"If we examine our thoughts, we shall find them always occupied with the past and the future."

"Those honor nature well, who teach that she can speak on everything."

"The weather and my mood have little connection. I have my foggy and my fine days within me; my prosperity or misfortune has little to do with the matter."

"Justice without force is powerless; force without justice is tyrannical."

"Few friendships would survive if each one knew what his friend says of him behind his back."

"It is man's natural sickness to believe that he possesses the truth."

"Man's greatness lies in his power of thought."

"Vanity of science. Knowledge of physical science will not console me for ignorance of morality in time of affliction, but knowledge of morality will always console me for ignorance of physical science."

"Two things control men's nature, instinct and experience."

"If man studied himself, he would see how incapable he is of going further."

"Everyone without exception is searching for happiness."