Does the notion "religion" have any serious religious meaning at all? Put another way: can one teach or invite people to be sympathetic to religion-in-general? What does it mean to be "religious"? Obviously it is not the same thing as being "devout" or "orthodox." My own view is that one cannot be religion in general any more than one can speak language in general; at any given moment one speaks French or English or Swahili or Japanese, but not "language." Similarly one is not "a religionist," but a believing Catholic, Jew, Presbyterian, Shintoist, or Tallensi. Religious beliefs may be options, as William James described them, but they are not generalized options. It is easy, of course, to misunderstand this point. I don't mean to say that one must be orthodox as a Jew, a Thomist as a Catholic, or a fundamentalist as a Protestant. The history of every important religious community is a complex one, and ... those figures who are afterwards acknowledged as great religious teachers have generally been in critical opposition to popular religious practices and to much within the past traditions of their own faiths. Nevertheless, for a believer the concept of "religion" (and of deciding to become religious) makes no sense as a category.... Neither does it make sense as a concept of objective sociological or historical inquiry. To be religious is always to be in some sense an adherent (even as a heretic) to a specific symbolism and a specific historical community, whatever the interpretation of these symbols and this historic community the believer may adopt. It is to be involved in specific beliefs and practices, not just to give assent to the philosophical assertions that a being whom we may call God exists, that life has meaning, etc. Religion is not equivalent to the theistic proposition.
(Susan Sontag, "Piety without Content" in Against Interpretation and Other Essays)
On the one hand, she seems to contradict herself in that she uses the terms of "religion" and being "religious" as terms of analysis--the last line especially gives that away--yet, on the other hand, she makes a point that "religion" and "religious" as general terms are not accurate descriptors or analytically useful terms for specific historical matrices, patterns, or schema of interlaced beliefs and practices--what Mary Douglas would call a symbolic system, although I would posit that all such symbolic systems are necessarily "open" rather than "closed" interacting neighboring cultures and socio-historical shifts. I don't think I use the terms "religion" or "religious" once in my dissertation. They are far too vague and, for that matter, meaningless.