For some students at Georgetown University, news that the school had assigned them to an intensive seminar in secularism elicited more than a little unease.

To Jeff Caso, a conservative Catholic from Long Island, N.Y., the word meant unreligious — not what the freshman was expecting from a Jesuit school. Taylor Griffith, a churchgoing evangelical from Albuquerque, feared the same thing. “I was worried about being in a class that was against my religion,” she said

Then they met professor Jacques Berlinerblau.

A hyperactive beanpole with two doctorates, he runs his class like a stand-up act — if there were a standup act about Thomas Jefferson or Supreme Court religion rulings. The punchline would be about the Jewish atheist who teaches secularism at a Catholic school.

That would be Berlinerblau.

The apparent contradictions in Berlinerblau’s bio fit a nascent field still trying to define itself. His class is one of a small cluster across the country that are being called “secular studies,” programs that don’t fit cleanly into any one discipline. Even the professors disagree about the tenets and truths of the field.

Berlinerblau’s classes focus on secularism as the study of relations between church and state. Others are focused on the spiritual or political lives of the nonreligious. All the players, however, are driven by the rise of Americans leaving organized religion and living more nonreligious lifestyles and exploring what that means.

For Berlinerblau, a 45-year-old biblical scholar, the point is teaching students that secularism is not atheism, but instead a value system that encourages moderation, tolerance and an ability to laugh at one’s self.

Most teachers in the field see secularism as a key to society’s survival at a historical moment of ferment and upheaval in American religion.

“So Thomas Jefferson, James Madison, John Locke, their fear was: Don’t let your religious freak flag fly in public too much” — meaning that too much religious passion can cause divisions and even violence, Berlinerblau said one recent Monday. He constantly shifted in his seat as he talked, and even left the room at one point to bring back Starburst candies for his 13 students. “Societies with no separation between church and state have troubles.”

The class was created this fall and is already known as one of the intensive seminars available only for students in Georgetown’s elite foreign service program. And Georgetown isn’t alone in seeing secular studies as worthy of academic scrutiny. Pitzer College in California launched the country’s first concentration in secular studies, also in the fall.

The first edition of the first academic journal of “secularism and non-religion” is to publish in January. People who study religion say more articles are being published about secularism and conferences that include the topic are packed, including an overflow crowd last month at the annual meeting of the American Academy of Religion. The number of chapters of the Secular Student Alliance has jumped from 42 in 2003 to 310 today.

Among the most notable trends in religion and spirituality is the growth in number of Americans who tell pollsters that they have no religion, now more than 15 percent. But statistics can mislead, as many who profess no religion have rich spiritual lives, while some who check an identity box don’t believe in God.

Thus the birth of a new academic field, meant to explore the role and meaning of secularism in America, and other trends such as interfaith marriage. Some compare it to the early years of women’s studies or African American studies.

Some say the new field stems from the alleged dominance in religious studies departments of academics who are themselves religious. Others contend that campuses are so secular that religious expression has been pushed out.

Berlinerblau tells students his goal is to “disentangle atheism from secularism.” He has them read Martin Luther and Locke, for whom the term “secular” is not about personal religious beliefs but about the relationship between church and state.

Berlinerblau believes that the vast middle of Americans are tolerant of alternative religious views, don’t participate in regular worship and feel wary of too much mixing of religion and politics. In other words, they are secular-ish.

“Whether they are religious or not is irrelevant,” he tells his students.

Others say that secularism is a challenge to traditional religiosity. If you aren’t sure you believe in God, say you have no religion and don’t plan to have a religious wedding or funeral, you’re pretty close to atheism.

Berlinerblau says people who share what he calls secular values need to band together. This is a movement that needs a self-help program. “The first step is: acknowledge that you need other people,” he said. On the other hand, he doesn’t necessarily play nice with everyone in his chosen category.

He calls himself an atheist but has little patience for some other atheists, at least those who slam religion, such as Richard Dawkins, the Oxford don who wrote “The God Delusion,” and fellow atheist writer Sam Harris. Berlinerblau thinks the anti-religion crowd is intolerant. He levels the same criticism at the religious right.

But the professor, who is director of Georgetown’s Program for Jewish Civilization, has managed to change the minds of most of his students. By the end of the semester, all but one raised a hand when asked whether they considered themselves secular.

Among them was Caso.

“It doesn’t mean abandoning any notion of religiosity; it’s saying you’re in favor of toleration and liberty of conscience and of allowing others to have the same rights in terms of government as you,” he said in an interview.

Thomas Banchoff, director of Georgetown’s Berkley Center for Religion, Peace, and World Affairs, had a similar opinion. “The study of the secular and secularism is not opposed to religion, but is part of an effort to understand religion’s changing role in the modern world,” he wrote in an e-mail.

So maybe the divisions between secularism and religion aren’t impossibly deep. Berlinerblau — atheist and admirer of secular sentiments — is, after all, a leader in his synagogue.