ONE recent Sunday, about 40 people turned up at their regular gathering place, a community centre in Seattle, and soon found themselves pondering an ethical dilemma: would it ever be right to punch a Nazi? The discussion was led by a husband-and-wife team, who pointed out that hurting people was usually a bad idea, but that it might sometimes be the only way to protect the innocent. “In a world as imperfect as this one, sometimes the choice is between a number of terrible ideas,” suggested the husband, Mickey Phoenix.

Other recent topics for debate at the Seattle Atheist Church have included the difference between compassion and empathy, and whether or not reparations should be paid to the descendants of American slaves, as argued by the writer Ta-Nehisi Coates in a recent story for Atlantic magazine. Once they have exhausted their discussion, participants can get to know each other over juice and snacks.

Like many similar clubs across the Western world, this “atheist church” aims to offer some features of a religious congregation (fellowship, collective enjoyment, a stimulus to moral behaviour) while eschewing any belief in a deity or the supernatural. Ruth Walther, the founder of the Seattle community, sums up its ethos by drawing a contrast with a Christian hymn, “God moves in a mysterious way”. At her church, she says, “We believe in good because good works in non-mysterious ways.”

In today’s kaleidoscope of beliefs and practices, atheist churches have carved out a niche. It is one that needs definition. In almost all Western countries, including the relatively pious United States, the number of people who acknowledge no religious affiliation (known as religious nones) is surging. But that is not necessarily the same as being atheist. One survey by Pew Resarch showed that the proportion of Americans who call themseles “unaffiliated” jumped from 16% in 2007 to 23% in 2014. That second figure includes 3% of the total population who call themselves atheists and 4% who identify as agnostic. Another pollster, the Public Religion Research Institute (PRRI), reports that among unaffiliated Americans, 22% believe in a personal God, 37% in an impersonal one, and 33% say they do not believe in God. On the other hand, plenty of people who do have a religious label are uncertain in their beliefs; PRRI finds that a quarter of Catholics sometimes doubt God’s existence.

So where do atheist churches belong in this spectrum? Obviously they appeal to people whose world-views reject the supernatural. But in their own way they are (as they themselves say) doing what all religious communities do, but simply without gods and the supernatural.

Take for instance the North Texas Church of Freethought, established in 1994 by a physician, Tim Gorski, in the generally devout area of Dallas-Fort Worth. Its attractions include “Sunday School”, where children go while parents attend “services”. But instead of Bible stories taught as fact, this Sunday School helps youngsters develop ways of understanding and thinking that will help them cope with classmates who come from more God-fearing homes. The church’s website lays out its founder’s passionate belief that science alone holds the key to objective reality, while religion speaks to subjective needs that everyone has. At their gatherings, members enjoy discussions of history, morals, personal and social problems, listen to music and learn about inspiring scientific breakthroughs.

Phil Zuckerman, professor of sociology and secular studies at Pitzer College in California, describes the phenomenon of atheist churches like this: a “small subset” of those people who have lost their faith in a supernatural being still want the community spirit and behavioural norms that go with religious experience.

In recent years, the most widely publicised and globally dispersed “atheist church” has been the Sunday Assembly, launched in London in 2013 by Sanderson Jones (a former salesman for The Economist) and Pippa Evans, who both had some experience as comic performers on stage. It now flourishes in 55 outposts, across Britain, continental Europe, North America and Australia, with a total of about 3,500 regular attendees. That is not quite the spectacular growth that initially looked possible, but the movement has morphed, in interesting ways. Under the motto “live better, help often, wonder more” it offers participants a chance to sing and laugh together, join in doing useful work, and contemplate reality in a spirit not of conventional devotion but of awe. Lots of lessons have been learned, says Mr Jones, especially about how one initiative can mesh constructively with others. The assembly’s branch in east London is used by a public housing association as a way of helping people whose problems, psychosomatic or psychological, might be eased by joining a community. In the Los Angeles branch there is a director who says she is applying principles learned while helping Barack Obama’s presidential campaign in 2012. Surveys of assembly-goers suggest that the great majority feel greater “life satisfaction” through participation.

For some sceptical sorts, both the Dallas community and Mr Jones’s assembly are too much like regular churches for their liking. But can these “atheist churches” be described as a form of religion? Ms Walther, founder of the Seattle gathering, responds with a definite “yes” to that question. But Mr Zuckerman is more ambivalent. “If you define religion as just belief in god(s) or supernatural beings, then it’s not religious,” he says. “But if you define religion more broadly as having a belonging component, and a behaviour component, then it does...fall under that umbrella.”