When the Church speaks definitively on morality — says that without exception something is wrong — is it declaring a truth or laying down a law? Confusion about that is rampant today.

Recently I came across this statement by a writer in a Catholic periodical: “The pope has not changed the Church’s teaching that sexual activity outside the marriage of a man and a woman is sinful.” The implication is that the pope could change the teaching if he wanted to, since it’s only a matter of law and therefore subject to change.

I’m not going to name the writer or the publication because, given how widely this confusion is spread, it would be unfair to single out one writer and one periodical for correction.

The name of the error, for those who like to name things correctly, is legalism, and it has plagued moral reasoning for a long, long time.

Returning to the example, its underlying assumption is that moral truth comes from being taught with authority (or, equivalently, enacted as law): change the teaching or the law, and the truth changes. But in reality it’s the other way around: if teaching or law is sound, that’s because it expresses moral truth — in the example, that sexual activity is morally good only in man-woman marriage.

This isn’t to say Church teaching on morals can’t undergo development. But in saying development is possible, we need to understand what “development” means. In short, then, development in the realm of morals is the recognition that a moral truth covers more cases than was previously recognized.

For example: Development has been underway in the Church’s thinking about capital punishment for some years as it has been increasingly understood that the inviolability of human life applies even to persons guilty of horrendous crimes. Thanks largely to legalism, the huge difference between “change” and “development” may not always be easy to discern, but it’s crucial.

St. Pope John Paul II discusses the reality of moral truth in his 1993 encyclical “Veritatis Splendor” (“The Splendor of Truth”). Speaking of “certain currents of modern thought,” which hold that people are free to adopt whatever values they like, he writes that this makes individual conscience the arbiter of morality: “The inescapable claims of truth disappear, yielding their place to … sincerity, authenticity and ‘being at peace with oneself’ ” (VS 32).

“Veritatis Splendor” is a landmark — the first papal encyclical to lay out the fundamental principles of Catholic morality. It stands now as a carefully argued, highly sophisticated treatise that dissenters from the Church’s moral tradition rightly view as an obstacle to the program of change visible, for instance, in the unhappy “Synodal Path” underway in Germany.

But not just in Germany. Part of the attraction of departures from authentic moral reasoning lies in their appeal to the permissive, nonjudgmental style in favor today, especially in regard to sex. Yet, strange to say, the ideologues of permissiveness and nonjudgmentalism are fanatical in their zeal to silence and cancel proponents of an older, ultimately more humane view of human freedom and its right use.

In the introduction of “Veritatis Splendor,” Pope John Paul speaks of a “new situation … within the Christian community itself” amounting to “an overall and systematic calling into question” of traditional morality. At its root, he cautions, are ways of thinking “which end by detaching human freedom from its essential and constitutive relationship to truth” (VS 4).

Far from being a textbook exercise, what’s at stake here could hardly be more timely than it is today.