When he was a young seminarian, the teacher in Luigi Giussani’s singing class played a recording of an aria from a Donizetti opera, “Spirto gentil” (“Gentle spirit, you once shone in my dreams, but after, I lost you forever. . .”). At that moment, Giussani “understood for the first time that God existed, and thus that nothing could exist without a meaning; that the heart could not exist unless the heart’s goal existed: happiness.”

What do we mean when we say “I”? Behind that word there exists today a deep and abiding confusion. And yet what could be more urgent for each and every one of us than an understanding of what it means to be a subject—a true protagonist in the world? Nothing is as fascinating as the discovery of the true dimensions of one’s own “I.”

There is an ancient Christian saying from the Patristic Era which is known in its most concise form as lex orandi, lex credendi. As the Catechism of the Catholic Church translates it: “The law of prayer is the law of faith: the Church believes as she prays.”

In 1980, two men sit down to record a conversation. They have much in common: both are passionate, articulate thinkers. But their differences are just as striking….