"The mind can only attend to one thing at a time."

"The true logic of this world is in the calculus of probabilities."

"The world may be utterly crazy, and life may be labour in vain; But I'd rather be silly than lazy, and would not quit life for its pain."

"The velocity of light is a quantity of which we have now a more accurate knowledge than of any other physical constant."

"The peculiar function of the scientific man is to make discoveries, not to talk about them."