Let everything you do be done as if it makes a difference.

So far war has been the only force that can discipline a whole community, and until an equivalent discipline is organized, I believe that war must have its way.

Man lives for science as well as bread.

There are two lives, the natural and the spiritual, and we must lose the one before we can participate in the other.

Good-humor is a philosophic state of mind; it seems to say to Nature that we take her no more seriously than she takes us. I maintain that one should always talk of philosophy with a smile.

Man can change his life simply by changing his attitude.

In any project the important factor is your belief. Without belief, there can be no successful outcome.