John XXIII. The very name is apt to elicit strong reactions from many Catholics. He was either the pope who finally began to free the Church from her medieval accretions and rigidities or, on the other hand, the pope who initiated the fatal compromise with the world which has proven to be such a disaster. In reality he was neither. In particular, his first encyclical, Ad Petri Cathedram, insists on matters often considered as embarrassments in today’s Church, especially the necessity of doctrinal truth and the uniqueness of the Catholic religion.
Pope John states a threefold theme for his encyclical: truth, unity and peace. And it is truth which is fundamental. “All the evils which poison men and nations … have a single cause and a single source: ignorance of truth – and at times even … a contempt for truth” (no 6). He distinguishes between natural truth which our intellects can attain, and “those truths which exceed the capacity of nature” and for which we require divine revelation. Hence, we “are bound to accept the teaching of the Gospel [without which] the very foundations of truth, goodness, and civilisation are endangered” (no. 8).
Then Pope John proceeds to unity – in society, in the family and in religion – and its foundation in the truth. He quotes Leo XIII: “the Catholic faith … cannot be placed on a level with other religions without serious injustice, since it alone is true” (no 17). Hence, “it is the will of God, the Church’s founder, that all the sheep should eventually gather into this one fold, under the guidance of one shepherd. All God’s children are summoned to the Father’s only home, and its cornerstone is Peter” (no 68).
The Church’s unity of doctrine rests upon “the necessity of believing firmly and faithfully all that God has revealed [both in] sacred scripture and in the oral and written tradition that has come down through the centuries from the apostolic age” (no 69). John XXIII addresses himself to separated Christians with the hope that “this wonderful spectacle of unity, by which the Catholic Church is set apart and distinguished … [may] stir your hearts and awaken you to what is really in your best interest” (no 79). For “We are not inviting you to a strange home, but to your own, to the abode of your forefathers” (no 84).
St John XXIII’s first encyclical reveals clearly both his orthodox and traditional sensibilities and his optimism and charity toward all. It is hard to deny that, due to his optimism, he undertook or permitted actions which turned out to be imprudent. But if we were to follow the teaching of Ad Petri Cathedram today, we would find a path not only toward truth, but toward the unity and peace that only truth can guarantee.