the majority of instances, because there are more who follow the senses than follow reason.

This concludes the questions on evil: what evil is, its kinds, and its cause.