Again from Slate Star Codex
The difference between “religion” and “culture” has always been pretty vague. Shinto is the best example; it’s less a coherent metaphysical narrative than a bunch of things Japanese people do and a repository for Japanese traditions and rituals. A quick look at Hinduism reveals that they have no idea what gods they believe in, it’s a bunch of different religions stuck together under one umbrella, but the point is that it’s the sort of thing Indian people do and a repository of Indian traditions. Even though Jews have a pretty coherent religion, the line between “Jewish culture” and “Jewish religion” is equally fuzzy. Religion as distinct from culture seems like a pretty Western phenomenon, the result of a triumphant Christianity colonizing cultures it never originated from, ending out with the modern conception of culture as ethnic food + silly costumes.