Thinking is to man what flying is to birds. Don’t follow the example of a chicken when you could be a lark.

In matters of trust and justice there can be no distinction between big problems and small, for the general principles which determine the conduct of men are indivisible. Whoever is careless with the truth in small matters cannot be trusted in important affairs.

I must try, however, as best I can, although I am very conscious of the fact that our feelings and strivings are often contradictory and obscure and that they cannot be expressed in easy and simple formulas.

Non-cooperation in military matters should be an essential moral principle for all true scientists.

This crippling of individuals I consider the worst evil of capitalism. Our whole educational system suffers from this evil. An exaggerated competitive attitude is inculcated into the student, who is trained to worship acquisitive success as a preparation for his future.

It stands to the everlasting credit of science that by acting on the human mind it has overcome man's insecurity before himself and before nature.

It almost seems to me that man was not born to be a carnivore.