A lot of people identify as spiritual but not religious. It would be interesting to have statistics on how common this is among professional philosophers. There are lots of naturalists and a significant minority of theists of definite religion, but I just haven’t run across many in between. But shouldn’t one expect that there be a lot of philosophers like that, convinced by argument or just intuition that there is much more to the world than science could possibly get at, but not convinced by the arguments for any particular religion? Maybe it’s because as a profession we prefer definite views? Or maybe there are many philosophers in this category but they just don’t talk about it that much?
I do think it’s important not to downplay the intellectual bona fides of the “spiritual but not religious”. The arguments that there is more to the world and to life than there is room for in naturalism, that there is something “spiritual”, are very strong indeed. (Josh Rasmussen’s and my forthcoming Necessary Existence is relevant here, as are considerations about the meaning of life, the narrow space for normativity and mind on naturalist views, the implausibility of holding that there be a whole category of human experience that is never veridical, etc.) I think there are strong arguments that this something “spiritual” includes God, and there are strong arguments that Catholic Christianity is correct. But it should be very easy to imagine being convinced by the arguments for a spiritual depth to the world but not being convinced by the further arguments (I am not taking a stance in this post on whether it would be rational full stop to be in this position—I do, after all, think the arguments going all the way to Catholicism are strong).