Interdependence is a law of nature. We make our life by sharing the joys and pleasures and sorrows of another, but it takes us a very long time to understand this one thing. Our observation and study of man's nature show that his life demands freedom; and yet on the other hand we find that selfishness develops naturally in man, more than in any other creature. The demands of his life are so much greater, and he becomes so absorbed in satisfying these demands, and possessing and enjoying them when he has them, that he really forgets the secret of nature; he forgets the secret of his own happiness as well as that of others.