A group of microscopic aliens invade earth and discover human brains are the perfect hosts for their people. The problem is that once humans know that the aliens are in their brains, the aliens automatically die. To keep humans from asking too many questions, the aliens invent religion. Further, because the parasites are clannish, they sometimes try to convince their human hosts to kill the hosts of other clans. Religions are evangelical because the aliens are so comfortable know that they breed frequently and their babies need more brains to populate.
The worst thing that can happen---if you are a microscopic alien--is for your host to begin to doubt. Doubting humans alter their brain chemistry and make life impossible for their alien guests so the aliens had to invent all sorts of little mental firewalls to prevent humans from asking too many questions. The concept of free will to explain how a god can be pure love and allow evil is an example of one of their mental fire walls. An alien named Zorp invented that and has an alien holiday every week. He is the real reason Christians changed the day of rest from Saturday to Sunday.
The worst thing that can happen---if you are a microscopic alien--is for your host to begin to doubt. Doubting humans alter their brain chemistry and make life impossible for their alien guests so the aliens had to invent all sorts of little mental firewalls to prevent humans from asking too many questions. The concept of free will to explain how a god can be pure love and allow evil is an example of one of their mental fire walls. An alien named Zorp invented that and has an alien holiday every week. He is the real reason Christians changed the day of rest from Saturday to Sunday.
