Anyone who has probed the inner life, who has sat in silence long enough to experience the stillness of the mind behind its apparent noise is faced with a mystery. Apart from all the outer attractions of life in the world, there exists at the center of human consciousness something quite satisfying and beautiful in itself, a beauty without features. The mystery is not so much that these two dimensions exist – an outer world and the mystery of the inner world – but that we are suspended between them, as a space in which both worlds meet ... as if the human being is the meeting point, the threshold between two worlds.