“Every attainment, every step forward in knowledge, follows from courage, from hardness against oneself, from cleanliness in relation to oneself.”

“Every acquisition, every step forward in knowledge is the result of courage, of severity toward oneself, of cleanliness with respect to oneself.”

“Every achievement, every step forward in knowledge, is the consequence of courage, of toughness towards oneself, of sincerity to oneself”

“Convictions are prisons.”

“When man does not have firm, calm lines on the horizon of his life- mountain and forest lines, as it were- then a man's innermost will becomes agitated, preoccupied, and wistful.”

“I am not upset that you lied to me, I am upset that from now on I cannot believe you.”

“The end of a melody is not its goal: but nonetheless, had the melody not reached its end it would not have reached its goal either. A parable.”