QUESTION 64: OF MURDER
In due sequence we must consider the vices opposed to commutative
justice. We must consider (1) those sins that are committed in relation
to involuntary commutations; (2) those that are committed with regard to
voluntary commutations. Sins are committed in relation to involuntary
commutations by doing an injury to one's neighbor against his will: and
this can be done in two ways, namely by deed or by word. By deed when
one's neighbor is injured either in his own person, or in a person
connected with him, or in his possessions.
We must therefore consider these points in due order, and in the first
place we shall consider murder whereby a man inflicts the greatest injury
on his neighbor. Under this head there are eight points of inquiry:
(1) Whether it is a sin to kill dumb animals or even plants?(2) Whether
it is lawful to kill a sinner?
(3) Whether this is lawful to a private individual, or to a public
(4) Whether this is lawful to a cleric?
(5) Whether it is lawful to kill oneself?
(6) Whether it is lawful to kill a just man?
(7) Whether it is lawful to kill a man in self-defense?
(8) Whether accidental homicide is a mortal sin?
Article 1: Whether it is unlawful to kill any living thing?
Objection 1: It would seem unlawful to kill any living thing. For the Apostle
says (Rm. 13:2): "They that resist the ordinance of God purchase to
themselves damnation [*Vulg.: 'He that resisteth the power, resisteth the
ordinance of God: and they that resist, purchase themselves
damnation.']." Now Divine providence has ordained that all living things
should be preserved, according to Ps. 146:8,9, "Who maketh grass to grow
on the mountains . . . Who giveth to beasts their food." Therefore it
seems unlawful to take the life of any living thing.
Objection 2: Further, murder is a sin because it deprives a man of life. Now
life is common to all animals and plants. Hence for the same reason it is
apparently a sin to slay dumb animals and plants.
Objection 3: Further, in the Divine law a special punishment is not appointed save for a sin. Now a special punishment had to be inflicted, according to the Divine law, on one who killed another man's ox or sheep (Ex. 22:1). Therefore the slaying of dumb animals is a sin.
On the contrary, Augustine says (De Civ. Dei i, 20): "When we hear it
said, 'Thou shalt not kill,' we do not take it as referring to trees, for
they have no sense, nor to irrational animals, because they have no
fellowship with us. Hence it follows that the words, 'Thou shalt not
kill' refer to the killing of a man."
I answer that, There is no sin in using a thing for the purpose for
which it is. Now the order of things is such that the imperfect are for
the perfect, even as in the process of generation nature proceeds from
imperfection to perfection. Hence it is that just as in the generation of
a man there is first a living thing, then an animal, and lastly a man, so
too things, like the plants, which merely have life, are all alike for
animals, and all animals are for man. Wherefore it is not unlawful if man
use plants for the good of animals, and animals for the good of man, as
the Philosopher states (Polit. i, 3).
Now the most necessary use would seem to consist in the fact that
animals use plants, and men use animals, for food, and this cannot be
done unless these be deprived of life: wherefore it is lawful both to
take life from plants for the use of animals, and from animals for the
use of men. In fact this is in keeping with the commandment of God
Himself: for it is written (Gn. 1:29,30): "Behold I have given you every
herb . . . and all trees . . . to be your meat, and to all beasts of the
earth": and again (Gn. 9:3): "Everything that moveth and liveth shall be
meat to you."
Reply to Objection 1: According to the Divine ordinance the life of animals and
plants is preserved not for themselves but for man. Hence, as Augustine
says (De Civ. Dei i, 20), "by a most just ordinance of the Creator, both
their life and their death are subject to our use."
Reply to Objection 2: Dumb animals and plants are devoid of the life of reason
whereby to set themselves in motion; they are moved, as it were by
another, by a kind of natural impulse, a sign of which is that they are
naturally enslaved and accommodated to the uses of others.
Reply to Objection 3: He that kills another's ox, sins, not through killing the
ox, but through injuring another man in his property. Wherefore this is
not a species of the sin of murder but of the sin of theft or robbery.
Article 2: Whether it is lawful to kill sinners?
Objection 1: It would seem unlawful to kill men who have sinned. For our Lord
in the parable (Mt. 13) forbade the uprooting of the cockle which denotes
wicked men according to a gloss. Now whatever is forbidden by God is a
sin. Therefore it is a sin to kill a sinner.
Objection 2: Further, human justice is conformed to Divine justice. Now
according to Divine justice sinners are kept back for repentance,
according to Ezech. 33:11, "I desire not the death of the wicked, but
that the wicked turn from his way and live." Therefore it seems
altogether unjust to kill sinners.
Objection 3: Further, it is not lawful, for any good end whatever, to do that
which is evil in itself, according to Augustine (Contra Mendac. vii) and
the Philosopher (Ethic. ii, 6). Now to kill a man is evil in itself,
since we are bound to have charity towards all men, and "we wish our
friends to live and to exist," according to Ethic. ix, 4. Therefore it is
nowise lawful to kill a man who has sinned.
I answer that, As stated above (Article ), it is lawful to kill dumb animals, in so far as they are naturally directed to man's use, as the imperfect is directed to the perfect. Now every part is directed to the whole, as imperfect to perfect, wherefore every part is naturally for the sake of the whole. For this reason we observe that if the health of the whole body demands the excision of a member, through its being decayed or infectious to the other members, it will be both praiseworthy and advantageous to have it cut away. Now every individual person is compared to the whole community, as part to whole. Therefore if a man be dangerous and infectious to the community, on account of some sin, it is praiseworthy and advantageous that he be killed in order to safeguard the common good, since "a little leaven corrupteth the whole lump" (1 Cor. 5:6).
Reply to Objection 1: Our Lord commanded them to forbear from uprooting the
cockle in order to spare the wheat, i.e. the good. This occurs when the
wicked cannot be slain without the good being killed with them, either
because the wicked lie hidden among the good, or because they have many
followers, so that they cannot be killed without danger to the good, as
Augustine says (Contra Parmen. iii, 2). Wherefore our Lord teaches that
we should rather allow the wicked to live, and that vengeance is to be
delayed until the last judgment, rather than that the good be put to
death together with the wicked. When, however, the good incur no danger,
but rather are protected and saved by the slaying of the wicked, then the
latter may be lawfully put to death.
Reply to Objection 2: According to the order of His wisdom, God sometimes slays
sinners forthwith in order to deliver the good, whereas sometimes He
allows them time to repent, according as He knows what is expedient for
His elect. This also does human justice imitate according to its powers;
for it puts to death those who are dangerous to others, while it allows
time for repentance to those who sin without grievously harming others.
Reply to Objection 3: By sinning man departs from the order of reason, and
consequently falls away from the dignity of his manhood, in so far as he
is naturally free, and exists for himself, and he falls into the slavish
state of the beasts, by being disposed of according as he is useful to
others. This is expressed in Ps. 48:21: "Man, when he was in honor, did
not understand; he hath been compared to senseless beasts, and made like
to them," and Prov. 11:29: "The fool shall serve the wise." Hence,
although it be evil in itself to kill a man so long as he preserve his
dignity, yet it may be good to kill a man who has sinned, even as it is
to kill a beast. For a bad man is worse than a beast, and is more
harmful, as the Philosopher states (Polit. i, 1 and Ethic. vii, 6).
Article 3: Whether it is lawful for a private individual to kill a man who has sinned?
Objection 1: It would seem lawful for a private individual to kill a man who
has sinned. For nothing unlawful is commanded in the Divine law. Yet, on
account of the sin of the molten calf, Moses commanded (Ex. 32:27): "Let
every man kill his brother, and friend, and neighbor." Therefore it is
lawful for private individuals to kill a sinner.
Objection 2: Further, as stated above (Article , ad 3), man, on account of sin, is
compared to the beasts. Now it is lawful for any private individual to
kill a wild beast, especially if it be harmful. Therefore for the same
reason, it is lawful for any private individual to kill a man who has
Objection 3: Further, a man, though a private individual, deserves praise for
doing what is useful for the common good. Now the slaying of evildoers is
useful for the common good, as stated above (Article ). Therefore it is
deserving of praise if even private individuals kill evil-doers.
On the contrary, Augustine says (De Civ. Dei i) [*Can. Quicumque
percutit, caus. xxiii, qu. 8]: "A man who, without exercising public
authority, kills an evil-doer, shall be judged guilty of murder, and all
the more, since he has dared to usurp a power which God has not given
I answer that, As stated above (Article ), it is lawful to kill an evildoer
in so far as it is directed to the welfare of the whole community, so
that it belongs to him alone who has charge of the community's welfare.
Thus it belongs to a physician to cut off a decayed limb, when he has
been entrusted with the care of the health of the whole body. Now the
care of the common good is entrusted to persons of rank having public
authority: wherefore they alone, and not private individuals, can
lawfully put evildoers to death.
Reply to Objection 1: The person by whose authority a thing is done really does
the thing as Dionysius declares (Coel. Hier. iii). Hence according to
Augustine (De Civ. Dei i, 21), "He slays not who owes his service to one
who commands him, even as a sword is merely the instrument to him that
wields it." Wherefore those who, at the Lord's command, slew their
neighbors and friends, would seem not to have done this themselves, but
rather He by whose authority they acted thus: just as a soldier slays the
foe by the authority of his sovereign, and the executioner slays the
robber by the authority of the judge.
Reply to Objection 2: A beast is by nature distinct from man, wherefore in the
case of a wild beast there is no need for an authority to kill it;
whereas, in the case of domestic animals, such authority is required, not
for their sake, but on account of the owner's loss. On the other hand a
man who has sinned is not by nature distinct from good men; hence a
public authority is requisite in order to condemn him to death for the
Reply to Objection 3: It is lawful for any private individual to do anything for
the common good, provided it harm nobody: but if it be harmful to some
other, it cannot be done, except by virtue of the judgment of the person
to whom it pertains to decide what is to be taken from the parts for the
welfare of the whole.
Article 4: Whether it is lawful for clerics to kill evil-doers?
Objection 1: It would seem lawful for clerics to kill evil-doers. For clerics
especially should fulfil the precept of the Apostle (1 Cor. 4:16): "Be ye
followers of me as I also am of Christ," whereby we are called upon to
imitate God and His saints. Now the very God whom we worship puts
evildoers to death, according to Ps. 135:10, "Who smote Egypt with their
firstborn." Again Moses made the Levites slay twenty-three thousand men
on account of the worship of the calf (Ex. 32), the priest Phinees slew
the Israelite who went in to the woman of Madian (Num. 25), Samuel killed
Agag king of Amalec (1 Kgs. 15), Elias slew the priests of Baal (3 Kgs. 18), Mathathias killed the man who went up to the altar to sacrifice (1
Mach. 2); and, in the New Testament, Peter killed Ananias and Saphira
(Acts 5). Therefore it seems that even clerics may kill evil-doers.
Objection 2: Further, spiritual power is greater than the secular and is more
united to God. Now the secular power as "God's minister" lawfully puts
evil-doers to death, according to Rm. 13:4. Much more therefore may
clerics, who are God's ministers and have spiritual power, put evil-doers
Objection 3: Further, whosoever lawfully accepts an office, may lawfully
exercise the functions of that office. Now it belongs to the princely
office to slay evildoers, as stated above (Article ). Therefore those clerics
who are earthly princes may lawfully slay malefactors.
On the contrary, It is written (1 Tim. 3:2,3): "It behooveth . . . a
bishop to be without crime [*Vulg.: 'blameless.' 'Without crime' is the
reading in Tit. 1:7] . . . not given to wine, no striker."
I answer that, It is unlawful for clerics to kill, for two reasons.
First, because they are chosen for the ministry of the altar, whereon is
represented the Passion of Christ slain "Who, when He was struck did not
strike [Vulg.: 'When He suffered, He threatened not']" (1 Pt. 2:23).
Therefore it becomes not clerics to strike or kill: for ministers should
imitate their master, according to Ecclus. 10:2, "As the judge of the
people is himself, so also are his ministers." The other reason is
because clerics are entrusted with the ministry of the New Law, wherein
no punishment of death or of bodily maiming is appointed: wherefore they
should abstain from such things in order that they may be fitting
ministers of the New Testament.
Reply to Objection 1: God works in all things without exception whatever is
right, yet in each one according to its mode. Wherefore everyone should
imitate God in that which is specially becoming to him. Hence, though God
slays evildoers even corporally, it does not follow that all should
imitate Him in this. As regards Peter, he did not put Ananias and Saphira
to death by his own authority or with his own hand, but published their
death sentence pronounced by God. The Priests or Levites of the Old
Testament were the ministers of the Old Law, which appointed corporal
penalties, so that it was fitting for them to slay with their own hands.
Reply to Objection 2: The ministry of clerics is concerned with better things
than corporal slayings, namely with things pertaining to spiritual
welfare, and so it is not fitting for them to meddle with minor matters.
Reply to Objection 3: Ecclesiastical prelates accept the office of earthly
princes, not that they may inflict capital punishment themselves, but
that this may be carried into effect by others in virtue of their
Article 5: Whether it is lawful to kill oneself?
Objection 1: It would seem lawful for a man to kill himself. For murder is a
sin in so far as it is contrary to justice. But no man can do an
injustice to himself, as is proved in Ethic. v, 11. Therefore no man sins
by killing himself.
Objection 2: Further, it is lawful, for one who exercises public authority, to
kill evil-doers. Now he who exercises public authority is sometimes an
evil-doer. Therefore he may lawfully kill himself.
Objection 3: Further, it is lawful for a man to suffer spontaneously a lesser
danger that he may avoid a greater: thus it is lawful for a man to cut
off a decayed limb even from himself, that he may save his whole body.
Now sometimes a man, by killing himself, avoids a greater evil, for
example an unhappy life, or the shame of sin. Therefore a man may kill
Objection 4: Further, Samson killed himself, as related in Judges 16, and yet he is numbered among the saints (Heb. 11). Therefore it is lawful for a man to kill himself.
Objection 5: Further, it is related (2 Mach. 14:42) that a certain Razias
killed himself, "choosing to die nobly rather than to fall into the hands
of the wicked, and to suffer abuses unbecoming his noble birth." Now
nothing that is done nobly and bravely is unlawful. Therefore suicide is
On the contrary, Augustine says (De Civ. Dei i, 20): "Hence it follows
that the words 'Thou shalt not kill' refer to the killing of a man---not
another man; therefore, not even thyself. For he who kills himself, kills
nothing else than a man."
I answer that, It is altogether unlawful to kill oneself, for three
reasons. First, because everything naturally loves itself, the result
being that everything naturally keeps itself in being, and resists
corruptions so far as it can. Wherefore suicide is contrary to the
inclination of nature, and to charity whereby every man should love
himself. Hence suicide is always a mortal sin, as being contrary to the
natural law and to charity. Secondly, because every part, as such,
belongs to the whole. Now every man is part of the community, and so, as
such, he belongs to the community. Hence by killing himself he injures
the community, as the Philosopher declares (Ethic. v, 11). Thirdly,
because life is God's gift to man, and is subject to His power, Who kills
and makes to live. Hence whoever takes his own life, sins against God,
even as he who kills another's slave, sins against that slave's master,
and as he who usurps to himself judgment of a matter not entrusted to
him. For it belongs to God alone to pronounce sentence of death and life,
according to Dt. 32:39, "I will kill and I will make to live."
Reply to Objection 1: Murder is a sin, not only because it is contrary to
justice, but also because it is opposed to charity which a man should
have towards himself: in this respect suicide is a sin in relation to
oneself. In relation to the community and to God, it is sinful, by reason
also of its opposition to justice.
Reply to Objection 2: One who exercises public authority may lawfully put to
death an evil-doer, since he can pass judgment on him. But no man is
judge of himself. Wherefore it is not lawful for one who exercises public
authority to put himself to death for any sin whatever: although he may
lawfully commit himself to the judgment of others.
Reply to Objection 3: Man is made master of himself through his free-will:
wherefore he can lawfully dispose of himself as to those matters which
pertain to this life which is ruled by man's free-will. But the passage
from this life to another and happier one is subject not to man's
free-will but to the power of God. Hence it is not lawful for man to take
his own life that he may pass to a happier life, nor that he may escape
any unhappiness whatsoever of the present life, because the ultimate and
most fearsome evil of this life is death, as the Philosopher states
(Ethic. iii, 6). Therefore to bring death upon oneself in order to
escape the other afflictions of this life, is to adopt a greater evil in
order to avoid a lesser. In like manner it is unlawful to take one's own
life on account of one's having committed a sin, both because by so doing
one does oneself a very great injury, by depriving oneself of the time
needful for repentance, and because it is not lawful to slay an evildoer
except by the sentence of the public authority. Again it is unlawful for
a woman to kill herself lest she be violated, because she ought not to
commit on herself the very great sin of suicide, to avoid the lesser sir;
of another. For she commits no sin in being violated by force, provided
she does not consent, since "without consent of the mind there is no
stain on the body," as the Blessed Lucy declared. Now it is evident that
fornication and adultery are less grievous sins than taking a man's,
especially one's own, life: since the latter is most grievous, because
one injures oneself, to whom one owes the greatest love. Moreover it is
most dangerous since no time is left wherein to expiate it by repentance.
Again it is not lawful for anyone to take his own life for fear he should
consent to sin, because "evil must not be done that good may come" (Rm. 3:8) or that evil may be avoided especially if the evil be of small
account and an uncertain event, for it is uncertain whether one will at
some future time consent to a sin, since God is able to deliver man from
sin under any temptation whatever.
Reply to Objection 4: As Augustine says (De Civ. Dei i, 21), "not even Samson is
to be excused that he crushed himself together with his enemies under the
ruins of the house, except the Holy Ghost, Who had wrought many wonders
through him, had secretly commanded him to do this." He assigns the same
reason in the case of certain holy women, who at the time of persecution
took their own lives, and who are commemorated by the Church.
Reply to Objection 5: It belongs to fortitude that a man does not shrink from
being slain by another, for the sake of the good of virtue, and that he
may avoid sin. But that a man take his own life in order to avoid penal
evils has indeed an appearance of fortitude (for which reason some, among
whom was Razias, have killed themselves thinking to act from fortitude),
yet it is not true fortitude, but rather a weakness of soul unable to
bear penal evils, as the Philosopher (Ethic. iii, 7) and Augustine (De
Civ. Dei 22,23) declare.
Article 6: Whether it is lawful to kill the innocent?
Objection 1: It would seem that in some cases it is lawful to kill the
innocent. The fear of God is never manifested by sin, since on the
contrary "the fear of the Lord driveth out sin" (Ecclus. 1:27). Now
Abraham was commended in that he feared the Lord, since he was willing to
slay his innocent son. Therefore one may, without sin, kill an innocent
Objection 2: Further, among those sins that are committed against one's
neighbor, the more grievous seem to be those whereby a more grievous
injury is inflicted on the person sinned against. Now to be killed is a
greater injury to a sinful than to an innocent person, because the
latter, by death, passes forthwith from the unhappiness of this life to
the glory of heaven. Since then it is lawful in certain cases to kill a
sinful man, much more is it lawful to slay an innocent or a righteous
Objection 3: Further, what is done in keeping with the order of justice is not
a sin. But sometimes a man is forced, according to the order of justice,
to slay an innocent person: for instance, when a judge, who is bound to
judge according to the evidence, condemns to death a man whom he knows to
be innocent but who is convicted by false witnesses; and again the
executioner, who in obedience to the judge puts to death the man who has
been unjustly sentenced.
On the contrary, It is written (Ex. 23:7): "The innocent and just person
thou shalt not put to death."
I answer that, An individual man may be considered in two ways: first,
in himself; secondly, in relation to something else. If we consider a man
in himself, it is unlawful to kill any man, since in every man though he
be sinful, we ought to love the nature which God has made, and which is
destroyed by slaying him. Nevertheless, as stated above (Article ) the
slaying of a sinner becomes lawful in relation to the common good, which
is corrupted by sin. On the other hand the life of righteous men
preserves and forwards the common good, since they are the chief part of
the community. Therefore it is in no way lawful to slay the innocent.
Reply to Objection 1: God is Lord of death and life, for by His decree both the
sinful and the righteous die. Hence he who at God's command kills an
innocent man does not sin, as neither does God Whose behest he executes:
indeed his obedience to God's commands is a proof that he fears Him.
Reply to Objection 2: In weighing the gravity of a sin we must consider the
essential rather than the accidental. Wherefore he who kills a just man,
sins more grievously than he who slays a sinful man: first, because he
injures one whom he should love more, and so acts more in opposition to
charity: secondly, because he inflicts an injury on a man who is less
deserving of one, and so acts more in opposition to justice: thirdly,
because he deprives the community of a greater good: fourthly, because he
despises God more, according to Lk. 10:16, "He that despiseth you
despiseth Me." On the other hand it is accidental to the slaying that the
just man whose life is taken be received by God into glory.
Reply to Objection 3: If the judge knows that man who has been convicted by false
witnesses, is innocent he must, like Daniel, examine the witnesses with
great care, so as to find a motive for acquitting the innocent: but if he
cannot do this he should remit him for judgment by a higher tribunal. If
even this is impossible, he does not sin if he pronounce sentence in
accordance with the evidence, for it is not he that puts the innocent
man to death, but they who stated him to be guilty. He that carries out
the sentence of the judge who has condemned an innocent man, if the
sentence contains an inexcusable error, he should not obey, else there
would be an excuse for the executions of the martyrs: if however it
contain no manifest injustice, he does not has no right to discuss the
judgment of his superior; nor is it he who slays the innocent man, but
the judge whose minister he is.
Article 7: Whether it is lawful to kill a man in self-defense?
Objection 1: It would seem that nobody may lawfully kill a man in
self-defense. For Augustine says to Publicola (Ep. xlvii): "I do not
agree with the opinion that one may kill a man lest one be killed by him;
unless one be a soldier, exercise a public office, so that one does it
not for oneself but for others, having the power to do so, provided it be
in keeping with one's person." Now he who kills a man in self-defense,
kills him lest he be killed by him. Therefore this would seem to be
Objection 2: Further, he says (De Lib. Arb. i, 5): "How are they free from sin
in sight of Divine providence, who are guilty of taking a man's life for
the sake of these contemptible things?" Now among contemptible things he
reckons "those which men may forfeit unwillingly," as appears from the
context (De Lib. Arb. i, 5): and the chief of these is the life of the
body. Therefore it is unlawful for any man to take another's life for the
sake of the life of his own body.
Objection 3: Further, Pope Nicolas [*Nicolas I, Dist. 1, can. De his clericis]
says in the Decretals: "Concerning the clerics about whom you have
consulted Us, those, namely, who have killed a pagan in self-defense, as
to whether, after making amends by repenting, they may return to their
former state, or rise to a higher degree; know that in no case is it
lawful for them to kill any man under any circumstances whatever." Now
clerics and laymen are alike bound to observe the moral precepts.
Therefore neither is it lawful for laymen to kill anyone in self-defense.
Objection 4: Further, murder is a more grievous sin than fornication or
adultery. Now nobody may lawfully commit simple fornication or adultery
or any other mortal sin in order to save his own life; since the
spiritual life is to be preferred to the life of the body. Therefore no
man may lawfully take another's life in self-defense in order to save his
Objection 5: Further, if the tree be evil, so is the fruit, according to Mt.
7:17. Now self-defense itself seems to be unlawful, according to Rm.
12:19: "Not defending [Douay: 'revenging'] yourselves, my dearly
beloved." Therefore its result, which is the slaying of a man, is also
On the contrary, It is written (Ex. 22:2): "If a thief be found
breaking into a house or undermining it, and be wounded so as to die; he
that slew him shall not be guilty of blood." Now it is much more lawful
to defend one's life than one's house. Therefore neither is a man guilty
of murder if he kill another in defense of his own life.
I answer that, Nothing hinders one act from having two effects, only one
of which is intended, while the other is beside the intention. Now moral
acts take their species according to what is intended, and not according
to what is beside the intention, since this is accidental as explained
above (Question , Article ; FS, Question , Article ). Accordingly the act of self-defense
may have two effects, one is the saving of one's life, the other is the
slaying of the aggressor. Therefore this act, since one's intention is to
save one's own life, is not unlawful, seeing that it is natural to
everything to keep itself in "being," as far as possible. And yet, though
proceeding from a good intention, an act may be rendered unlawful, if it
be out of proportion to the end. Wherefore if a man, in self-defense,
uses more than necessary violence, it will be unlawful: whereas if he
repel force with moderation his defense will be lawful, because according
to the jurists [*Cap. Significasti, De Homicid. volunt. vel casual.], "it
is lawful to repel force by force, provided one does not exceed the
limits of a blameless defense." Nor is it necessary for salvation that a
man omit the act of moderate self-defense in order to avoid killing the
other man, since one is bound to take more care of one's own life than of
another's. But as it is unlawful to take a man's life, except for the
public authority acting for the common good, as stated above (Article ), it
is not lawful for a man to intend killing a man in self-defense, except
for such as have public authority, who while intending to kill a man in
self-defense, refer this to the public good, as in the case of a soldier
fighting against the foe, and in the minister of the judge struggling
with robbers, although even these sin if they be moved by private
Reply to Objection 1: The words quoted from Augustine refer to the case when one
man intends to kill another to save himself from death. The passage
quoted in the Second Objection is to be understood in the same sense.
Hence he says pointedly, "for the sake of these things," whereby he
indicates the intention. This suffices for the Reply to the Second
Reply to Objection 3: Irregularity results from the act though sinless of taking
a man's life, as appears in the case of a judge who justly condemns a man
to death. For this reason a cleric, though he kill a man in self-defense,
is irregular, albeit he intends not to kill him, but to defend himself.
Reply to Objection 4: The act of fornication or adultery is not necessarily
directed to the preservation of one's own life, as is the act whence
sometimes results the taking of a man's life.
Reply to Objection 5: The defense forbidden in this passage is that which comes
from revengeful spite. Hence a gloss says: "Not defending
yourselves---that is, not striking your enemy back."
Article 8: Whether one is guilty of murder through killing someone by chance?
Objection 1: It would seem that one is guilty of murder through killing
someone by chance. For we read (Gn. 4:23,24) that Lamech slew a man in
mistake for a wild beast [*The text of the Bible does not say so, but
this was the Jewish traditional commentary on Gn. 4:23], and that he was
accounted guilty of murder. Therefore one incurs the guilt of murder
through killing a man by chance.
Objection 2: Further, it is written (Ex. 21:22): "If . . . one strike a woman
with child, and she miscarry indeed . . . if her death ensue thereupon,
he shall render life for life." Yet this may happen without any intention
of causing her death. Therefore one is guilty of murder through killing
someone by chance.
Objection 3: Further, the Decretals [*Dist. 1] contain several canons
prescribing penalties for unintentional homicide. Now penalty is not due
save for guilt. Therefore he who kills a man by chance, incurs the guilt
On the contrary, Augustine says to Publicola (Ep. xlvii): "When we do a
thing for a good and lawful purpose, if thereby we unintentionally cause
harm to anyone, it should by no means be imputed to us." Now it sometimes
happens by chance that a person is killed as a result of something done
for a good purpose. Therefore the person who did it is not accounted
I answer that, According to the Philosopher (Phys. ii, 6) "chance is a
cause that acts beside one's intention." Hence chance happenings,
strictly speaking, are neither intended nor voluntary. And since every
sin is voluntary, according to Augustine (De Vera Relig. xiv) it follows
that chance happenings, as such, are not sins.
Nevertheless it happens that what is not actually and directly voluntary
and intended, is voluntary and intended accidentally, according as that
which removes an obstacle is called an accidental cause. Wherefore he who
does not remove something whence homicide results whereas he ought to
remove it, is in a sense guilty of voluntary homicide. This happens in
two ways: first when a man causes another's death through occupying
himself with unlawful things which he ought to avoid: secondly, when he
does not take sufficient care. Hence, according to jurists, if a man
pursue a lawful occupation and take due care, the result being that a
person loses his life, he is not guilty of that person's death: whereas
if he be occupied with something unlawful, or even with something lawful,
but without due care, he does not escape being guilty of murder, if his
action results in someone's death.
Reply to Objection 1: Lamech did not take sufficient care to avoid taking a man's
life: and so he was not excused from being guilty of homicide.
Reply to Objection 2: He that strikes a woman with child does something unlawful:
wherefore if there results the death either of the woman or of the
animated fetus, he will not be excused from homicide, especially seeing
that death is the natural result of such a blow.
Reply to Objection 3: According to the canons a penalty, is inflicted on those
who cause death unintentionally, through doing something unlawful, or
failing to take sufficient care.