I’m thinking of things like heliocentrism where there was some modern discovery or revelation by science that invalidated a common assumption prior.
My understanding is that flat earth is more a recent phenomena but I’d love to hear some ancient ideas people now miss. Did people think trees weren’t alive? Did people think evaporation was where things simply disappeared?
I’d would love to hear these ideas.
Before that, nurses and midwives were well aware that cleanliness was important to not spreading disease. But that’s left out of history altogether.