Infallibility of the Church
The infallibility of the Church is the belief that the Holy Spirit preserves the Christian Church from errors that would contradict its essential doctrines. It is related to, but not the same as, indefectibility, that is, "she remains and will remain the Institution of Salvation, founded by Christ, until the end of the world." The doctrine of infallibility is premised on the authority Jesus granted to the apostles to "bind and loose" (Matthew 18:18; ) and in particular the promises to Peter (Matthew 16:16–20; Luke 22:32) in regard to papal infallibility. Infallibility of the ecumenical councils. The  doctrine of the infallibility of ecumenical councils states that solemn definitions of ecumenical councils, approved by the Pope, which concern faith or morals, and to which the whole Church must adhere, are infallible. Such decrees often have an attached anathema, a penalty of excommunication, against those who refuse to believe the teaching. The doctrine does not claim that every aspect of every ecumenical council is infallible. The Roman Catholic Church holds this doctrine, as do most or all Eastern Orthodox theologians. However, the Orthodox churches accept only the Seven Ecumenical Councils from Nicaea I to Nicaea II as genuinely ecumenical , while Roman Catholics accept twenty-one. Only a very few Protestants believe in the infallibility of ecumenical councils, and these usually restrict infallibility to the Christological statements of the first seven councils. Lutheran Christians recognize the first four councils, whereas most High Church Anglicans accept all seven as persuasive but not infallible. A popular view among Orthodox Christians, especially Greek Orthodox and churches that fall within the Ecumenical Patriarchate, is that an ecumenical council is itself infallible when pronouncing on a specific matter such as Christology, whereas others hold that a council can be considered of full ecumenical authority only  once its declarations have been embraced by the faithful, an opinion more common among the Slavic Churches, such as the Russian Orthodox. Catholic Church. Catholicism teaches that Jesus Christ, "the Word made Flesh" (), is the source of divine revelation and, as the Truth, he is infallible. The Second Vatican Council states, "For this reason Jesus perfected revelation by fulfilling it through His whole work of making Himself present and manifesting Himself: through His words and deeds, His signs and wonders, but especially through His death and glorious resurrection from the dead and final sending of the Spirit of truth." ("Dei  verbum", 4). The content of Christ's divine revelation is called the deposit of faith, and is contained in both sacred scripture and sacred tradition, not as two sources but as a single source. The magisterium (Latin: "magister", "teacher") is the teaching office of the Catholic Church. Catholic theology divides the functions of the teaching office into two categories: the infallible "sacred magisterium" and the fallible "ordinary magisterium". The infallible sacred magisterium includes the extraordinary declarations of the pope speaking "ex cathedra" and of ecumenical councils (traditionally expressed in conciliar creeds, canons, and decrees). Examples of infallible extraordinary papal definitions  (and, hence, of teachings of the sacred magisterium) are Pope Pius IX's definition of the Immaculate Conception of Mary, and Pope Pius XII's definition of the Assumption of Mary. Before these definitions both sovereign pontiffs asked the bishops throughout the world whether these truths were indeed held by the faithful. Nowhere is it said that the Pope's charism involves special revelations, and the Pope must ascertain whether a belief is universally maintained before speaking "ex cathedra" on it. The above two instances of infallible definition outside an ecumenical council are the only two that can be cited  in the history of the Catholic church. A document signed by then-Cardinal Ratzinger and Cardinal Bertone speaks of Notable here is the confirmation that the "sensus fidelium" is critical in determining whether a doctrine can be called infallible teaching. Of the ordinary magisterium, the Second Vatican Council said: "Bishops, teaching in communion with the Roman Pontiff, are to be respected by all as witnesses to divine and Catholic truth. In matters of faith and morals, the bishops speak in the name of Christ and the faithful are to accept their teaching and adhere to it with a religious assent ." The ordinary magisterium includes the potentially fallible teachings of the pope and ecumenical Councils (i.e., not given ex cathedra) and, more commonly, of individual Bishops or groups of Bishops as taken separately from the whole College of Bishops. Such teachings are fallible and could possibly contain errors; they are subject to revisions or revocation. In the case of the teachings of individual bishops to their diocese, there can of course even be disagreement among the individual bishops on such issues. However, these potentially fallible teachings are necessary to contribute to the development of doctrine. Example of ordinary magisterium includes the  social teachings of recent popes or theological opinions that the Popes or bishops make public. Catholics are not free to merely dismiss such teachings. The Church demands a "submission of the intellect and will" to them, even if not supernatural faith. However, this is to varying degrees depending on a variety of things, especially when teachers disagree. Catholics must respectfully hear all opinions from equal authorities and judge which is best, makes more sense, and is more consonant with the tradition of the whole history of the Church. However, the use of a higher level of authority trumps past disagreement —for example, if a pope condemns the teaching of a bishop (even if both the condemnation and the teaching are fallible), or if an infallible teaching disagrees with a past fallible teaching. Catholics are free to weigh a variety of factors, however, in judging divergent opinions. In the end all must follow their own, well-formed conscience. Infallible teachings can be divided into two categories of precedence. The highest are called "de fide credenda" teachings, that is to say teachings defined as explicitly and specifically revealed in the deposit of faith: "Wherefore, by divine and Catholic faith all those things  are to be believed which are contained in the word of God as found in Scripture and Tradition, and which are proposed by the Church as matters to be believed as divinely revealed, whether by her solemn judgment or in her ordinary and universal Magisterium." (First Vatican Council, "Dei Filius" 8.) The other category are called "de fide tenenda" teachings. These are equally infallible but are proposed not as being explicitly in the deposit of faith, but nevertheless implied by it or intrinsically connected to it logically or historically. These too demand supernatural faith, but not specifically in themselves on  the authority of the Word of God. Further discernment may lead to the conclusion that a "de fide tenenda" teaching is not merely implied by the deposit of faith, but explicitly contained and thus it may advance to "de fide credenda" status. Both extraordinary definitions and the universal magisterium may teach "de fide credenda" or "de fide tenenda" teachings. An example of "de fide credenda" teachings taught by extraordinary definition are the Christological teachings of the early ecumenical councils or the Marian dogmas of the Immaculate Conception and Assumption taught by the popes. An example of "de fide credenda" teachings  taught by infallible ordinary and universal magisterium include the immorality of directly taking an innocent human life. Examples of "de fide tenenda" teachings taught by extraordinary definition include the canonizations of saints and Pope Leo XIII's declaration of Anglican orders as null and void (so-called "dogmatic facts"). Neither of these could advance to "de fide credenda" status as they are contingent on historical facts. However, certain teachings on grace and justification from the Council of Trent, currently regarded as infallible but only "de fide tenenda" due to disagreement about whether they are explicitly contained in the deposit of  faith or merely logically implied, could someday advance to "de fide credenda" status either through extraordinary definition or through the consensus of the universal magisterium. An opinion from a former member of the Congregation For the Doctrine of the Faith, Ratzinger holds Examples of de fide tenenda teachings taught by infallible ordinary and universal magisterium include the validity of papal elections, earlier non-papal canonizations now universally accepted (of St. Agnes, for example), or the immorality of pornography. However, none of these could advance to de fide credenda status as they are contingent on historical facts or developments, as for  example pornography is condemned, and infallibly so, but is likely not included specifically in the deposit of faith (there was no such concept at the time), but is nevertheless an infallibly discerned implication of the more general revealed teachings on human sexuality and chastity. However, certain teachings taught in such a manner may someday advance to de fide credenda status, either through extraordinary definition or the consensus of the ordinary universal magisterium. As, for example, the teaching on papal infallibility was infallibly taught for a long time de fide tenenda by the universal magisterium, but not de fide credenda until  the extraordinary definition at Vatican I, because there was disagreement on whether it was a specifically revealed truth from the deposit of faith or merely the logical implication of other things in the deposit of faith (as, for example, the authority of Saint Peter in the college of apostles, the constitution of the Church, her unity, her episcopal structure, etc.) Pope. The doctrine of papal infallibility states that when the pope teaches "ex cathedra" his teachings are infallible and irreformable. Such infallible papal decrees must be made by the pope, in his role as leader of the whole Church, and  they must be definitive decisions on matters of faith and morals which are binding on the whole Church. An infallible decree by a pope is often referred to as an "ex cathedra" statement. This type of infallibility falls under the authority of the sacred magisterium. The doctrine of papal infallibility was formally defined at the First Vatican Council in 1870, although belief in this doctrine long predated this council and was premised on the promises of Jesus to Peter (Mat 16:16-20; Luke 22:32). The encyclicals of the First Vatican Council, however were rejected by a small minority of bishops  who separated themselves from union with the Bishop of Rome to form, or preserve, the Old Catholic Church. Ordinary and universal magisterium. The ordinary and universal episcopal magisterium is considered infallible as it relates to a teaching concerning a matter of faith and morals that all the bishops of the Church (including the Pope) universally hold as definitive and only as such therefore needing to be accepted by all the faithful. This aspect of infallibility only applies to teachings about faith and morals as opposed to customs and prudential practices. Additionally, the ordinary and universal episcopal magisterium applies to a  teaching to be held definitively by all the bishops at any given moment in history. Such teachings are extremely hard to prove. Thus, even if a teaching on a matter of faith and morals is out of favor among the bishops of a later date, once it has been held definitively by all bishops to be accepted by the faithful as infallible, then it is considered infallible and unchangeably true. However, Bishops all agreeing to a teaching to be held inconclusively are not teaching it to be definitive. It must be clearly established to be definitive for all time. This  was attempted to be thoroughly done and documented in the case of several statements contained in Evangelium vitae. Eastern Orthodox Church. The Eastern Orthodox Churches also believe in apostolic succession through which Christ promised to preserve the Church from teaching error. This grace and authority, however, does not make any of the bishops being individually infallible, however, but rather means that, in consensus, in combined agreement, they are charged with preserving the universal faith from error. Thus the Orthodox Church does not use the term "infallible" to discuss the works of any bishop or council. Orthodox Christians regard the concept  of infallibility to be uniquely Western and therefore avoid the use of defining or terming even Ecumenical Councils as infallible. Ecumenical Councils are felt, in the East, to be a continuation of the apostolic faith, and that the apostolic faith does not change. However, it also believes that not every council that proclaims itself ecumenical is so in fact. The Orthodox would also not accept the infallibility of the ordinary and universal magisterium. Lutheranism. Lutheran theology teaches that the Church is indefectible, as with Catholic doctrine. The Lutheran Churches hold that the "maintenance of this indefectibility as the sovereign work  of God." Anglicanism. The Church of England claimed this type of authority over the people of England, but the idea is no longer popular within the church, owing to a lack of commonly-accepted traditions and to disputes as to some peripheral doctrines. However, Anglicanism holds to a unique ecclesiology: in the Anglican view, churches in the historic episcopate (such as the Anglican, Roman Catholic, Scandinavian Lutheran, Moravian, Old Catholic, Persian, Eastern Orthodox and Oriental churches) that maintained apostolic succession, belief, and practice are all branches of the Universal Church. Anglicans believe there will always be a section of the  Christian Church, although possibly not the Anglican Church itself, which will not fall into major heresy. Tradition and scripture. Catholics and Orthodox Christians believe that divine revelation (the one "Word of God") is contained both in the words of God in sacred scripture and in the deeds of God in sacred tradition. Everything asserted as true by either scripture or tradition is true and infallible. Methodists and Anglicans teach the doctrine of "prima scriptura", which suggests that Scripture is the primary source for Christian doctrine, but that "tradition, experience, and reason" can nurture the Christian religion as long as they  are in harmony with the Bible. Yves Congar, who thought Catholics could acknowledge a substantial element of truth in the Lutheran and Reformed doctrine "sola scriptura," wrote that "we can admit "sola scriptura" in the sense of a material sufficiency of canonical Scripture. This means that Scripture contains, in one way or another, all truths necessary for salvation." This has led to the tenable position of the "two modes" theory. In his book, James F. Keenan reports studies by some academics. A study by Bernard Hoose states that claims to a continuous teaching by the Church on matters of sexuality , life and death, and crime and punishment are "simply not true." After examining seven medieval texts about homosexuality, Mark Jordan argues that, "far from being consistent, any attempt to make a connection among the texts proved impossible." He calls the tradition's teaching of the Church "incoherent". Karl-Wilhelm Merks considers that tradition itself is "not the truth guarantor of any particular teaching." Keenan, however, says that studies of "manualists" such as John T. Noonan Jr. has demonstrated that, "despite claims to the contrary, manualists were co-operators in the necessary historical development of the moral tradition." Noonan, according to  Keenan, has provided a new way of viewing at "areas where the Church not only changed, but shamefully did not." Consequences for ecumenism. The Roman Catholic, Eastern Orthodox, and Oriental Orthodox Churches, and the various Protestant denominations are divided by their different views on infallibility. The ecumenical movement, which hopes to reunify all of Christianity, has found that the papacy is one of the most divisive of issues between churches. Infallibility has often been misunderstood by most Christian denominations. Infallibility cannot be understood properly unless a sound comprehension of the administration and theology of each Christian group has first  been understood.