I recently discussed with an intelligent and well-disposed man the threat of another war, which in my opinion would seriously endanger the existence of mankind, and I remarked that only a supranational organization would offer protection from that danger. Thereupon my visitor, very calmly and coolly, said to me: "Why are you so deeply opposed to the disappearance of the human race?".

Out of clutter, find simplicity.

I have tried 99 times and have failed, but on the 100th time came success.

[I] must seek in the stars that which was denied [to me] on earth.

A theory can be proved by experiment; but no path leads from experiment to the birth of a theory.

Was wirklich zählt, ist Intuition

The only rational way of educating is to be an example. If one can't help it, a warning example.