All means prove but blunt instruments, if they have not behind them a living spirit.

Out of complexity, find simplicity!

Just because you believe in something does not mean that it is true.

To see with one's own eyes, to feel and judge without succumbing to the suggestive power of the fashion of the day, to be able to express what one has seen and felt in a snappy sentence or even in a cunningly wrought word - is that not glorious? Is it not a proper subject for congregation?

Unless Americans come to realize that they are not stronger in the world because they have the bomb but weaker because of their vulnerability to atomic attack, they are not likely to conduct their policy at Lake Success [the United Nations] or in their relations with Russia in a spirit that furthers the arrival at an understanding.

The content of scientific theory itself offers no moral foundation for the personal conduct of life.

A theory can be proved by experiment; but no path leads from experiment to the birth of a theory.