OK, this link is to a page about a contraversion theory from biology. When it was first proposed, people were outraged and said it was wrong, saying “spontaneous generation” was the answer, not this theory. People called it “just a theory”.
Now it is the very baseline of modern biology and medicine; without it we would have to resort to supernatural explanations, and would be much worse off.
Sound familiar? No, it’s not evolution. Click here to find out what it is.