Back to the idea of spontaneous generation: The quote yesterday about how snakes could be spontaneously generated from horse hairs in stagnant water has reminded me of a very strong belief I held as a second- and third-grader at Buena Vista Elementary School in Walnut Creek, California:
We had drinking fountains set up above a long metal horse-trough-like structure in the playground of the school, where we could see what we called horse-hair worms in the stagnant water at the bottom of the trough, and we really did believe that those were horse hairs that had turned into worms.
Why not? The fact that there were no horses anywhere near our playground didn't change our belief that horse hairs must have gotten in there, and then turned into those disgusting wiggly worms.
So of course we wouldn't drink from that trough. But we weren't scientists, were we. We just saw what we saw: a bunch of long wiggly worms that were larger in diameter than horse hairs, and we saw no other way for those creatures to get there.
Now that I'm thinking about this, though, I'm remembering that the girl who spread that rumor about the horse hairs turning into worms was also the one who told us, after the school finally installed real ceramic drinking fountains that drained the used water into pipes and away from there, that we still shouldn't drink from the fountain if a certain dark-skinned and black-haired boy drank first, because we would get his cooties.
So, here's another way that superstitions and false beliefs get passed on: the knowledgeable person of the group, like Aristotle, or my blonde-haired and blue-eyed friend Marilyn, makes an authoritative statement, and we all believe it, and repeat it.
(Or, like me, we go home and ask our parents about what Marilyn asserted, and they tell us, "No! That's not true! What a horrible and disgusting thing to say!")
(In case you think no one was installing drinking-fountain-troughs like this in the schools in the 20th century, check out this article.)