Surveys have consistently shown that, since the time of the Second Vatican Council (1962-65), Catholics under the age of 50 know less about the content of their faith-tradition than did their pre-Vatican II counterparts. There are many reasons for this development, but they cannot be listed and explained in the space of a single column. Indeed, they require book-length analyses.

The question is: what difference does it make? What difference does it make, for example, if an under-50 Catholic today cannot distinguish between the Immaculate Conception and the virginal conception?

While it is surely better to know than not to know such information, such information is hardly essential to a fully conscious Catholic life. In other areas, however, religious illiteracy is more serious because it can undermine one's sense of religious identity, not only as a member of the Catholic Church but, more fundamentally, as a Christian.

Staying with the Marian example above, it may not be a matter of overriding importance that a Catholic know the difference between the Immaculate Conception (of Mary) and the virginal conception (of Jesus), but it surely is of the highest importance that Catholics know that their church does not approve of, much less promote, the "worship" of Mary, as if she somehow shared in the divinity of her Son.

Mary is the greatest of the saints, which means that she is the most luminous model or exemplar of what Christian discipleship is all about, namely, giving oneself totally to the following of Christ, allowing Christ and his Gospel to shape and to transform one's whole being, one's whole value system, one's whole network of relationships with others.

As in many things, however, it is better to know too little than to claim to know too much. Thus, in the realm of Marian devotion, there are many Catholics for whom Mary is a virtual cipher. They never advert to her, much less seek her intercession through prayer. If they belong to a parish dedicated to her, that is about as close as they will come to any conscious devotional relationship to the mother of Jesus.

On the other hand, there are Catholics for whom Mary shares almost equal spiritual billing with her Son. They regard her as his key partner, as it were, in the drama of salvation. She is the one who, in various appearances around the world, constantly goads us into greater fidelity to her Son's message, using threats of damnation and global catastrophe as her primary tools of persuasion.

Such Catholics are constantly bemoaning the loss of religious literacy among their fellow Catholics, but one has to ask which is worse: illiteracy or a serious distortion of what one takes to be Catholic doctrine?

The religiously illiterate Catholic may not know the difference between the Immaculate Conception and the virginal conception, but that same Catholic knows instinctively that if we have been redeemed, it is Jesus Christ who redeemed us, not his mother.

Such Catholics also know, again instinctively rather than in some consciously doctrinal fashion, that the Gospel means "good news," not "bad news," that the essence of the message that Christ came to share with us is a message of joy and hope, not of gloom and doom.

Is sin a part of the total picture? Of course, it is. Can sin derail our progress toward salvation? Of course, it can.

But in the Catholic faith-tradition, based as it is on the preaching of Jesus himself and of his Apostles, "where sin increased, grace overflowed all the more" (Romans 5:20). The power of God's grace is always stronger than the power of sin.

The fundamental message of the Gospel, therefore, is not that the world and all of us with it are teetering on the brink of damnation, but that the whole of God's creation is destined for glory (Romans 8:18-25).

In an article in the current issue of Celebration magazine, Tom Beaudoin, a visiting assistant professor of theology at Boston College and a widely published commentator on the faith of younger Catholics like himself, distinguishes between "conceptual literacy" and "performative literacy," that is, between "knowing" what one is to believe as a Catholic and actually "doing" what is consistent with Catholicism's core beliefs.

Beaudoin regards this performative literacy as "a major success story" for post-Vatican II religious education, expressed in the practice of volunteerism, social justice, ecumenism, and lay responsibility for the church.

In the end, it is not the one who says, "Lord, Lord," who will enter the kingdom of heaven, but the one who actually does the will of God (Matthew 7:21).

Father Richard P. McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame.