Part 1
4 The gradual abasement of the Soul from Truth to Falsehood by the abuse of her freedom of Choice.
Having departed from the contemplation of the things of thought, and using to the full the several activities of the body, and being pleased with the contemplation of the body, and seeing that pleasure is good for her, she was misled and abused the name of good, and thought that pleasure was the very es sence of good: just as though a man out of his mind and asking for a sword to use against all he met, were to think that soundness of mind. 2. But having fallen in love with pleasure, she began to work it out in various ways. For being by nature mobile, even though she have turned away from what is good, yet she does not lose her mobility. She moves then, no longer according to virtue or so as to see God, but imagining false things, she makes a novel use of her power, abusing it as a means to the pleasures she has devised, since she is after all made with power over herself. 3. For she is able, as on the one hand to incline to what is good, so on the other to reject it; but in rejecting the good she of course entertains the thought of what is opposed to it, for she cannot at all cease from movement, being, as I said before, mobile by nature. And knowing her own power over herself, she sees that she is able to use the members of her body in either direction, both toward what is, or toward what is not. 4. But good is, while evil is not; by what is, then, I mean what is good, inasmuch as it has its pattern in God Who is. But by what is not I mean what is evil, in so far as it consists in a false imagination in the thoughts of men. For though the body has eyes so as to see Creation, and by its entirely harmonious construction to recognise the Creator; and ears to listen to the divine oracles and the laws of God; and hands both to perform works of necessity and to raise to God in prayer; yet the soul, departing from the contemplation of what is good and from moving in its sphere, wanders away and moves toward its contraries. 5. Then seeing, as I said before, and abusing her power, she has perceived that she can move the members of the body also in an opposite way: and so, instead of beholding the Creation, she turns the eye to lusts, showing that she has this power too; and thinking that by the mere fact of moving she is maintaining her own dignity, and is doing no sin in doing as she pleases; not knowing that she is made not merely to move, but to move in the right direction. For this is why an apostolic utterance assures us “All things are lawful, but not all things are expedient.”
5. Evil, then consists essentially in the choice of what is lower in preference to what is higher.
But the audacity of men, having regard not to what is expedient and becoming, but to what is possible for it, began to do the contrary; whence, moving their hands to the contrary, it made them commit murder, and led away their hearing to disobedience, and their other members to adultery instead of to lawful procreation; and the tongue, instead of right speaking, to slander and insult and perjury; the hands again, to stealing and striking fellow-men; and the sense of smell to many sorts of lascivious odours; the feet, to be swift to shed blood, and the belly to drunkenness and insatiable gluttony. 2. All of which things are a vice and sin of the soul: neither is there any cause of them at all, but only the rejection of better things. For just as if a charioteer, having mounted his chariot on the race-course, were to pay no attention to the goal, toward which he should be driving, but, ignoring this, simply were to drive the horse as he could, or in other words as he would, and often drive against those he met, and often down steep places, rushing wherever he impelled himself by the speed of the team, thinking that thus running he has not missed the goal—for he regards the running only, and does not see that he has passed wide of the goal—so the soul too, turning from the way toward God, and driving the members of the body beyond what is proper, or rather, driven herself along with them by her own doing, sins and makes mischief for herself, not seeing that she has strayed from the way, and has swerved from the goal of truth, to which the Christ-bearing man, the blessed Paul, was looking when he said, “I press on toward the goal unto the prize of the high calling of Christ Jesus:” so that the holy man, making the good his mark, never did what was evil.
6. False views of the nature of evil: viz., that evil is something in the nature of things, and has substantive existence. (a) Heathen thinkers: (evil resides in matter). Their refutation. (b) Heretical teachers: (Dualism). Refutation from Scripture.
Now certain of the Greeks, having erred from the right way, and not having known Christ, have ascribed to evil a substantive and independent existence. In this they make a double mistake: either in denying the Creator to be maker of all things, if evil had an independent subsistence and being of its own; or again, if they mean that He is maker of all things, they will of necessity admit Him to be maker of evil also. For evil, according to them, is included among existing things. 2. But this must appear paradoxical and impossible. For evil does not come from good, nor is it in, or the result of, good, since in that case it would not be good, being mixed in its nature or a cause of evil. 3. But the sectaries, who have fallen away from the teaching of the Church, and made shipwreck concerning the Faith, they also wrongly think that evil has a substantive existence. But they arbitrarily imagine another god besides the true One, the Father of our Lord Jesus Christ, and that he is the unmade producer of evil and the head of wickedness, who is also artificer of Creation. But these men one can easily refute, not only from the divine Scriptures, but also from the human understanding itself, the very source of these their insane imaginations. 4. To begin with, our Lord and Saviour Jesus Christ says in His own gospels confirming the words of Moses: “The Lord God is one;” and “I thank you, Father, Lord of heaven and earth.” But if God is one, and at the same time Lord of heaven and earth, how could there be another God beside Him? Or what room will there be for the God whom they suppose, if the one true God fills all things in the compass of heaven and earth? Or how could there be another creator of that, whereof, according to the Saviour's utterance, the God and Father of Christ is Himself Lord. 5. Unless indeed they would say that it were, so to speak, in an equipoise, and the evil god capable of getting the better of the good God. But if they say this, see to what a pitch of impiety they descend. For when powers are equal, the superior and better cannot be discovered. For if the one exist even if the other will it not, both are equally strong and equally weak equally, because the very existence of either is a defeat of the other's will: weak, because what happens is counter to their wills: for while the good God exists in spite of the evil one, the evil god exists equally in spite of the good.
7. Refutation of dualism from reason. Impossibility of two Gods. The truth as to evil is that which the Church teaches: that it originates, and resides, in the perverted choice of the darkened soul.
Source: Against the Heathen (New Advent)