§ I. On The Intention Required For A Vow

379. • For the validity of a vow there is required a true and deliberate intention of emitting a vow, or a true promise made to God and inducing obligation; for a vow is like a certain law which the one vowing, otherwise capable of weighing the burden which he assumes, imposes upon himself. But the will and deliberation are required which are necessary for the perfect and direct voluntary. Wherefore a vow emitted in drunkenness, even if foreseen beforehand, is invalid.

Hence a vow differs essentially from a purpose; because a purpose, however firm, or even uttered with some solemnity - as the purpose among our people of abstaining from every intoxicating drink (the pledge) - does not produce a bond of obligation, nor is the omission of the thing proposed a sin, except perhaps sometimes accidentally, for example because of inconstancy, weariness, or negligence, which of themselves do not exceed venial sin.¹

380. Questions. - Quaer. 1° Is a vow valid when made with ignorance of the obligation, or with inadvertence to the obligation already known?

Resp. to the first. A vow made with complete ignorance of the obligation which it induces is not valid, because without the intention of obligating oneself there is no vow.

Resp. to the second. It is valid if he who emits the vow habitually knows clearly its obligation, although he does not actually attend to it; or also if he who vows, although he does not know the obligation clearly, nevertheless apprehends it confusedly, or wills it implicitly, when, for example, he wills to vow this or that as others are accustomed to vow. Yet generally it must be held that no greater obligation is induced than that which someone shall have willed to impose upon himself and shall have apprehended.

Quaer. 2° Is a vow emitted from error valid?

Resp. 1° Negatively, if the error concerns either the substance of the thing, as if you vow a chalice to some church which you believed silver, when it is gold; - or concerning substantial circumstances, as if someone vows a pilgrimage to the House of Loreto, thinking that it is distant only so many leagues, when it is distant by many more; - or concerning the final cause of the vow, as a vow of giving alms to poor Titius because he is a blood relative, when he is not.²

Resp. 2° Affirmatively, if the error concerns accidental circumstances of lesser moment, which would not have stood in the way of the vow if, error excluded, they had been known, as if you vow alms to poor Caius, whom you think upright, when he is not.³

Yet note that vows which are emitted in any approved religious institute are not invalid because of any error, unless only a substantial one concerning the substance. St. Alphonsus.⁴ "The reason is," says Lugo,⁵ "because in those things which constitute a state firm and irrevocable by its own nature, such as profession and matrimony, the will, according to the nature of the thing in question, accommodates itself and consents without restriction or condition, and altogether absolutely and independently from other conditions besides those which are of the substance of the same contract. For from those conditions marriages and professions would remain uncertain, and therefore the state itself, which is not according to the nature of the thing in question." And, as Sanchez¹ adds, "From dependence of this kind it would follow that many professions and most marriages would have to be judged invalid; which would yield to the grave harm and scandal of the commonwealth."

381. • Quaer. 3° Is a vow made by fear valid?

Resp. 1° Negatively, if the fear is grave, unjust, and inflicted for extorting the vow. The reason is that what is extorted from someone by force through injury cannot be acceptable to God, when the law of nature postulates that the right be restored in full. And this indeed proves that vows of this sort are invalid by the law of nature. But it is established from Canon Law as to solemn vows of Religion, and more probably also as to the other vows, according to the more common interpretation of theologians.²

Resp. 2° Affirmatively, if the fear arises from within or from a necessary cause, unless it takes away from the one vowing the use of reason; the reason is that vows of this sort are simply voluntary. Likewise if the fear proceeds from a light cause, because light fear is not judged to influence the act efficaciously, and is rather the occasion than the cause of the vow. - Thus commonly with Sanchez, Azor, the Salmanticenses; and St. Alphonsus says this is more probable.³

Quaer. 4° Is he bound by a vow who doubts: 1. whether he emitted a vow or a mere purpose; 2. whether he had sufficient deliberation; or whether he was compelled by grave fear?

Resp. to the first. Negatively. This is established from what was said on Probabilism (n. 67. 1°). But if while he promised he believed that he would sin if perchance he did not execute the thing proposed, it can be judged that he truly vowed.⁴

Resp. to the second. Affirmatively, in any doubt, according to what was said n. 67. 2°, unless certainly he had vowed before the seventh year.⁵