[burnafter185]

Yuval Noah Harari in "Sapiens" has an interesting take on religion. Essentially they form a fictional narrative that deigns this and that. In doing so they create a system which can thread together far larger groups of people, we're thought to be near maximum capacity in dealing with 150 people (according to Dunabr's number). But the fictional narratives of religion (and later government, laws, corporations...) help us to identify our personal relationships, and also help us to ascertain expected behavior, both of self and of other. Thus we can drastically expand interoperability between individuals and groups. This is of course entirely contingent on belief, which basically serves the argument issued in "The Social Contract". He defines this as inter-subjectivity.

I think it's a pretty interesting take.