Relativity teaches us the connection between the different descriptions of one and the same reality.

But the creative principle resides in mathematics. In a certain sense, therefore, I hold true that pure thought can grasp reality, as the ancients dreamed.

Playfullness is the essential feature of productive thought.

The value of a man should be seen in what he gives and not in what he is able to receive.

The scientist is activated by a wonder and awe before the mysterious comprehensibility of the universe which is yet finally beyond his grasp. In its profoundest depths it is inaccessible to man.

It is only men who are free, who create the inventions and intellectual works which to us moderns make life worth while.

I am satisfied with the mystery of the eternity of life.