We must remember that we do not observe nature as it actually exists, but nature exposed to our methods of perception. The theories determine what we can or cannot observe...Reality is an illusion, albeit a persistent one.

My scientific work is motivated by an irresistible longing to understand the secrets of nature not by other feelings.

It takes a touch of genius - and a lot of courage to move in the opposite direction.

All that's different about me is that I still ask the questions most people stopped asking at age five.

Understanding of our fellow human beings...becomes fruitful only when it is sustained by sympathetic feelings in joy and sorrow.

In the teaching of geography and history a sympathetic understanding (should) be fostered for the characteristics of the different peoples of the world, especially for those who we are in the habit of describing as "primitive.

I believe that I have really found the relationship between gravitation and electricity, assuming that the Miller experiments are based on a fundamental error. Otherwise, the whole relativity theory collapses like a house of cards.