The Visible Unity of the Church I – on what it means to believe in “One” Holy, Catholic and Apostolic Church

The Visible Unity of the Church

Part I The visible unity of the Church in her profession of faith, and problems faced today.
Part II Further authorities establishing beyond any doubt the meaning of this teaching.
Part III Hypothesis reconciling the teaching of the Church with apparently contradictory facts of the crisis.

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Première partie

This article was originally published by LifeSiteNews in April 2021 as What does it mean for Catholics to believe in ‘One’ Holy Catholic Apostolic Church?[1] Reprinted with permission. In August 2022, I made several updates to clarify that the visible unity here pertains to those things which are taught as divinely revealed to be believed as such, and that it is possible for greater or lesser degrees of unity when it comes to doctrinal points taught at a lower degree. Image is Murillo, Good Shepherd, from Wiki Commons.

Every Sunday we profess belief in one holy catholic and apostolic Church. Many Catholics know that our Lord Jesus Christ founded one Church, rather than many, and that this is the Roman Catholic Church.[2] Indeed, this claim has driven many converts to enter her fold over the years. This is sometimes called the unicity (or ‘uniqueness’) of the Church, distinguishing it from her unity.

Unicity is not all it means for the Church to be one. In 1928, Pope Pius XI wrote his encyclical Mortalium animos against the twentieth-century ecumenical movement. This movement held that there was indeed only one visible Church, but that it was “composed of various communities of Christians, even though they adhere to different doctrines, which may even be incompatible one with another.”[3]

Against this, Pius XI taught not only that the Catholic Church is ‘one’, i.e. unique, but also in that she is united – and already enjoying the unity for which our Lord prayed when he said: “That they all may be one…. And there shall be one fold and one shepherd.” (John 17.21, 10.16) Rather than wishing for an unrealised ideal, our Lord’s prayer was the efficacious cause of a remarkable unity of faith and charity, which she continued to enjoy for centuries.[4]

Given the division amongst those calling themselves Catholics today, it can seem hard to believe that this unity of faith was treated in apologetics as a fact which actually proved the Church’s claims. In other words, the truth of the Church’s claims was in part established by this visible unity of faith. But even if this seems strange now, it is the teaching of the Church: rather than dismiss it, we must try to understand what it means.

To consider this idea, we will turn to magisterial documents from before Vatican II, and a range pre-conciliar (English-language) dogmatic theology and ecclesiology manuals. We have previously established why this is necessary elsewhere.[5] In this article we will mainly refer to Fr E. Sylvester Berry’s 1927 manual The Church of Christ, and establish our theses further with other texts in a subsequent article. Fr Berry was the Professor of Apologetics at St Mary’s Seminary, Emmitsburg, Maryland, and his manual is a respected and clear expression of standard ecclesiology. Any similar text would serve for this purpose, and as such Fr Berry is a witness to these claims, as well as an authority.

This is a big topic, and we will be limiting ourselves just to what it means for the Church to be united in her external profession of the same faith.

One Lord, One Faith, One Baptism

Starting with the basics, the Penny Catechism states the following:

The Church is One because all her members agree in one Faith, all have the same Sacrifice and Sacraments, and all are united under one Head.[6]

The same doctrine is expressed in the fairly recent Baltimore Catechism and the Catechism of St Pius X. It is a part of a beautiful tapestry of other truths, corresponding to the words of St Paul: “One Lord, one Faith, one Baptism.” (Eph 4.5.) It also corresponds to Pius XII’s definition of who is a member of the Church in Mystici Corporis Christi:

Actually only those are to be included as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body, or been excluded by legitimate authority for grave faults committed.[7]

Pope Pius XII

Pius XII’s teaching is a standard treatment of membership,[8] and although the idea is ancient, the modern expression of it essentially comes from St Robert Bellarmine, Doctor of the Church.[9]

Even before Pius XII, the First Vatican Council made several beautiful points on this idea, including:

The eternal shepherd and guardian of our souls, in order to render permanent the saving work of redemption, determined to build a church in which, as in the house of the living God, all the faithful should be linked by the bond of one faith and charity.[10]

Vatican I

We can see that there are different unities here, but what does it mean for the Church to enjoy unity of faith? How did the Church and her theologians understand this idea?

Unity of Profession

According to Berry, the general concept of supernatural faith entails:

  1. A doctrine taught (‘objective faith’);
  2. Its internal acceptance by those who are taught it (‘subjective/internal faith’); and
  3. Its external profession of the internal faith.[11] This is the main focus of this article.

What does the Church teach about this external profession of faith?  Vatican I taught that:

So that we could fulfil our duty of embracing the true faith and of persevering unwaveringly in it, God, through his only begotten Son, founded the church, and he endowed his institution with clear notes to the end that she might be recognised by all as the guardian and teacher of the revealed word. […]

The Church herself, by reason of […] her catholic unity and her unconquerable stability is a kind of great and perpetual motive of credibility and an incontrovertible evidence of her own divine mission.[12]

Vatican I

In other words, the Church taught that she has ‘clear notes’, proving her claims: and that one of these is unity. This remarkable unity in the Church is itself a proof of her divine mission. As explained in Session IV of Vatican I, this unity is specifically in faith and charity. This sense was explained by theologians in following decades. Consider again Fr Berry:

Unity in the profession of faith is a natural consequence of the unity of doctrine; a mere corollary to be explained rather than proved.[13]

Fr E. Sylvester Berry

Even as a ‘natural consequence’, this external unity of faith was seen as an evident, astonishing fact.[14] Elsewhere, Berry continues:

He who rejects the very principles of a society by word or act, thereby rejects the society itself and ceases to be a member. Therefore, every member of the Church [must] make at least an outward profession of faith.[…] Since this outward profession concerns the one faith taught by the Church, it will be essentially the same for all its members; in other words, there will be unity in the outward profession of faith.[15]

Fr E. Sylvester Berry

The content of this profession

What is the content of this faith? “The one faith taught by the Church”, says Berry. It is not merely “an acceptance of Christ as Saviour, with confidence in his merits and will to save.”[16] It is not just a set of ‘fundamental doctrines’ upon which all who claim to be Christian could agree (e.g., just things like the Trinity, or the Resurrection). It is not just those things solemnly defined by a pope or a council. Instead, it is primarily an adherence to the whole body of revealed doctrine, as Berry says:

It is a well-known fact that the Church has always demanded the strictest unity in the profession of faith; those who refused to profess even a single doctrine, were condemned as heretics who had already ceased to be members.[17]

Fr E. Sylvester Berry

This is substantially the same idea given magisterial authority by Leo XIII in his encyclical Satis cognitum:

It was thus the duty of all who heard Jesus Christ, if they wished for eternal salvation, not merely to accept His doctrine as a whole, but to assent with their entire mind to all and every point of it, since it is unlawful to withhold faith from God even in regard to one single point. […]

Hence as the Apostles and Disciples were bound to obey Christ, so also those whom the Apostles taught were, by God’s command, bound to obey them. And, therefore, it was no more allowable to repudiate one iota of the Apostles’ teaching than it was to reject any point of the doctrine of Christ Himself. […]

The practice of the Church has always been the same, as is shown by the unanimous teaching of the Fathers, who were wont to hold as outside Catholic communion, and alien to the Church, whoever would recede in the least degree from any point of doctrine proposed by her authoritative Magisterium.[18]

Pope Leo XIII

As noted, this visible unity pertains, properly speaking, to dogmas taught as being revealed, and of faith. There is no indication in this text, not even in the word ‘authoritative’, that this is limited to the solemn definitions such as that of the Assumption or the Immaculate Conception (as opposed to those things taught by the universal ordinary magisterium). It also pertains to the whole body of dogma: as Leo XIII says, “One single point… one iota… in the least degree from any point”.

In a more fundamental way, this visible unity pertains to the actual, visible submission to the teaching authority of the magisterium.

For example, let’s consider a part of the dogma of transubstantiation. It is a revealed and defined dogma, to be believed with divine and Catholic faith, that in the Eucharist, the substance of bread does not remain, but is converted into the Body of Christ.

When we say that the Church is visibly united in her profession of faith, we can say that this unity is produced by true submission to the Church’s magisterium in all matters of faith – including this one – by all the faithful.

Second – though perhaps more obvious – this unity is manifested by all Catholics professing belief in this dogma.

While some Catholics may be mistaken or confused about this dogma, we can say that they remain visibly united so long as they are visibly submissive to the Church’s magisterium (or at least give no public reason to conclude otherwise). As a corollary, anyone who manifests his rejection of this dogma and the magisterium which teaches is is visibly divided from the Church in her faith. In other words, he is not a Catholic.

In a “tertiary” or “improper” sense, a visible unity extends to a greater or lesser degree to the whole body of authoritative teaching, viz. even those points which are not taught as being revealed and of faith per se. We might still call this a “unity of faith” by analogy, but as it does not properly refer to divine and Catholic faith, it is susceptible to a greater or lesser degree of perfection.

Submission to the magisterium

This unity of faith is based on two things: the content of the doctrine professed, which is caused by the readiness of the faithful to be submissive to the Church’s magisterium as their proximate rule of faith.[19]

We must avoid binary thinking here. The writers consider that the united profession of faith is not jeopardised by some being wrong or ignorant – nor even by vehement disagreement on disputed questions – so long as all continued to be submissive to the magisterium.[20]

This is because what is important here is the submission itself – and not a mere claim to be submissive to the magisterium. The idea that the unity of the magisterium can be preserved by mere claims (some of which might be manifestly false) is crass and legalistic, manifesting either an imaginary or merely political union. This is not what the theologians meant.

Rather, if someone claims to be submissive to the magisterium, and yet is openly denying or doubting dogma and obviously knows what they are doing, their claim is vain. Consider this text from Cardinal Juan de Lugo (died 1660):

If it be certain by some other means – for example, if the doctrine in question be well known, or if it be obvious from the kind of person and other circumstances involved – that the accused person could not have been ignorant of the opposition of his doctrine to that of the Church, he will automatically be judged a heretic.[21]

Cardinal Juan de Lugo

It is simply obvious that those with greater learning have a lower burden of proof to establish their rebellion. We can certainly recognise some situations like this, such as when educated priests publicly deny well-known dogmatic truths on social media platforms. This is not to say that any time a priest appears to deny or doubt a dogma, we can thereby tell that he is a heretic, as he may have misspoken, or just be mistaken. But it is to say that there are sometimes cases wherein we can discern the presence of this pertinacity, the consciousness of withdrawing from submission to the magisterium.

So there are cases where we can know that the necessary subjection is present; some where we can know that it is not present, and many where we cannot know, and so can mostly give the benefit of the doubt.

This is not about judging souls – it is just about recognising reality and being able to know who is and is not a Catholic. Indeed, individuals are not even primarily under discussion here, except as parts of the overall picture.

But regardless, when the Church and her theologians say that the unity of faith is a proof of the Church’s claims, they are referring to the wonderful, indisputable fact that Catholics in practice all believed the same things as each other, and as their ancestors and predecessors, and that they are docilely taught by that magisterium, even outside of its solemn extraordinary definitions. They not only all believe that our Lord became man, that there are three persons in one God, and so on: this is because they are habitually docile to the exercise of the magisterium, including – to a greater or lesser degree – even when the authorised teachers of the Church are not teaching a point of doctrine as revealed. This is why Pius XII could write in his encyclical Humani generis:

Nor must it be thought that what is expounded in Encyclical Letters does not of itself demand consent, since in writing such Letters the Popes do not exercise the supreme power of their Teaching Authority. For these matters are taught with the ordinary teaching authority, of which it is true to say: “He who heareth you, heareth me”; and generally what is expounded and inculcated in Encyclical Letters already for other reasons appertains to Catholic doctrine. But if the Supreme Pontiffs in their official documents purposely pass judgment on a matter up to that time under dispute, it is obvious that that matter, according to the mind and will of the Pontiffs, cannot be any longer considered a question open to discussion among theologians.[22]

Pope Pius XII

Note again that when he talks about popes passing judgements, Pius XII is explicitly not talking about “the supreme power of [the pope’s] Teaching Authority”.

Even granting exceptions for mistakes about the faith, and even for debates about some theological matters, it is this visibly united profession of faith, and not some unified but merely verbal submission to the magisterium, that so astonished Catholics and non-Catholics alike, and served as a mark of the Church. A merely verbal submission is not astonishing in itself. In fact, Salaverri could even teach that this unity of profession of faith is (like the Church’s other unities) “manifestly visible, easily recognizable and more known [to us] than the Church herself [is] recognized as true” – namely, there were more people who knew that the Roman Church was thus united, than who knew that she was the true Church.[23] Which makes sense, “for otherwise it would not be a help to recognize the true Church.”[24]

All this shows that, without reading such pre-conciliar sources, we cannot truly appreciate how serious our current crisis is. Because this unity – which was taught to be a necessary part of the Church’s visible nature and proof of her claims – appears to have vanished today.

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The current situation

The external fact is the disunity of the Church, visible in the disunity of the bishops among themselves, and with the Pope.[25]

Thus Professor Romano Amerio, peritus at Vatican II, in his landmark work Iota Unum: A Study of Changes in the Catholic Church in the XXth Century.

Consider recent events, following the CDF’s document on blessing particular types of unions. Even without considering which side is right, it is evident that there is enormous disunity, supposedly ‘within the Catholic Church’, about some very basic issues.

Let’s return to the topic of transubstantiation. Consider the following, from two 2019 Pew Research polls. According to one study, only 50% of US Catholics know about the Church’s dogmatic teaching on transubstantiation.[26]

Another poll of US Catholics found that only 31% actually believed that “the bread and wine actually become the body and blood of Jesus.”[27] By contrast, 69% believe that “the bread and wine used in Communion ‘are symbols of the body and blood of Jesus Christ.’” Of this latter group, most actually think that this is the Church’s teaching! But about one third of them said that they knew that they were rejecting the Church’s teaching.

In the same study, even 37% of weekly Mass-goers did not accept the Church’s teaching on transubstantiation.

We see here again, the three basic groups: those who believe the Catholic faith; those who believe something different but are probably or possibly submissive to the magisterium (and amongst the laity, can be given the benefit of the doubt); and those who knowingly reject both the content of the faith and the magisterium teaching it.

We can leave aside the question of whether privately answering a poll constitutes a public departure from the profession of faith – this is not important here. The important thing is that some of the people who consciously reject both the teaching and the authority will manifest this in a public way: and in fact, the practices of some parish Masses may already sufficiently manifest this.[28] And yet all of these people continue to be considered as Catholics, as members of the Catholic Church.

Again, this is not judging souls, as individual cases are not the point. We are simply recognising that today, it appears that those who are called Catholics are not united in what they profess to believe. There is not even a pretence to profess these things.

This same phenomenon would surely apply to other dogmas if they were polled, and indeed a certain Catholic dating agency allows its users to select which of six certain dogmas they accept. Other users can even filter their searches by adherence or rejection to these dogmas. Does that create the impression of a visibly united organisation?

Unity of Doctrine or Teaching

All this is to say nothing of the fact that in this parish one might hear the Catholic faith preached, and yet in that parish one might hear heresy from the pulpit – and this is even clearer in the age of livestreamed services. The general situation is beyond mistakes and misspeaking, and given his office and training, a priest can generally be expected to know when he is refusing submission to the magisterium. And yet all of these parishes and preachers will be in good standing, in the same organisation.

In fact, this disunity in preaching is itself not possible for the Church – and in some ways it is the cause of the disunity in belief and profession of the faith. As mentioned above, Berry teaches that the unity of doctrine on the part of the hierarchy is the cause of the unity of belief and profession in the Church.[29] The converse follows.

Elsewhere, Berry teaches that it is well-known “that the Catholic Church demands complete and unqualified acceptance and profession of all her teachings.”[30] And all this echoes the countless teachings of the popes and Vatican I, stating that adherence to their doctrinal authority efficaciously leads to unity of faith.

But those that are apparently in authority generally do not demand this acceptance of their teaching and subsequent profession. In fact, they sometimes do not seem to teach at all, nor do even the best of them seem sufficiently troubled by this disunity. On the contrary, they tolerate massive doctrinal disunity amongst the flock and most do nothing to remedy it. To return to Amerio, the quote above is immediately followed by this:

The internal fact producing [this disunity] is the renunciation that is, the non-functioning, of papal authority itself, from which the renunciation of all other authority derives.[31]

Some apparently in authority demand obedience to their office when they restrict the traditional Mass and private masses, or enforce holy communion in the hand, but this ‘weaponized orthodoxy’ is hardly teaching with authority. Imagine if bishops enforced adherence to the faith with the same authority with which they have imposed mask mandates, social distancing and track-and-trace forms.

All this forms the background for a wider question: is it even possible for the Church to stop demanding, as Berry wrote, a “complete and unqualified acceptance and profession of all her teachings”?

Conclusion to Part I

Given the prevalence of such serious, conscious error, it is necessary to question whether our situation contradicts what the Church authoritatively teaches about her own unity. It certainly appears that we have a situation where there is a division in the Church’s profession of faith.

But it is impossible for the One, Holy, Catholic and Apostolic Church to lose one of these four marks. The Roman Catholic Church exists until the end of the world, retaining her essential nature and constitution – including her unity.[32] There must, therefore, be a solution which preserves every aspect of the Church’s teaching about herself, whilst being in conformity with the facts that we see around us.

The teaching is certain: we have expressed it amply with magisterial texts and given an overview from Fr Berry. We will establish it further with other theologians. However, the external facts are also certain. The division is real and visible. We cannot deny it. But sometimes we cannot see the wood for the trees, and so can interpret the facts wrongly.

To someone who has never heard of an eclipse, a photograph of such an event would look like a floating white ring against a black sky.

Someone who grew up under an extended eclipse (if such a thing were possible) might think that he is looking at one thing, a single floating white ring – but in reality he is looking at two separate things and taking them for a single thing. If it continued long enough, he might be led to believe that this floating white ring is the sun, or even redefine his understanding of the sun altogether.

He might never realise that a glorious brightness is being temporarily obscured by the moon.

To reassure readers, we affirm that the Roman Catholic Church is the mystical body of Christ, outside of which there is no salvation; that we profess and believe everything that she teaches; and that she remains in the world with all of her essential marks intact. We will examine this further in Part II.

This article was originally published by LifeSiteNews in April 2021 as What does it mean for Catholics to believe in ‘One’ Holy Catholic Apostolic Church?[1] Reprinted with permission. In August 2022, I made several updates to clarify that the visible unity here pertains to those things which are taught as divinely revealed to be believed as such, and that it is possible for greater or lesser degrees of unity when it comes to doctrinal points taught at a lower degree.

The Visible Unity of the Church

Part I The visible unity of the Church in her profession of faith, and problems faced today.
Part II Further authorities establishing beyond any doubt the meaning of this teaching.
Part III Hypothesis reconciling the teaching of the Church with apparently contradictory facts of the crisis.

Version française:
Première partie


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[1] 8 April 2021,

[2] I refer to the Roman Catholic Church throughout to make clear what should be obvious: I am talking about the Church of who counted St Peter, St Thomas Aquinas, St Robert Bellarmine, St Therese of Lisieux, John Henry Newman, St Pius X and so on as members, and no other body – such as a one made up of all Christian confessions, or of the Roman Catholic Church and the Orthodox, or whatever other combination could be conceived.

[3] Mortalium Animos 6:

[4] Leo XIII, Satis cognitum 6,, Mortalium animos 7.


[6] A Catechism of Christian Doctrine, Catholic Truth Society, 1921. A.95.

[7] Mystici corporis Christi 22.

[8] Cf. also Van Noort Dogmatic Theology Vol. II: Christ’s Church, The Newman Press, Westminster Maryland 1959, p 236.

[9] St Robert Bellarmine, On the Church Militant, in On the Church translated by Ryan Grant, Mediatrix Press 2017, page 238

[10] Vatican I, Pastor Aeternus; SESSION 4 : 18 July 1870 First dogmatic constitution on the church of Christ.

[11] E. Sylvester Berry, The Church of Christ, B. Herder Book Co. London 1927. p 94.

[12] Vatican I, Chapter 3 on Faith, 10, 12.

[13] Berry 98

[14] Note that someone can continue to externally profess the same faith even if he does not believe it internally. This is a key point for issues around membership and visibility of the Church.

[15] Berry 98

[16] Berry 94

[17] Berry 99

[18] Satis Cognitum 8-9

[19] Berry 225

[20] Berry 225

[21] Cardinal de Lugo, Disputationes Scholasticae et Morales, Disp. XX, De Virtute Fidei Divinæ. Translated by Mr John Daly, taken from

[22] Humani Generis 20,

[23] Joachim Salaverri, On the Church of Christ, in Sacrae Theologia Summa IB translated by Kenneth Baker SJ 2015. 1222.

[24] Salaverri 1211.

[25] Romano Amerio, Iota Unum – A study of the changes in the Catholic Church in the XXth century, Sarto House, Kansas City MO, 1996. 143.



[28] Consider da Silveira’s classic Essay on Heresy, translated by John Daly, available here:

[29] Berry 98

[30] Berry 160

[31] Amerio 143.

[32] Cf. Salaverri, Thesis Ch III A.1. Th. 7 .

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