If the bees disappear, man would have only four years of life left.

The really valuable method of thought to arrive at a logically coherent system is intuition.

[There is] a duty in refusing to cooperate in any undertaking that violates the Constitutional rights of the individual. This holds in particular for all inquisitions that are concerned with the private life and the political affiliations of the citizens.

I believe, indeed, that overemphasis on the purely intellectual attitude, often directed solely to the practical and factual, in our education, has led directly to the impairment of ethical values. I am not thinking so much of the dangers with which technical progress has directly confronted mankind, as of the stifling of mutual human considerations by a 'matter-of-fact' habit of thought which has come to lie like a killing frost upon human relations. Without 'ethical culture' there is no salvation for humanity.

The trite objects of human efforts-possessions, superficial success, luxury-have always seemed contemptible to me.

To be free means to be independent, not to be influenced by what others think and say.

Only a monomaniac gets anything done.