§ I. On the Nature of Those Things Which De-Obligate

108. • De-obligating causes are either exempting or impeding. The former are those which totally withdraw one from the dominion of the law, for example, if someone betakes himself outside the place which the law affects. The latter are those which impede, or excuse, a subject remaining under the law from the fulfillment of it. But these impeding causes are reduced to ignorance and impotence.

Principles. - I. Exempting causes totally free from the obligation of law; for no one can impose a precept on a man not subject to himself. Moreover where some exempting cause is present, he who was subject to the law ceases to be subject to the same law either by reason of territory from which he is absent, or by reason of privilege. - Recall what was said above concerning travelers, no. 94.

II. Invincible ignorance excuses from observing the law, because no one can be obligated to something altogether unknown to him. - But vincible ignorance does not excuse from fault, since it could have been or can be put away by serious diligence. - St. Lig., Apostolic Man, no. 43. - Recall what was said On Human Acts, no. 13, and On Conscience, no. 36.

III. Physical impotence always excuses from observing the law, as the common axiom has it: No one is held to the impossible. Moral impotence likewise excuses; because the legislator is not considered to urge an obligation with an inconvenience which, according to the common interpretation of Doctors, can be had as grave. - See what was said above on the obligation of law, no. 100.

Hence grave fear, damage to society or Religion being excluded, excuses from human law; because human law does not oblige with grave harm, as was said above, no. 100. It also sometimes excuses, although with more difficulty, from a positive divine precept, for example, from the integrity of confession; indeed also from an affirmative natural precept, for example, of preserving a deposit with danger of life. Yet it never excuses from a negative natural precept, because the object of this is intrinsically evil. Nor say that it is licit to steal in extreme necessity; for then it ceases to be theft. - St. Lig., no. 175; Apostolic Man, no. 44.

109. • QUESTION. Whether one who is unable for the whole is held to the part?

I answer affirmatively, when the matter of the law is divisible, and in the individual parts the reason of the precept remains. It is clear besides from prop. the following proposition condemned by Innocent XI: He who cannot recite Matins and Lauds, but can recite the remaining Hours, is held to nothing, because the greater part draws the lesser to itself. Except if the possible part is so slight that it conduces in no way to the end of the precept. - Thus commonly.

Hence 1. He who cannot fast in Lent ought to abstain from flesh meat, if he can. Likewise he who cannot fast on all days is held on the days on which he can without grave inconvenience.

2. If someone lacking a Breviary knows a few things from the Hours by memory, he is not held to recite them; otherwise, if he holds by memory a notable part, for example, Vespers or Compline. - St. Lig., book 4, no. 134, rightly says that an infirm Priest who is not able to read the whole Office, and doubts whether he can read a part, is not held even to a part, lest he undergo danger of anxiety, or notable detriment of health.

3. He who vowed a pious pilgrimage, and is not strong enough to complete the whole journey, is not held to begin it, because neither the end nor the reason of the vow can be obtained. - St. Lig., Apostolic Man, no. 45.