491. Other specific determinations of the law include: (a) Inculpable ignorance of the law itself excludes moral imputability (Canon 2202, Sec.1); actual inculpable inadvertence or error in regard to the law has the same effect (Canon 2202, Sec.3). (b) Culpable ignorance, or culpable inadvertence, or error concerning the law or concerning the fact diminish imputability more or less in proportion to the culpability of the ignorance (Canon 2202, Sec.1). (c) If the ignorance, even inculpable, affects only the fact of the existence of the penalty, it does not exclude imputability of the delict, but it does diminish it (Canon 2202, Sec.2). 492. Absolute or physical impossibility (i.e., the want of the power or of the means of complying with a law), of course, excuses from its observance; for no one is bound to what is impossible. This applies to divine law, and hence much more to human law. Example: He who is unable to leave the house is not obliged to go to Mass. 493. Moral impossibility--that is, the inability to comply with the law without extraordinary labor, or the imminent danger of losing a notable good or of incurring a great evil--does not excuse from the observance of ecclesiastical law when this law receives through circumstances the added force of the negative law of nature. This happens when the evil that will result through the observance of the law bears no proportion to the evil that will result from its violation, the former being private or temporal or human, the latter public or spiritual or divine; for the law of nature forbids that the common welfare, or the salvation of a soul, or the honor of God be sacrificed for the benefit of an individual, or for the life of the body, or for the welfare of a creature. Example: The command to abstain from meat on Friday obliges, if one has been ordered to violate it as a sign of contempt of God or of religion, even though death is threatened for refusal. 494. Moral impossibility excuses from the observance of a human law in the following cases: (a) One is excused when a considerable loss in health, reputation, spiritual advantage, property, etc., or a grave inconvenience will result from observing a law which is not a prohibition of nature in the sense of the previous paragraph; for the legislator cannot impose obligations that are needlessly heavy, and hence positive law does not oblige in case of such moral impossibility. Example: Our Lord reproved the inhuman rigor of the Pharisees, who insisted that their regulations must be observed, whatever the difficulty or cost.