§ IV. On Causes Excusing from Obligation

A cause excusing is one which brings it about that one who is subject to the law is not held to observe it. It differs from a cause exempting, which brings it about that someone ceases to be subject to the law (St. Alphonsus, I, 152).

The excusing causes are ignorance and inability. Ignorance brings it about that one who transgresses the law does not sin formally, but not that material sin is absent. Inability averts not only formal sin, but also material sin. Ignorance was discussed where there was speech about impediments of liberty (nn. 30-32), so that only inability must be treated.

I. Notion and division of inability. Inability is twofold, physical and moral. The former is had when someone absolutely cannot observe the law; the latter, when he cannot observe it without a grave extrinsic inconvenience, or without grave danger of such an inconvenience. I said "without a grave extrinsic inconvenience," because there is not question of the inconvenience which the law itself, or the work imposed by the law, contains in itself. It is clear that an inconvenience of this sort does not excuse. Hence, for example, shame does not excuse one who has sinned gravely from premising confession to communion; nor does it excuse someone from the precept of confessing integrally.

II. Inability which excuses. That physical inability excuses is manifest. Moral inability:

1. Does not excuse from the obligation of the natural law, since it is immutable, so that that which is opposed to it, notwithstanding moral inability, remains illicit. The examples which are brought forward against this doctrine are explained by a change of circumstances; this change brings it about that the case is no longer included in the law (cf. n. 86).

2. Generally excuses from positive law, both divine and human. For the legislator, on account of equity, is not considered to require that the subject undergo both the burden of the law itself and another grave burden, so that, if one of these, namely the burden of the law, cannot be undergone without the other burden, he is held to nothing. Moreover, the legislator is considered all the more not to require this both because the common good does not require that the law be urged in difficult cases of this sort, and because a law which were urged in this way would tend to the damage of many, considering, namely, the frailty of men. Hence rule 4 of the law in the Sixth: what is not licit in the law, necessity makes licit (cf. can. 2205, § 2). I said generally, because positive law obliges even with the gravest inconvenience: first, when common necessity or the extreme spiritual necessity of an individual requires it; second, when violation of the law would tend to contempt of God or of religion (St. Thomas, I-II, q. 96, a. 6, ad 1; St. Alphonsus, I, 175, 176; cf. can. 2205, § 3). Besides, as regards the moral inability required, note:

a) In order that someone be excused from the obligation of law, a relatively grave extrinsic inconvenience is required; in other words, the inconvenience must be graver according as the matter of the law and the end of the legislator are graver; likewise according as the legislator is more worthy and the obligation recurs less frequently. Thus, for example, of itself you are more easily excused from the observance of human law than of divine law; more easily from the law of fasting than from the law of annual communion. In addition, it suffices that relatively grave damage is probably going to follow from observance of the law; in other words, that it is prudently feared. Hence, for example, he is excused from the law of fasting who prudently fears that fasting is going to bring grave damage upon him (St. Alphonsus, IV, 154).

b) In doubt whether the cause suffices for excusing, you seem to be held to the law, because an interpretation of the legislator's mind of this sort would give occasion to illusions and undue transgressions (St. Alphonsus, I, 97). Nevertheless, one is excused even from partial observance of the law who is certainly excused from entire observance, but doubts whether the inconvenience attached to some part is sufficiently grave. The opposite opinion would open the way to anxieties (St. Alphonsus, IV, 154, 4°). Hence "if someone, because of his weakness, is certain that he cannot recite the whole office, and doubts whether he can recite a part, he is probably held to nothing" (St. Alphonsus, IV, loc. cit.).

c) One who cannot observe the whole law, but can fulfill a part, is held to this part as follows:

alpha) He is held to the possible part if the matter is morally divisible and the possible part is notable. I said "if the matter is morally divisible," that is, if it can be divided into parts in which, taken separately, the reason or end of the law is preserved. Hence proposition 54 was condemned by Innocent XI: "He who cannot recite Matins and Lauds, but can recite the remaining Hours, is held to nothing." Therefore one excused from fasting is not of himself excused from the law of abstinence; one who lacks a breviary is held to recite a notable coherent part, if he retains any in memory, suppose a little hour, Vespers, or Compline.

beta) He is not held to the possible part if the matter is morally indivisible, or the possible part is not notable. Thus one who vowed a pilgrimage to a sacred place and cannot arrive there is not held to a part of the journey, because the reason or end of the law is not preserved; one who lacks a breviary and retains only a few things in memory, or only non-coherent things, suppose separate Psalms, is obligated to nothing¹ (St. Alphonsus, I, 176, 177).

¹ Cf. Theol. Mechl., p. 149.