The word "orthodoxy" is derived from a Greek word that literally means "right praise." A secondary meaning is "right belief." Although the word "orthodoxy"does not appear in the New Testament, the concern for right belief was certainly present there (Rom 16:17: I Cor 11:2, 28; 15:1-3; 1 Tim 1:10; 6:3-4; 2 Tim 4:3; Titus 1:9; 2:1).
In the earliest centuries of the church, orthodox faith was professed in creeds, especially the Apostles', the Nicene, and the Athanasian. Other sources of orthodoxy include solemn conciliar and papal teachings, beliefs of the church that have been universally held down through the centuries, and the consensus of the church fathers and its theologians. The main practical criterion of orthodoxy is the Liturgy, following the ancient Latin axiom lex orandi lex credendi (the rule by which we worship is the rule by which we believe).
Unfortunately the word "orthodoxy" has taken on a polemical cast in recent decades. For certain ultra-conservative Roman Catholics, orthodoxy is implicitly identified with the neo-Scholastic theology that was dominant in Catholic catechisms and textbooks prior to Vatican II and also with the spiritual, liturgical, devotional and canonical practices of that same period. It was the time when Catholics had no living memory or experience of significant change in the church's liturgical and sacramental rites.
Indeed there had been no changes (for all practical purposes) since the 16th century. The Mass and the sacraments were celebrated in Latin, with little or no participation by the laity. It was also an era when Catholics gauged their fidelity to the church by things they did (attending weekly Mass, reciting the rosary, defending the church against all criticism) and by things they avoided (eating meat on Friday, practicing birth control, getting divorced, praying with Protestants) : as well as by their unquestioning loyalty to the pope.
Vatican II changed all this. It taught that the church is the whole people of God, not just the hierarchy and the clergy; that the "church" is bigger than the Catholic Church alone, and that Protestants and other Christians are part of the Body of Christ as well : even if their degree of communion varies; that the liturgy and the sacraments are meant to be understood and celebrated by all : laity as well as clergy; that the church is to be governed by the whole body of bishops and not by the bishop of Rome alone; and that the church is always in need of renewal and reform.
The two popes and the many bishops who were leading figures at Vatican II represented the Catholic center : the "orthodoxy" of the day, if you will: Pope John XXIII, Pope Paul VI, and Cardinals Suenens, Dopfner, Marty, Lienart, Frings and Bea, Patriarch Maximus IV Sayegh and various others as well. All of them fully supported John XXIII's call for an aggiornamento (updating) of the church. Their views and the documents they helped the council fashion and adopt would have marked these men today as "progressives."
Yet in comparison with the views of so many of their successors in today's hierarchy, these Vatican II leaders might even be dismissed nowadays as "dissidents." Yet they were solidly orthodox. Their program of reform was unhesitatingly approved by the two popes who presided over that council between 1962 and 1965.
Today, in a strange twist of events, many Catholics promoting the initiatives of Vatican II are regarded as "unsafe." Why? Because they criticize particular church practices and policies, do not regard the pope as the last word on any and every ecclesiastical topic, and believe that the laity should have more input in the governing of parishes and dioceses, and the bishops (instead of the Curia!) should have more say in the governance of the universal church.
These Catholics welcomed the liturgical renewal mandated by Vatican II and now resist efforts to reverse the course back to the pre-conciliar period when the emphasis was on "mystery" in the narrow and erroneous sense of the word, on clerical dominance in the rituals, and on adoration of the Eucharist. The "restorationists" seek not only to return to the views of that council's defeated minority, but also to suppress those standing with the council's majority.
The spirit of the new "orthodoxy" is one of intolerance. There are no gray areas. They have convinced themselves that they alone deserve to be heard and read. They alone deserve positions of pastoral leadership and they alone determine what Catholic "fidelity" means. They alone have the obligation to protect the church from people who do not meet their particular standards. But that is not a recipe for unity, but for division.