Pope Francis recently appointed Bishop Americo Aguiar of Lisbon, Portugal to the College of Cardinals. Vatican watchers noted that Francis's incardinating an auxiliary bishop like Aguilar instead of his superior was an extraordinary move.

Aguiar is the coordinator of this year's World Youth Day (WYD), the annual global gathering of Catholic young people. The bishop-turned-cardinal stirred up controversy in an interview with a Portuguese television station about the event. He said:

We want it to be normal for a young Catholic Christian to say and bear witness to who he is or for a young Muslim, Jew, or of another religion to also have no problem saying who he is and bearing witness to it, and for a young person who has no religion to feel welcome and to perhaps not feel strange for thinking in a different way.... We don’t want to convert the young people to Christ or to the Catholic Church or anything like that at all.... That we all understand that differences are a richness and the world will be objectively better if we are capable of placing in the hearts of all young people this certainty...

The now-Cardinal Aguiar attempted to walk these remarks back in an interview with the Pillar, claiming he had intended to discourage "proselytism" rather than evangelism as such. Whatever the merits of that distinction, I will be charitable to the newly appointed prince of the Church and assume he didn't mean what he plainly seemed to, and instead will comment on what I perceive to be a broader problem, of which the cardinal's remarks are a symptom.

Christianity is either true, or it is not. Islam is either true, or it is not. Judaism is either true, or it is not. Each may be useful, in all sorts of ways, even if it is not true. Believers might be better people on account of their beliefs. They might be more charitable, more patient, more kind. But that is different from saying that each of the three faiths, in its own way, is true. They aren't.

Take Christianity and Islam. Christianity and Islam make mutually exclusive claims about the most fundamental matters of theology and philosophy: the nature of God, the person of Christ, the path to salvation, and more. It is possible that neither Christianity nor Islam is true. It is possible that either Christianity or Islam is true. It is not possible that both Christianity and Islam are true.

And if Christianity is true, I'm afraid it doesn't give us the option to believe that "differences" in belief about the nature of God and Jesus Christ "are a richness," nor that the world would "be objectively better" if people tolerated with a passive indifference the error of other faiths on the most essential questions of human existence. If Christianity is true, we must—not should, but must—"want to convert the young people to Christ." If that's impolite, so be it. Christ came to bring the sword, not to set up an NGO.

Catholics, particularly Catholics in positions of authority, should act as though they believe Catholicism is true—not just that it can be used to create a more just society, or make life meaningful, or tell a compelling story about God's relationship to human beings—but actually, really true. Flannery O'Connor said of the Eucharist, "If it's just a symbol, to Hell with it." Some young people, I'm afraid, are saying the same of the Catholic Church.