The evolution of higher and of lower forms of life is as well and as soundly established as the eternal hills. It has long since ceased to be a theory, it is a law of Nature as universal in living things as is the law of gravitation in material things and in the motions of the heavenly spheres.

~ Henry Fairfield Osborn

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It must have appeared almost as improbable to the earlier geologists, that the laws of earthquakes should one day throw light on the origin of mountains, as it must to the first astronomers, that the fall of an apple should assist in explaining the motions of the moon.

~ Charles Lyell

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