Article I. On Simple Cessation

The causes of simple cessation are: 1. lapse of time attached for ending the obligation; 2. substantial change of the matter promised; 3. defect of the condition on which the vow depends; 4. defect of the final cause (can. 1311).

I. Lapse of time, namely time attached for ending the obligation. When time ought to be judged attached in this way, see n. 649.

II. Substantial change of the matter promised. This has place if the matter becomes evil, indifferent, or less good than its omission. Likewise if the matter is notably changed because of a supervening and unforeseen circumstance. The reason is that the intention of the one vowing is judged to be interpreted in this way; indeed, not without foundation is notable change said to constitute a morally diverse object (St. Alphonsus, III, 226). Hence one who has vowed, for example, to build a church, is not bound by the vow if and as long as, because of damage following in the state of his fortune, the execution of the vow is rendered difficult. Except from the rule stated: 1. if it is a question of public vows, which are: religious vows, solemn as well as simple, perpetual as well as temporary, substantial as well as those which are annexed to them; likewise a vow annexed to Sacred Order; 2. if the discussion concerns a supervening difficulty which the matter of the vow carries with it by its nature, or which follows from the changed disposition or will of the one vowing. The reason is that in the former case, since the common good demands it, every supervening circumstance is judged to have been comprehended in the vow; in the latter case, the circumstance of grave supervening difficulty, since the very nature of the thing carries it with it, is judged to be contained in the vow. Hence, for example, a vow of chastity, even one emitted in the world, does not cease because of a difficulty afterward arising, even if it was unforeseen (St. Alphonsus, IV, 50). Besides, note:

1. If the matter of the vow has become unsuitable or impossible in part, the obligation also ceases as to the other part if the matter of the vow is either indivisible by nature, or was intended undividedly by the one vowing; but it persists if the matter of the vow both is divisible by its nature and was intended dividedly by the one vowing. Hence one who vowed 100 Masses and can offer only 50 is bound to these. If in the matter of the vow principal and accessory can be distinguished, when the principal falls, the accessory falls, but not conversely.

2. One who has emitted a disjunctive vow - for example, "I vow that I will undertake a pilgrimage or cause 10 Masses to be celebrated" - in the case in which one part has become unsuitable or impossible, is bound in this way:

a) If before election one part becomes unsuitable or impossible, the one vowing is per se immune from every obligation. For the circumstance that the one vowing now cannot choose is not judged to have been comprehended in the vow. Except: 1. if with sufficient certainty he intended one or the other part absolutely, that is, whatever might happen; 2. if the other part became unsuitable or impossible through the fault of the one vowing (St. Alphonsus, III, 224).

b) If after election the part not elected becomes unsuitable or impossible, the one vowing is bound to perform the part elected, because in that case the election seems to have to be regarded as validly determinative of the prior vow (St. Alphonsus, cited place).

c) If the part elected, not yet put into execution, becomes unsuitable or impossible, the one vowing per se is bound to nothing, according to what was said under a).

Corollary. One who has chosen one part can sufficiently probably commute it with the other part, because the election is not judged to have been intended in such a way that the one vowing deprived himself of the faculty of choosing the other part (St. Alphonsus, cited place).

III. Defect of the condition, namely the condition on which the vow depends; for example, if someone vows a pilgrimage if this or that should succeed: when the thing does not succeed, the vow collapses.

IV. Defect or cessation of the final cause, that is, of the cause for which the vow was emitted uniquely or principally, and without which it would not have been emitted; as if someone vowed a pilgrimage for obtaining his father's health, and the father dies before the vow is fulfilled.