evil out of the evil treasure of his heart.”24 What, then, is an evil man but an evil entity natura mala, since man is an entity? Now, if a man is something good because he is an entity, what, then, is a bad man except an evil good? When, however, we distinguish between these two concepts, we find that the bad man is not bad because he is a man, nor is he good because he is wicked. Rather, he is a good entity in so far as he is a man, evil in so far as he is wicked. Therefore, if anyone says that simply to be a man is evil, or that to be a wicked man is good, he rightly falls under the prophetic judgment: “Woe to him who calls evil good and good evil.” For this amounts to finding fault with God’s work, because man is an entity of God’s creation. It also means that we are praising the defects in this particular man because he is a wicked person. Thus, every entity, even if it is a defective one, in so far as it is an entity, is good. In so far as it is defective, it is evil.
14. Actually, then, in these two contraries we call evil and good, the rule of the logicians fails to apply.25 No weather is both dark and bright at the same time; no food or drink is both sweet and sour at the same time; no body is, at the same time and place, both white and black, nor deformed and well-formed at the same time. This principle is found to apply in almost all disjunctions: two contraries cannot coexist in a single thing. Nevertheless, while no one maintains that good and evil are not contraries, they can not only coexist, but the evil cannot exist at all without the good, or in a thing that is not a good. On the other hand, the good can exist without evil. For a man or an angel could exist and yet not be wicked, whereas there cannot be wickedness except in a man or an angel. It is good to be a man, good to be an angel; but evil to be wicked. These two contraries are thus coexistent, so that if there were no good in what is evil, then the evil simply could not be, since it can have no mode in which to exist, nor any source from which corruption springs, unless it be something corruptible. Unless this something is good, it cannot be corrupted, because corruption is nothing more than the deprivation of the good. Evils, therefore, have their source in the good, and unless they are parasitic on something good, they are not anything at all. There is no other source whence an evil thing can come to be. If this is the case, then, in so far as a thing is an entity, it is unquestionably good. If it is an incorruptible entity, it is a great good. But even if it is a corruptible entity, it still has no mode of existence except as an aspect of something that is good. Only by corrupting something good can corruption inflict injury.
15. But when we say that evil has its source in the good, do not suppose that this denies our Lord’s judgment: “A good tree cannot bear evil fruit.”26 This cannot be, even as the Truth himself declareth: “Men do not gather grapes from thorns,” since thorns cannot bear grapes. Nevertheless, from good soil we can see both vines and thorns spring up. Likewise, just as a bad tree does not grow good fruit, so also an evil will does not produce good deeds. From a human nature, which is good in itself, there can spring forth either a good or an evil will. There was no other place from whence evil could have arisen in the first place except from the nature—good in itself—of an angel or a man. This is what our Lord himself most clearly shows in the passage about the trees and the fruits, for he said: “Make the tree good and the fruits will be good, or make the tree bad and its fruits will be bad.”27 This is warning enough that bad fruit cannot grow on a good tree nor good fruit on a bad one. Yet from that same earth to which he was referring, both sorts of trees can grow.
Chapter V.
The Kinds and Degrees of Error
16. This being the case, when that verse of Maro’s gives us pleasure,
“Happy is he who can understand the causes of things,”28
it still does not follow that our felicity depends upon our knowing the causes of the great physical processes in the world, which are hidden in the secret maze of nature,
“Whence earthquakes, whose force swells the sea to flood, so that they burst their bounds and then subside again,”29
and other such things as this.
But we ought to know the causes of good and evil in things, at least as far as men may do so in this life, filled as it is with errors and distress, in order to avoid these errors and distresses. We must always aim at that true felicity wherein misery does not distract, nor error mislead. If it is a good thing to understand the causes of physical motion, there is nothing of greater concern in these matters which we ought to understand than our own health. But when we are in ignorance of such things, we seek out a physician, who has seen how the secrets of heaven and earth still remain hidden from us, and what patience there must be in unknowing.
17. Although we should beware of error wherever possible, not only in great matters but in small ones as well, it is impossible not to be ignorant of many things. Yet it does not follow that one falls into error out of ignorance alone. If someone thinks he knows what he does not know, if he approves as true what is actually false, this then is error, in the proper sense of the term. Obviously, much depends on the question involved in the error, for in one and the same question one naturally prefers the instructed to the ignorant, the expert to the blunderer, and this with good reason. In a complex issue, however, as when one man knows one thing and another man knows something else, if the former knowledge is more useful and the latter is less useful or even harmful, who in this latter case would not prefer ignorance? There are some things, after all, that it is better not to know than to know. Likewise, there is sometimes profit in error—but on a journey, not in morals.30 This sort of thing happened to us once, when we mistook the way at a crossroads and did not go by the place where an armed gang of Donatists lay in wait to ambush us. We finally arrived at the place where we were going, but only by a roundabout way, and upon learning of the ambush, we were glad to have erred and gave thanks to God for our error. Who would doubt, in such a situation, that the erring traveler is better off than the unerring brigand? This perhaps explains the meaning of our finest poet, when he speaks for an unhappy lover:
“When I saw her I was undone,
and fatal error swept me away,”31
for there is such a thing as a fortunate mistake which not only does no harm but actually does some good.
But now for a more careful consideration of the truth in this business. To err means nothing more than to judge as true what is in fact false, and as false what is true. It means to be certain about the uncertain, uncertain about the certain, whether it be certainly true or certainly false. This sort of error in the mind is deforming and improper, since the fitting and proper thing would be to be able to say, in speech or judgment: “Yes, yes. No, no.”32 Actually, the wretched lives we lead come partly from this: that sometimes if they are not to be entirely lost, error is unavoidable. It is different in that higher life where Truth itself is the life of our souls, where none deceives and none is deceived. In this life men deceive and are deceived, and are actually worse off when they deceive by lying than when they are deceived by believing lies. Yet our rational mind shrinks from falsehood, and naturally avoids error as much as it can, so that even a deceiver is unwilling to be deceived by somebody else.33 For the liar thinks he does not deceive himself and that he deceives only those who believe him. Indeed, he does not err in his lying, if he himself knows what the truth is. But he is deceived in this, that he supposes that his lie does no harm to himself, when actually every sin harms the one who commits it more that it does the one who suffers it.
Chapter VI.
The Problem of Lying
18. Here a most difficult and complex issue arises which I once dealt with in a large book, in response to the urgent question whether it is ever the duty of a righteous man to lie.34 Some go so far as to contend that in cases concerning the worship of God or even the nature of God, it is sometimes a good and pious deed to speak
