In recent years the Catholic Church has been under renewed assault not only by the usual panoply of Protestant writers decrying the "Scarlet Woman on the Seven Hills" but also by a number of converts to Eastern Orthodoxy from the ranks of former Protestant evangelicals as well as by traditional Eastern Orthodox writers who are taking advantage of rampant liturgical abuses as well as clerical scandals in the Catholic Church to trumpet once again Eastern Orthodox claims to be the "true Church". The result of the doctrinal, liturgical, and moral disorders in the Catholic Church has been to unfortunately obscure in the minds of some non-Catholics the Holiness of the Church as well as those other marks of the Church characterizing the True Church, that is, The One Church founded by Christ Himself.
That true Church was declared to be "One, Holy, Catholic, and Apostolic" by the 150 Fathers of the 2nd Ecumenical Council (Constantinople - 381 A.D.). In the Creed emanating from the Council, the 150 Fathers declared the Church of which they were Bishops to be The One and only Church which had maintained the fullness ("Catholic") of the orthodox ("right-believing") faith handed down from the Apostles in contrast to the already proliferating congregations of heretical and schismatical bodies. Possessing the 4 marks noted in the Creed : "One, Holy, Catholic, and Apostolic", the "True Church" could, therefore, always be easily distinguished from other Christian groups whose teachings deviated from that visible Church founded by Christ which soon became known everywhere simply as "The Catholic Church".
THE FOUR MARKS REVEAL CHRIST LIVING IN HIS CHURCH
These 4 marks of the Church emphasized by the Council Fathers were considered to be the visible effects of the Presence of Christ in the unique society-institution He had established and equipped to "teach all nations" the message of salvation. As Fr. Robert Slesinski has written:
"The marks of the Church... are all signs of the presence of Christ in the Church. The latter point is the profound, theological meaning of the marks of the Church that is so often misunderstood by the rank and file faithful.
1. The Church is One, because Her Lord is One;
2. the Church is Holy, because Her Lord is Holy;
3. the Church is Catholic, because she is the Body of Him Who enjoys the fullness of Truth and Life;
4. and the Church is Apostolic, because Her mission in and to the world is a continuation of the work of the first Apostles, itself a holy charge of Her Redeemer Who alone can guarantee Her success." ("On the Catholicity of the Church", Faith and Reason, Winter 1984, p. 314)
Thus, the Church manifests the properties of Christ Himself since it is One with Christ as the Body of Christ in this world and living His Life. The Church is One with the unity of His Person, Holy with the holiness of His Person, Catholic in being the Divine Redeemer's Ark of Salvation open to all, and Apostolic in always maintaining the purity of the "deposit of faith" originally given to the Apostles by Christ Who commissioned them to "make disciples of all nations". The words "one, holy, catholic, apostolic" as they appear in the Creed reflect the invisible properties or qualities of Christ Himself, but as internal qualities are not sufficient to reveal to the ordinary person the true Church. It is true that these words were not defined with precision and exactness, but they were also clearly understood by the 150 Fathers at the Council and thereafter throughout the Church as constituting distinctive visible and external marks identifying that one unchanging visible Church which had been personally founded by Christ and against which the "Gates of Hell" could never prevail (Matt. 16:18 ff.). Thus, though "One, Holy, Catholic and Apostolic" signified primarily internal and invisible properties belonging to the essence of the Church, these terms also signified perpetual visible marks or notes easily enabling people of good will to distinguish the true Church of Christ from any other claimant to that title.
THE NAME OF "CATHOLIC" ALWAYS IDENTIFIES THE TRUE CHURCH
Already by the 4th century, such writers as Bishop Philastrius of Brixen, St. Epiphanius of Salamis, and St. Augustine of Hippo had compiled long lists of heresies being spread by heretical churches and sects that had broken away from the visible unity of the Catholic Communion ruled by Bishops in communion with the See of Peter. As St.Augustine wrote in his "De Fide et Symbolo":
"We believe in Holy Church; for even heretics and schismatics style their assemblies 'churches'. But whereas heretics violate the faith by their false ideas about God, schismatics, by their wicked separation, cut themselves off from fraternal charity. Hence neither do heretics belong to the Catholic Church, for it loves God; nor do schismatics, for the Catholic Church loves its neighbour.."
The same St. Augustine who wrote so much concerning the "sacrilege of schism" died before he was able to attend the 3rd Ecumenical Council of Ephesus (431 A.D.), but he left his unforgettable witness to the Faith of the Catholic Church of his time:
"There are many other things which rightly keep me in the bosom of the Catholic Church, the consent of peoples and nations keeps me, her authority keeps me, from the very seat of the Apostle Peter (to whom the Lord after His Resurrection gave charge to feed His sheep) down to the present episcopate. And so, lastly, does the name itself of Catholic, which not without reason, amid so many heresies, the Church has alone retained; so that though all heretics wish to be called Catholics, yet when a stranger asks where the [Catholic] Church is, no heretic will venture to point to his own chapel or house. Such in number and in importance are the precious ties belonging to the Christian name which keep a believer in the Catholic Church."
(Contra Ep. Fund., 4, 5)
In the teaching of the Fathers, the title "Catholic" is an exclusive and inalienable visible mark identifying Christ's true Church. Still today, most non-Catholics and non-Christians, and even atheists instinctively acknowledge which body of Christians constitutes the Catholic Church. The most bigoted anti-Catholics know who their enemy, the Catholics, are: namely those Christians in union with the See of Peter. Repeatedly sounded in St.Augustine's writings is his famous axiom "Securus judicat orbis terrarum" ("it is the whole world which judges with certainty"). It remains as true today that the "whole world judges with certainty" in identifying as "Catholic" only that Church which is subject to the authority of the Pope. The venerable word "Catholic" is in no need of any qualifiers for anyone seeking the true Church.
As everyone knows, it is Catholic doctrine that the Catholic Church is the true Church of Jesus Christ, the very same Church whose internal properties and external marks are set forth in the Nicene-Constantinopolitan Creed. These four visible marks (taken both singly and collectively) identify with certainty the imperishable Church which Christ established on the Apostles united to their head and center of unity, Peter, the Rock.
The First Vatican Council (1869-1870) had declared:
"The Church itself, with her marvelous propagation, eminent holiness, and inexhaustible fruitfulness in everything good, her Catholic Unity and invincible stability, is a great and perpetual motive of credibility and irrefutable witness of her divine mission."
(Chapter III, "Of Faith")
An interesting contemporary Apologetics problem is presented by the counter-claim of adherents of the dissident Byzantine Greco-Slav churches (which maintain a hierarchy of validly ordained Bishops, the 7 sacraments, and adhere to most Catholic doctrine) to be the "true Church" of Jesus Christ, and even to be the Catholic Church. It is unfortunate that Catholic texts dealing with the Marks of the Church have not adequately treated the Four Marks with respect to the dissident Eastern Orthodox churches. As to their claim to constitute the Catholic Church or to assume the label "Orthodox Catholic Church", Eastern Orthodox theologians conveniently ignore the trenchant comments of St. Augustine regarding easy identification of the true Church amidst the heretical and schismatic churches and assemblies which vied for the loyalty of Christians in his own time. Writing to Maximus, he said:
"I know what the Catholic Church is. The nations of the world are Christ's inheritance and the ends of the earth are His possession. You also know what the Catholic Church is - or if you do not, apply your attention to discern it, for it may very easily be known by those who are willing to be taught."
(Epist. XXIII, Ad Maximun., c.2)
To Faustus the Manichaean he wrote:
"The Church is conspicuously visible, a city set on a mountain which cannot be hid."
(Contra Faustum Manichaeum, XIII, 6)
"Repudiating therefore all those who seek neither philosophy in sacred things nor holiness in philosophy... we must hold fast to the Christian religion and to communion with that Church which is Catholic, and is called Catholic, not only by its own members but also by all its enemies. For whether they will or not, even heretics and schismatics when talking, not among themselves but with outsiders, call the Catholic Church nothing else but the Catholic Church. For otherwise they would not be understood unless they distinguished the Church by that name which she bears throughout the whole world."
(De Vera Relig., vii., 12)
An Eastern Father of the Church, St. Cyril of Jerusalem (340 A/D.) echoed the same teaching to his catechumens:
"Now it [the Church] is called Catholic because it is throughout the world, from one end of the world to the other... The Faith has delivered to thee by way of security the article, 'And in One Holy Catholic Church': that thou may avoid their [the heretics'] wretched meetings, and ever abide with the Holy Catholic Church, in which thou was regenerated. And if ever thou are sojourning in any city, inquire not simply where the Lord's House is (for the sects of the profane also attempt to call their own dens houses of the Lord), nor merely where the Church is, but where is the Catholic Church. For this is the peculiar name of the Holy Church and mother of us all, which is indeed the Spouse of our Lord Jesus Christ."
(Lect. 18, 22-28)
The renowned Cardinal Newman who knew the Fathers so well was to exclaim in one of his writings:
"This is the great, manifest historical fact which converted me. Christianity is an external fact - one continuous fact or thing, the same from first to last. Where was this thing? The answer was undeniable. The Church called Catholic now is that very same thing in hereditary descent, in organization, in principles, in external relations, which was called the Catholic Church then. Name and thing have ever gone together."
This verdict of the Fathers regarding the unchanging identity of the Catholic Church may be said to receive daily reinforcement as one reads Eastern Orthodox literature roundly condemning the Catholics for their many "heresies".
The claim to represent "genuine Catholicism" by the "Orthodox Church" is also negated by the fact that nowhere do the official Creeds of the ancient Church (e.g., the Apostles' Creed and the Nicene-Constantinopolitan Creed) profess belief in "the Orthodox Church". Rather they express belief in the Catholic Church as the one which uniquely preserves the orthodox faith handed down from the Apostles. Moreover, it should be stressed that the Eastern Orthodox communion is not one Church, but rather a loose assemblage of 16 or so autocephalous and autonomous national churches which possess no visible unity because they lack that visible center of unity (the Church's Rock-foundation) which Christ constituted as necessary for safeguarding the Church's unity of faith and hierarchical communion.
MARKS OF THE CHURCH OFTEN MISAPPLIED
In various Catholic apologetics texts, it is the invisible properties and attributes of the Church which are treated rather than engaging in a convincing demonstration that other specific claimants do not and can not possess the four visible marks. Also, the four marks are often misapplied by Catholic apologists to Protestant communities as if each Protestant denomination was competing with the Catholic Church to prove itself the "true Church". The fact is that no Protestant community identifies itself as "the true Church of Christ" claiming complete historical and dogmatic continuity with the primitive Church. Most Protestants believe that there is no "true Church" on earth, but that all who truly believe in Christ, whoever and wherever they are, make up the "Church". For Protestants the Church is not at all one perduring visible society maintaining its historical identity across the centuries. In their eyes, the "Church" is a purely invisible and spiritual assembly of the "saved", the chosen elect, the just, or the predestined. One former Protestant who became a convert to Eastern Orthodoxy has observed:
"[Protestant] Christians... believe that the One, Holy, Catholic, and Apostolic Church of Christ was not physically visible. For them it was invisible and existed only by faith. Some believed that each church possessed one aspect of the One, True Church of Christ. Therefore, if it were possible to combine all of the churches together, the end result would be the one Church of Christ. Never mind the contradictions of belief and practice which existed among these churches. This common supposition was a necessary one for Christians, who centuries before had separated from the historical, Apostolic Church of Christ. I was convinced, however, that this Church must still exist somewhere, although I had no idea where to find it... I read not less than fifty books and engaged in dialogue with a dozen different ministers, always searching, looking, hoping to find the 'pearl of great price' - the Bride and Body of Christ... Not one of these ministers dared to believe or to teach me that I had found the One, True Church, not even the Catholic priests of the Newman Center!"
(Journeys to Orthodoxy, ed. Thomas Doulis, 1986; page 24)
Abstracting from the miserable witness of the priests at the Newman Center who disgraced the memory of Cardinal Newman with his great zeal for souls, it is apparent that there was a serious failure to deal with a genuine search for the True Church by a sincere inquirer. A rigorous analysis and application of the traditional Marks of the Church would have helped lead him to the Catholic Church.
Marks of the Church, as has already been indicated, presume the visibility of the One Church as a concrete historical society that is imperishable. The value of the 4 marks (enumerated in the Nicene-Constantinopolitan Symbol of Faith) in traditional Catholic theology lies in their constituting external visible effects or signs which anyone can see, thereby enabling the most simple as well as the most erudite to easily distinguish Christ's true Church from any other body of Christians claiming to be the historical continuation of Christ's true Church. Since no Protestant community or confession claims to be the one indefectible visible Church of Christ on earth, and plainly did not even exist before the 16th century, each Protestant denomination is clearly excluded from being considered the "true Church".
The best Catholic apologists have acknowledged that recourse to the 4 visible Marks is not efficacious with regards to Protestants who regard the Church as an essentially invisible entity whose members are known to God alone. A visible Church with visible marks as found in the Creed and so confirmed in the writings of the Fathers of the Church - may well suffer rejection by Protestants obstinately defending "Sola Scriptura" and their "biblical" understanding of an invisible Church. However, there remains some real value in having recourse to the Fathers' use of the "via notarum" with those Protestants who are more open to the ancient Church's understanding of its own nature as an indefectible and visible society-institution possessing a unity of faith, worship, and government.
COMMON GROUND WITH EASTERN ORTHODOX
Contrary to Protestant sectarians who posit an ideal invisible Church, Eastern Orthodox (like Catholics) do believe in a visible Church which is indefectible in the preservation of the orthodox faith handed down by the Seven Ecumenical Councils. Despite unresolved disputes concerning the Church 's organ of infallibility, some Eastern Orthodox theologians still theoretically consider their Church infallible when defining dogma. There remains "Common Ground" in their agreeing with Catholics that visibility, indefectibility, and infallibility are attributes and properties belonging to the Church's nature as the Body of Christ. Also, like Catholics, they believe that outside the Church there is no salvation, and that it is necessary that every human being should be incorporated into the organism of their visible communion. Also, like Catholics, they acknowledge that one can become a member of the "true Church" only if that Church is knowable as such, and can be with certainty distinguished from every other claimant. Since God, in His Wisdom and Justice cannot make demands which it would be impossible for man to comply with, the true Church must of necessity be visible, so that she may easily be recognized with certainty and clearly distinguished from any counterfeit or heterodox body.
In the past there was general acceptance by Eastern Orthodox theologians of the concept of Marks of the Church (our "via notarum") and an attempt to verify the traditional marks of unity, holiness, catholicity, and apostolicity for their own communion.
Catholics, however, should be aware of the unwarranted contemporary reinterpretation of these marks of the Church by dissident Eastern Orthodox theologians which, in effect, empties them of their visible and external character so as to make them useless to the ordinary person for discovering the True Church. This is doubtless due to the embarrassment resulting from such theologians' acknowledged failure to demonstrate that modern Eastern Orthodoxy is more one, more holy, more Catholic, and more apostolic than the more unified, more impressive with a plethora of well-known Saints, more geographically world-wide, and far more active missionary body known throughout the world as the Catholic Church under the supreme authority of the Successor of Peter.
VISIBLE MARKS RENDERED INVISIBLE
It has not been sufficiently noted by Catholic writers that "alleged deficiencies" of the fourfold Marks have constrained Eastern Orthodox theologians to substitute the "mark" of "immutability" or "indefectibility" or "orthodoxy" for distinguishing the True Church from all other similar heterodox bodies. Thus, Greek and Russian Orthodox seminarians are taught:
"Only that Church is the true Church of Jesus Christ which truly and immutably preserves the infallible teaching of the ancient universal Church, and remains faithful to her in all things. This note is commonly used by our theologians."
Since Catholics also claim that their Church alone has preserved in all its integrity and purity the "infallible teaching of the ancient Church", this "mark" provides no criterion to resolve the debate between similar but rival bodies. Immutability of doctrine, indefectibility in doctrine, orthodoxy of doctrine, and even infallibility in teaching doctrine, though all properties essential to the true Church, do not constitute outwardly visible marks of the Church at all. They do not help identify the true Church from a heterodox rival making the same claims. It should not be forgotten that the ancient Assyrian (Nestorian) Church and the Oriental Orthodox (Monophysite) communion continue in our own days to claim complete orthodoxy in faith and to accuse the Eastern Orthodox churches (as well as the Catholic Church) of having innovated in matters of doctrine. Professing their adherence to Apostolic Tradition, these ancient Eastern Christian churches reject some of the Seven Ecumenical Councils considered by the Byzantine Greco-Slav autocephalous churches to be normative of orthodoxy.
The fatal consequence of Eastern Orthodox rejection of the traditional fourfold marks of the Church as visible and outward signs of the true Church is the "mystical" spiritualization of each mark. The visible Unity or "oneness" of the Church is reduced to a spiritual unity of faith in the Holy Spirit. But, an invisible "spiritual or mystical unity" cannot, of course, serve as a visible mark of the true Church. The mark "Holy", understood as the possession of "holy doctrine" will certainly not be questioned by Catholics as a feature of the true Church but "holy doctrine" cannot be a visible Mark of the Church since the determination of holy (and true or orthodox) doctrine depends on a prior identification of the true Church which teaches holy doctrine. The term "catholic" similarly has become identified by Eastern Orthodox writers with "orthodox" (but "orthodox" is an invisible quality subject to subjective interpretations and its use as a mark begs the question as to whether the dissident Byzantine Greco-Slav churches in their schism from the Petrine See of Rome have truly remained orthodox in every regard). In stressing catholicity as an internal quality and equating it simplistically with "orthodoxy", one sees a vain effort to offset the Catholic Church's "universal ecclesiology" with its obvious world-wide geographical diffusion and continuous missionary expansion.
Eastern Orthodox writers are certainly correct in understanding "Apostolic" as the true Church teaching the same orthodox doctrine that was taught by the Apostles but, once again, the possession of "apostolic doctrine or teaching" can not serve as a visible mark. This is because knowledge of the entire body of doctrine committed by Christ to His Apostles presumes a person's having already identified the true Church which, in fact, does and must teach all the apostolic doctrine which Christ committed to the Apostles. Moreover, since every dissident Christian communion and sect may be said to teach some apostolic doctrines, the ordinary inquirer seeking the true Church would find it practically impossible to decide with certainty which conflicting doctrines put before him are in agreement with what the Apostles did teach.
Interestingly, all the various dissident Eastern churches (not just the Eastern Orthodox communion) which have a venerable hierarchy of bishops of apostolic origin seek to apply exclusively to themselves the term "Orthodox", thereby claim to preserve unfailingly the orthodox doctrine handed down from the Apostles. The Eastern Orthodox are especially noted for declaring "orthodoxy" the one unfailing mark of the true Church. However, as previously noted, "orthodoxy" is not a visible Mark and therefore fails utterly to identify that body of Christians which is identical with the original Church of the Apostles described by St. Paul as the "pillar and ground of truth" (1Tim. 3:15). It is not orthodoxy or "teaching the right faith" that is the visible touchstone of the truth, but rather the true Church which is the touchstone of orthodoxy and authentic apostolic doctrine.
VISIBLE MARKS INTRINSICALLY LINKED TO ROMAN PRIMACY
It should be evident that since the 4 Marks of the Church deal with visible manifestations of invisible properties, they must involve inclusion of that one visible structural element that is essential to the very notion of the Church as a visible organized body, namely, its hierarchical government. Both the Catholic Church and the Eastern Orthodox churches clearly possess visible rulers claiming to be the apostolic ministry which has succeeded to the place of the Apostles who originally governed the true Church. The Catholic Church appears particularly striking and unique to everyone in that its visible apostolic ministry of bishops is united under a visible head and center of unity. The first and most basic visible mark of the Church, i.e, its Unity or Oneness, is only intelligible if its Episcopate governing the Church is, in fact, graced with the character of indivisibility. A visible oneness of the Episcopate that can easily be broken or dissolved by historical divisions taking place over matters of faith and morals is no oneness. An "undivided Church" of the past to which Eastern Orthodox theologians make appeal in their controversies with Catholics would be a fiction if it did not exist "undivided" in the present.
The notion of an imperishable "undivided Church", moreover, can make no sense except where there exists an indefectible visible center of unity which serves to identify the bishops who maintain Catholic orthodoxy amidst the developments of heresy and schism. In the Catholic Church Unity has been brought about and preserved by the subordination of a multiplicity of bishops to their common visible head. The true Church's indivisible Unity reveals its concrete reality only where the Roman Primacy of headship and supreme teaching authority in the Church is seen to be an essential feature of the Church's visible organization and hierarchical constitution. The visible marks of Unity, Sanctity, Catholicity, and Apostolicity, therefore, cannot prescind from their linkage to the Roman Primacy as instituted by Christ. As Rev. Fr. T. Zapalena, S.J., observed in his "De Ecclesia Christi: Pars Apologetica" (Romae 1955):
the "via notarum" "takes its nature and entire apologetical force from the promise, prediction and institution of Christ. But Christ instituted His Church upon Peter. Therefore, the primacy necessarily forms part of the Church's true unity, catholicity, apostolicity, and indeed sanctity, at least the active, since the lawful administration of the means of salvation can only occur in dependence on Peter and his successor."
In other words, use of the "via primatus" (the apologetic approach setting forth the Roman Primacy itself as a visible mark of the true Church) may be said to handily capsule the "via notarum" in all its force in identifying most easily the true Church against the claim of the Eastern Orthodox communion to be Christ's one visible Church.
The Church as visibly One is found only where the authority of Roman Primacy of Peter's successor makes possible an indivisible hierarchical Unity that can never be lost, no matter how many patriarchs and bishops may choose to separate from the one Catholic communion. As St. Ambrose wrote in the 4th century in praise of communion with the See of Rome, "Where Peter is, there is the Church."
The Church as "visibly Holy" is certainly found in the Catholic Church which continuously produces such an extraordinary number of canonized Saints from all walks of life who respected and obeyed the authority of the Roman Pontiff, and whose miracles have been rigorously examined as confirming the "seal of God" on the Catholic communion. This is not to deny the heroic sanctity of some separated Eastern brethren in good faith who made use of valid sacraments and the traditional spiritual practices of the Eastern Fathers of the Church. But the obvious sanctity of so many canonized and beatified sons and daughters of the Catholic Church dispel the ludicrous charges that "the Papacy is not a valid Church; it does not have Apostolic Succession; its sacraments are invalid" – [charges levelled by] the Greek Orthodox Archimandrite Cyril Kostopoulos of Patras in a book "The Papacy is Heresy" (1996) which was unfortunately praised by the present Archbishop of Athens Christodoulos.
The Church as visibly Catholic is found only where the Roman Primacy makes possible the coordination of the Church's missionary efforts to spread the One Church throughout the world against the hostile powers (both earthly and demonic) which are always arrayed against it. The continuous dynamic geographic spread of the One Church in its Petrine Unity (i.e., its universal diffusion under one visible head, the Successor of Peter) constitutes yet another moral miracle that reveals the true Bride of Christ among the various Christian communities or confessions. If there was ever established a visible Church commissioned to "TEACH ALL NATIONS", and to teach them "ALL THINGS" whatsoever He had commanded, and to continue such teaching "ALL DAYS", even to the consummation of the world, it can only be that historic Church bearing the mark of Catholicity in time and space combined with the mark of an indivisible Unity grounded in the visible "Cathedra Petri".
The Church as visibly Apostolic, i.e., identical with the Church established upon Peter and the Apostles, can only be found in the Catholic Church in communion with the See of Peter. The various dissident Eastern churches may indeed have Bishops claiming to be the successors of the Apostles in ruling the Church and transmitting apostolic doctrine, but they notoriously lack a necessary union with the visible head of the Apostolic College, the Successor of Peter, the Roman Pontiff who presides over the entire Church to safeguard its visible Unity and to guarantee its invincible stability.
The Pope's own line of succession in the Roman See is due to Christ's founding the Church on the head and leader of the Apostles whom He made the Rock-foundation of the entire Church. In declaring to Peter, "Thou art Rock and upon this Rock I will build My Church", Christ assured the enduring indivisible Unity of His hierarchical Church. The Apostles were not complete as the Apostolic College without Peter, the Rock, the Bearer of the Keys, the Confirmer of the brethren, and Chief Shepherd of the lambs and sheep of Christ (Cf. Matt. 16: 18-19; Luke 22: 31-32; Jn. 21:15-17). Any body of bishops which has become sadly separated from the visible Rock and supreme authority on which the entire Church is built, can no longer be said to possess that visible unity which uniquely graces the true Church. In departing from the Church's Rock-foundation and center of unity, such bishops are no longer fully "apostolic", i.e., as manifesting the Church's Unity in time or adhering to the Lord's doctrine concerning the government of His Church.
The four marks of the Church manifest the oneness of Christ's historical Church with Christ Himself. Each mark is a visible sign which enables one to discover the Presence of the Invisible Head of the Church in His one and only Church. Each mark singly, and even more so in combination with the others, identifies the true Church of Jesus Christ from any other body claiming to be historically identical with the one visible Church founded by Christ to teach without error the faith necessary for salvation. Christ's true Church can never lose its marks of Unity, Holiness, Catholicity, and Apostolicity - each of which presumes the existence and activity of the Petrine Office of the Papacy which gives the Church Her perfect and indivisible visible unity which, in turn, reflects the perfect and indivisible unity of the Blessed Trinity.
Whereas the 2nd Ecumenical Council taught that there were 4 visible marks of the Church which identifies the true Church from any other hierarchical body making a similar claim to be the One Body and Spouse of Christ in this "vale of tears", Eastern Orthodoxy is left devoid of any visible Mark to which its polemicists can convincingly appeal as demonstrating their communion to be the true Church of Jesus Christ. In dealing with Eastern Orthodox (both unlearned and learned) who acknowledge the need for an indisputable and easily discerned visible mark to identify with certainty the true hierarchical Church of Jesus Christ, that indelible mark is found only in the Catholic Church. It is provided by the perpetual Primacy of the Roman Church whose Pastor possesses by Christ's institution the Office of "supreme teacher of the Universal Church, in whom the Church's charism of infallibility is present in a singular way." (Vatican II's Lumen Gentium, #25)
The one true Church of Jesus Christ, therefore, is easily discoverable by any sincere inquirer who believes that Christ founded but one visible and imperishable Church. He cannot fail to observe that only one visible communion of bishops and faithful bears the distinctive and singular mark of a visible head and center of unity, and this in the person of the Bishop of Rome as Chief Pastor of all the lambs and sheep of Christ. Adherence to the visible communion of the Roman Pontiff who succeeds Peter in his divine Primacy identifies the members of the "One, Holy, Catholic, and Apostolic Church".