This pieces was written as a response to Karen Taliaferro’s post, “A Tale of Three Laws,” which can be found here.

By: Sherif Girgis

It’s had a shaky history. Unknown among pagans, it was—as Karen Taliaferro reminds us—quietly endorsed by some early Church Fathers. Augustine wrote something about it, Aquinas much more. A distortion of it was championed by French Revolutionaries and denounced by several Popes. A better version found its way into history’s most consequential political charter (the US Constitution) and through thinkers shaped by it (such as John Courtney Murray) to some of the Catholic Church’s most solemn pronouncements (at Vatican II). As recently as the 1990s, bills promoting it won the nearly unanimous consent of Congress and the signature of a Democratic president; today it’s depicted as the lonely cause of a socially conservative fringe. I mean the right to religious liberty.

Taliaferro reminded us that religious liberty is grounded in something higher than human law but less contentious than divine command: the natural moral law, disclosed to us by reason. But how? And what can its natural-law defense teach us about current controversies?

The natural moral law begins with a vision of the human good—whose outlines we know by reason. One man has a healthy body and a happy family, a nice complement of hobbies, and a keen sense for Dylan. By day he teaches students to savor Chaucer’s rhythm and wit; by night friends help him savor Bordeaux. A second man is debilitated, depressed, desensitized, and detached. It does not take a poet or a saint to see who is better off.

Of course, there are countless ways of blending the basic ingredients of human thriving. But the ingredients themselves—the most foundational ways in which we can flourish, what we might call “basic human goods”—are more limited. These are the conditions or activities that in themselves make us better off, whether or not they bring us other goods. It makes sense for us to want these for their own sake. As the above examples suggest, health, knowledge, play, and aesthetic delight are a few examples; another is friendship.

Still another basic good is religion. It’s about harmony with the divine—the ultimate source(s) of reality. It’s the human good that explains the search for ultimate truths as well as adherence to truths already found. It’s what motivates wavering college freshmen studying Richard Dawkins as much as it does seminarians studying for the priesthood. The value of being in line with the Supreme Being—and hence of determining if one exists, or what it demands—is something we can appreciate, whatever our views about religion.

But religion, like friendship and other forms of harmony, is worthless unless freely chosen. So respect for people’s religious flourishing requires respect for their freedom to look into religious matters and live by their best conclusions. That freedom is a requirement, then, of the natural moral law, which calls us to honor and promote every basic good.

Applied to the state, this moral vision clearly rules out policies aimed at banning or mandating religious belief, or a particular practice on account of its religious character.And it requires the state to avoid incidental burdens on religion wherever it reasonably can.

But some think this vision of religious liberty too broad—especially where it conflicts with changing mores and laws regarding sexuality, marriage, and family. Should Evangelical bakers and florists be free to decline to serve same-sex weddings? Should Catholic adoption agencies be free to choose homes that will give children a mother and father? Should employers be free not to pay for insurance that covers abortifacient or other contraceptives, which undermine their moral principles or mute their theological witness?

Faced with these questions, some would cut religious liberty down to the right to worship plus freedom of conscience. But religion and conscience rights cover different territory.

Rights of conscience protect our integrity or authenticity: the coherence of our convictions with our actions. They’re about our freedom to discharge perceived moral obligations. Religious liberty has different facets, all explained by its central point, harmony with God. It covers the freedom to look into religious truth-claims and to live by your conclusions (in rituals, worship, and other acts whose main point is harmony with God). But it also covers the freedom to assemble and build for religious ends, to organize religious communities (especially by choosing their leaders), to proselytize and convert, and to distribute and use materials for all these purposes. Crucially, it includes the right to live out your vocation—in family life, professionally, and otherwise—in ways that bear witness to your faith.

So religious liberty goes beyond the right not to do what you think wrong. It protects your freedom for activities that you don’t consider binding religious duties. Thus, it would not violate my conscience rights if I were prevented from attending Mass on any given Monday, but it would violate my religious liberty, by preventing me from living out my faith. Or to inch closer to today’s debates: even if I feel no obligation to open a business or run it according to my faith, the state has some reason not to stop me. This is the same reason it has for respecting my freedom of worship in the first place: the value of religion as a basic human good.

Of course, religious liberty isn’t absolute. If a policy is crucial for a serious, neutral policy purpose—rooting out injustice, say, or protecting public health or national security—its incidental burdens on religion might well be justified.

But in determining when that high bar is met, we should remember that religious liberty protects politically weak as well as dominant groups; the marginalized as well as the ascendant; Sikhs, Buddhists, and atheists as well as Catholics or Evangelicals; concerns congenial to the left as well as the right; in matters of war and medicine and labor as much as sexuality. A still-unfolding Sexual Revolution has only recently made “religious liberty” sound like the partisan cause of conservative Christians—and this development hurts everyone, since religion is a human good, as the natural moral law confirms.

Sherif Girgis is a doctoral candidate in Philosophy at Princeton University and a J.D. student at Yale University.

This piece was originally authored on August 12, 2015 for the Religious Freedom Project at Georgetown’s Berkley Center for Religion, Peace, and World Affairs.