Chapter I. On Promise

I say. Given the conditions of a true promise, there arises an obligation of fulfilling it. The reason is that a promise is a true contract, and it is impossible for there to be a contract without some obligation. Moreover, the conditions of a true promise are: 1st, that there be the intention of binding one's faith, and not merely of stating a purpose; 2nd, that the consent of the one promising be fully free and spontaneous; 3rd, that the promise itself be outwardly manifested and accepted, because every contract requires mutual consent of two or more persons upon the same object.

You Will Resolve. - 1st. It is certain that a true promise imports some obligation, but theologians dispute much concerning its quantity. But the more common and more probable opinion teaches that it depends upon the intention of the one promising. Wherefore if he intends to oblige himself from justice, he is obliged under mortal sin in grave matter; but if he intends only to oblige himself from fidelity, he is obliged only under light sin. Moreover, for grave matter in a promise, the Doctors require a quantity four times greater than in grave theft. - Cf. St. Alphonsus, n. 720.

2nd. In doubt, whether there was a true promise or a simple purpose, or whether someone wished to oblige himself under grave sin or rather under light sin, one must stand by the least part according to the rules of probabilism. - Indeed Kenrick says: "English law, which also obtains in these regions, attributes no force to a promise made by word only or altogether gratuitous, that is, one which rests on no equitable cause, either work furnished, or nearness of family, or another grave reason." - Cf. St. Alphonsus, n. 720. - Kenrick, n. 22.

Question 1. When does the force of an accepted promise cease?

Resp. It ceases: 1st, if the promisee spontaneously condones or yields from his right; 2nd, if the thing promised becomes illicit or useless; 3rd, if the promisee does not stand by his promises; 4th, if the state of things or persons is so changed that the promise does not seem to comprehend that event; 5th, if the end which moved to promising in no way subsists, and can no longer be obtained. - Cf. St. Alphonsus, ibid.

Question 2. Whether, or to what extent, a promise obliges if before execution the promisee or the promisor dies?

Resp. In the case of the death of the promisee, the promise in no way obliges if it was made principally for the favor of the promisee, because with him dead, the end intended in the promise ceases; but otherwise if it was made chiefly in view of the family of the promisee or of his heirs. But in the case of the death of the promisor, the promise clothed with due conditions must be fulfilled by his heirs; because every real obligation must pass to the heirs in the same way and under the same title by which the promisor was obliged. Therefore under grave or under light sin, from justice or fidelity, the heirs will be held just as the promisor was held while he was living. Nevertheless they will be able to be freed from every obligation if from the adjuncts it is manifest that the promisor wished only to oblige himself personally.