Chapter — Koch–Preuss

Chapter V: Positive Duties in Regard to Life and Health

¶1.

Though man may not end his life at will, he is in duty bound to sacrifice it under certain conditions. The reason for this obligation is twofold: First, there are higher duties than that of preserving life, and, secondly, every man possesses certain rights over his own person. Hence the duty of preserving and safeguarding life and health, with which we dealt in the last Section, does not bind absolutely, but is subject to certain limitations.

¶2.
  1. Man is bound to give his life, or to allow others to take it, if he can preserve it in no other way than at the expense of truth and virtue, i. e., at the cost of his soul's salvation,1 or if the duties of his vocation or state require him to sacrifice health or life, as often happens with priests, physicians, nurses, firemen, and others; or whenever it becomes a duty to run a serious risk for the sake of the common welfare.2

1 Cfr. Matt. X, 39; XVI, 25 sq.; Mark VIII, 35–37; Luke IX, 24–26; XVIII, 33; John XII, 25.

2 Acts XX, 24; Eph. III, 13; Phil. II, 17; 1 John III, 16. Cfr. J. de Lugo, De Iust. et Iure, disp. 10, qu. 1: "For a great common good, or because of a special obligation arising from a contract or office which a soldier, governor, bishop, or pastor has, they can lawfully and are bound to prefer death." —H. Busembaum, S.J., Medulla Theol. Mor., III, tr. 4, c. 1, dub. 1: "A soldier can, indeed is bound to remain at his post, even if he is morally certain that he will be killed." (Tournay, 1876, I, 172). Cfr. St. Alphonsus, Theol. Mor., l. IV, n. 366.

¶3.
  1. It is permissible for a man to sacrifice his life or to expose himself to certain danger of death: a) If he knows no other way of escape from a physically proximate occasion of mortal sin. Thus a virgin may risk death in order to preserve her chastity, e. g., by leaping into a river with the purpose of reaching the other side, even though there be no reasonable hope of attaining safety, or by offering resistance to her assailant, even though she run immediate danger of being killed and cannot escape except by a miracle. We say such conduct would be permissible; but it would not be obligatory, for it is not absolutely impossible to refuse internal consent. A person does not share the guilt of another's sin, says St. Augustine, as long as he does not give his consent. 3 The Roman Breviary quotes St. Lucy as saying: "The body is not stained except by the consent of the mind, and if you command me to be violated against my will, my chastity will be to me a double crown." 4 Similarly, a woman has the right, though she is not in duty bound, to refuse to allow herself to be physically examined or operated upon in order to preserve her modesty or bodily integrity.5 She may furthermore refuse to submit to medical examination ordered by a court for the purpose of ascertaining whether she has committed infanticide, even though her refusal would be interpreted as a confession of guilt and result in her conviction. For although in the case of crimes of this kind a physical examination is often important for ascertaining the guilt of the accused, and it may happen that a guilty woman escapes punishment by her refusal to be examined, modesty must be protected at all costs, and Catholics should use their influence to prevent the adoption of laws that run counter to this principle.6

3 Epist., 98 (al. 23), n. 1: "One who consents by no will of his own cannot be bound by the bond of another’s iniquity." (Migne, P. L., XXXIII, 359). —IDEM, De Mendacio, c. 19, n. 40 (P. L., XL, 514). —St. Jerome, Hebraicae Quaest. in Gen., c. 12: "It is not violence but the will that stains the body of holy women." (P. L., XXIII, 957). —St. Alphonsus says (Theol. Mor., III, n. 368): "Here the question presses more urgently whether a virgin is bound to permit herself to be killed rather than violated—for example, if an assailant threatens her with death if she does not acquiesce in intercourse. There are two opinions. The first says that, although she can do so, a woman is nevertheless not bound to suffer death, but can then conduct herself permissively while intercourse occurs, provided that she positively resists with her will and the danger of consent is absent; because, as they say, that permission is then not moral cooperation but only material, and therefore she is sufficiently excused by the danger of death. The second opinion teaches that this is altogether unlawful, because, since the woman can prevent intercourse, if she remains passive through fear, her cooperation then becomes truly moral and voluntary; for in a woman that passivity during intercourse is reckoned as an action. This reason, however, is not convincing, because the woman’s passivity cannot in reality be called an action, since it is in no way positive. Therefore the first opinion, speaking speculatively, does not seem to lack probability. Nevertheless, it must not be denied that in practice the second opinion is altogether to be recommended, at least because of the danger of consent, which can easily be present in that permission." —Cfr. A. Lehmkuhl, S.J., Theol. Mor., Vol. I, 10th ed., n. 580.

4 Breviarium Rom., Festum S. Luciae (13 Dec.), lect. 6: "The body is not defiled except by the consent of the mind, and if you command me to be violated against my will, my chastity will be doubled for me unto a crown." —Cfr. Busembaum, Medulla, I. c.: "Although it is not lawful for a virgin to kill herself directly in order to preserve chastity, it is nevertheless lawful for her to expose herself to certain danger of death even for bodily integrity alone, even if she could reasonably presume that she would not consent, because that integrity is highly esteemed."

5 Cfr. Gury, Comp. Theol. Mor., Vol. I, n. 403: "A virgin is not bound to undergo a shameful operation at the hands of a physician, even though her life is endangered, because love of modesty can equal or even surpass the evil feared in death." —St. Alphonsus, Theol. Mor., III, n. 372: "A virgin could nevertheless permit herself to be touched; indeed, she would be bound to allow herself to be treated by another woman, as Diana rightly says."

6 Cfr. F. v. Holtzendorff, Das Verbrechen des Mordes und die Todesstrafe, Berlin 1875, pp. 337 sq.

¶4.

As regards the so-called suicidia martyrum7 it is safe to say that the holy persons who thus voluntarily incurred death were divinely inspired 8 or at least acted in good faith.9 Samson's deed, as recorded in the Book of Judges,10 was justifiable from another point of view, besides that mentioned by St. Augustine.* He may be said to have willed his death only indirectly as a means of destroying the Philistines, and hence acted for the common good (ex caritate boni communis).11 b) It is also permissible to sacrifice one's life or to expose oneself to certain danger of death in order to escape a serious temptation. The older moralists held that a patient would be justified in refusing to submit to an extremely painful operation, even though it were likely to save his life, if he knew, or at least had reason to fear, that the pain would cause him to sin grievously by anger, impatience, despair, or blasphemy. In the present advanced stage of surgery this danger is slight,12 although, because of the more or less well-founded fear of death under the knife, no general obligation can be established.

7 See Eusebius, Hist. Eccles., l. VI, c. 42; l. VIII, c. 12 (Migne, P. G., XX, 608, 772).

8 St. Augustine, De Civitate Dei, l. I, c. 16-19 (Migne, P. L., XLI, 30–34): "But certain holy women, they say, in time of persecution, in order to escape the assailants of their chastity, cast themselves into a river that would seize and kill them, and died in that way; and their martyrdoms are celebrated with most renowned veneration in the Catholic Church. I dare to judge nothing rashly concerning them. For I do not know whether divine authority persuaded the Church through some trustworthy testimonies to honor their memory thus, and it is possible that this was so. What if they did this not because they were deceived by human judgment, but because they were commanded by God—not erring, but obeying? Just as we may believe nothing else concerning Samson." (P. L., XLI, 39). —IDEM, Tract. in Ioan., 51, n. 10 (P. L., XXXV, 1767). —St. Thomas, Summa Theol., 2a 2ae, qu. 64, art. 5, ad 3: "It is not lawful for a woman to kill herself lest she be corrupted by another, because she ought not commit against herself the greatest crime, which is killing herself, in order to avoid the lesser crime of another. For violence is no crime of the woman if consent is absent, because the body is not defiled except by consent of the mind, as Lucy said.... Likewise, it is not lawful for anyone to kill himself through fear that he may consent to sin, because evils must not be done that goods may come (Rom. III, 8), or that evils may be avoided, especially lesser or less certain evils; for it is uncertain whether anyone will consent to sin in the future, and God is able to deliver a man from sin when any temptation supervenes." —Ibidem, ad 4: "It must be said that, as Augustine says, Samson is not otherwise excused for crushing himself with his enemies by the fall of the house except that the Holy Spirit, who performed miracles through him, had secretly commanded this. And he assigns the same reason concerning certain holy women who killed themselves during persecution, whose memory is celebrated in the Church."

9 Lessius, De Iust., II, c. 9, n. 23.

10 Judges XVI, 23 sqq. * See note 8, supra.

11 Cfr. Sporer-Bierbaum, Theol. Mor., Vol. II, 2nd ed., Paderborn 1903, tr. 5, n. 390; F. X. Linsenmann, Lehrbuch der Moraltheologie, p. 259.

12 Cfr. Chas. Coppens, S.J., Moral Principles and Medical Practice, New York 1897.

¶5.

The duty of employing the resources of medicine and surgery to save one's life must not be interpreted as compelling a patient to employ such extraordinary means as would be harder to bear than death itself. No one is obliged, for instance, to consent to the amputation of a limb if he is not certain that the operation will not kill him. In the present stage of medical science there is nearly always at least a possibility of saving life, and hence it may be said, in a general way, that patients are bound to allow themselves to be operated upon if advised to do so by a reputable physician.

¶6.

Of course, no man is obliged for the restoration of his health to employ means which would entail poverty upon his family or cause extraordinary hardship to himself, especially if the result is uncertain.

¶7.

From what we have said the reader will have rightly concluded that the duty of submitting to medical or surgical treatment is never absolute, but always relative. When life can be saved in no other way, and it is very probable that the treatment suggested will prove successful, the patient should take it if he has the means to do so. But as long as there is hope of restoring health in some other way, there is no strict duty to take medicine or submit to the knife. If the disease is so far advanced that no reasonable hope can be entertained of saving the patient's life, he should not be molested, and the more doubtful the effect of a medicine or an operation, and the less inclined the patient is to take or undergo it, the less should he be harassed. No matter how far advanced the disease or how meagre the hope of recovery, it is never allowed to give a patient drugs which are apt to directly cause death, but it is permissible to employ medicines that may possibly hasten the end, provided there is hope, or at least a possibility, that they will have a beneficial influence upon the patient.

¶8.

To hasten death artificially by the employment of anaesthetics (εὐθανασία) when all hope of recovery is gone, can be regarded as permissible only if the drugs employed for this purpose do not entirely deprive the sufferer of consciousness. No man should be robbed of the capacity of acquiring merits in the hour of death, when, as Dr. Delany rightly says "the competency of acting meritoriously is most necessary and its products invested with finality." 13 "The time just before death," says Father Slater, "is very precious; a sinner may then be reconciled with God and save his soul; one who is in the state of grace may very much increase his merit by a good use at that time. Euthanasia, then, in this sense, is unlawful; it is virtually shortening a man's life." 14 Dr. Delany further says that there can be no doubt that "the administration of drugs of the nature specified is, in the premises, if not formally, at all events equivalently, a shortening of the life of the patient. Hence as long as the stricken person has as yet made no adequate preparation for death, it is always grievously unlawful to induce a condition of insensibility. In no contingency ... can any positive indorsement be given to means whose scope is to have one die in a state of unconsciousness. What has been said applies with equal force and for the same reasons to the case of those who have to suffer capital punishment by process of law." 15 c) Another motive which would justify a man in sacrificing his life or exposing himself to the danger of certain death, would be the desire to escape death in some other, equally certain but more painful form. Thus one who is unable to flee from a burning building would be allowed to leap, at the risk of breaking his neck, even though the hope of saving his life were very small.16

13 Cath. Encyclopedia, Vol. V, p. 630.

14 Thos. Slater, Manual of Moral Theology, Vol. I, p. 164.

15 Cath. Encyclopedia, Vol. V, p. 630. —Dr. Delany, in the excised portions of the paragraph above quoted, goes farther than most other Catholic writers by granting that "those charged with responsibility in the case" may "take up a passively permissive demeanor whenever it is certain that the departing soul has abundantly made ready for the great summons," and adds: "This is especially true if there is ground for apprehending from the dying person's continued possession of his faculties, a relapse into sin." This sounds plausible, but is dangerous doctrine. (See O'Malley, The Ethics of Medical Homicide, pp. 13 sqq.)

16 Cfr. St. Alphonsus, Theol. Mor., l. III, n. 367: "It is asked whether it is lawful to kill oneself in order to avoid a harsher death. Reply: It is never lawful to kill oneself directly.... But it is lawful to kill oneself indirectly—for example, if someone throws himself from a window to escape a fire, especially if there is some hope of escaping death." — Sporer-Bierbaum, Theol. Mor., Vol. II, 2nd ed., tr. 5, n. 389; A. Lehmkuhl, S.J., Theol. Mor., Vol. I, 10th ed., n. 580.

¶9.
  1. To give up one's life when such a sacrifice is necessary or justifiable for the common welfare, is not only permissible, but positively virtuous. a) A man is allowed to engage in occupations which may, though they need not necessarily be dangerous to life and limb, e. g., working on "sky-scrapers," church steeples, etc. He may also choose a vocation which involves proximate danger of disease or death, even though in so doing he have no higher motive than to earn a living or win pecuniary gain.
¶10.

Dangerous occupations are not only those in which sudden injury and death are caused by machinery or unguarded perils, but also, and in the technical sense of the term particularly those in which some form of poison or disease is incidental to the trade itself as at present carried on.17 Most of the trades and occupations of this class are necessary for society as a whole and also for those individuals who make a living by following them.18

17 See Bliss, Encyclopedia of Social Reform, 2nd ed., p. 360.

18 Cfr. Gury, Comp. Theol. Mor., Vol. I, n. 403, 6°: "Workmen do not sin who climb upon the roofs of buildings and expose themselves to various dangers in practicing their craft, nor blacksmiths who shorten their lives by handling fire daily, because they act for a reasonable cause."

¶11.

For the sake of gaining a livelihood, (which is a dira necessitas), it is also legitimate for a man to engage in a hazardous occupation for the amusement, recreation, or utility of others, such as tight-rope walking, acrobatics, show athletics, etc., provided, of course, no divine or human law is directly transgressed.

¶12.

To endanger one's life merely for the purpose of displaying agility or courage, without strict necessity or a reasonable cause, is always sinful.19 b) It is permitted to volunteer one's services in war, nay even to risk one's life at or without the express command of a superior officer, if some essential object can be attained thereby, e. g., if considerable damage can be done to the enemy or a great advantage gained for one's own side.20

19 "Bold men sin gravely who, from a rash wager and vainglory, cast themselves into various dangers by climbing high, lowering themselves downward, and carrying heavier loads." etc. (Ibid.)

20 Cfr. Judges XVI, 23–30; 1 Macc. VI, 73 sqq. —Cfr. St. Alphonsus, Theol. Mor., III, n. 366: "A soldier can, indeed is bound to remain at his post, even if he is morally certain that he will be killed. Likewise, to overthrow an enemy tower or destroy the enemy, he can ignite gunpowder even if he knows that he will be buried under the ruins, and similarly sink or burn a ship lest the enemy gain possession of it with grave harm to the commonwealth." —Ibid., n. 367: "It is asked whether it is lawful to burn a ship with evident danger to life lest it come into the hands of the enemy.... Lugo, with Lessius, affirms that it is lawful if there is at least some very slight hope of avoiding death, or even if death is certain, provided that it is expedient to avert public harm."

¶13.

But no one is allowed to seek death merely for glory or in order to escape the hardships of prison life.21 Committing hara-kiri, as the Japanese are said to do, to escape falling into the hands of the enemy or being tortured by an angry prince, is immoral and therefore forbidden.22 c) A man may give up his life in the service of charity when there is question of the salvation of souls or the safeguarding of life, or some other equivalent good on the part of his fellowmen. Aside from the vocational duties of physicians and priests, it is a heroic act of virtue to expose oneself to immediate danger of death, for instance, in nursing a patient afflicted with a contagious disease.23 We have here a just cause (iusta causa), i. e., the exercise of a duty or virtue of such great importance that the accompanying danger fades into insignificance and the sacrifice approaches martyrdom.24 To incur such a risk out of obstinacy, pride, presumption, anger, or pique can, however, in no wise be regarded as permissible because no higher moral good is involved, and to risk life thoughtlessly or presumptuously would be opposed to the divine commandment of self-love.

21 2 Macc. XIV, 37–46.—Cfr. St. Augustine, Epist., 204 (al. 61), n. 6: "What wonder is it if proud exaltation crept upon [Razias] as a man, so that he preferred to perish by his own hand rather than, after that eminence in the eyes of his people, endure unworthy servitude in the hands of his enemies?" —Ibid., n. 7: "In these books of the Maccabees, although the man himself was praised, nevertheless his deed was narrated, not praised, and set before our eyes to be judged rather than imitated—not indeed to be judged by our judgment, such as we too might have as men, but by the judgment of sound doctrine, which is clear even in those ancient books. For this Razias was far from those words where it is written: ‘Accept whatever is brought upon you, and endure in sorrow, and have patience in your humiliation’ (Eccli. II, 4). Therefore this man was not wise in choosing death, but impatient in enduring humiliation." —Ibid., n. 8: "It is written that he wished ‘to die nobly and manfully’ (2 Mach. XIV, 37–46), but was it therefore wisely?... These things are great, yet they are not good; for not everything that is great is good, since evils too can be great." (Migne, P. L., XXXIII, 941). —IDEM, Contra Gaudent., I, c. 31, n. 39: "Therefore, however this praised life of Razias is understood by you, his death does not have wisdom as its praiser, because it does not have the patience worthy of God’s servants; and that saying of Wisdom (Eccli. II, 16), which is not of praise but of condemnation, applies rather to him: ‘Woe to those who have lost endurance.’"

22 Cfr. Sporer-Bierbaum, Theol. Mor., Vol. II, 2nd ed., tr. 5, n. 389: "It is certain among all that it is not lawful to kill oneself directly in order to escape a more atrocious unjust death. Therefore the custom of the Japanese is damnable whereby, in order to escape an atrocious death—for example, by slow fire—they free themselves by killing themselves with their abdomen cut open." —Cfr. V. Cathrein, S.J., Moralphilosophie, Vol. I, 4th ed., p. 599.

23 Sporer-Bierbaum, op. cit., n. 386: "One can visit, serve, administer the sacraments, and so forth, to persons infected with plague or suffering from a similar contagious disease, although the danger of one’s own infection and death is feared and actually present; still more praiseworthily will a wife—or conversely a husband—assist a spouse infected with plague at probable danger to her life. John Sanchez piously admits that this is lawful not only for necessary service, but even solely to give comfort or show love." —Ibid., n. 387: "One can expose oneself to a weapon to preserve the life of a prince or parent for the sake of filial duty and the common good; indeed, according to a probable opinion of great doctors, it is also lawful to expose one’s own life for the bodily life of a neighboring friend who otherwise would be killed unjustly. Thus, if Titius were unjustly condemned to death, you, his friend, could probably offer yourself to be killed in order to save your friend. They say ‘unjustly,’ however; for if he had been justly condemned, you could not do so, because then you would induce the judge, who wished to kill only the guilty man justly, to kill you unjustly."

24 Phil. II, 29 sq. (Epaphroditus). Cfr. S. Dionysius of Alex, apud Euseb., Hist. Eccles., VII, c. 22; (Migne, P. G., XX, 689); St. Cyprian, De Mortalit., c. 17 (Corpus Script. Eccles. Lat., Vindob., III, 1, 307).

¶14.

Of those who charitably sacrifice or risk their lives for their fellowmen Jesus Christ says: "Greater love than this no man hath, that a man lay down his life for his friends." 25 The highest exemplar of such heroic devotion is our Divine Saviour Himself, dying on the cross for the salvation of mankind.26

25 John XV, 13.

26 Cfr. Rom. V, 6–9; 1 John III, 16. —St. Thomas, Comment. in Sent., III, dist. 29, art. 5, ad 3: "Perfectissimus actus virtutis." — St. Alphonsus, Theol. Mor., III, 366.

¶15.

However, let it be well understood that, with the exception of those who are bound to do so by their vocation, no man is obliged to lay down his life for his fellowmen. The reason is that no man need love his neighbor more than himself. Therefore one who is caught in a shipwreck is not obliged to surrender his place in a lifeboat to another; 27 a mother is not obliged to submit to an indisputably dangerous operation in order to insure the life of her unborn child. In both cases, moreover, the success of the sacrifice would be problematical. The mother, in the instance mentioned, would, of course, be allowed, nay should in certain circumstances be advised, to perform what would be an act of heroic charity on behalf of her child. d) It is also permissible to sacrifice health and life in the interest of science for the common welfare. There is no moral objection, for instance, to participating in a polar expedition for scientific or research purposes, nay, such an act might be rendered positively virtuous by the circumstances of the case. The same is true of the act of undergoing inoculation with some virus to ascertain whether a certain disease is transmissible from beast to man, or for a similar purpose.28 (e) It is permissible for a murderer to surrender himself to the public authorities in order to pay the death penalty for his crime, though no man is strictly bound to do so unless an innocent person would otherwise be executed for the deed through his fault.29

27 Aug. Lehmkuhl, S.J., Theol. Mor., Vol. I, 10th ed., n. 580, 5: "In a shipwreck it is lawful to yield to a friend a plank already taken and thus to provide for his life rather than one’s own, unless one’s own life should perhaps be more necessary than the friend’s life."

28 Cfr. Juvenal, Sat., IV, 91: "Vitam impendere vero." —St. Alphonsus, Theol. Mor., III, n. 369: "Ad experiendum antidotum."

29 Cfr. St. Th. Aquinas, Summa Theologica, 2a 2ae, qu. 69, art. 4, ad 2: “No one is condemned in such a way that he should inflict death upon himself, but that he should suffer death; and therefore he is not bound to do that from which death follows, namely, to remain in the place from which he is led to death.” —Sporer-Bierbaum, Theol. Mor., Vol. II, 2nd ed., tr. 5, n. 394: "One condemned or about to be condemned to death, even if a way of escape lies open, can decline to flee and conform himself to the judge’s sentence out of love of justice; indeed, one who has merited death is not forbidden voluntarily to offer himself to the judge and furnish an occasion for justice to be exercised. Yet he is certainly bound to neither course, but can lawfully flee, not only before the judge’s sentence has been passed—unless he promised or swore that he would remain—but also after the judge has passed sentence, in order to avoid the most grave danger of his own death." Cfr. A. Lehmkuhl, S. J., in the Theol. -prakt. Quartalschrift, Linz, 1907, pp. 116 sqq.

¶16.

A fugitive who has been innocently condemned to death may not of his own accord return to the country in which the sentence was pronounced, because to do so would be to incur death voluntarily. If, however, the circumstances of the case were such that he would be able to save his parents or friends from great distress, imprisonment or disgrace, it would be an act of heroic virtue to return.

¶17.

It is not permissible for a criminal to commit suicide, even though the death sentence be already passed and its execution certain.

¶18.

Were a Catholic condemned, like Socrates, to be his own executioner, would he be allowed to obey? Moralists differ on this point. Assuming the judgment to be just, some answer the question affirmatively, saying that the culprit would end his life merely to obey the law and thus would cooperate in his own death only in a material and remote manner. Others take a negative view, for the reason that in a sentence of vindictive justice judge and culprit must be distinct and separate persons. As it is not certain that the act is intrinsically evil, Fr. Lehmkuhl says such a culprit would be permitted to execute the judgment upon himself at the command of the supreme judge; but he would not be obliged to do so, because it can be defended as a probable opinion that this act is forbidden by the natural law, and it is, moreover, abhorrent to nature. The sententia communis of Catholic moralists is against the act, though it is regarded as licit by Haunold, Elbel, Illsung, Lacroix, and others. St. Alphonsus seems to defend it as "probabilis." Victoria, Aragon, Sa, and others draw a distinction: they hold that a guilty culprit legally condemned to execute judgment upon himself would be allowed to take poison, as Socrates did, but not to kill himself with the sword.30

30 Aug. Lehmkuhl, S.J., Theol. Mor., Vol. I, 11th ed., p. 404. —Cfr. St. Alphonsus, Theol. Mor., III, 369.

¶19.

A criminal who has been justly condemned to die of starvation may refuse to take food offered to him.31

31 St. Thomas, Summa Theol., 2a 2ae, qu. 69, art. 4, ad 2: "If someone is condemned to die of hunger, he does not sin if he takes food secretly supplied to him, because not to take it would be to kill himself." —Sporer-Bierbaum, Theol. Mor., Vol. II, 2nd ed., tr. 5, n. 393: "One condemned to undergo death by starvation can abstain from food offered secretly, because such a person does not actively cooperate in his own death, but, conducting himself only passively, courageously endures it out of love of justice. Yet he is not bound to this, but can accept food secretly offered by the very law of nature, by which anyone can lawfully preserve his life as far as he is able; indeed, if such a person were unjustly condemned, speaking in itself he would be bound to eat, because then there would be no just cause for sacrificing his life except the cause of martyrdom."

¶20.

READINGS. —H. Noldin, S.J., Summa Theologiae Moralis, Vol. II, 11th ed., pp. 345 sqq., 90 sqq.—Aug. Lehmkuhl, S.J., Theologia Moralis, Vol. I, 11th ed., pp. 401 sqq. —De Lugo, De Iustitia et Iure, disp. X.