There are interesting implications however you answer the question.
Several writers — Alain De Botton and Peter Sloterdijk come to mind — have considered the plight and future of the secular practice of community. The fulcrum of the discussion seems to boil down to commitment. Membership in a religious community is ‘transactional’ — a declaration of faith/devotion to a creed/doctrine in ‘exchange’ for belonging/identity.
In a sense, of course, all communities are transactional. (If you punch your friends in the face every time you see them, you will undoubtedly be seeing less of them.) But one could argue that religious communities tap into something more primordial. For example, in In Gods We Trust: The Evolutionary Landscape of Religion and Violent Extremism and Sacred Values, anthropologist Scott Atran speculates about the possibility that belief in the spiritual served as the psychological basis for civilization itself. Perhaps believing in gods was the evolutionary precursor to collectively believing in things like states and constitutions. Before we could believe in kings, laws, and borders, perhaps we had to nurture the capacity to believe transcendent ideas by first believing in things like gods and the idea of order itself?
One could make the argument that a religious community is unlike any other kind of community and that a religious community ‘delivers’ something that no other group of humans can provide. If you move into a new city, as a person of faith, you can probably look up a list of religious communities that share the essential points of your beliefs. Amazingly, at least to some extent, your deepest, most cherished tenets — the convictions that orientate you to and in the world — find resonance and affirmation. Your creeds are sung.
Conversely, if you move into a new community as a nonreligious person, your ‘innermost circle’ typically forms around shared interests and experiences — work, hobbies, civics, etc. But do these associations ever reach ‘religious-grade’ community in the support, solidarity, and inclusion they provide?
Can you be a part of a ‘religious-grade’ community without ‘religious-grade’ commitment?
On the other hand, what if religion doesn’t have any exclusive claim to the depth or legitimacy of community? Anecdotally speaking, there seems to be a ‘scale’ of social integration that correlates with any shared values — especially shared values held in spite of external pressure. Consider the bonds of a military division or any high-stress, dangerous work that requires unequivocal trust among team members. A potential implication here is that the ‘thing’ to which people commitment in unison may not necessarily need to be a supernatural proposition, but perhaps just about any cause, narrative, rhetoric, or identity will do. What matters is sharing it in common.
Furthermore, a sense of ‘duty’ may superficially differentiate religious communities from ‘secular’ communities. Do people join chess clubs out of interest and churches out of duty? Or is participation in either simply and equally driven by the human need to belong? Or does the sense of duty felt by a detachment of soldiers create a connection deeper than any chess club or church can provide?
In the end, the relativity of our question creates more problems than it solves. If this is a research question, it is plagued with severe study design challenges. What seems evident is that people who need religious orders join churches, mosques, temples, and synagogues, and people who need chess clubs join chess clubs. Defining a certain ‘type’ or ‘grade’ of community is arbitrary to the extent that we humans (apparently) have a diverse range of needs and desires of association and tribe.
So, do religious communities provide ‘something’ that no other kind of community can provide? Probably, yes. But chess clubs probably provide ‘something else’ that religious communities cannot deliver. Perhaps the question should be less about the particular nature of religious belief and more about the dynamic and diverse nature of human community in general.
That said, I think there are still lessons that the rest of us can learn from religious communities — even if for no other reason than that religious traditions have been sculpting and experimenting with community for centuries. With Alain De Botton, I suspect that there is something profound (and, yes, likely primordial and evolutionary selective) in the idea of scheduling ‘sacred’ times to gather and in the practice of preparing and sharing meals together. Religion effectively constructs a bureaucratic hierarchy that coordinates the dreary logistics of gathering for the faithful. Taking an intentional approach to organizing live, in-person sharing of ideas and meals is the critical lesson that religion has been evolving over millennia. But can we genuinely commit to community without the gods?