Okay, let's go back to before science. Your circa 1000AD village blacksmith has special knowledge and authority about handling metals that you don't, and he pro

Okay, let's go back to before science. Your circa 1000AD village blacksmith has special knowledge and authority about handling metals that you don't, and he probably can't explain it to you in an afternoon. That doesn't make him like a member of a priesthood, he's someone with specialized knowledge that could train you, but it would take a while and you'd probably have to pay him for his time. He'd similarly dismiss uninformed speculation about how he could do his job better, because he's trained in it and you aren't. There are lots of domains like this that are much older than science and older than the Catholic Church. If anything, systems like the Church are like guild systems, rather than guilds being like priesthoods. Science certainly is a bit like guild systems of old- lots of specialized jargon and training, mentorship, internal hierarchies, etc. But that didn't come from the Church, that's just the stuff that seems to spring up around specializations.