“My dear: in this world there is always danger for those who are afraid of it.”
“Those who can do, those who can't teach.”
“Those who cannot change their minds cannot change anything.”
“Those who do not know how to live must make a merit of dying.”
“The power of accurate observation is commonly called cynicism by those who have not got it.”
“Progress is impossible without change; and those who cannot change their minds cannot change anything.”