In the history of the world the prize has not gone to those species which specialized in methods of violence, or even in defensive armor. In fact, nature began with producing animals encased in hard shells for defense against the ill of life. But smaller animals, without external armor, warm-blooded, sensitive, alert, have cleared those monsters off the face of the earth.

There is no more common error than to assume that, because prolonged and accurate mathematical calculations have been made, the application of the result to some fact of nature is absolutely certain.

The purpose of education is not to fill a vessel but to kindle a flame.

Peace is self-control at its widest-at the width where the "self" has been lost, and interest has been transferred to coordinations wider than personality.

Algebra reverses the relative importance of the factors in ordinary language.

...the self-satisfied dogmatism with which mankind at each period of its history cherishes the delusion of the finality of existing modes of knowledge.

Every epoch has its character determined by the way its population reacts to the material events which they encounter.