Validity and liceity are concepts in the Catholic Church. Validity designates an action which produces the effects which were intended; an action which does not produces the effects which were intended is considered "invalid". Liceity designates an action which has been performed legitimately; an action which has not been performed legitimately is considered "illicit". Some actions can be illicit, but still be valid.
Catholic canon law also lays down rules for licit, also called lawful, placing of the act, along with criteria to determine its validity or invalidity. Valid but illicit and valid but illegal (Latin: valida sed illicita) are descriptions applied in the Catholic Church to describe the same act: an unauthorized celebration of a sacrament, or an improperly placed juridic act, that nevertheless has effect. Validity is presumed whenever an act is performed by a qualified person and includes those things which essentially constitute the act itself as well as the formalities and requirements imposed by law for the validity of the act.
Except in a case of necessity, it is unlawful for anyone without due permission to confer baptism outside his own territory, even upon his own subjects. Administration of baptism is one of the functions especially entrusted to the parish priest.
However, any person, even someone not baptized, can baptize, if he has the required intention. The intention required is to will to do what the Church does when she baptizes, and to apply the Trinitarian baptismal formula. If done in an emergency situation, such a baptism is always valid and licit.
A bishop is the ordinary minister of confirmation and he may licitly administer it to his own subjects everywhere and, in his own territory, even to Catholics who are not his subjects, unless their ordinary has expressly forbidden it. In the Latin Church, simple priests (presbyters) can validly and licitly confirm in some circumstances, such as when they baptize adults or receive them into the church and when there is danger of death.
Priests of the Eastern Catholic churches can validly confer the sacrament on any Catholic, even a Catholic of the Latin Church, but they can do so licitly only on those who belong to their own particular church and on other Catholics who meet the conditions of either being their subjects or of being lawfully baptized by them, or of being in danger of death.
A prime example of valid but illicit celebration of a sacrament would be the use of leavened wheaten bread for the Eucharist in the Latin Rite or in certain Eastern Catholic Churches. If, on the other hand, rice or rye flour are used instead of wheat, or if butter, honey, or eggs are added, particularly in large quantities, the Mass would be invalid ("transubstantiation" would not occur).
Likewise, wine used for the Eucharist must be valid and licit. Invalid wine would be any wine containing high levels of volatile acidity (vinegar) or made of non-grape fruits. Valid but illicit wines would be any containing water (amelioration), non-grape sugars such as corn syrup, cane sugar, beet sugar and non-grape flavorings, and those wine fortified with grain alcohol and other non-grape distilled spirits.
Church laws regarding confession require that priests who are hearing confessions must have valid faculties and jurisdiction. As penance is not only a sacramental act but also one of jurisdiction, such faculties are required for both for validity and liceity.
Those who are provided with the faculty of hearing confessions by reason of office or grant of a competent superior of a religious institute or society of apostolic life possess the same faculty everywhere by the law itself as regards members and others living day and night in the house of the institute or society. They also use the faculty licitly unless some major superior has denied it in a particular case as regards his own subjects.
Confessions in which the priest does not have the faculties to hear confession, yet without good reason pretends to have them, are valid but illicit. The Church supplants the faculties leading to validity of the sacrament (Canon 144).
However, in danger of death or a very grave emergency, any priest anywhere, even a suspended, interdicted, excommunicated or laicized priest, one who would not have faculties anymore, or one who for some reason does not have them, may validly and licitly absolve the person, even if a priest in good standing with faculties is nearby. Even for priests whose privileges have been suspended or revoked, a bishop or other superior may grant faculties for the sacrament of confession for a time or for certain purposes.
Pope Francis allowed priests of the canonically irregular Society of Saint Pius X to hear confessions during the Year of Mercy, in 2015 and 2016; Pope Francis extended the concession indefinitely in the apostolic letter Misericordia et Misera of 20 Nov. 2016.
Every priest can administer the sacrament of anointing of the sick validly. The duty and the right to administer it pertains to the priest to whom the spiritual care of the person concerned is entrusted. However, any other priest may administer it instead for a good reason if he has the presumed consent of the priest who has the duty and right.
Without that presumed consent, he is in the same position as a priest who has been laicized or suspended or excommunicated. The administration of the sacrament is then valid but illicit.
All bishops are able to ordain a deacon, priest, or bishop. In the sacrament of holy orders, a valid but illicit ordination, as the name suggests, is an ordination in which a bishop uses his valid ability to ordain someone a bishop without having first received the required authorization. The same would apply to a bishop's ordaining of a man who has not undergone and completed necessary seminary schooling, as required by canon law. The bishop is then acting in a manner deemed illicit or illegal.
A Catholic bishop who consecrates someone to the episcopate without a mandate from the Pope is automatically excommunicated according to canon law even if his ordination may be considered valid. The person who receives consecration from him is also automatically excommunicated. The excommunication can be lifted by only the Holy See.
In the 20th century, Archbishop Marcel Lefebvre earned automatic excommunication for his valid but illicit ordinations of four bishops for the SSPX without a papal mandate. After Lefebvre's death, the Holy See, on 21 January 2009, lifted the excommunication of the four bishops. However, his defenders argue that he acted under grave necessity, which the 1983 canon law stipulates is a valid excuse to avoid automatic excommunication in this case (canon 1323, §4).
A marriage celebrated in due form but without express permission of the competent authority of the Catholic Church between a Catholic and another baptized person enrolled in a church or ecclesial community not in full communion with the Catholic Church is "prohibited" (illicit) but valid. On the other hand, a marriage celebrated in due form between a Catholic and an unbaptized person is invalid unless dispensation has previously been obtained from the competent church authority.