The 50th anniversary of Pope Paul VI’s landmark encyclical letter “Humanae Vitae” (“Of Human Life”) furnishes Catholics with a unique opportunity to reexamine our relationship with the Church’s magisterium.

As much as society at large changed in the climactic year of 1968, the effects were not as deep, lasting, or far-reaching as the changes that occurred within the Catholic Church, all because of the publication of one 8,000-word papal letter.

In the midst of civil and social turbulence, Paul published his last encyclical, reaffirming the Church’s perennial teaching regarding the regulation of birth. This document occasioned a tectonic shift in the way that countless Catholics would henceforth view the Church and her teaching.

Without wishing to put too fine a point on it, the most damaging fallout of the encyclical was a widespread “Protestantization” of the way many Catholics began to deal with the Church. This change was not simply the practical disregard for Catholic teaching on birth control, but rather the more insidious theoretical conclusion that the papal magisterium had simply “got that one wrong.”

Failing to fully live up to the Christian moral life is, after all, the story of Catholics going back to the time of Jesus. People fall, they repent, they get up, and with God’s grace, they try again. Distrust in Church teaching, on the other hand, leaves Catholics bereft of moral certainty with only their subjective ethical compass to guide them.

What is, in the final analysis, the fundamental difference between Protestants and Catholics? It is surely not the Catholic doctrine on purgatory. It is not the Blessed Virgin Mary. It is not the Eucharist or the ordained priesthood. It is not even the vexed question of justification that so troubled Martin Luther and his followers. 

The essential difference between Protestants and Catholics is the question of authority, understood not as power but as a reliable source of truth. It is the question of where one can confidently turn to find Christ’s teaching conveyed in all its integrity. It is the question of the papacy.

When Martin Luther proclaimed that there was a single source of divine truth, namely sacred Scripture, he surely meant what he said. What Luther failed to realize was that the doctrine of “sola Scriptura” (“Scripture alone”) is a human impossibility. The single authority of Scripture immediately splits into the twin authorities of Scripture and its subjective interpretation. 

For Protestants, this interpretation theoretically takes place at the level of the individual believer, but often parallel authorities are permitted, such as the writings of the founder of one’s denomination or even the teaching of one’s local pastor or minister. This subjectivism allows for, and indeed necessitates, a plurality of beliefs among Protestants regarding Christian doctrine and the moral law.

Catholics, on the other hand, have always believed that Christ intended to preserve the unity of moral and doctrinal belief in the Church through the authentic teaching of her anointed pastors. When doubts arose — as they evidently would and did — it was the magisterium that resolved them, not by imposing an opinion or reaching a consensus, but by revealing God’s truth.

Realistically, why do Catholics believe in purgatory in the first place? Is it because they have each pored over the Bible and after years of study have reached the conviction that Scripture attests to its existence? No. 

It is simply because the Church teaches it, and Catholics believe the Church. Catholic belief in the Church is one with their belief in Christ, since she is his body and the carrier and guardian of his saving truth.

This is why the events of 1968 rocked Catholics in a way that they could never rock Protestants — or even broader society. The bumper-sticker motto urging all to “Question Authority” merely reinforced a sentiment already prevalent among Protestants and good citizens. For Catholics, however, it proposed a radical alteration of their relationship with the teaching Church.

This questioning of authority was incarnated in the organized, systematic resistance to the teaching of “Humanae Vitae” among the laity, theologians, and even bishops. It seemed like such a simple thing: a single question among so many more important issues. 

A lack of assent to one moral teaching surely could not compromise the identity or good standing of so many well-intentioned Catholics. Yet, it did, and the reason is simple.

Once one element of official Catholic teaching (it matters not what it is) is rejected, something transcendent happens. The point of reference for moral truth shifts. No longer is the magisterium the reliable source of divine truth. It is the individual. 

It is now the individual (perhaps backed up by the majority, or by the opinions and studies of eminent thinkers and “experts,” but perhaps not) who determines moral truth. The final filter and arbiter for truth is the judgment of the individual.

But what of all the countless other teachings, both moral and doctrinal, where the individual still coincides with the Church? How can one deviation drastically modify the person’s relationship with the Church as teacher? Because when a person’s subjective opinion outranks the Church’s teaching in any area, then it outranks her in every area. 

In this case, the only reason Catholics accept her other teachings is because they do not contradict their own reasoned conclusions (or, in all too many cases, because they do not challenge their inclinations). If they did, Catholics would presumably reject them, as well.

From 1968 on, a good number of Catholics began to relate to the Church the way that Protestants relate to their own denominations. They weigh the “Roman position,” evaluate it, and proceed to judge for themselves what is good and true. 

Without a battle, many Catholics relinquished one of their most precious treasures: trust in the reliability of Church teaching. Our modern moral crisis is not a crisis of conscience; it is a crisis of faith.

In recent years, the Church has made a concerted effort to show the reasonableness of her moral teachings and their alignment with the Natural Law. This is both good and important. We must realize that God only commands what is good for us, and he does so because he loves us. 

We must also be equipped to convincingly present Catholic moral teaching to a world that does not share our faith convictions. On the other hand, if our acceptance of Catholic moral teaching is contingent upon our personal understanding of that teaching, then we find ourselves in a precarious position.

The gift of the magisterium shines in all its splendor not when moral truth is evident to all, but when confusion reigns. We don’t need a magisterium to tell us that auto theft is evil, or that adultery is displeasing to God. It is when good, holy, intelligent people disagree on moral questions that the value of the papal magisterium reveals itself.

The 50th anniversary of Paul’s controversial encyclical offers us Catholics a splendid opportunity to think over our own faith and our relationship with the Church. A revolution happened 50 years ago. Perhaps another can happen today.

Thomas D. Williams is a moral theologian living in Rome and the author of 15 books, including “Who Is My Neighbor? Personalism and the Foundations of Human Rights” (Catholic University of America Press, 2005).

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