Thomas Aquinas, Summa Theologiae

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 himself.

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 not unlawful.

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.

Articulus 5

Argumentum 1

Ad quintum sic proceditur. Videtur quod alicui liceat seipsum occidere. Homicidium enim est peccatum inquantum iustitiae contrariatur. Sed nullus potest sibi ipsi iniustitiam facere, ut probatur in V ethic..

Ergo nullus peccat occidendo seipsum.

Argumentum 2

Praeterea, occidere malefactores licet habenti publicam potestatem. Sed quandoque ille qui habet publicam potestatem est malefactor. Ergo licet ei occidere seipsum.

Argumentum 3

Praeterea, licitum est quod aliquis spontanee minus periculum subeat ut maius periculum vitet, sicut licitum est quod aliquis etiam sibi ipsi amputet membrum putridum ut totum corpus salvetur. Sed quandoque aliquis per occisionem sui ipsius vitat maius malum, vel miseram vitam vel turpitudinem alicuius peccati.

Ergo licet alicui occidere seipsum.

Argumentum 4

Praeterea, Samson seipsum interfecit, ut habetur iudic. XVI, qui tamen connumeratur inter sanctos, ut patet Heb. XI.

Ergo licitum est alicui occidere seipsum.

Argumentum 5

Praeterea, II machab. XIV dicitur quod Razias quidam seipsum interfecit, eligens nobiliter mori potius quam subditus fieri peccatoribus et contra natales suos iniuriis agi.

Sed nihil quod nobiliter fit et fortiter, est illicitum.

Ergo occidere seipsum non est illicitum.

Sed Contra

Sed contra est quod Augustinus dicit, in I de CIV. Dei, restat ut de homine intelligamus quod dictum est, non occides.

Nec alterum ergo, nec te.

Neque enim aliud quam hominem occidit qui seipsum occidit.

Corpus

Respondeo dicendum quod seipsum occidere est omnino illicitum triplici ratione. Primo quidem, quia naturaliter quaelibet res seipsam amat, et ad hoc pertinet quod quaelibet res naturaliter conservat se in esse et corrumpentibus resistit quantum potest.

Et ideo quod aliquis seipsum occidat est contra inclinationem naturalem, et contra caritatem, qua quilibet debet seipsum diligere. Et ideo occisio sui ipsius semper est peccatum mortale, utpote contra naturalem legem et contra caritatem existens.

Secundo, quia quaelibet pars id quod est, est totius. Quilibet autem homo est pars communitatis, et ita id quod est, est communitatis.

Unde in hoc quod seipsum interficit, iniuriam communitati facit, ut patet per philosophum, in V ethic..

Tertio, quia vita est quoddam donum divinitus homini attributum, et eius potestati subiectum qui occidit et vivere facit.

Et ideo qui seipsum vita privat in deum peccat, sicut qui alienum servum interficit peccat in dominum cuius est servus; et sicut peccat ille qui usurpat sibi iudicium de re sibi non commissa.

Ad solum enim deum pertinet iudicium mortis et vitae, secundum illud Deut. XXXII, ego occidam, et vivere faciam.

Ad 1

Ad primum ergo dicendum quod homicidium est peccatum non solum quia contrariatur iustitiae, sed etiam quia contrariatur caritati quam habere debet aliquis ad seipsum. Et ex hac parte occisio sui ipsius est peccatum per comparationem ad seipsum.

Per comparationem autem ad communitatem et ad deum, habet rationem peccati etiam per oppositionem ad iustitiam.

Ad 2

Ad secundum dicendum quod ille qui habet publicam potestatem potest licite malefactorem occidere per hoc quod potest de ipso iudicare. Nullus autem est iudex sui ipsius. Unde non licet habenti publicam potestatem seipsum occidere propter quodcumque peccatum. Licet tamen ei se committere iudicio aliorum.

Ad 3

Ad tertium dicendum quod homo constituitur dominus sui ipsius per liberum arbitrium. Et ideo licite potest homo de seipso disponere quantum ad ea quae pertinent ad hanc vitam, quae hominis libero arbitrio regitur. Sed transitus de hac vita ad aliam feliciorem non subiacet libero arbitrio hominis, sed potestati divinae. Et ideo non licet homini seipsum interficere ut ad feliciorem transeat vitam. Similiter etiam nec ut miserias quaslibet praesentis vitae evadat.

Quia ultimum malorum huius vitae et maxime terribile est mors, ut patet per philosophum, in III ethic..

Et ita inferre sibi mortem ad alias huius vitae miserias evadendas est maius malum assumere ad minoris mali vitationem.

Similiter etiam non licet seipsum occidere propter aliquod peccatum commissum. Tum quia in hoc sibi maxime nocet quod sibi adimit necessarium poenitentiae tempus. Tum etiam quia malefactorem occidere non licet nisi per iudicium publicae potestatis.

Similiter etiam non licet mulieri seipsam occidere ne ab alio corrumpatur. Quia non debet in se committere crimen maximum, quod est sui ipsius occisio, ut vitet minus crimen alienum (non enim est crimen mulieris per violentiam violatae, si consensus non adsit, quia non inquinatur corpus nisi de consensu mentis, ut Lucia dixit)p constat autem minus esse peccatum fornicationem vel adulterium quam homicidium, et praecipue sui ipsius, quod est gravissimum, quia sibi ipsi nocet, cui maximam dilectionem debet. Est etiam periculosissimum, quia non restat tempus ut per poenitentiam expietur. Similiter etiam nulli licet seipsum occidere ob timorem ne consentiat in peccatum. Quia non sunt facienda mala ut veniant bona, vel ut vitentur mala, praesertim minora et minus certa.

Incertum enim est an aliquis in futurum consentiat in peccatum, potens est enim deus hominem, quacumque tentatione superveniente, liberare a peccato.

Ad 4

Ad quartum dicendum quod, sicut Augustinus dicit, in I de CIV. Dei, nec Samson aliter excusatur quod seipsum cum hostibus ruina domus oppressit, nisi quia latenter spiritus hoc iusserat, qui per illum miracula faciebat.

Et eandem rationem assignat de quibusdam sanctis feminis quae tempore persecutionis seipsas occiderunt, quarum memoria in ecclesia celebratur.

Ad 5

Ad quintum dicendum quod ad fortitudinem pertinet quod aliquis ab alio mortem pati non refugiat propter bonum virtutis, et ut vitet peccatum. Sed quod aliquis sibi ipsi inferat mortem ut vitet mala poenalia, habet quidem quandam speciem fortitudinis, propter quod quidam seipsos interfecerunt aestimantes se fortiter agere, de quorum numero Razias fuit, non tamen est vera fortitudo, sed magis quaedam mollities animi non valentis mala poenalia sustinere, ut patet per philosophum, in III ethic., et per Augustinum, in I de CIV. Dei.