I do not say think as I think, but think in my way. Fear no shadows, least of all in that great spectre of personal unhappiness which binds half the world to orthodoxy.

Science is nothing but trained and organized common sense differing from the latter only as a veteran may differ from a raw recruit: and its methods differ from those of common sense only as far as the guardsman's cut and thrust differ from the manner in which a savage wields his club.

Man's Place in Nature.

Teach a man to read and write, and you have put into his hands the great keys of the wisdom-box.

Mathematics may be compared to a mill of exquisite workmanship, which grinds you stuff of any degree of fineness; but, nevertheless, what you get out depends upon what you put in; and as the grandest mill in the world will not extract wheat-flour from peascods, so pages of formulae will not get a definite result out of loose data.

For every man the world is as fresh as it was at the first day, and as full of untold novelties for him who has the eyes to see them.

It is better to read a little and thoroughly than cram a crude undigested mass into my head, though it be great in quantity.