"Only as you do know yourself can your brain serve you as a sharp and efficient tool. Know your own failings, passions, and prejudices so you can separate them from what you see."

"If you have made a mistake, cut your losses as quickly as possible."

"Old age is always fifteen years older than I am."

"Never answer a critic, unless he's right."

"Of all the self-fulfilling prophecies in our culture, the assumption that aging means decline and poor health is probably the deadliest."

"The surprising thing about young fools is how many survive to become old fools."

"Young men's minds are always changeable, but when an old man is concerned in a matter, he looks both before and after."

"A person is always startled when he hears himself seriously called an old man for the first time."

"In case you're worried about what's going to become of the younger generation, it's going to grow up and start worrying about the younger generation."

"The denunciation of the young is a necessary part of the hygiene of older people, and greatly assists in the circulation of their blood."