A billboard written in Hebrew and English sponsored by the American Atheists is seen next to the Kosciuszko Bridge in the Brooklyn borough of New York March 7, 2012. The billboard is meant to serve as an advertisement for the upcoming "Reason Rally" in Washington, D.C., which is being billed as the largest atheist gathering in U.S. history followed by the Atheist convention. REUTERS/Shannon Stapleton (UNITED STATES - Tags: RELIGION SOCIETY POLITICS) (SHANNON STAPLETON/REUTERS)

Usually when a person ditches religion, he or she also happily ditches the antiquated rules and regulations that go along with a strict observance of faith. Good-bye, stupid rules about who can have sex with whom, and under what circumstances! Good riddance to prohibitions against women doing (or saying) things without the approval of men!

It’s the outdated rules, in fact, that often prompt a person to doubt the value of religion in the first place. God, in its broadest definition, is not the problem for most of us. It’s how to live in a modern world and still abide by a Scripture that contains regulations thousands of years old that govern the minutest aspects of domestic life: eating, farming, menstruating, sex and the slaughter of beasts for sacrifice.

Polls show Americans’ growing frustration with a rules-bound approach to religious faith. Although 19 percent of us call ourselves “unaffiliated” from any religious tradition (up from 5 to 7 percent in the 1960s), more than 90 percent continue to believe in God.

So when someone does the opposite — ditches God but keeps the rules — it’s notable. Why would someone choose to live within the confines of religious laws but reject the God who commanded people to live by them?

Zeke Emanuel, the bioethicist, Obama adviser and brother to Ari and Rahm, has done just that. He is, according to a recent profile in the Philadelphia Inquirer, a kosher atheist. The profile shows Emanuel, a devoted foodie, hosting a dinner party. There, a friend razzes him for his faithfulness to the dietary laws written in Leviticus and Deuteronomy, which command the people of Israel to – among other things — eat meat only from animals with cloven hooves. “Atheism and Judaism are completely compatible,” Emanuel tells his friend. “Orthodoxy and orthopraxy are not the same.”

Here Emanuel makes a distinction between belief (orthodoxy) and practice (orthopraxy). Judaism isn’t about what people think, he seems to be saying. It’s about what they do. It follows, according to that argument, that it’s more Jewish to keep kosher than it is to believe unthinkingly in God. This is not as crazy as it sounds: Doubt is a traditional Jewish value, and the Hebrew Bible is full of characters who wrestle and argue with God. Jacob spends a night in combat with one of God’s angels – and wins. Job, the Bible’s greatest doubter, is rewarded at the end of his story with more riches than he had at the beginning.

Rabbi Shmuley Boteach, author of “Kosher Sex,” appears to agree with Emanuel. “Judaism,” he told me in a phone call, “is not a religion primarily of faith. It is a religion primarily of practice. Should a man who does not at present feel love for his wife – should he treat her lovingly, respectfully? The answer is, ‘Of course.’ Marriage is more than what we feel at any given time. Jewish tradition is more than what we believe at any given time.” Christianity, on the other hand, is a religion of dogmas and creeds. Avowals of belief are a requirement of faith. Without them, one is faithless.

I would argue that both Emanuel and Boteach stand on wobbly ground, for the Jewish tradition also presupposes a belief in a supernatural God who, in the Torah, smites the unfaithful (see the story of Sodom) and threatens the worshippers of lesser gods with vicious penalties.

What’s interesting here is the yearning of this rational-minded scientist to follow the ancient rules of kashrut despite a rejection of the supernatural. Judaism is a religion, yes, but it’s also a culture, a tradition and an ethnicity. These multiple strands of belonging allow a person to reject the faith while continuing the habit, thousands of years old, of abstaining from pork and shellfish and consuming meat and milk separately — and thus claim a Jewish identity.

Keeping kosher is “a way of asserting that you are a conscious Jew,” explains Rabbi James Ponet, chaplain at Yale University and a family friend, “when you join friends out for dinner but decline the lobster, shrimp, oysters and all the meat entrees [or] when you ask the waiter if the tomato soup” is made from vegetarian stock.

Echoing Achad Haam’s pithy observation about Shabbat observance, one might hold that more than the Jews have kept kosher, kosher eating has kept the Jews. A Jewish atheist’s children might grow up with a learned distaste for pork and thereby call themselves Jewish.

But it is Rebecca Goldstein, the philosopher, atheist and author of the novel “36 Arguments for the Existence of God” who offers the most resonant possible rationale for an atheist to continue kosher practices. Kashrut is a discipline – like running, or writing or yoga – that can put a person in touch with the transcendent aspects of life, even in the absence of God.

“One of the interesting aspects of law-heavy Judaism,” Goldstein wrote to me in an e-mail, “as opposed to that new-fangled spinoff, Christianity, is that it infuses the most quotidian acts of life with mindfulness.” One doesn’t usually associate Leviticus with a concept as broad and modern as mindfulness, but Goldstein does, and maybe Zeke Emanuel, too.