"In any developing science there are disagreements. But scientists — and here is what separates real scientists from the pseudoscientists of the school of intelligent design — always know what evidence it would take to change their minds. One thing all real scientists agree upon is the fact of evolution itself. It is a fact that we are cousins of gorillas, kangaroos, starfish, and bacteria. Evolution is as much a fact as the heat of the sun. It is not a theory, and for pity’s sake, let’s stop confusing the philosophically naive by calling it so. Evolution is a fact."
January 1, 1970
https://en.wikiquote.org/wiki/Evolution