IV. On the Killing of the Innocent

Is it ever lawful to kill an innocent person? - It is never lawful directly to kill an innocent person, whether by private or public authority, even for procuring the public good. For it is an intrinsically evil action, and expressly prohibited by divine law, against charity and against justice, inflicting injury upon God, Society, and neighbor. Exod. 23:7: The innocent and the just you shall not kill. S. Th. 2. 2, q. 64, a. 2 ad 3, a. 6; L. 393; Struggl 11, 32; Lugo d. 10, n. 104.

You will resolve: It is not lawful to kill those lethally wounded, nor any others whatever who are dying, lest they suffer longer; nor the rabid, lest they harm others, provided they can otherwise be restrained from doing harm. The reason is that, according to the well-known maxim, evils are not to be done in order to obtain good. It is not lawful to kill an innocent person in order to satisfy a tyrant demanding his death, even under penalty of the city being overthrown, and even if he should consent to his own death, because he does not have dominion over his own life. More probably, however, he could be compelled to hand himself over to the tyrant for the public good, and probably, if he were unwilling, even be handed over. For he has this obligation for the public good, to expose himself to a danger of this sort. L. 393; Struggl 11. But it would be otherwise if the tyrant should demand a girl to be violated, or sacred books to be burned. For each is intrinsically evil. In the former case the girl would be exposed to the proximate danger of sinning; in the latter there would be contempt of God. Cf. Lugo d. 10, nn. 114-116.

It is not lawful to kill legates or hostages, even if the enemies who sent them have not kept the faith given, and have unjustly killed the hostages or legates sent to them, because they are innocent. L. ib.

Is it lawful at least indirectly to concur in the death of an innocent person?

It is lawful, because of a grave cause, to posit an action good in itself, from which, besides the intention, the death of an innocent person follows. The reason is that then from a proportionate cause the death of the innocent person is merely permitted.

You will resolve: It is lawful in war to direct artillery against the stations of enemies, although from this also some innocent persons are going to suffer death, because their death follows besides the intention. L. 393. If, when an enemy is pursuing, you cannot flee death except through a narrow way, in which someone sitting there would be crushed, nevertheless it is lawful to flee with his danger and destruction, besides your intention, provided however that, if he is an infant, he has been baptized. The same must be said if the aggressor, by placing the body of an infant before himself, protects himself. For if the death of the innocent person follows, it will be imputed to the aggressor. Lugo d. 10, nn. 124-127; Struggl 13; L. 393, 599.

Note: He is not guilty of homicide who, even without cause, but with diligence used, posits an action, even otherwise illicit, which does not of itself bring death, although it is dangerous, but from which death rarely occurs. For then the homicide is altogether fortuitous and involuntary; for example, if a cleric, engaging in prohibited hunting, by chance kills a man, provided he used due diligence that this not happen. But it is otherwise if he posits an action which, although it does not of itself bring death, is nevertheless commonly dangerous, even if diligence is used for guarding against harm. For it is voluntary in its cause, provided however that he foresees it at least confusedly; for example, if someone, for instance, hurls stones with a sling into a public road. Inst. l. 4, t. 3, sections 3, 4, 5; S. Th. 2. 2, q. 64, a. 8; L. 398. By the name of voluntary homicide, where the matter concerns reservation, is understood not homicide culpable in any way whatever, but homicide sought on purpose and procured by design. Otherwise that added word would be altogether useless. Cf. Ithur. Cas. 40, n. 19 seqq.

Is it lawful to kill a drunken or insane aggressor? R. Affirmatively, more probably, unless it is evident to you that he is in the state of mortal sin. The reason is that although a drunken or insane man is not your formally unjust aggressor, nevertheless he is materially unjust, and you preserve your right of repelling force by force. The right of defense arises from the right to one's own life, not from the injustice of the other. But if you know certainly, which is rare, that he is in the state of lethal sin, and there is hope that he will do penance after the frenzy or drunkenness, but on the contrary you morally believe that you are in the state of grace, since he is in extreme necessity, charity requires that you prefer his eternal salvation to the preservation of your temporal life. Yet nothing prevents you from striking or wounding him in such a way that, with his life preserved, you take away from him the power of harming. Lugo d. 10, n. 143.