When I examine myself and my methods of thought, I come to the conclusion that the gift of fantasy has meant more to me than my talent for absorbing positive knowledge. (Reading this makes me wonder how much sooner man could have walked on the moon... had we listened to a child's fantasies. It is truly a pity that so many lose their gift of imagination to the steady hum of the status quo.)

The measure of intelligence is the ability to change.

The most important human endeavor is the striving for morality in our actions. Our inner balance and even our very existence depend on it. Only morality in our actions can give beauty and dignity to life.

As long as there will be a man, there will be wars.

Science has gone a long way toward helping man to free himself from the burden of hard labor; yet, science itself is not a liberator. It creates means, not goals. It is up to men to utilize those means to achieve reasonable goals.

A theory is the more impressive the greater is the simplicity of its premises, the more different are the kinds of things it relates and the more extended the range of its applicability.

If you want to know the future, look at the past.