When is Someone A Heretic? A Look at “Heresy” and “Suspicion of Heresy”

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Heresy and Suspicion of Heresy: An Analysis

Table of Contents

Introduction………………………………………………………………………………….. 2

Definition of “Heresy”…………………………………………………………………… 3

The Principles and Early Use of the Canonical Term “Suspicion of Heresy”……………………………………………………………………………………….. 9

The Use of the Term “Suspicion of Heresy” in the 1917 Code of Canon Law and its Disappearance…………………………………………………………… 15

Conclusive Considerations…………………………………………………………… 19

Selected Bibliography………………………………………………………………….. 21



A widely misunderstood term is “heresy”, which apart from being misunderstood, instills fear in many. So, what exactly is heresy? What makes one a heretic? What happens with someone entertaining erroneous thoughts about the faith but who does not display them? Can one be a ‘semi-heretic’ or are there only ‘full blown’ heretics? Bringing answers to these questions is the purpose of this analysis. To do so, the first part of this paper will present a definition of “heresy”, its consequences, both on the external and internal fora and, its limits. Then, the next parts will cover the now forgotten category of those “suspected of heresy”, which, as it will be argued, began as wide and complex before becoming simpler and finally shading away. Finally, some conclusive considerations will complete this analysis.

This essay will be thorough but will possibly not develop on everything it could. Indeed, as one may be aware, such a topic as defining heresy, and suspicion of it, is quite varied and extended…

Definition of “Heresy”

Heresy is defined as “the obstinate denial or doubt, after baptism, of a truth which must be believed by divine and catholic faith.”[1] There are critical elements here.

First, heresy contains an obstinate denial or doubt, which implies that it involves an act or thought which is made with sufficient knowledge and will to be ‘obstinate’. If the denial or doubt is hidden, if it is not manifested by any exterior and moral act, “committed most commonly by words, written or spoken,”[2] it cannot be legally imputable; cannot receive any canonical penalty.[3] Although, one who interiorly has an obstinate denial or doubt is still interiorly guilty of the sin of heresy, as it goes against the faith – an element to be soon developed -. Canonical penalties regarding heresy are contained in cc. 1364 and 1336, §§1-2, and are respectively a latæ sententiæ excommunication and some other expiatory penalties. Also, both the faithful under 16 years of age and those who entered heresy “in good faith”[4] or who are ignorant that they violate the law do not incur canonical penalties.[5]

Secondly, to be “heresy”, the obstinate denial or doubt must concern a truth to be believed by divine and catholic faith. Such truths are described as:

Those things … which are contained in the word of God as it has been written down or handed down by tradition, that is, in the single deposit of faith entrusted to the Church, and which are at the same time proposed as divinely revealed either by the solemn magisterium of the Church, or by its ordinary and universal magisterium, which is manifested by the common adherence of Christ’s faithful under the guidance of the sacred magisterium. All are therefore bound to shun any contrary doctrines. (CIC/83, c. 750, §1.)

In other words, to be held with catholic and divine faith, a truth must be contained in the written or orally transmitted Word of God, included in the deposit of faith entrusted to the Church of Christ, and this truth must be presented to the faithful as a revealed one.[6] Usually, the truths of the catholic and divine faith are defined in certain magisterial acts as in the solemn magisterium of the Pope (described in c. 749, §1), which is infallible when the Pontiff acts in his office as “chief Shepherd and Teacher of all Christ’s faithful;”7 when the teaching is a revealed truth on matters of faith and morals; and when this teaching is proclaimed as a definitive matter of an obligatory object of faith. Ergo, the intention of the Pope to define a truth as definitive and infallible must be clearly stated by using particular words, signs and decorum.[7] The infallible and solemn magisterium can also be exercised by all the bishops united to the Pope in an ecumenical council. Heresy is also not only the post-baptismal denial or doubt of a truth defined by the solemn magisterium but also of one defined by the ordinary and universal magisterium of the Church, expressed by the whole College of Bishops united together and with the Supreme Pontiff, outside of an ecumenical council, teaching particular matters of faith and morals to be held as definitive. Although, to be infallible, the doctrines defined by the dispersed but united College of Bishops must be declared in an authentic declaration from the Pope. A critical element to note is that infallibility extends “as far as the deposit of Revelation extends.”[8]

In 1998, John Paul II gave the Apostolic Letter Ad tuendam fidem, adding §2 to c. 750. The purpose of this letter was to adjust the profession of faith required for some people taking ecclesiastical offices.[9] This profession of faith is a manifest way to profess one’s assent of faith and religious submission of will and intellect. The intention of the Pontiff in adding elements to this profession was to fight “against errors arising from certain members of the Christian faithful”11 and to give “norms which expressly impose the obligation of upholding truths proposed in a definitive way by the Magisterium of the Church, and which also establish related canonical sanctions.”[10] Such were the reasons that lead to the addition of §2 of c. 750, which says:

The faithful are also required to accept and hold each and every one of the teachings that are definitively proposed by the Church’s magisterium regarding faith or morals, which are required to safeguard the deposit of the faith reverently and to expound it faithfully. Anyone who denies that these propositions are to be held definitively is therefore opposed to the Church’s teaching. (CIC/83, c. 750, §2.)

The main difference between §§1 and 2 is the obligation imposed on the faithful. §1 says: “Those things are to be believed by divine and catholic faith,” while §2 says: “to accept and hold each and every one of the teachings.”[11] This means that the proposed teachings to be held as definitive and that help to safeguard, expound, the teachings of the deposit of faith are not part of the truths to be held with divine and catholic faith.[12] Although, the Church imposes the same penalties on the persons who refuse the teachings of §1 (the heretics) and on the ones who refuse those of §2, hence implying that those concerned with §2 are to be treated similarly to manifest heretics.15 Also, even if certain teachings are not presented as definitive matters, if they are about faith and morals and authentically proclaimed by the Pope or the College of Bishops, a religious assent of the intellect and will is required, under the risk of being imposed penalties as those refusing the teachings mentioned in c. 750, §§1-2.[13]

In continuity with c. 750, Thomas Aquinas presents the heretic, the one who denies or doubts an element of the above citation, as “though he intends to assent to Christ, yet he fails in his choice of those things wherein he assents to Christ, because he chooses not what Christ really taught, but the suggestions of his own mind.”[14] Thus, one is not a heretic because he disagrees with the Pope on the taste of poutine or on the ‘perfect’ recipe of Italian sauce, but only on “what Christ really taught” in the matters described in c. 750.

The final critical element is that the heretic must be a baptized person. Indeed, Aquinas argues that heresy is a form of unbelief, which is a vice contrary to the virtue of faith. Ergo, as the heretic is someone who disbelief one of the elements mentioned in c. 750, he sins against the faith[15] and inasmuch, against the virtue of faith, which, in the baptized, is no more simply a natural virtue as in the unbaptized, but an infused supernatural virtue, conferred by Baptism.[16] To be a heretic, one must first have accepted the truths and then turned away from them. Unbaptized persons cannot turn away from something they did not accept or encountered in the first place…

In summary, to be an imputable heretic in the external forum, one must be a baptized person with a completed 16 years of age and to obstinately deny or doubt, through an exterior and moral act, a truth to be believed by divine and catholic faith, as described in c. 750 and proclaimed or defined in magisterial acts described in c. 749. Even more, a person denying or doubting a teaching mentioned in cc. 750, §2 and 752 may be canonically treated similarly as heretics, as they can be imposed strong canonical penalties. A baptized person who entertains erroneous thoughts about the faith can still be imputable of heresy, in the internal forum, hence risking falling in the state of mortal sin. Outside of these clear elements, one may not be accused of heresy but may still be suspected of it…

The Principles and Early Use of the Canonical Term “Suspicion of Heresy”

The previous part of this analysis covered in detail the term “heresy”, its limits, and consequences. The canonical category of the heretics is thus quite precise and to accuse one of such a crime, proofs are required. These proofs are usually the expressed and obstinate heretical proposition, the denial or doubt, made by a concrete mean of communication, like a statement in a public manner, a thesis or book, or some other means, sharing “a mind that is aware of, and a will that is freely committed to, a sinful act.”[17] Although, MacKenzie argues that even an act commonly associated with a heretical attitude, even if it does not look like a grave matter or if it is only implicitly known as erroneous, is enough to suspect a person of heresy. Such an act appearing as not grave per se or an implicitly known error could be, respectively, to not take off one’s hat in a church or to practice some esoteric activity while being a in apparent good standing with the Church. For this specific example, being aware that participating in esoteric activities is erroneous, in the case of a faithful Catholic with basic catechetical formation, usually does not require one to have been expressly warned about this specific act that it is contrary to the faith.[18] Although, one must be careful if suspecting a person of heresy, as the concept of “suspicion of heresy” never entailed to judge thoughts or matters of the internal forum but, as in the case of manifested heresy, only acts. This means that one cannot suspect a person of heresy because an ‘inner voice’ inspires them to judge a person’s thoughts. Only exterior and moral acts can lead to suspicion of heresy. Now that the principles of “suspicion of heresy” were discussed, it is critical to look at the history of the term.

There is no clear date or document presenting when the term “suspicion of heresy” began to be used, although it gained a certain prominence in the Middle Ages. Indeed, the term appears in the Canons of the Fourth Lateran Council. At this time, suspicion of heresy was a crime and could involve canonical punishments, such as an anathema and an excommunication.[19] The concept of suspicion of heresy, and to consider it as a delict, was common in the Middle Ages, as the Malleus Maleficarum, a treatise on witchcraft allegedly written in the 15th century by the Dominicans Henrich Kramer and Jacob Spenger, largely uses the term. This treatise describes the canonical term of “suspicion” in general as follows:

the Canonists note that suspicion is of three kinds. The first of which the Canon says, “You shall not judge anyone because he is suspect in your own opinion.” The second is Probably; and this, but not the first, leads to a purgation. The third is Grave, and leads to a conviction. (Malleus Maleficarum, part III, Third Head, q. XIX.)

There are some critical points to analyze here. First, the treatise recognizes that one cannot condemn a person as a suspected criminal because he simply believes so, without any external and moral act. Then, the concept of “suspicion” is separated in three kinds… technically two kinds, as the first one means there can be no, or at least, there should be no canonical punishment as there are no external and moral act to judge but only a subjective suspicion of someone. The kinds of suspicion that can result in canonical punishments are the “probable suspicion”, which results in a “purgation”, a certain penance to be completed, usually the daily practice of a pious devotion. The other kind is the “grave suspicion”, which, if not proven to be wrong, leads to a conviction as a manifest criminal. These kinds of suspicion concern any kind of crime, whether it is heresy or adultery, etc.

When it comes specifically to “suspicion of heresy”, the treatise also presents three kinds of suspicion, closely associated with the general ones presented above. The first is a “light suspicion of heresy” and is caused by simple acts that do not necessarily manifest the intention of the suspected person such as a change of habitudes[20] or if there is no witnesses, or confession made by the suspected person of believing in heretical propositions, or no plausible evidences of heresy.[21] Such a suspicion could, even if only ‘light’, lead to canonical punishments, but these would only serve as preventive means to ensure the person truly does not hold heretical beliefs, even if no strongly manifested exterior and moral act have happened.25 The second kind is a “great, strong or vehement suspicion of heresy”. About this specific kind, the treatise says:

Therefore a great suspicion is called vehement or strong; and it is so called because it is dispelled only by a vehement and strong defence, and because it arises from great, vehement, and strong conjectures, arguments, and evidence. As, to take an example of simple heresy, when people are found to shelter known heretics, and show favour to them, or visit and associate with them and give gifts to them, receive them into their houses and protect them, and such like: such people are vehemently suspected of heresy. And similarly in the heresy of witches, they are brought under suspicion when they share in the crimes of witches. (Malleus Maleficarum, part III, Third Head, q. XIX.)

People who fall under this kind are not necessarily manifest heretics as they do not make any heretical statement through the usual way of words, spoken or written, as argued earlier in this analysis, but they still make external and moral acts which can lead to a strong suspicion of heresy. Here, the excuses to make oneself innocent of heresy are few, as, for example, in the case of hiding heretics in one’s house. This leads the authors of the treatise to say that “there is no doubt that such persons act in this way out of some heretical sympathy.”[22] As a grave suspicion of heresy usually leads to a proven manifest heresy, canonical penalties can be imposed. Even, the treatise argues grave or vehement suspicion of heresy is enough to lead to a purgation and judgment.[23] Finally, the third kind is “violent suspicion of heresy”, which is called as such because “it violently constrains and compels a Judge to believe it, and cannot be cast off by any evasion; and also because it arises from violent and convincing conjectures.”28 Strictly speaking, a suspicion of this kind is no more to be considered simply as a suspicion, but as a manifest heresy, although one may still be able to prove his innocence with a strong argument. Such a ‘suspicion’ usually results from manifest heretical acts as attending heretical religious services or by a strong and manifest support to known heretics.[24]

Interestingly, the treatise says that the reason people who are only “probably, or lightly” and those “vehemently” suspected of heresy may still have to undergo certain canonical penalties is that, by accepting them, they manifest a repudiation of their possible errors and a desire to prove by any means that they are not guilty of heresy.30 This concept of manifesting one’s innocence by undergoing penalties was also mentioned in the Fourth Lateran Council.31 In the case of violently suspected heretics, as there are evidences of heretical beliefs and practices, the Malleus Maleficarum argues that they can and should be imposed canonical penalties. Also, the treatise states that one way to become gravely or violently suspected of heresy is by refusing to manifest one’s good will to present oneself when summoned for trial in matters related to the faith.[25]

In summary, suspicion of heresy differs from heresy itself by involving exterior and moral acts displaying heretical behavior without fully revealing the intention of the suspected person. Those suspected of heresy can be of three kinds: lightly suspected; vehemently or strongly suspected; or gravely and violently suspected. The first ones do not make any heretical propositions or do not necessarily have any behavior to be investigated upon, but they still do some acts that can inspire suspicion in some attentive people. The second ones enter a bit more into the spectrum as they have a questionable behavior and seem to manifest sympathy to heresy. The third ones are, simply put, heretics who did not openly confess it but have a highly suspicious behavior as they frequent heretical gatherings and manifestly support heresy. On each one of them, the Church used to impose canonical penalties. For the first two kinds, it was for preventive reasons and for the third, it was because heresy is hardly not present…

The Use of the Term “Suspicion of Heresy” in the 1917 Code of Canon Law and its Disappearance

After having discussed about the principles of “suspicion of heresy” and the early use of the term in the medieval period, it is important to analyze it in the context of the 1917 Codex Iuris Canonici, sometimes called the Pio-Benedictine Code of Canon Law, as it was first ordered by Pius X and then promulgated by Benedict XV. It is critical to look at its use of “suspicion of heresy” as it is the first substantial codifications of canon law in the Latin Church. Before its promulgation, the medieval Jus Commune composed of five decretals, organized the Church’s laws.[26] Hence, the CIC/17 is a rare available work to statute on the use of “suspicion of heresy” in centuries.

One remarkable evolution of “suspicion of heresy” in the CIC/17 is the removal of its canonical penalties, hence implying it was no longer a delict or a condemnable act by a judge. Indeed, the CIC/17 did not associate suspected heretics to canonical penalties connected to their ‘level’ of suspicion, but it redefined the term as the consequence of a delict punishable by canonical penalties and the consequence of becoming “suspected of heresy”.[27] In other words, a suspected heretic would receive canonical penalties either because he committed a delict that gave rise to suspicion of heresy or because he his actually a heretic, but not because he was simply found guilty of ‘being suspicious’. Such a delict could be any of those found in cc. 2316, 2319-2320, 2332, 2340, or 2371. The canon defining what is one suspected of heresy is c. 2315:

One suspected of heresy who, having been warned, does not remove the cause of suspicion is prohibited from legitimate acts; if he is a cleric, moreover, the warning having been repeated without effect, he is suspended from things divine; but if within six months from contracting the penalty, the one suspected of heresy does not completely amend himself, let him be considered as a heretic and liable to the penalties for heretics. (CIC/17, c. 2315.)

Those “causes of suspicion” to be “removed” are to be interpreted as the delicts clearly stated as having the consequence of causing suspicion of heresy.[28] Indeed, with a codified Code, the judgment of what is a cause of suspicion of heresy is no more volatile as in the Malleus Maleficarum covered earlier. The causes of suspicion are no longer left to particular judges or courts to discern and impose penalties even if no criminal act other than ‘being suspected of heresy’ was committed. No, the Pio-Benedictine Code defines clear delicts that cause suspicion of heresy.

The second part of c. 2315, about the time limit of six months to remove the cause of suspicion and the consequence of being considered a heretic with the penalties coming along, should not be interpreted as the consequence of being suspected of heresy, but as the consequence of not removing the cause that first led one to be suspected. Hence, a person, as described in c. 2319, §1, nn. 1-2, who enters marriage with a non-Catholic minister or who enters the sacrament while refusing to educate their children in the faith, becomes excommunicated and suspected of heresy, it is because of the delict they committed. If the same person, now excommunicated and suspected of heresy, does not give an explanation or make a purgation for the committed delict in the next six months, they will be considered as heretics, but not because they were first suspected of it, but because they would have failed to remove the cause of this suspicion, which is here the delict regarding their marriage or their possible children’s education. Their refusal to make reparation for this specific delict will make them no longer suspected of heresy but truly considered as heretics. Finally, it must be said that the CIC/17, even if, in theory, still contained “suspicion of heresy”, the term was never really used in trial but only in essays.[29]

In 1983, a new Code of Canon Law was promulgated by John Paul II. This new code manifests a significant evolution in the use of “suspicion of heresy”. Indeed, the current legislation is empty of the term… This does not mean that there is no ‘level’ of external and moral acts inspiring suspicion of doctrinal error. As a matter of fact, c. 1365, cited in previous footnotes, seems to be a heritage of “suspicion of heresy”. This canon contains penalties for people teaching doctrinal errors, warned of it, and not yet retracting their positions, while stipulating that there is a difference between such persons and ‘full blown’ heretics excommunicated and mentioned in c. 1364. Also, following the 1917 Code, the CIC/83 still imposes sanctions on people committing delicts that used to give rise to suspicion of heresy, as CIC/83, c. 1365, which is the equivalent of CIC/17, c. 2316, minus the term “suspected of heresy”. Also, the Church still recognizes sins against the virtue of faith that used to give rise to suspicion of heresy, if they were manifested by acts.[30]

In summary, before the 1917 Code, “suspicion of heresy” was widely used for almost anything that could be perceived as heretical behavior, going even as far as separating the suspected in categories. The CIC/17 presented an evolution of the term by pointing out in its canons the actual delicts, quite few, that could inspire suspicion. Finally, the term disappeared in the 1983 Code while still containing traces of this antique canonical category.

Conclusive Considerations

This analysis began with a definition of “heresy”, of its consequences and limits. It was argued that heresy is both a sin against faith and an imputable delict when an external and moral act is involved. Heresy was also described as the denial or doubt of truth to be held with divine and catholic faith, although it was discussed that making an assent of faith to what requires it is only part of the minimum. Indeed, the faithful must also adhere with religious submission even to doctrines safeguarding the deposit of faith.

The analysis then introduced “suspicion of heresy” by laying down its principles and early use. it was stated that suspicion of heresy never involved judging unknown thoughts – only acts, sometimes even quite insignificant, could lead to be suspected. These suspected persons were separated in different categories and imposed various penalties to ‘bring them back on the good track’…

Finally, the recent development of “suspicion of heresy” and its disappearance was discussed in the last part. The 1917 Code was clearer about what could give rise to suspicion of heresy, while stipulating that such suspicion was a consequence associate with a committed delict, not a delict per se separated by categories from lightest to gravest. Then, the 1983 Code abandoned the term but remnants of it can be found in numerous canons.

The fact that “suspicion of heresy” was a complex reality has been argued in numerous parts of this essay, although it shows an important point: there was, there is, and there will be doctrinal confusion and clear limits must be drawn. To be suspicious of certain people’s behavior is not necessarily wrong. Indeed, “certain actions, if repeated over longenough a period of time, could indicate that, behind such actions, there [is] heresy at work.”[31] It is not because the canonical category of those suspected of heresy is no more that there is no suspicious doctrinal behavior. The faithful have a duty to be vigilant, and first, with themselves. They have a duty to abide to the truths of divine and catholic faith and to give religious submission of intellect and will even to what is not definitively held as an infallible teaching. the faithful of Christ have the duty to firmly embrace and retain the Truth. Hence, it is important, as the title of John Paul II Apostolic Letter Ad tuendam fidem’s title reads, to take means “to protect the faith”…

Selected Bibliography

The Code of Canon Law: in English Translation. London: Collins, 1983. Accessed via CanonLaw.Ninja

The 1917 or Pi o-Benedictine Code of Canon Law: in English Translation. San Francisco, Ignatius Press, 2001. See the PDF attached to the email. Code of Canon Law Annotated, 4th Edition. QC: Librairie Wilson & Lafleur inc., 2022.

MacKenzie, Rev. Eric F. “The Delict of Heresy in its Commission, Penalization, Absolution.” Canon Law Studies, Number 77, The Catholic University of America, 1932. See the PDF attached to the email.

Malleus Maleficarum, part III, Third Head. Accessed here Malleus Maleficarum Third Part.

Allen, OP, Rev. Benedict. The Application of Roman Canon Law in Medieval England, in The Papacy, ed. by Rev. C. Lattey, SJ. Cambridge, England: W. Heffer & Sons LTD, 1923.

Mosconi, Marino. “La santa custodia e la fedele esposizione del deposito della fede (can. 750 § 2)”, in Quaderni di diritto ecclesiale 15 (2002) 177-196. See the PDF attached to the email.


[1] The Code of Canon Law: in English Translation. London: Collins, 1983, c. 751.

[2] Rev. Eric F. MacKenzie,  “The Delict of Heresy in its Commission, Penalization, Absolution,” p. 46/129 of PDF or p. 34 of text. If MacKenzie says the most common way of expressing a heretical thought is by words, spoken or written, he also argues that a subtle act as refusing to take off one’s hat in a church because one interiorly has heretical beliefs and refuses to respect the Blessed Sacrament reserved in that church he enters is an exterior and moral act manifesting heresy. Although, such a judgement may be rash and it would be wiser to associate it with the upcoming part of this analysis about suspicion of heresy. About this, see ibid., p. 47/129 of PDF or p. 35 of text.

[3] See Rev. Eric F. MacKenzie, “The Delict of Heresy in its Commission, Penalization, Absolution,” Canon

Law Studies, Number 77, The Catholic University of America, 1992, p. 45/129 of PDF or p. 33 in text: “The principle was established from early times that canonical punishments cannot be incurred by subjective sins.” And p. 46/129 of PDF or p. 34 in text: “The second essential characteristic of a delict is that it be morally imputable. The external act must be (or at least must seem to be), the expression of a mind that is aware of, and a will that is freely committed to, a sinful act.”

[4] See commentary on c. 751 in Code of Canon Law Annotated, 4th Edition, (QC: Librairie Wilson & Lafleur inc., 2022).

[5] See CIC/83, c. 1323, §§1-2. About those under 16 years of age, MacKenzie argues that the canonical penalties cannot be imposed even “if the said minor has attained the use of reason and has actually sinned in conscience.” See Rev. Eric F. MacKenzie, “The Delict of Heresy in its Commission, Penalization, Absolution,” p. 49/129 of PDF or p. 37 of text. Also. §§3-4 of c. 1323 speak of the loss of imputability for those acting under physical force or grave fear. MacKenzie argues that a person accused of heresy may fall under these categories, and inasmuch, the level of imputability for such persons would vary and may be completely lifted, as in a case of someone fearing for the safety of their family if they leave their heretical group. Although, he also argues that one still enjoys a certain level of freedom in relation to their will and intellect, even in such cases. This question is quite wide, and touches matters of both the internal and external fora that, for brevity, will not be covered here. For further readings on this topic, see ibid., pp. 4950/129 of PDF or pp. 37-38 of text.

[6] See commentary on c. 750 in Code of Canon Law Annotated, 4th Edition. 7 CIC/83, c. 749.

[7] See CIC/83, c. 749, §3. “No doctrine is understood to be infallibly defined unless this is manifestly demonstrated.”

[8] Second Vatican Council, Dogmatic Constitution Lumen Gentium, 25.

[9] This profession of faith is not simply the well-known Apostles’ Creed or Nicene-Constantinopolitan Creed, but is the one published by the Congregation (now Dicastery) for the Doctrine of the Faith in 1989. 11 John Paul II, Apostolic Letter issued motu proprio Ad tuendam fidem, introduction.

[10] John Paul II, Apostolic Letter issued motu proprio Ad tuendam fidem, introduction.

[11] The Latin edition typica of the CIC/83, c. 750, §2 reads “to accept and hold” as “Firmiter etiam amplectenda ac retinenda”, which translates in the Code of Canon Law Annotated, 4th Edition as “to be firmly embraced and retained”.

[12] These truths do not oblige the faithful will the assent of faith but more probably the religious submission of intellect and will. For this argument, see Marino Mosconi, “La santa custodia e la fedele esposizione del deposito della fede (can. 750 § 2)”, in Quaderni di diritto ecclesiale 15 (2002) 177-196, p. 12/20 of PDF or p. 188 of text. “Il can. 750 § 2 non offre una definizione del significato teologico di tale magistero e della sua giustificazione; secondo la natura propria delle norme canoniche determina piuttosto un fatto e il necessario comportamento richiesto ai fedeli: esistono dottrine proposte dal magistero infallibile che non chiedono l’adesione di fede, pur esigendo di essere accolte con fermezza in ragione della loro definitività15 See CIC/83, c. 1365. “A person who, apart from the case mentioned in canon 1364 §1, teaches a doctrine condemned by the Roman Pontiff, or by an Ecumenical Council, or obstinately rejects the teaching mentioned in canon 750 §2 or canon 752 and, when warned by the

Apostolic See or the Ordinary, does not retract, is to be punished with a censure and deprivation of office; to these sanctions others mentioned in canon 1336 §§2-4 may be added.” It seems that the only penalty not imposed on people specifically concerned in c. 1365 is the latæ sententiæ excommunication that manifest heretics occur.

[13] See CIC/83, c. 752; see also c. 1365 for the said penalties.

[14] Thomas Aquinas, Summa Theologica, trans. by the Fathers of the English Dominican Province (Notre Dame, IN: Ave Maria Press, 1981), II-II, q. 11, a. 1.

[15] For further details on sins against faith, see Catechism of the Catholic Church, 2nd ed. (Washington DC:

United States Conference of Catholic Bishops, second print, 2020), 2088.

[16] Even if the question regarding the virtue of faith and how it evolves between an unbaptized and a baptized person is an important one, especially in the context of the proper definition of heresy, brevity requires not to spend unlimited time on this matter. For further readings on this topic, see Peter Trahan,

“The Theological Virtue of Faith: Assent and Certitude”, Homiletic & Pastoral Review Magazine (2017), The Theological Virtue of Faith: Assent and Certitude Homiletic & Pastoral Review (hprweb.com) (accessed June 2023).

[17] Rev. Eric F. MacKenzie, “The Delict of Heresy in its Commission, Penalization, Absolution,” p. 46/129 of PDF or p. 34 of text.

[18] See footnote 2 and the referenced document in it.

[19] See Fourth Lateran Council (1215), Canon 3 – On Heresy. “Those who are only found suspect of heresy are to be struck with the sword of anathema, unless they prove their innocence by an appropriate purgation, having regard to the reasons for suspicion and the character of the person. Let such persons be avoided by all until they have made adequate satisfaction. If they persist in the excommunication for a year, they are to be condemned as heretics.”

[20] See Malleus Maleficarum, part III, Third Head, q. XIX. “As an example of simple heresy, if people are found to be meeting together secretly for the purpose of worship, or differing in their manner of life and behaviour from the usual habits of the faithful; or if they meet together in sheds and barns, or at the more

Holy Seasons in the remoter fields or woods.”

[21] See Malleus Maleficarum, part III, Third Head, q. XXIII. “this is when the accused is not taken in heresy, nor is convicted by her own confession or by the evidence of the facts or by the legitimate production of witnesses, and there are no other strong or vehement indications of heresy against her; but only a small and light indications of such a sort as, in the opinion of the Court, to engender a light suspicion against her.” 25 See Malleus Maleficarum, part III, Third Head, q. XIX. “They who are by a slight argument discovered to have deviated from the teaching and path of the Catholic religion are not to be classed as heretics, nor is a sentence to be pronounced against them.” Such a person would not be condemned as a heretic and would usually not undergo strong canonical penalties, but they could still be asked to undergo some minor penalties and abjure their supposed heresy to manifest their good will. See below in this analysis, p. 10.

[22] Malleus Maleficarum, part III, Third Head, q. XIX.

[23] See Malleus Maleficarum, part III, Third Head, q. XIX. “And as for the grave suspicion, which suffices for a conviction, note that it is of two kinds. One is of the law and by the law, as when the law fixes and determines some point against which no proof can be admitted. For example, if a man has given a woman a promise of matrimony, and copulation has ensued, then matrimony is presumed, and no proof to the contrary is admitted. The second is of the law but not by the law, as where the law presumes but does not determine a fact. For example, if a man has lived for a long time with a woman, she is presumed to have had connexion with him; but against this, proofs are admitted.” 28 Malleus Maleficarum, part III, Third Head, q. XIX.

[24] See Malleus Maleficarum, part III, Third Head, q. XIX. “if persons are found to show a reverent love for heretics, to receive consolation or communion from them, or perpetrate any other such matter in accordance with their rites and ceremonies: such persons would fall under and be convicted of a violent suspicion of heresy and heretical beliefs. (See many chapters on this subject in Book VI of the Canon.) For there is no doubt that such persons act in this way out of a belief in some heresy.” 30 See Malleus Maleficarum, part III, Third Head, q. XIX. “ 31 See footnote 22 of this analysis.

[25] See Malleus Maleficarum, part III, Third Head, q. XXV. “if he should then be summoned on a charge concerning the faith, and should not appear but contumaciously refuse to appear, and therefore be excommunicated, then he would be strongly suspected of heresy; for then the light suspicion would become a strong one.”

[26] These decretals were: the Decretals of Gregory IX (1234), the Sext of Boniface VIII (1298), the Clementines of Clement V (1313), the Extravagantes Communes (promulgated laws from the successive popes). Before that, only the Decretum of Gratian (1150) and the Corpus Juris Canonici of Innocent III (1210) were seen as important collections of Church’s laws, although they were mostly textbooks for canonical formation in universities. For further details on this topic, see Rev. Benedict Allen, OP, The Application of Roman Canon Law in Medieval England, in The Papacy, ed. by Rev. C. Lattey, SJ (Cambridge, England: W. Heffer & Sons LTD, 1923.), pp.142-143.

[27] In The 1917 or Pio-Benedictine Code of Canon Law: in English Translation (San Francisco, Ignatius Press, 2001), c. 2195, §1, a delict is described as “an external and morally imputable violation of a law to which a canonical sanction, at least an indeterminate one, is attached.” If suspicion of heresy is no longer a delict, heresy is still one, as for example, the CIC/17 refers to heretics as “irregular by delict”. See CIC/17, c. 985, n. 1.


[28] Examples of such delicts contained in the CIC/17 canons were presented in the previous page. These are cc. 2316, 2319-2320, 2332, 2340, or 2371.

[29] Edward Peters, “A glance back at a forgotten canonical category,” In the Light of the Law (2015) A glance back at a forgotten canonical category | In the Light of the Law (wordpress.com) (accessed June 2023). “In any case the fact patterns that could give rise to “suspicion of heresy” were complicated and, it seems, lent themselves more to canon law essay exams than to trials.”

[30] See CCC, 2088. Also mentioned earlier.

[31] Edward Peters, “A glance back at a forgotten canonical category”.