We are one church and we need just one Mass, this Catholic argues-even if that one Mass is celebrated in any number of languages.

At one end of the archdiocese where I live, a Mass is held in a gymnasium every Sunday, and a group of lively folk musicians accompany the assembly through a relaxed and informal liturgy. The mood reflects the music. Because it's a gym, children seem to act less restrained, feeling free to roam a bit. Folding chairs are set up in a semi-circle around a portable altar that this group has used for many years.

There are no kneelers, of course, reflecting to some extent the impracticality of portable kneelers, but reflecting to a greater extent the theology of those gathered: These are "looking up to God in trust, not bowing down to God in fear" Catholics, nurturing a view of church and theology that was born at the Second Vatican Council.

I know many of these Catholics and consider them to be very good people. Their liturgy is, I believe, a scandal.

At the other end of the archdiocese, a priest adorned in shimmering vestments murmurs prayers in Latin, facing the tabernacle, his voice barely audible to the assembly of worshipers kneeling behind him. Many of these are silently and privately praying the rosary. At certain moments there is an exchange of words between the priest and the assembly. These words are in Latin.

The atmosphere is reverent, reflecting to some extent the mood naturally created by silence, candles, and Latin, but reflecting to a greater extent the theology of those gathered: These are "kneeling before God in awe, not back-slapping brother Jesus" Catholics, preserving a view of church and theology set aside at the Second Vatican Council.

I know one of the people in the assembly to be one of the finest human beings alive-my father-but his liturgy is, I believe, a scandal.

 An outsider observing the two rituals Would never guess they belonged to the same church. And in fact, many of the participants at the respective assemblies might admit that they don't really share a faith with the participants in the "other" group.

This is what makes these liturgies scandalous. They represent such polarized expressions of worship that they drift from the central purpose of liturgy as stated in the introduction of Sacrosanctum Concilium, the Second Vatican Council's Constitution on the Sacred Liturgy: "to be a sign lifted up among the nations, to those who are outside, a sign under which the scattered children of God may be gathered together until there is one fold and one shepherd." A church practicing such divergent forms of worship will hardly unite the scattered children of God.

Currently we are many folds under a shepherd who last year stirred the pot with his apostolic letter Summorum Pontificum (Of the Supreme Pontiffs), sanctioning wider use of the old Latin or Tridentine Mass. Besides allowing individual parishes to conduct Latin Masses at the pastor's discretion, secondhand reports suggest that Pope Benedict XVI would like to see a Latin Mass offered at every parish. Upon hearing this, I felt a rumbling that I'm certain was Pope John XXIII, who opened the Second Vatican Council, rolling in his grave.

 The problem with the gym mass is not the gym, or the folk music, or even the lack of kneelers. The gym liturgies I've participated in mostly adhere to the rite promulgated by the Second Vatican Council. The scandal is the fact that 100 yards from the gym, a splendid church sits where liturgy is celebrated by the other 90 percent of the parish every Sunday.

Once, when gym repairs required the gym Mass to move back into the regular church for a while, there was some talk that the gym altar should be moved in to replace the regular church altar. Two altars at one parish screams division to me: "Our church is not your church; our worship is not your worship; we are not you." Such practices divide the Body of Christ-not the sort of thing those who led the council had in mind when they promulgated changes.

In the zeal that followed the council, many well-intentioned but liturgically ill-informed experiments cropped up in parish liturgies. Some progressive liturgies went too far and abused the intent of the council's changes.

Many of these alternative practices have fueled the reaction of extremists who now want to rewind church history and drop us all back into a Bells of St. Mary's world, as black and white as the cassock and surplice of a 10-year-old altar boy. At one end of our church, progressives dance to the beat of their very own drummer, while at the other end nostalgic traditionalists turn back the hands of time.

 In my judgment, the progressive, alternative Masses are much less troubling than the return of the Tridentine Mass. As mentioned, gym liturgies are mostly faithful to the changes promulgated in the council. While they may cross the line at times, at least they seem to be reaching in the direction the council members were pointing us toward.

And let's face it, my generation, the flower-power gang, is, well, beginning to push up daisies. Progressive liturgies are fading away as the jingle-jangle of our tambourines increasingly exits stage left.

But prancing in stage right are the Tridentine Troubadours, flipping the altar around and turning their backs to the monumental progress of the Second Vatican Council.

What is scandalous about this practice is not the Latin. After discussing the issue with theologians and liturgists Keith Pecklers, S.J. and Mark Francis, C.S.V., both independently made the distinction between the Tridentine Mass, celebrated by Catholics between 1570 and approximately 1965, and the post-conciliar rite practiced in the Latin language.

Pecklers explains that the church has, since the council, always allowed the use of Latin in the reformed liturgy. Saying the Mass in Latin is no different than saying it in Spanish or Polish or English.

The reformed liturgy is flexible enough to allow the use of Latin at times. Many parishes replace the "Lamb of God" and the "Holy, Holy, Holy" with the Agnus Dei and the Sanctus during the season of Lent. Besides being in complete conformity with the changes promulgated by the council, this appropriate use of the Latin can often deepen the spiritual tone of the liturgy and underline the gravity of the season.

But limited use such as this is far different from a complete 180-degree nostalgic return to an outdated rite.

 The Tridentine Mass is not simply the current Mass (the one promulgated by Pope Paul VI in 1970) spoken in Latin. The Tridentine Mass, which dates from 1570, reflects a very different-and incomplete-understanding of the early church. Francis argues that "the 16th-century framers [of the Tridentine Missal] lacked adequate historical resources, as they were unable to refer to manuscripts dating earlier than the pontificate of Innocent III, around 1216."

A church digging in its defensive heels at the peak of the Reformation developed the Tridentine Mass, taking shots at pagans, heretics, schismatics, and "perfidious" Jews. The rich revelation of the Old Testament is mostly absent, and the participation of the laity barely exists.

The Second Vatican Council had some very good reasons to call for an end to the Tridentine Mass and to promulgate a new rite. More sophisticated research uncovered a fuller understanding of how liturgy was celebrated in the early church. Improved scripture scholarship developed into a new lectionary with a wider selection of readings. Better historical research removed fictional saints from the liturgical calendar.

Perhaps most important for the average Catholic, the Mass was celebrated in the language of the people. Interestingly, while the Tridentine Mass began to be used in 1570, Masses were celebrated in Latin as early as A.D. 350. Originally, the Latin replaced Greek because people understood Latin, and using Latin allowed more people to understand what was going on. In 1965 the church once again came to the seemingly obvious conclusion that people should understand what is being said in Mass.

 The Mass that emerged from the reform of Vatican II is wonderful, divine, human, and sublime. It works, and it is enormously superior to the Tridentine rite. We do not need to celebrate an old rite. We need to get more people to celebrate the existing rite well.