What we call death is our impression of a change. Life is subject to change, and death is only a change of life. But making people believe in immortality and making them rise above the fear of death should be done gradually and not suddenly, for otherwise this knowledge would frighten a person more than death itself. It is for that reason that the knowledge of this truth was made a mystical, secret science. Otherwise there would have been no reason for withholding something as precious as that knowledge from one's fellow-men. When a person is awakened suddenly he suffers a great shock, physically and mentally, and it takes him a long time to recover. It is the same with all spiritual truths; this is why there are initiations and a vow of secrecy. One cannot place a dinner before a new-born infant; he must first be fed with milk.