Section — Wouters, Manual of Moral Theology
Section II. Excommunications Reserved to the Roman Pontiff in a Special Manner
This excommunication is contracted by:
I. All apostates from the Christian faith, and all and each heretics or schismatics (canon 2314, § 1, 1°, and § 2). This excommunication is reserved to the Apostolic See in a special manner only insofar as absolution is to be imparted in the forum of conscience (cited canon, § 3; cf. 3, b). Who come under the name of apostates, heretics, and schismatics, see canon 1325, § 2 and volume I, n. 492. Note, however, that it is required that apostasy, heresy, or schism be externally manifested. For the rest, observe:
As to apostates. Here belong both those who reject every religion, such as atheists, pantheists, naturalists, and so-called free-thinkers; and those who pass over, for example, to Judaism, Mohammedanism, or paganism; but not those who are only practically indifferent.
As to heretics. It is not required that someone be enrolled in some heretical sect. Those enrolled in a sect, however, are deemed, for the external forum, to have contracted the censure, although perhaps internally they are not formal heretics and therefore have not in fact contracted the censure (n. 862).
Schismatics. It is not required that someone be enrolled in a schismatic body; but neither is it enough that someone, even habitually, transgress special commands of the Supreme Pontiff. For the rest, note:
a) Unless they, namely apostates, heretics, or schismatics, having been warned, come to their senses, they are to be deprived of benefice, dignity, pension, office, or other function, if they have any in the Church; they are to be declared infamous; and clerics, after a repeated warning, are to be deposed (canon 2314, § 1, 2°). If they have given their name to a non-Catholic sect or publicly adhered to it, they are ipso facto infamous, and clerics ipso facto and without any declaration lose any offices whatever, and, after a warning has been given in vain, are to be degraded (canon 2314, § 1, 3°).
b) As to absolution from the excommunication set forth, observe:
alpha) Absolution to be imparted in the forum of conscience is reserved to the Apostolic See in a special manner (canon 2314, § 2). The faculty of absolving any penitents whatever, except heretics who purposely disseminate heresy among the faithful, from any censures and ecclesiastical penalties incurred on account of heresies externalized either with no one hearing or noticing, or before others, is customarily granted through the Sheet of the Sacred Penitentiary. Nevertheless it cannot be exercised except in the act of sacramental confession and for the forum of conscience only, after a secret abjuration has first been made before the confessor. Moreover, a salutary penance is to be imposed, together with frequency of the sacraments and the obligation of repairing the scandals caused. For the forum of conscience no form of abjuration seems prescribed; hence, for example, these words of the Profession of Faith at the end suffice: "I likewise condemn and reject any heresies whatever condemned by the Church."
beta) If the delict of apostasy, heresy, or schism has in any way been brought to the external forum of the local Ordinary, even by voluntary confession, that same Ordinary, but not the Vicar General without a special mandate, can by his ordinary authority absolve in the external forum the one who has come to his senses, after an abjuration juridically performed and with the other things to be observed by law observed; and one thus absolved can then be absolved from sin by any confessor in the forum of conscience. Abjuration is held to have been juridically performed when it is made before the local Ordinary himself or his delegate and at least two witnesses (canon 2314, § 2). As to the form of abjuration, in practice the Profession of Faith which is placed at the beginning of the Code suffices.
Question: whether those doubtfully baptized or doubtfully validly baptized, who are guilty of apostasy, heresy, or schism, are subject to excommunication.
Response: They are or are not subject to the excommunication according as in fact they were validly or not validly baptized. Since this here and now is doubtful, absolution is to be granted as a precaution if they are converted to the Church. If you object that those doubtfully baptized or doubtfully validly baptized are not subject to the laws of the Church, I answer: if it concerns laws which deprive someone of some good, they are subject or not subject to them according as valid baptism did or did not take place; if the discussion is of laws which regard an act, see volume I, n. 130.
II. One suspected of heresy who, having been warned and punished according to the norm of canon 2315, has not completely amended himself within six months from the penalty contracted (canon 2315). Moreover, the following are suspected of heresy:
Whoever in any way willingly and knowingly helps the propagation of heresy (canon 2316).
Whoever communicates in divine things with heretics by actively assisting at their rites (canon 2316; p. 732).
Those who enter marriage with an explicit or implicit agreement that all or some of the offspring be educated outside the Catholic Church (canon 2319, § 1, n. 2, § 2).
Those who knowingly presume to offer their children to non-Catholic ministers for baptism (ibid., n. 3).
Parents, or those holding their place, who knowingly hand over their children to be educated or instructed in a non-Catholic religion (ibid., n. 4).
Whoever has thrown away consecrated species or has taken them away or retained them for an evil purpose (canon 2320).
Those appealing from the laws or mandates and decrees of the Roman Pontiff to a Universal Council (canon 2332).
Whoever, with hardened spirit, has wallowed for a year in excommunication (canon 2340, § 1).
All, even those of episcopal dignity, who knowingly through simony have promoted someone to Orders or have been promoted, or have administered or received other Sacraments (canon 2371).