Give back to the world at least what you've received.

The next world war will be fought with stones.

.. free and responsible development of the individual, so that he may place his powers freely and gladly in the service of all mankind. There is no room in this for the divinization of a nation, of a class, let alone of an individual. Are we not all children of one father, as it is said in religious language?

The world is so full of possibilities that dogmatism is simply indecent.

There is no salvation for civilization, or even the human race, other than the creation of a world government.

Keep fighting until the last buzzer sounds.

Never memorize something that you can look up.