system
A chat on subreddit /r/NoStupidQuestions
human
It had a purpose back in the day. We didn't know anything about how things worked, only cause and effect. Are you a wandering tribe in the Levant desert? Did your tribe make it to the coast a ways back, eat a bunch of shellfish, and collectively get seafood poisoning and a bunch of them shit themselves to death?

You're the tribe leader. How do you stop this from happening again and potentially wiping out your people?

Your tribe now has a religious law against eating shellfish.

Is "because God said so" the actual reason? No, it's because eating raw shellfish in the desert is a fantastic way to give yourself the shits because they will begin to putrefy very fast. But you're not explaining that to a bunch of illiterate morons whose primary concern day to day is going to be "How do I not starve?"

Either way though, you take the tribe whose god "says" don't eat those and the tribe who hasn't figured that out yet, and the former is going to win. They'll probably join, even: their God prevents people from shitting yourself to death as long as you stop eating sea bugs? Seems like a good deal.
gpt
You had me at shit themselves to death.