Why Secret Societies are kept secret

Here is a really interesting insight about religion and conspiracy theories I found (I think) on Digg:

"However they deck it out with the rhetoric of mystery and wonder, theirs is a universe of blind force," Booth writes, and you don't have to believe in Isis and the philosopher's stone to see his point. Most people will still choose to believe in something "more," whether it's the ninefold path of the Buddha or the pillars of Islam or pyramid power. Chances are that whatever they choose will sound ridiculous to anyone who doesn't also believe. That's something religion has always had in common with sex: If you're not into it, it looks silly. Which explains why all the really clever people do it behind closed doors."