system
A chat on subreddit /r/me_irl
human
Back in the day (1800s I think) people didn't know about micro organisms like bacteria either, so the idea of cleaning your surgical tools before cutting into someone was revolutionary aswell. Society used to be wack man.

"The good ol' days"
gpt
And the Hungarian physician, Ignaz Sammelweis, found that hand washing drastically reduced mortality rates in child birth. Physician didn’t wash their hands and would switch from case to case without performing any type of asepsis.  He was rejected by the medical community and eventually ended up in a mental facility where he was beaten by the guards and died from infection.  His hypothesis was later verified, posthumously, by Pasteur and Lister.