Perhaps the real phenomenon here is that while we find supernatural beliefs in all societies, advanced or primitive, those beliefs are independent of each other, and often enough in outright conflict as to the nature, number and rankings of their supernatural beings.
If a supernatural realm existed, with its own properties and system of government, we'd expect the great majority of reports of it to agree on its general outline and functions. Instead we get enormous variety, great incompatibilities, irreconcilable claims.
This suggests that religion is a cultural rather than a supernatural phenomenon, doesn't it? The "truth" of Christianity owes its success worldwide thanks to being imposed, often enough with much bloodshed, rather than being enlarged by any innate and persuasive "truth", no? The same is true of Islam, and in parts of Asia, Buddhism, and I'm confident there are countless examples of winning tribes imposing their religion on the conquered.
