“All is a riddle, and the key to a riddle...is another riddle.”

“Every revolution was first a thought in one man's mind, and when the same thought occurs to another man, it is the key to that era.”

“The key to every man is his thought. Sturdy and defying though he look, he has a helm which he obeys, which is the idea after which all his facts are classified. He can only be reformed by showing him a new idea which commands his own.”

“All the mistakes I make arise from forsaking my own station and trying to see the object from another person's point of view.”

“The secret of education lies in respecting the pupil. It is not for you to choose what he shall know, what he shall do. It is chosen and foreordained and he only holds the key to his own secret.”

“Speak your latent conviction. . . Else tomorrow a stranger will say with masterly good sense precisely what we have thought and felt all the time, and we shall be forced to take with shame our own opinion from another.”

“Good luck is another name for tenacity of purpose.”