456. As to the effects of ignorance on acts irritated by law, the Code states that ignorance of irritating (invalidating) and inhabilitating (disqualifying) laws does not excuse from their observance, unless the law expressly states otherwise (Canon 16, Sec. 1). Moralists discuss the influence of ignorance (as well as force or fear) on such acts as follows: (a) if the law is irritant and not penal, it has its effect, in spite of ignorance, oversight, etc.; for this the common good requires. Example: One who marries his cousin in good faith, being invincibly ignorant that it is against the law, contracts invalidly; (b) if the law is irritant and penal, the irritation being decreed solely as a punishment, ignorance, oversight, etc., sufficient to excuse from fault, excuse also from the penalty of irritation; for penalty presupposes fault. Before the law, however, ignorance and error as to law or penalties are not presumed but must be proved. (Nevertheless, it must be noted that according to some authors no penalty is necessarily or primarily intended in ecclesiastical irritating and inhabilitating laws. Though punishment actually results from the matrimonial impediment of crime, for example, the impediment as such primarily is a personal disqualification intended to protect the dignity of the sacrament and good morals. Ignorance, then, does not excuse from it. Some authors maintain that this is true of all ecclesiastical disqualifying laws.) 457. Generally speaking, _epieikeia_ may not be used in the interpretation of irritating and inhabilitating laws. Since they transcend the individual welfare, they demand uniform observance of all subject to them. Some authors permit the use of _epieikeia_, however, in particular cases in which the law itself aims to protect the individual, whereas its observance would tend rather to harm the individual or at times even the interests of the community. Accordingly, it seems probable that an irritant law may cease in case of impossibility or of a most grave inconvenience that is common. Example: If in a pagan country Christians were so few that they could marry only infidels, and if distance or other circumstances made it impossible to seek a dispensation, the diriment impediment of disparity of worship would seem to cease for those Christians. 458. Some authors hold that an irritant law may also cease on account of impossibility, or of a most grave inconvenience that is only private; but this opinion cannot be deemed certain. An example of private inconvenience is the case of an invalidly married person who is near to death and unable to seek the dispensation from the impediment that has made the marriage null.