It sounds kinda weird when I put it in a question, but we’ve all felt static shocks before and we all understand the science behind it now. What would people think static electricity was before there was an official, scientific answer? Would it have been considered black magic or something?
Not to discourage other answers, but this is a very popular question and has a great answer given by u/hillsonghoods.
I think the long and the short of it is best summed up by /u/hillsonghoods' sentence, "It’s worth remembering that, in antiquity and the middle ages, the workings of the natural world were fundamentally mysterious."