From the foregoing observations it will be seen that man’s being is built up of four principles: the physical body, the etheric body, the astral body, and the vehicle of the ego. The ego works within the three other principles, and transforms them. By means of this transformation, are formed on a lower level, the sentient-soul, the rational- or intellectual-soul, and the consciousness-soul: on a higher level of human existence, are formed the Spirit-Self, the Life-Spirit, and Spirit-Man. The relations existing between these human principles and the whole universe are of a most varied character and their evolution is related to that of the universe. By studying this evolution an insight is obtained into the deeper mysteries of man’s being. It is clear that human life is related in the most varied ways to the environment or dwelling place in which it evolves. Physical science, through the facts presented to it, has already been driven to the opinion that the earth itself, man’s dwelling place in the broadest sense of the word, has undergone evolution. Science points to former conditions of the earth when man, in his present form, did not yet exist on our planet and it shows how man has slowly and gradually evolved to his present condition from primitive states of civilization. Physical science, therefore, comes also to the conclusion that there is a connection between man’s evolution and that of the heavenly body on which he lives—the earth. Occult science traces this connection by means of a knowledge which obtains its data from observation quickened by spiritual organs of perception. It traces man backwards in his course of development, and the fact becomes evident to occult science that the real inner spiritual being of man has progressed through a series of lives on this earth. Occult research arrives in this way at an epoch far back in the remote past, when for the first time that inner being of man made its entry into “external life” as we understand it. It was in this first earthly incarnation that the ego began to function in the three bodies—the astral body, the etheric or vital body, and the physical body; and it then carried over the results of that activity into its next life. If in our investigation we proceed backwards, in the manner indicated, as far as that epoch, we discover that the ego finds an earth condition in which the three bodies, physical, etheric, and astral, are already developed and in which they bear a certain relation to each other. The ego is, for the first time, united with the being composed of these three bodies; and henceforth takes part in the further evolution of the three bodies. Hitherto, up to the stage at which that ego came in touch with them, they had evolved without a human ego.