If a theory can not be explained to a child, then the theory is probably worthless.

I have become rather like King Midas, except that everything turns not into gold but into a circus.

Imagination is more important than knowledge.

Well, I have considered myself to be very fortunate in that I have been able to do mostly only that which my inner self told me to do... I am also aware that I do receive much criticism from the outside world for what I do and some people actually get angry at me. But this does not really touch me because I feel that these people do not live in he same world as do I.

Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world.

A knowledge of the existence of something we cannot penetrate, of the manifestations of the profoundest reason and the most radiant beauty - it is this knowledge and this emotion that constitute the truly religious attitude; in this sense, and in this alone, I am a deeply religious man.

The great need to grasp principles had caused me to spend most of my time on fruitless persuits.