When I read Eliade, the realization that struck me was his observation that in modernity we are no longer religious in the sense he used that word, that the world to us is homogenous, that we no longer divide the world, space or time, into sacred and profane. We have inherited ways and language from our religious ancestors, but they have lost their meanings. At most what we call religious today is nostalgia. It is sentiment. It is sorrow.This strikes me as exactly right. My response has generally been that certain emotions we call religious are very likely part of our evolved biological nature. What emotions? Awe. A sense that there is something afoot in the world that we do not fully understand, something deep and mysterious that is worthy of attention, celebration. A cosmic humility.
It seems like the greater challenge you face is not defending religious naturalism from claims that it is a supernatural belief. Instead, the challenge is to show that the word "religious" means something more than nostalgia. That is what any of us face who use the word "religious."
Of course, there are other things that are part of our nature that are also sometimes associated with religion. Fear of the other. Aggression. Authoritarianism. Credulity. We choose to repress these emotions and behaviors as not part of "the better angels of our nature." We are not slaves to biology.
But do we need to repress those aspects of our nature that are generally benevolent, that bind us together in constructive communities, that lead us to treat non-human nature with a greater degree of respect? What is wrong with nostalgia when it is directed to things sweetly remembered, to the more benign landscapes of our evolutionary and cultural pasts? Nostalgia is a mostly innocent emotion, a form of love that anchors us in a tradition -- "the mystic chords of memory" (to quote Lincoln again). I make no apology for it.
Last evening I attended a concert of gospel music by a group who call themselves Living Water. I grew up in Tennessee in the 1950s listening to gospel on my little Silvertone radio. Loved it then, love it now. Love the sense of joyous celebration. Love the assurance of triumph over adversity ("I'm blessed and highly favored," Living Water sang). Love the confidence that there is a redemptive power (in the Creator? in the creation? in ourselves?) that can turn ugliness to beauty. Gospel music is "religious," but can you imagine anyone in a gospel choir doing violence to another human being or to any of "God's creatures"?
Nostalgia? Yes, I suppose so. Why not?