Peace cannot be kept by force; it can only be achieved by understanding.

The number of natural hypothesis that can explain any given phenomena is infinite.

Knowledge is limited.

I know quite certainly that I myself have no special talent; curiosity, obsession and dogged endurance, combined with self-criticism, have brought me to my ideas.

It may be possible to fight intolerance, stupidity, and fanaticism seperately, but when they come together there is no hope.

It is very difficult to explain this feeling to anyone who is entirely without it, especially as there is no anthropomorphic conception of God corresponding to it. The individual feels the nothingness of human desires and aims and the sublimity and marvelous order which reveal themselves both in Nature and in the world of though. He looks upon individual existence as a sort of prison and wants to experience the universe as a single significant whole.

Conventional words or other signs have to be sought for laboriously only in a second stage, where the associative play already referred to is sufficiently established and can be reproduced at will.