No path leads from a knowledge of that which is to that which should be.

I would absolutely refuse any direct or indirect war service and would try to persuade my friends to do the same, regardless of the reasons for the cause of a war.

Only six men in the world know about relativity. I am not one of them. When I ask them to explain, they confused me.

People should be more like animals . . . they should be more intuitive; they should not be too conscious of what they do while they do it.

This is what the painter, the poet, the speculative philosopher, and the natural scientists do, each in his own fashion.

Overemphasis of the competitive system and premature specialization on the ground of immediate usefulness kill the spirit on which all cultural life depends, specialized knowledge included.

This is a question too difficult for a mathematician. It should be asked of a philosopher"(when asked about completing his income tax form)