If you want your children to be intelligent, read them fairy tales. If you want them to be more intelligent, read them more fairy tales.

There is, fortunately, a minority composed of those who recognize early in their lives that the most beautiful and satisfying experiences open to humankind are not derived from the outside, but are bound up with the development of the individual's own feeling, thinking and acting. The genuine artists, investigators and thinkers have always been persons of this kind. However inconspicuously the life of these individuals runs its course, none the less the fruits of their endeavors are the most valuable contributions which one generation can make to its successors.

Since I have introduced this term I had always a bad conscience. . . . I cannot help to feel it strongly and I am unable to believe that such an ugly thing should be realized in nature.

Fantasie is belangrijker dan kennis, want kennis is begrensd.

The ideals which have always shone before me and filled me with the joy of living are goodness, beauty, and truth.

We owe a lot to the Indians, who taught us how to count, without which no worthwhile scientific discovery could have been made.

There two things that are infinite, human stupidity and the universe, I don't know about the universe