Summa summae S. Thomae, Tomus II

You will ask 1° whether a human law binds when there is certain danger of death or of other grave harm.

I answer. 1°. A human law binds with danger of life, when its observance is of greater moment than the life of any particular person: which happens in two cases. The first is, when the observance of the law is necessary for the common good. The second, when its violation would redound to the contempt of religion, or of the Church, or of ecclesiastical power. This is common opinion.

It is proved. Natural reason itself says and commands that the greater good be preferred to the lesser. But the common salvation of the commonwealth, and that religion and the Church be not despised, nor God in them, is a greater good than the life of one private person. Therefore.

I answer. 2°. Outside the twofold case of the first conclusion, a human law does not bind with danger of life or of other grave harm to honor, reputation, health, goods of fortune.

It is proved. 1° Divine law itself does not bind with grave detriment, as is evident in the Apostles who plucked ears of corn on the sabbath, and in the integrity of confession which, although of divine law, does not bind with grave harm. 2° Because otherwise the law would not be accommodated to the frailty of men, nor possible according to the morals and custom of the country. 3º Because the legislator has neither from God nor from the people the power of disposing of the life, reputation and goods of subjects, except where the necessity of the common good and of religion requires it.

You will ask 2º whether a law founded upon a false presumption binds in conscience.

I answer. 1° The legislator does not intend to bind, except when the presumption corresponds to truth. Whence, if a law prescribes something presumed to be licit or useful to the common good, and it is illicit or harmful to the common good, it does not bind.

[2° When a law presumes that that on account of which it is enacted happens in all and singular cases, it does not bind in those cases in which it does not happen, because they remain outside the intention of the legislator. 3º But when the law presumes that that on account of which it is enacted happens not in all and singular cases, but only for the most part, or that there is danger lest it happen; although it do not so happen in a particular case, the law does not therefore cease to bind in conscience, for the legislator certainly intends to bind even in this case. For he enacted the law because he presumed that for the most part it is so, or that there is danger lest it be otherwise; which remains true notwithstanding cases which ought to be held as exceptions.

Since, in the supposition, the presumption is not false, it must be said generally that every law founded upon a false presumption does not bind in conscience.]

You will ask 3° whether several laws can be satisfied by one act, or by several acts exercised at the same time.

I answer. 1°. By one act several laws can be satisfied, if they prescribe the same matter; otherwise, if diverse matters.

The reason of the first part is, because by this very thing that the prescribed matter is performed, whether by one act or by several, there is had the whole which is prescribed by the diverse laws. Thus by a single recitation of the Hours a beneficed priest satisfies the double law by which he is bound, as priest and as beneficed, to recite the Hours.

The reason of the second part is evident from the opposite reason; because by one act there is not had the whole which is prescribed by diverse laws dealing with diverse matters. Thus he to whom a confessor enjoins hearing Mass, beyond that to which he is bound from the precept of the Church, does not satisfy by one Mass; because he does not perform the whole which is prescribed by the diverse laws. Consult our treatise on Religion, dissertation 11, a. 8, § 3.

I answer. 2º That several laws can be satisfied by several acts exercised at the same time, when they are not incompossible, or one does not impede the other; because then there is had the whole which the legislators prescribe. Thus he who makes a pilgrimage by vow can recite the office on the way. Likewise he who hears Mass of precept can at that time recite the Hours, or fulfill his sacramental satisfaction.

Otherwise, if they were incompossible, as if anyone during Mass were performing a prescribed work which would impede the attention required at Mass. Concerning him who confesses sacramentally during Mass, and certain other cases belonging to the present matter, see our treatise on Religion, dissertation VI, a. 5.

You will ask 4° whether he who cannot fulfill the whole law is bound to the possible part.

I answer. Affirmatively, if the law concerns a divisible thing, and the term of ability and inability is not uncertain and ambiguous.

It is evident 1° from this proposition condemned by Innocent XI, n. 54: « He who cannot recite Matins and Lauds, but can recite the remaining Hours, is bound to nothing, because the greater part draws to itself the lesser. » 2º Because precisely for this reason someone is excused from the whole, because the whole is impossible to him. But, as is supposed, the part is not impossible to him. Therefore he is not excused from it.

Understand however a part notable in some manner, v. g., in the recitation of the Hours, entire psalms, or the greater part of them, not altogether slight, such as, in the same matter, one or another psalm or hymn, because in moral matters a little is reputed as nothing.

I said also: « If the term of ability and inability is not uncertain and ambiguous, » as v. g., in the sick, in whom it can scarcely, or hardly, be determined what they are able to do, how far they are able, and no further. Whence, if while unable to fulfill the whole law they were bound to the part, there would be place for most grave scruples and continual perplexity in determining the part to which they would be bound. And therefore by right it is presumed of the mind of an equitable legislator that he would not will to bind to the part in similar cases. So say grave theologians.

You will ask 5° whether it is licit to place, or not to remove, impediments to the observance of a human law before the time for fulfilling the law arrives.

I answered this question in the treatise on Religion, dissertation VI, a. 6, question 2, that this is not licit without legitimate cause, especially with the direct intention of exempting oneself from the law.