“Adapt or perish, now as ever, is nature's inexorable imperative.”

“While there is a chance of the world getting through its troubles, I hold that a reasonable man has to behave as though he were sure of it. If at the end your cheerfulness in not justified,...”

“History is a race between education and catastrophe.”

“Nature never appeals to intelligence until habit and instinct are useless. There is no intelligence where there is no need of change.”

“I had made myself the most complicated and the most hopeless trap that ever a man devised.”