CHAPTER III
ON JUSTIFIABLE HOMICIDE
I. IN defence of my own life from unjust attack I may use whatever violence is necessary and even go to the length of killing the aggressor, if I cannot otherwise save my life. This right of self-defence all laws, human and divine, concede, as Innocent III declared. Nature herself teaches us that an act which is necessary for self-defence is lawful, and even if it lead to the taking of the life of the unjust aggressor it does not cease to be lawful. A higher value must be set on the life of the innocent than on that of the guilty, especially when the guilty one is the cause of his life being put in jeopardy. No one is justified in using greater violence than is necessary for the purpose of self-defence, so that if by striking or wounding an assailant of my life I can effectually defend myself, I am not justified in killing him. On the same principle no private person can take vengeance for violence which has already been done, by offering violence in return; vindictive justice is reserved for public authority, at any rate in more serious matters. Nor may one whose life is threatened anticipate the attack; defence is only lawful when the attack is practically being made or is at any rate imminent. Unless the attack is practically imminent it is always possible to resort to other means than homicide for the defence of one's own life; one may invoke the protection of the law or at least fly the intending assailant.
2. Under the same limitations it is lawful to kill the assailant not only of one's life, but also of limb, of chastity, and of property. For all these goods belonging to an innocent person may be lawfully defended by him even at the cost of the life of the unjust assailant of them, who is responsible for his own death by his unwarrantable action. When it is said that we may kill an unjust assailant in defence of property, it is supposed that the property which is threatened is of considerable amount. Innocent XI condemned a proposition which asserted that, " As a rule I may kill a thief for the preservation of a gold piece." This proposition is false, for a rich man would not be justified in shooting a thief whom he
