"Scientific knowledge is in perpetual evolution; it finds itself changed from one day to the next."

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Evolution is a theory in a special philosophical sense of science, but in terms of ordinary laymen's use of language, it's a fact, .. Evolution is a fact in the same sense that it's a fact that the Earth is round and not flat, [that] the Earth goes round the Sun. Both those are also theories, but they're theories that have never been disproved and never will be disproved.

— Richard Dawkins