"Man's life cannot "be lived" by repeating the pattern of his species; he must live. Man is the only animal that can be bored, that can be discontented, that can feel evicted from paradise. Man is the only animal for whom his own existence is a problem which he has to solve and from which he cannot escape. He cannot go back to the prehuman state of harmony with nature; he must proceed to develop his reason until he becomes the master of nature, and of himself."