"My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram or the most intricate analysis, and I am in my own proper atmosphere. I can then dispense with artifi…"

"One of the most dangerous things for a man's mind is to be without an object."

"The easiest way to make a man a fool is to give him an opinion and then contradict it."

"A man should keep his little brain attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber-room of his library, where he can get it if he wants it."

"What you do in this world is a matter of no consequence. The question is what can you make people believe you have done."