1. _Not to return evil for good._--This is, one may say (all things being equal), the feeblest of the virtues, as to return evil for good constitutes the greatest of wrongs. Say, for example, homicide: is it not evident that the murder of a benefactor is the most abominable of all? that to rob a benefactor is the most horrible of robberies? that the slander of a benefactor is the most criminal of slanders? On the other hand again, not to kill, not to steal, not to slander, not to deceive a benefactor, is the minimum of moral virtue. To abstain from doing harm to him who has done you good, is a wholly negative virtue, which is simply the absence of a crime. We cannot call that gratitude, for gratitude is a positive virtue, not a negative one; it is all in action, and not in omission; but, before being grateful, the first condition at least, is to be not ungrateful. We shall then say that the greatest of crimes is _ingratitude._ It is by reason of this principle that the crimes towards parents are the most odious of all; for we have no greater benefactors than our parents, and without mentioning the crimes nature finds repugnant enough, it is evident that the same kind of harm (wounds, blows, insults, negligence, etc.) will always be more blamable when done to parents than to any other benefactors, and to benefactors in general, than to any other men. 2. _Not to do harm to those who have not done us any._--The violation of this maxim is the second degree of crime and of sin, somewhat less serious than the preceding one, but still odious enough that to abstain from it is, in many cases, a rather feeble virtue. Not to kill, not to steal, not to deceive, not to expose one's self to the punishments of the law, are, indeed, of a very feeble moral value; whilst their contraries constitute the basest and most odious of actions. The kind of vice which injures others without provocation is what is called _injustice_, and when the pleasure of doing wrong is joined thereto, it is called _cruelty_. Cruelty is an injustice which rejoices in the harm done to others; injustice contents itself with taking advantage of it. There is, therefore, a higher degree of evil in cruelty than in injustice pure and simple. The virtue opposed to injustice is _justice_, which has two degrees and two forms: the one negative, which consists simply in abstaining from doing _injury to any one_; the second positive, which consists in _rendering to each his due_. This second form of justice is more difficult than the first, for it is active. It is more difficult to restore to others what we hold as our own, or to pay one's debts, than to abstain from stealing; it is more difficult to speak well of one's rivals, than to abstain from slandering them; it is more difficult to give up one's position to another who deserves it, than to abstain from taking his; and yet there are cases where justice requires one should act instead of simply abstaining.