We think we know that chimpanzees are higher animals and earthworms are lower, we think we've always known what that means, and we think evolution makes it even clearer. But it doesn't. It is by no means clear that it means anything at all. Or if it means anything, it means so many different things to be misleading, even pernicious.
Richard Dawkins, The Greatest Show on Earth: The Evidence for Evolution
evolution, science