"Protestantism is dangerous. ..."
No, that isn't from a Catholic apologist; it is from Ronald K. Rittgers, who teaches German Reformation studies at Valparaiso University in Indiana, in his review, for The Christian Century, of Alister McGrath's recently published Christianity's Dangerous Idea: The Protestant Revolution—A History from the Sixteenth Century to the Twenty-First:
McGrath also stresses that early Protestantism was not a single, unified, coherent movement; it was a movement of movements that was characterized by conflict, tension and flux from the start. The only thing the early Protestants shared was the dangerous idea. And they quickly learned just how dangerous it could be when they found themselves unable to reach consensus on important matters of doctrine. After examining the failure of Luther, Zwingli and others to resolve their differences on the Lord's Supper, McGrath observes, "We see here the fundamental difficulty that the Reformation faced: the absence of any authoritative interpreter of scripture that could give rulings on contested matters of biblical interpretation."
And? What then?
Which finally leads to this:
Some people view the Bible largely as a human artifact that contains important human wisdom about God but needs to be supplemented and corrected by more modern sources of wisdom. McGrath makes clear that such liberal Protestants are a small minority in the Protestant world. It seems that most—including McGrath, perhaps—continue to believe in the perspicuity of scripture. It is remarkable, after all, that the vast majority of Protestants agree with one another and with most non-Protestant Christians about the essentials of salvation—that is, that it comes only through Christ and requires grace and faith. But one wonders if this surprising agreement is not owing to another yet dangerous idea that was present in the primordial materials from which Protestantism burst forth and that thus became part of its genetic code: the importance of clinging to the ancient rule of faith. If this is the case, Catholicism did not simply motivate the construction of a unified Protestant front; it also provided Protestants with a certain immunity against the most destructive possibilities of their core idea.
That is part of the argument, interestingly enough, made by Fr. Louis Bouyer (a former Lutheran pastor), in his important book, The Spirit and Forms of Protestantism. In reviewing that book, Mark Brumley wrote:
Bouyer contends that the only way to safeguard the positive principles of the Reformation is through the Catholic Church. For only in the Catholic Church are the positive principles the Reformation affirmed found without the negative elements the Reformers mistakenly affixed to them. But how to bring this about?
Bouyer says that both Protestants and Catholics have responsibilities here. Protestants must investigate their roots and consider whether the negative elements of the Reformation, such as extrinsic justification and the rejection of a definitive Church teaching authority and Tradition, are necessary to uphold the positive principles of sola gratia and the supremacy of Scripture. If not, then how is continued separation from the Catholic Church justified? Furthermore, if, as Bouyer contends, the negative elements of the Reformation were drawn from a decadent theology and philosophy of the Middle Ages and not Christian antiquity, then it is the Catholic Church that has upheld the true faith and has maintained a balance regarding the positive principles of the Reformation that Protestantism lacks. In this way, the Catholic Church is needed for Protestantism to live up to its own positive principles.