I’d like you to imagine for a moment that you are a member of a small tribal village living in the depths of the Amazon. Your people have had little contact with the outside world for generations. However, your village has recently been stricken with a plague. People are sick and dying.

Following the ancient traditions handed down by your parents and grandparents, you believe that there is a sacred order to the universe. When things go wrong, there is a reason. A local shaman informs the village elders that one of the gods has become angry and is punishing the people. This god must be appeased by way of a sacrifice or ritual, then the plague will end. So, the elders begin soliciting offerings from you and your neighbors for the sacrifice: animals, crops, etc. Your ancestors have always trusted people like this shaman; there’s no reason to doubt.