In the Life of Darwin by his son, there is related an incident of how the great naturalist once studied long as to just what a certain spore was. Finally he said, "It is this, for if it isn't, then what is it?" And all during his life he was never able to forget that he had been guilty of this unscientific attitude, for science is founded on certitude, not assumption.

Formal religion was organized for slaves: it offered them consolation which earth did not provide.

Your neighbor is the man who needs you.

If men will not act for themselves, what will they do when the benefit of their effort is for all?

Every spirit makes its house, but as afterwards the house confines the spirit, you had better build well.

To make mistakes is human, but to profit from them is divine.

Wise Man: One who sees the storm coming before the clouds appear.