"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."

"He who is of calm and happy nature will hardly feel the pressure of age, but to him who is of an opposite disposition youth and age are equally a burden."

"The secret of staying young is to live honestly, eat slowly, and lie about your age."

"Age is not a particularly interesting subject. Anyone can get old. All you have to do is live long enough."

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

"I am not young enough to know everything."

"Old age, calm, expanded, broad with the haughty breadth of the universe, old age flowing free with the delicious near-by freedom of death."