Should mistaken Catholics be called “material heretics”?

“The Church is visible by reason of the visibility of her members and her organisation. But the edges are very blurred.”

Objection: Some Catholics profess heretical doctrines in good faith, and they are sometimes called “material heretics.” Therefore, the description of the Church’s “visible unity” is overly idealised, and arguments about heresy and membership based on this unity are unsound.

Having established an understanding of how Louis Cardinal Billot explains heresy and membership in an earlier part, I would like to address some objections that frequently arise. Photo by Andraz Lazic on Unsplash

Response: First, let’s note that in most cases of Catholics professing error, we can give the benefit of the doubt, and that a small number of ambiguous cases “around the edges” do not jeopardise the Church’s visible unity. In 1941, Fr Victor White OP wrote in an article about Billot and membership:

“There is something wrong with the facile assumption that the distinction of Catholics from non-Catholics, of members of the Church from non-members of the Church, is always a manifest one. Certainly there are those who clearly are such, and those who pretty clearly are not. […]

“Certainly the Church is visible, and visible by reason of the visibility of her members and her organisation. But the edges are very blurred.”[1]

Billot explains this further – with specific reference to the visibility of the Church:

“This visibility also deals with the whole group considered all together, and not each person taken singly […] For this visibility certainly does not require that there be no doubt about anyone at all about whether he be a member of the Church or not, but it is sufficient that there be certitude about most of them; and I mean that certitude which is moral certitude, and sufficient in practice among men.”[2]

It is also possible for the clarity and perfection of the Church’s marks to be accidentally diminished – which is distinct from these marks being lost. The non-functioning of authority (however this is explained) can make it hard to say what is truly authorised and what is forbidden, as well as who is a Catholic and who isn’t – even among the hierarchy.

However, to suggest that this obscurity or difficulty would mean that non-Catholics must therefore remain a part of the Church is something different: it is to suggest the loss, rather than diminution, of visibility and the mark of unity.

This could suffice to reply to the objection – but let’s see what more can be said.

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Material heretics

In the original essay, I suggested that we should consider heresy merely as a human act, abstracted from questions around sinfulness and criminality. The object of this act of heresy is the choosing of dogma, without regard for the magisterium as one’s rule of faith, by one who is baptised and still professes to believe in Christ.

Cast in these terms, it becomes clear why it is that a Protestant or Orthodox in good faith and invincible ignorance is nonetheless not a member of the Church. In Billot’s terms, these are the men whom we should call “material heretics”:

“[M]aterial heretics are those who labor under invincible ignorance about that same Church, and in good faith choose a different rule to guide them. […]

“[W]ith regard to real incorporation into the visible Church of Christ of which we are now speaking the thesis does not make any distinction between formal and material heretics, but understands everything according to our notion of material heresy […] which alone is proper and genuine heresy.”[3] (Emphasis added)

It is true that an heretical proposition itself might be called “material heresy” – but on the level of propositions, there is arguably no difference between formal heresy and material heresy – “which,” Billot says of the latter, “alone is proper and genuine heresy.” After all, what is the difference between propositions which are materially heretical, and formally heretical? How is the heretical proposition as a proposition of a material heretic to be distinguished from that of a formal heretic?

The answer is that they cannot be distinguished. If the material/formal distinction with relation to heresy is to serve any purpose, it must be rooted in the person adhering to the proposition. It is no good to say that “material heresy” is the heretical proposition expressed innocently by a material heretic – this is to concede that the distinction is rooted in the agent.

But even if this is so, and even if we were to concede this unhelpful use of language, it would not necessarily follow that one who expresses such a proposition is a material heretic, or “in material heresy.” Such a conclusion falls victim to false equivalences and categorical errors between propositions, states and persons. As Billot states:

The rejection of the rule of the ecclesiastical magisterium is of the notion of heresy, which does not happen in this case [of Catholics in error], since it is simply an error of fact about what the rule requires. And therefore [for such cases] there cannot be room for even material heresy.”[4] (Emphasis added)

As such, according to Billot, this term should not be used for Catholics who are mistaken in good faith. The distinguishing feature between good-faith Protestants and Catholics who are in error is their relationship to the Church’s magisterium as their rule of faith. Imposing the term “material heretic” on both groups obscures more than it clarifies. Billot states that, if we call such Catholics “material heretics”, then “the very meaning of that term [viz. “material heresy”, but also “heresy” itself] would be completely changed.”[5]

Although theologians have used different terms in different ways – and some have indeed applied the term “material heretic” to mistaken Catholics – the distinction between mistaken Catholics and good-faith non-Catholics is important, and it is blurred or lost by the use of one term for both.

As a result of this blurring, we see all sorts of confusion about who is and is not a member of the Catholic Church – and sometimes we even see this very question confused with the question of who can be saved. Some even posit the absurd conclusion that good-faith Orthodox must be true members – as if non-membership of the Church was a punishment that could not be imposed upon someone who has no personal guilt.

Billot’s use has the real advantage of expressing the distinction between two groups that have almost nothing in common.

Catholics in error

As already stated, the thesis – that open heretics are not members of the Church – can only apply to a putative Catholic if he is clearly not just mistaken or misspeaking, but clearly departing from the Church’s profession of faith. This is not to say that we must attain some sort of metaphysical certitude before concluding such a thing: moral certitude is sufficient. Ambiguous cases can be put to one side, and given the benefit of the doubt.

But why should we give them the benefit of the doubt?

Let’s mention first that the state of other persons is often not our business. We are not inquisitors, going around checking whether those around us are true Catholics or not. It is only in a few, rare occasions that we may be obliged to come to some sort of conclusion on these matters.  

However, we should give the benefit of the doubt, because this is what is rooted in the truth. Those who are manifestly submissive to the Roman Catholic Church and are either a) mistaken in good faith about what she teaches, or b) acting inadvertently, such as by misspeaking, simply cannot be considered as heretics, even materially (without adopting an infelicitous use of terms). Billot states above that the errors of such a Catholic are simply errors of fact about the content of the Church’s teaching – and errors of fact are not sufficient to make someone into a heretic.

In these cases, the parties involved may be mistaken about the facts, or their duties, or be acting under hypothetically extenuating circumstances. An abiding and visible submission to the magisterium of the Church also accounts for any apparent disunity that may arise from theological disputes – even those which become quite heated. None of these cases of apparent disunity threaten the Church’s visible unity if the parties remain visibly and actually submissive to the magisterium – or at least, if they give no reason causing a reasonable man to conclude the contrary.

This actual submission is not achieved by mere claims (as we discussed in the previous objection), as if saying a manifestly false formula of words can prevent open heresy from having its natural effect – or as if we could hide behind a “hermeneutic of charity” like a blindfold. We could say that the profession of faith resolves itself into actual submission to the magisterium, but it is not reducible to it or equivalent to it – still less to a mere form of words.


I have argued that Catholics who err in good faith do not necessarily jeopardise the Church’s visible unity of faith, even if they make her edges “blurred”; and that therefore, they do not necessarily cease to be Catholics by virtue of their errors.

However, being in error is a real evil for a man, and it brings with it certain dangers. For example, while someone may enter into error in good faith, it can easily happen that he becomes attached to his error (perhaps through convenience, habit, human respect, or something else). When eventually he becomes aware of the contradiction between his favoured error and the teaching of the Church, he may be forced into a difficult choice – and may ultimately choose to persevere in his error.

At this point, of course, he no longer is submissive to the Church’s magisterium – and if it pertains to dogma, then he is, at least internally, a heretic. If this non-submission becomes known openly, then he is an open heretic, and ceases to be a member of the Church.

This should give us all pause. Who amongst us is free from all error? Who can be confident that he will make the right choice, if at some point he is revealed to be in error? Who can be confident that he will have the grace or the natural strength to choose the Church’s truth over his favoured ideas?

We do not know until we are tested.

This, perhaps, is why we pray in the Psalm:

“Who can understand sins? From my secret ones cleanse me, O Lord.”
Ps 18.13

Tradivox Catechism Review
Part I: How can we find the teaching of the universal ordinary magisterium?
Part II: What do the catechisms tell us about heretics and the Church?
Part III: How is the Church “visibly united in faith,” according to Cardinal Billot?
Part IV: Why is it essential that the Church is visibly united in faith?
Part V: What sort of heresy results in being outside the Church?
Part VI: What is the difference between an excommunicate and an open heretic?

Obj. I: Are we obliged to believe every person who calls himself a Catholic?
Obj. II: Should mistaken Catholics be called “material heretics”?
Obj. III: What is the state of a Catholic who submits to a false magisterium?


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[1] Victor White OP, ‘Membership of the Church’, Blackfriars, September 1941, Vol. 22. No. 258 (September 1941), pp 455-470. P 457.

[2] Louis Cardinal Billot, Tractatus de Ecclesia Christi, Tomus Prior, Prati ex Officina Libraria Giachetti, Filii et soc, 1909, 282. Quoted in English in White, 456.

[3] Billot, trans. Fr Julian Larrabee. 292

[4] Ibid.

[5] Ibid.

4 thoughts on “Should mistaken Catholics be called “material heretics”?

  1. Griff Ruby

    Material heresy pertains to the Church’s visible structure, which is why theologians avoid (maybe not perfectly in a few cases, put properly) applying the phrase “Material Heretic” to a Catholic who is sincerely mistaken (and open with his wrong belief) as to the content of the teachings of the Church. That is different (despite the grammatical similarity) from saying that a person is “materially in heresy” or “speaking a heresy materially,” which could be said, providing that the Church teaching contradicted has the theological note of Dogma (anything less and it is simply error) and that it is openly (visibly and publicly) expressed. So long as the person is disposed to learn from the Church they are visibly to be recognized as part of the Church, even though they err.
    The Protestants and others who are commonly intended by the phrase (as properly used by theologians) “Material Heretic” are visibly no part of the Church since they look not to the Church’s teaching but to the teachings of other bodies and teachers disapproved by the Church, or else to their own opinions.
    There are really two levels on which one must look to these questions, one being that of the individual level, and the other having to do with the societal identity and visibility of the Church. A proper analysis of the question should be performed on each level separately in order to put the whole picture together.

    The WM Review:

    Thanks for your comment Griff. Personally, we are inclined to follow Billot here. You wrote:

    “That is different (despite the grammatical similarity) from saying that a person is “materially in heresy” or “speaking a heresy materially,” which could be said, providing that the Church teaching contradicted has the theological note of Dogma (anything less and it is simply error) and that it is openly (visibly and publicly) expressed. So long as the person is disposed to learn from the Church they are visibly to be recognized as part of the Church, even though they err.”

    But as it says in the article, it’s difficult to see what is gained or distinguished by the use of the modifiers material or formal in relation to a proposition abstracted from the state of the agent.

    Thank you for stopping by and leaving your comment!

  2. Michael Wilson

    What distinguishes a heretic from a Catholic is the adherence to a false doctrine; this adherence may be innocent, or merely “material” or. deliberate, then it would be “formal”. What about Catholics? Can a Catholic be a “material” (innocent) heretic? i.e. Adhere to a false doctrine? It would seem that in the “normal” times of the Church, when the Magisterium is functioning, and any questions concerning the teaching of the Church can be readily resolved by approaching the existing authorities; whether one’s parish priest, bishop or other authority, that this would not be possible. But what about in our present day, when confusion and error not only are disseminated by the declared enemies of Our Lord, but what is most horrible, even by those who (ostensibly) hold positions of authority in the Church, such as the false Pope (s), Cardinals, bishops, etc. etc. Could a Catholic then when adhering in good faith to these open and public heretics as being legitimate authorities, not then embrace their errors? Do they not then become “material” heretics? It is my opinion that in my conversations with Catholics who do assist at the N.O.M. that many of them do hold to these false doctrines, and therefore, can rightly be regarded as material heretics. For they have mistakenly adhered to a false rule of faith i.e. That of the Conciliar Church. Does this mean that we can make a blanket statement such as, that all those who attend the N.O.M. Are at least “material heretics”? I think that this is possible. Because as Msgr. Van Noort explained in his “Christ’s Church” Vol. II, pg. 241, The Church is a “visible society” in which one can identify those who are members from those who are not, by their outward profession of the Catholic faith; for if those who did not confess this Catholic faith publicly were to be considered as actual members of the Church, what would become of the Church’s unity? :
    Van Noort:
    “Public heretics (and a fortiori, apostates) are not members of the Church. They are not members because they separate themselves from the unity of Catholic faith and from the external profession of that faith. Obviously, therefore, they lack one of the three factors-baptism, profession of the same faith, union with hierarchy-pointed out by Pius XII as requisite for membership in the Church (see above, p. 238). The same pontiff has explicitly pointed out that, unlike other sins, heresy, schism, and apostasy automatically sever a man from the Church. “For not every sin, however grave and enourmous it be, is such as to sever a man automatically from the Body of the Church, as does schism or heresy or apostasy”. (M.C.C. 30) By the term public heretics at this point we mean all who externally deny a truth (for example Mary’s Divine Maternity), or several truths of divine and Catholic faith, regardless of whether the one denying does so ignorantly and innocently (a merely “material” heretic), or willfully and guiltily (a “formal” heretic)……If public material heretics remained members of the Church, the visibility and unity of Christ’s Church would perish. If these purely material heretics were considered members of the Catholic Church in the strict sense of the term, how would anyone ever locate the Catholic Church? How would the Church be one body? How would it profess one faith? Where would be its visibility? Where its unity?

    The WM Review:

    Much as it pains us to do so, we have to disagree somewhat here, as the point of this article was to explain almost the contrary point. But thank you for your comment nonetheless.

  3. Michael Wilson

    W.M. Review,
    thanks for your response and disagreement.
    These are extra-ordinary times, and it is not easy to always see who is right or wrong on the application of Catholic doctrine to what is a novel situation in the Church. Keep up the good work.

    The WM Review:

    Many thanks Mike!

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