You could argue that the beginning of religion is the beginning of humanity — that whatever moment our ancestors first looked up and burned to know why they existed is the same moment they became recognizably us. Religion was the first tool for grappling with that question. Before it, I'm not sure "human" means much.
What strikes me is that the question has outlived the tool. More and more people are setting traditional religion down, and for many, God simply isn't needed anymore — yet they remain just as humane, sometimes more so. Take away the doctrine and the quest for understanding isn't bound to a fixed set of answers; it's free to follow the evidence. So is science the replacement religion? Not really — science is a method, not a worldview, and methods don't hand you meaning. What people are actually reaching for is closer to a philosophy: science plus a few things it can't supply on its own.
Because morality won't fully reduce to logic, and meaning certainly won't. If I try to build a worldview up from science alone, I get the scaffolding but not the reason to climb it. I end up adding a small number of values by hand — that the universe and other people are real; that life is a rare and precious emergent property worth protecting; that greater connectedness between living things is good, which makes the whole of human life matter more than any one of us. They're close to utilitarian, and they're chosen, not derived.
Martin Seligman put the useful half of religion well:
[Religion] is ethical alchemy. It's about behaving in a way that changes you, that gives you intimations of holiness and sacredness. It doesn't really matter what you believe as long as it leads you to practical compassion. — Martin Seligman
That's the part I don't think science can give you. People need to feel part of something larger than themselves. Maybe the deepest open question isn't whether God exists, but whether — through sheer connectedness — we can find that feeling without one.