structural:summarization, quality:corruption
Catholic responses

The view of the Catholic Church is that Protestant denominations cannot be considered churches but rather that they are ecclesial communities or specific faith-believing communities because their ordinances and doctrines are not historically the same as the Catholic sacraments and dogmas, and the Protestant communities have no sacramental ministerial priesthood and therefore lack true apostolic succession. According to Bishop Hilarion (Alfeyev) the Eastern Orthodox Church shares the same view on the subject.

Contrary to how the Protestant Reformers were often characterized, the concept of a catholic or universal Church was not brushed aside during the Protestant Reformation. On the contrary, the visible unity of the catholic or universal church was seen by the Protestant reformers as an important and essential doctrine of the Reformation. The Magisterial reformers, such as Martin Luther, John Calvin, and Huldrych Zwingli, believed that they were reforming the Catholic Church, which they viewed as having become corrupted. Each of them took very seriously the charges of schism and innovation, denying these charges and maintaining that it was the Catholic Church that had left them. The Protestant Reformers formed a new and radically different theological opinion on ecclesiology, that the visible Church is "catholic" (lower-case "c") rather than "Catholic" (upper-case "C"). Accordingly, there is not an indefinite number of parochial, congregational or national churches, constituting, as it were, so many ecclesiastical individualities, but one great spiritual republic of which these various organizations form a part, although they each have very different opinions. This was markedly far-removed from the traditional and historic Catholic understanding that the Roman Catholic Church was the one true Church of Christ.

Yet in the Protestant understanding, the visible church is not a genus, so to speak, with so many species under it. In order to justify their departure from the Catholic Church, Protestants often posited a new argument, saying that there was no real visible Church with divine authority, only a spiritual, invisible, and hidden church —this notion began in the early days of the Protestant Reformation.

Wherever the Magisterial Reformation, which received support from the ruling authorities, took place, the result was a reformed national Protestant church envisioned to be a part of the whole invisible church, but disagreeing, in certain important points of doctrine and doctrine-linked practice, with what had until then been considered the normative reference point on such matters, namely the Papacy and central authority of the Catholic Church. The Reformed churches thus believed in some form of Catholicity, founded on their doctrines of the five solas and a visible ecclesiastical organization based on the 14th- and 15th-century Conciliar movement, rejecting the papacy and papal infallibility in favor of ecumenical councils, but rejecting the latest ecumenical council, the Council of Trent. Religious unity therefore became not one of doctrine and identity but one of invisible character, wherein the unity was one of faith in Jesus Christ, not common identity, doctrine, belief, and collaborative action.

There are Protestants, especially of the Reformed tradition, that either reject or down-play the designation Protestant because of the negative idea that the word invokes in addition to its primary meaning, preferring the designation Reformed, Evangelical or even Reformed Catholic expressive of what they call a Reformed Catholicity and defending their arguments from the traditional Protestant confessions.