Take a reasonably secular bunch of people. They don’t participate in the local religious rituals, have a worldly morality that pays no attention to what the religious leaders say, and are inclined to think of sacred stories as a boring genre of fiction. They don’t identify with any particular religion, think religiously colored politics is a really bad idea, and don’t spend much time worrying about “the meaning of life” and existential matters.

Yet I would guess a clear majority among such very secular people will be inclined toward one or more of the following:

• If pressed, they will agree with sentiments such as “There’s got to be more than this to life” or “there’s got to be a reason for everything that happens.”
• They will tend to interpret certain odd events in a paranormal, or what I’d call a low-intensity supernatural fashion. Perhaps more importantly, they will respond to anecdotes about paranormal events.
• They will evaluate beliefs on pragmatic grounds, emphasizing therapeutic value rather than truth.
• They will be mind-matter dualists, not just in the implicit, folk-psychological fashion that everyone is, but also in some more explicit contexts.

(I could extend the list, but you get the idea.)

None of this adds up to religiosity in any substantial way; it does not even bring us into New Age or “spiritual but not religious” domains. Yet I suspect that such minimal spiritual tendencies characterizes even very secular populations. We know something about what societies without widespread God-belief look like—we even have countries in Western Europe that come close. But we really have no clue what a society dominated by, say, a scientific naturalist outlook would look like.