Front Page Titles (by Subject) QUESTION LXIV.: OF HOMICIDE. - Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 2 (Summa Theologica - Secunda Secundae Pt.2)
Return to Title Page for Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 2 (Summa Theologica - Secunda Secundae Pt.2)
The Online Library of Liberty
A project of Liberty Fund, Inc.
QUESTION LXIV.: OF HOMICIDE. - St. Thomas Aquinas, Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 2 (Summa Theologica - Secunda Secundae Pt.2) 
Aquinas Ethicus: or, the Moral Teaching of St. Thomas. A Translation of the Principal Portions of the Second part of the Summa Theologica, with Notes by Joseph Rickaby, S.J. (London: Burns and Oates, 1892).
About Liberty Fund:
Liberty Fund, Inc. is a private, educational foundation established to encourage the study of the ideal of a society of free and responsible individuals.
The text is in the public domain.
Fair use statement:
This material is put online to further the educational goals of Liberty Fund, Inc. Unless otherwise stated in the Copyright Information section above, this material may be used freely for educational and academic purposes. It may not be used in any way for profit.
Article I.—Is the killing of living creatures in all cases an unlawful act?
R. No one does wrong in using a thing for the purpose for which it exists. Now in the order of being, less perfect things exist for the sake of the more perfect, as in the way of generation nature proceeds from imperfect to perfect things. Hence it is that as in the generation of man there is first the living thing, then the animal, and lastly the man; so also the things that merely live, as plants, exist generally for the sake of animals; and all animals exist for the sake of man. And therefore if man uses plants for the benefit of animals, and animals for the benefit of mankind, it is not unlawful. But of all uses the most necessary seems to be that animals should use plants for food, and men animals, which cannot be without putting them to death. And therefore it is lawful to do plants to death for the use of animals, and animals to death for the use of men. For it is said: “Behold I have given you every herb and all trees to be your meat, and to all beasts of the earth;”1 and, “Everything that moveth and liveth shall be meat for you.”2
§ 1. By divine ordinance the life of animals and plants is preserved, not for their own sakes, but for the sake of man. Hence as Augustine says, “both their life and their death are subject to our uses.”
§ 2. Dumb animals and plants have no rational life, thereby to be led of themselves; but they are always led as it were of another, by natural impulse; and this is a sign that they are naturally slaves,1 and suited to serve the uses of others.
Article II.—Is it lawful to slay sinners?
R. Every part is referred to the whole as the imperfect to the perfect; and therefore every part naturally exists for the whole. And therefore we see that if it be expedient for the welfare of the whole human body that some member should be amputated, as being rotten and corrupting the other members, the amputation is praiseworthy and wholesome. But every individual stands to the whole community as the part to the whole. Therefore, if any man be dangerous to the community, and be corrupting it by any sin, the killing of him for the common good is praiseworthy and wholesome. For “a little leaven corrupteth the whole lump.”2
§ 1. To preserve the wheat, that is, the good, our Lord has commanded us to abstain from rooting out the cockle,3 teaching us rather to let the wicked live than to let the good be slain with them. But when from the slaying of the wicked there arises no danger to the good, but rather protection and deliverance, then the wicked may be lawfully slain.
§ 2. God, according to the order of His wisdom, sometimes punishes sinners on the spot for the deliverance of the good; sometimes again He leaves them time to repent, according as He knows to be expedient for His elect. And this method of procedure human justice imitates to the best of its power: for those who are ruinous to others it slays; but those who sin without grievous hurt to others, it reserves to repentance.
§ 3. Man by sinning withdraws from the order of reason, and thereby falls from human dignity, so far as that consists in man being naturally free and existent for his own sake; and falls in a manner into the state of servitude proper to beasts, according to that of the Psalm: “Man when he was in honour did not understand: he hath matched himself with senseless beasts and become like unto them;”1 and, “The fool shall serve the wise.”2 And therefore, though to kill a man, while he abides in his native dignity, be a thing of itself evil, yet to kill a man who is a sinner may be good, as to kill a beast. For worse is an evil man than a beast, and more noxious, as the Philosopher says.3
Article III.—Is it lawful for a private person to slay a sinner?
R. The slaying of an evil-doer is lawful inasmuch as it is directed to the welfare of the whole community, and therefore appertains to him alone who has the charge of the preservation of the community; as the amputation of an unsound limb belongs to the surgeon, when the care of the welfare of the whole body has been entrusted to him. Now the care of the common good is entrusted to rulers having public authority; and therefore to them is it lawful to slay evil-doers, not to private individuals.
§ 2. A beast is naturally distinguishable from a man: hence on this point there is no need of judgment whether it ought to be slain, if it is in the wild state; but if it is domesticated, judgment is required, not on the creature’s own account, but for the owner’s loss. But a sinner is not naturally distinguishable from just men; and therefore he needs a public judgment to make him out, and determine whether he ought to be slain for the benefit of the common weal.
§ 3. To do a thing for the public benefit that hurts no man, is lawful to any private person: but if the doing be with the hurt of another, it ought not to be done, except according to the judgment of him to whom it belongs to estimate what is to be withdrawn from the parts for the well-being of the whole.
Article V.—Is it lawful for any man to kill himself?
R. To kill oneself is altogether unlawful, for three reasons. First, because naturally everything loves itself, and consequently everything naturally preserves itself in being, and resists destroying agencies as much as it can. And therefore for any one to kill himself is against a natural inclination, and against the charity wherewith he ought to love himself. And therefore the killing of oneself is always a mortal sin, as being against natural law and against charity. Secondly, because all that any part is, is of the whole. But every man is of the community; and so what he is, is of the community: hence in killing himself he does an injury to the community. Thirdly, because life is a gift divinely bestowed on man, and subject to His power who “killeth and maketh alive.”1 And therefore he who takes his own life sins against God; as he who kills another man’s slave sins against the master to whom the slave belongs; and as he sins who usurps the office of judge on a point not referred to him. For to God alone belongs judgment of life and death, according to the text: “I will kill and I will make to live.”2
§ 1. Homicide3 is a sin, not only as being contrary to justice, but also as being contrary to the charity which a man ought to bear towards himself; and in this respect suicide is a sin in regard to oneself. But in regard to one’s neighbour and to God, it has the character of a sin even against justice.
§ 2. He who holds public authority may lawfully put a malefactor to death, by the fact that he is empowered to judge him. But no one is judge in his own cause. Therefore the holder of public authority is not allowed to put himself to death for any sin; he may however submit himself to the judgment of others.
§ 3. Man is made his own master by free-will; and therefore man may lawfully dispose of himself in things that relate to this life, which is ruled by the free-will of man. But the passage from this life to another and happier one is not subject to the free-will of man, but to the divine power; and therefore it is not lawful for a man to kill himself to pass to a happier life. Neither must he do so to escape any evils of the present life, because the extremest and most terrible of the evils of this life is death, as appears from the Philosopher; and therefore to compass one’s own death in order to avoid the other miseries of this life, is to take the greater evil to escape the less.1 In like manner again it is not lawful to kill yourself for any sin that you have committed, both because thereby you do yourself the direst mischief, taking away from yourself the time necessary for repentance, and also because it is not lawful to put an evil-doer to death except by the judgment of public authority. Nor again is it lawful for a woman to kill herself to save her honour: because she ought not to commit on her own person the greatest crime, which is suicide, to avoid a less crime to be committed by another: for it is no crime of a woman to be ravished by force, if there is no consent of hers; because the body is not defiled except by the consent of the mind, as St. Lucy said. But it is certain that fornication or adultery is a less sin than murder, and especially self-murder, which is the most grievous thing of all, because you harm yourself, whom you are most bound to love; and again the most dangerous thing of all, because no time is left to expiate it by repentance. Again, it is lawful to no one to kill himself for fear of consenting to sin, because evil must not be done that good may come of it,1 or that evil may be escaped, especially less evil and less certain; for it is uncertain whether one will consent to sin in the future, seeing that God is able to deliver a man from sin, no matter what temptation supervenes.
§ 5. It is a point of fortitude not to shrink from being put to death by another for the good gift that virtue is, and for the avoidance of sin; but for a man to put himself to death to escape penal inflictions, has indeed a certain appearance of fortitude, but it is not true fortitude: rather it is a sort of flabbiness of mind unable to endure penal ills, as appears by the Philosopher.2
Article VI.—Is there any case in which it is lawful to kill an innocent man?
R. A man may be looked at in two ways, in himself, and in reference to some other being. Looked at in himself, it is lawful to slay no man; because in every man, even in the sinner, we ought to love the nature which God has made, and which is destroyed by killing. But the slaying of the sinner becomes lawful in reference to the good of the community that is destroyed by sin. On the other hand, the life of the just makes for the preservation and promotion of the good of the community, seeing that they are the chiefer part of the people. And therefore it is nowise lawful to slay the innocent.
§ 3. If a judge knows that a party is innocent, whose guilt is being evidenced by false witnesses, he ought to examine the witnesses more diligently, to find occasion of discharging the unoffending party, as Daniel did. If he cannot do that, he ought to leave him to the judgment of a higher court. If he cannot do that either, he does not sin by passing sentence according to the evidence before him; because it is not he that slays the innocent, but they who assert him to be guilty. But whoever is charged to carry out the sentence of a judge that condemns the innocent, ought not to obey, if the sentence contains intolerable error; otherwise the executioners who put the martyrs to death would be excused. But if the sentence does not involve manifest injustice, he does not sin in doing as he is bid: because it is not his business to discuss the sentence of his superior; nor is it he that slays the innocent, but the judge whose officer he is.1
Article VII.—Is it lawful to slay a man in self-defence?
R. There is nothing to hinder one act having two effects, of which one only is in the intention of the agent, while the other is beside his intention. But moral acts receive their species from what is intended, not from what is beside the intention, as that is accidental. From the act therefore of one defending himself a twofold effect may follow, one the preservation of his own life, the other the killing of the aggressor. Now such an act, in so far as the preservation of the doer’s own life is intended, has no taint of evil about it, seeing that it is natural to everything to preserve itself in being as much as it can. Nevertheless, an act coming of a good intention may be rendered unlawful, if it be not in proportion to the end in view. And therefore, if any one uses greater violence than is necessary for the defence of his life, it will be unlawful. But if he repels the violence in a moderate way, it will be a lawful defence: for according to the Civil and Canon Laws it is allowable “to repel force by force with the moderation of a blameless defence.” Nor is it necessary to salvation for a man to omit the act of moderate defence in order to avoid the killing of another; because man is more bound to take thought for his own life than for the life of his neighbour. But because to kill a man is not allowable except by act of public authority for the common good, it is unlawful for a man to intend to kill another man in order to defend himself, unless he be one who has public authority, who intending to kill a man in order to his own defence, refers this to the public good, as does a soldier fighting against the enemy, or an officer of justice fighting against robbers, though these two sin if they are moved by lust of private vengeance.1
Article VIII.—Is the guilt of homicide incurred by killing a man accidentally?
R. According to the Philosopher, chance is a cause that acts beside the intention. And therefore the events of chance, absolutely speaking, are not intended nor voluntary. And because every sin is voluntary, consequently the events of chance, as such, are not sins. Sometimes however what is not actually and in itself willed or intended, is willed or intended incidentally, inasmuch as what removes an obstacle is called an incidental cause. Hence he who does not remove the conditions from which homicide follows, supposing it to be his duty to remove them, incurs in a manner the guilt of wilful homicide; and this in two ways: in one way when, being engaged upon unlawful actions which he ought to avoid, he incurs homicide; in another way when he does not observe due precaution. And therefore, according to the Civil and Canon Laws, if one is engaged upon a lawful action, taking due care therein, and homicide follows from it, he does not incur the guilt of homicide. But if he is engaged upon an unlawful action, or, being engaged upon a lawful one, neglects to observe due precaution therein, he does not escape the charge of homicide, if the death of a man follows from his doing.
[1 ]Genesis i. 29.
[2 ]Genesis ix. 3.
[1 ]A celebrated phrase of Aristotle, Politics, i. 5. (Trl.)
[2 ]1 Cor. v. 6. On the way in which this corruption works, cf. Ethics and Natural Law, p. 348. St. Thomas puts the abstract lawfulness of slaying sinners first, and the practical limitations to it afterwards. (Trl.)
[3 ]St. Matt. xiii. 29.
[1 ]Psalm xlviii. 15.
[2 ]Prov. xi. 9.
[3 ]On the importance of this remark, see Ethics and Natural Law, p. 350. (Trl.)
[1 ]1 Kings ii. 6.
[2 ]Deut. xxxii. 39.
[3 ]That is to say, suicide. Suicidium does not disfigure the pages of St. Thomas. The word is not in any Latin Dictionary, not even Du Cange’s Glossary. (Trl.)
[1 ]See Ethics and Natural Law, pp. 216, 217, 94, 95. (Trl.)
[1 ]Evil must not be done that good may come of it. This express declaration of St. Thomas is, in so many words, the contradiction of what is so constantly alleged by Protestants to be the teaching of Catholic moralists. See also I-II. q. 20. art. 2. (Trl.)
[2 ]For the arguments against suicide, cf. Ethics and Natural Law, pp. 213—219. It is rash to discard the first of the three arguments that St. Thomas gives. (p. 43.) It is perhaps the best of the three: certainly a very solid and sufficient argument, technically viewed. (Trl.)
[1 ]See further, II-II. q. 67. art. 2. (Trl.)
[1 ]For a vindication of the argument of this important Article, see Ethics and Natural Law, pp. 208—213; also p. 353. (Trl.)