Because of our instilled belief in authority when we are young (like trusting your mom when she says not to touch the fire), humans are predisposed to believe certain things without requiring proof. Put this into a computer model and voila - religion flourishes.

Excerpt:

The model assumes, in other words, that a small number of people have a genetic predisposition to communicate unverifiable information to others. They passed on that trait to their children, but they also interacted with people who didn't spread unreal information.

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