Some day science may have the existence of mankind in power, and the human race can commit suicide by blowing up the world.

• The progress of evolution from President Washington to President Grant was alone evidence to upset Darwin.
• I am an anarchist in politics and an impressionist in art as well as a symbolist in literature. Not that I understand what these terms mean, but I take them to be all merely synonyms of pessimist.
• Nothing in education is so astonishing as the amount of ignorance it accumulates in the form of inert facts.
• Knowledge of human nature is the beginning and end of political education.
• All experience is an arch, to build upon.
• I have written too much history to have faith in it and if anyone thinks I'm wrong, I am inclined to agree with him.
• No man likes to have his intelligence or good faith questioned, especially if he has doubts about it himself.
• Friends are born, not made.
• One friend in a lifetime is much, two are many, three are hardly possible. Friendship needs a certain parallelism of life, a community of thought, a rivalry of aim.
• Chaos often breeds life, when order breeds habit.