§ 1. On the Unlawful Use of Probability Where There Intervenes the Danger of Some Evil Absolutely to Be Avoided

80. All theologians, at least the more recent, teach that the use of probability is not lawful in any matter whatever; for there are circumstances in which, antecedently to every doubt, the law of choosing safer things possesses (cf. n. 42 and 54).

For easier understanding of the question, a threefold danger in the use of a probable opinion must be distinguished, namely danger of error, of sin, and of an evil effect (Vind. Alph., P. I, c. 1, § 1, a. 1, n. 3).

1. The danger or fear of error, with which the danger of materially violating the law is necessarily connected, is always present in the use of a probable opinion, as is clear from the very notion of probability. But such a danger, when moral diligence for finding the truth has been made, we neither can nor are bound to avoid, because the error, if it is present, is invincible (cf. n. 95).

2. The danger of sinning formally is wholly removed in doubt of mere law by reflex principles. For conscience, relying on these principles, drives away practical fear and forms for itself a certain and prudent dictate concerning the honesty of its action, as was shown above (n. 38-39) and will be confirmed below.

3. Another danger, diverse from formal transgression of the law, can intervene in doubts of fact, namely the danger of some damage or evil, temporal or spiritual, on the part of the thing. Thus, for example, homicide embraces both moral evil, or sin, and physical evil, or grave damage, which is inflicted on the neighbor by deprivation of life. Here the matter concerns this last danger.

81. Principle. Whenever in doubts of fact there intervenes danger of damage or evil which does not depend on conscience and which we are certainly bound to avoid, the use of any probability whatever is unlawful, and the safer part is to be followed. So commonly, against certain laxists.

Proof. It is not lawful to expose an end absolutely to be pursued (such as that concerning which the matter here is) to the danger of frustration. But, the safer part being left aside, a danger of that sort (in the case) is not avoided; for, whatever may be true concerning the probability of the opinion, that danger perseveres in the thing itself; nor can it be removed by reflex principles, since it does not depend on the conscience or persuasion of the agent, but on the fact itself.

Thus an opinion, however probable, cannot make what is not a sacrament be a sacrament, or make what is rather poison be medicine.⁸ Namely, in cases of this kind, the matter is not about a doubtful law, but about a certain law, which forbids us to incur the danger of disturbing another from the certain possession of his right. Wherefore St. Alphonsus: "If," he says, "an arrow is shot in probable doubt whether that object is a man or a beast, one does not act against a doubtful law, but against a certain law: for in such a case the law is certain, that the life of one's neighbor, who has a certain right not to be injured, not be cast into probable danger" (H. Ap., I, 68).

We said: Danger of evil which we are bound to avoid; for sometimes there are just causes of permitting evil, indeed of creating the danger itself from which evil may arise: either because between two evils the lesser must be chosen, or because the safer part is judged morally impossible, or because the neighbor is not in certain possession of his right. In cases of this kind, it is lawful, the safer opinion being left aside, to choose the less safe (cf. n. 315).

82. But the necessity of an end absolutely to be pursued can arise from the law, whether of religion, justice, or charity, either toward oneself or toward one's neighbor. Whence the following flow:

Corollaries. I. In the conferral of the sacraments the minister cannot, concerning their value, use an opinion either probable or even more probable; but he is bound to follow a safe opinion, such as one which is either safer or morally certain. This is clear from the first proposition proscribed by Innocent XI: "It is not unlawful in conferring sacraments to follow a probable opinion concerning the value of the sacrament, the safer being left aside."⁹ The reason for the condemnation is that to confer a sacrament with only a probable opinion is contrary not only to charity, on account of the danger of grave harm, but also to religion and the reverence owed to the Author of the sacraments.

Except 1. If necessity urges, and by the use of an opinion even slightly probable concerning the value of the sacrament, the salvation of the neighbor is better consulted. For since men are not for the sacraments, but the sacraments for men, it is lawful to expose them to the danger of frustration, so that in this way, in the best way possible, help may be given to the salvation of a man certainly in danger. Hence, when certain matter is lacking, an infant who is in danger of death must be baptized with doubtful matter. Yet he is to be baptized under condition, lest injury be inflicted on the sacrament if perhaps it is made invalidly.¹⁰

2. Unless the Church can and is reasonably presumed to supply: which indeed can be done either in the sacrament of penance, if from a just cause it is administered with jurisdiction probable by probability of law; or in the sacrament of marriage, if there is present an impediment introduced by ecclesiastical discipline, also probable by probability of law.¹¹ But when the Church supplies, there is practically moral certitude, and therefore the sacrament is to be conferred not under condition, but absolutely. See more in the Treatise on Penance and on Matrimony.

Note. The question is whether in the reception of the sacraments it is lawful to use a probable opinion. Some affirm; but others not undeservedly deny, both because it is against the reverence due to the sacraments to expose them to danger of frustration, and because the opposite opinion can almost never be brought into practice without detriment to one's own soul (I, 51).

83. II. It is not lawful to use a probable opinion in danger of one's own damage, whether spiritual or temporal, necessarily to be avoided.

Hence: 1. In things necessary for salvation by necessity of means, for example in the matter of faith, the safer religion must be followed, which, without doubt, is our Catholic religion. The reason is that in things absolutely necessary for salvation, persuasion of conscience does not remove the danger of damnation. Therefore in these things the axiom has force: No security is too great where eternity is in danger. And the following fourth proposition was deservedly condemned by Innocent XI: "An infidel not believing, led by a less probable opinion, will be excused from infidelity."¹²

2. In a proximate occasion of sin, and generally in every probable danger of sinning formally, the safer thing must similarly be chosen, as will be explained more fully in its place (n. 373 ff.). Hence it is unlawful to follow several opinions which are indeed speculatively probable, but which, with attention to the common or special fragility of the one acting, are in practice certainly joined with probable danger of a fall into formal sin. Opinions of this kind are concerned with reading prohibited books, with kisses, touches, dances, comedies, the matter of simony, etc.

3. In danger of life it is not lawful, without necessity, to expose oneself to probable death, for example, by taking food probably harmless and probably poisonous.¹³

84. III. It is not lawful to follow a probable opinion in danger of spiritual or temporal harm to the neighbor, whenever the neighbor is in certain possession of his right.

Wherefore: 1. on account of the scandal of the neighbor, we are sometimes bound to observe a law which probably or even certainly does not exist.¹ Hence St. Paul (1 Cor. 8:13): "Wherefore," he says, "if food scandalizes my brother, I will not eat flesh forever, lest I scandalize my brother."

2. In healing, the physician is bound to apply the safer remedies. But if the case were desperate, it is sufficiently probable that it is lawful to use a doubtful remedy, that is, one probably going to help and probably going to harm; because, in a case of this kind, some hope of life is to be preferred to the danger of hastening death. But for the sake of experiment alone it is not lawful to apply wholly uncertain and untried remedies to the sick, even to the desperate, with danger of gravely harming them (I, 44 ff.).

3. In the direction and care of souls, the confessor is bound, regularly, to follow benign opinions, which commonly remove penitents more from the danger of formal sin. "But where benign opinions render proximate the danger of formal sin, as are some opinions of authors, for example, as to avoiding proximate occasions, and others of that kind; then it is always expedient that the confessor use, indeed I say that he himself, as a physician of souls, is bound to use the safer opinions, which conduce to preserving penitents in the state of grace" (I, 83; VI, 456).

4. In civil judgment, if neither party possesses, the judge is bound to render sentence in favor of that party for whom the more probable opinion stands. The reason is that the judge, by divine and human precept, must render to each his right, according to the greater weight of reasons which favor each one. Hence proposition 2 was condemned by Innocent XI: "I think it probable that a judge can judge according to an opinion even less probable."² But if the cause of each litigant seems equally probable, he must divide the contested thing, or its price, equally. The reason is that he himself is not the master of the things, but the distributor according to the rights of the parties. Hence proposition 26 was condemned by Alexander VII: "When litigants have for themselves equally probable opinions, the judge can accept money for rendering sentence in favor of one rather than the other"³ (I, 47).

Note. It was said: a) In civil judgment; because in criminal cases, where the matter concerns inflicting a penalty, especially a capital one, among opposed probable sentences the sentence favoring the accused must always be followed, even if it is less probable; otherwise the judge would expose himself to the danger of condemning an innocent man, which is intrinsically evil. b) If neither party possesses; because if one of the litigants possesses the thing in good faith, and has for himself a probable reason, he cannot be despoiled, even if the other adduces more probable reasons for himself. For legitimate possession gives the possessor a certain right of retaining the thing, until the right of the other is evident (I, l. c.; IV, 210). Cf. above n. 45.

5. In hunting, the hunter who doubts whether that which he sees in the forest is a wild beast or a man cannot strike it, even if he thinks it more probable that it is a wild beast.

The same must be said in similar cases (I, 52).