The vehicle of this lastly developed capacity is now “the body of the ego,” the fourth principle of the human being.[4] This body of the ego is the vehicle of the higher human soul, and through it man is the crown of all earthly creation. But the ego in present humanity is by no means a simple entity. Its nature can be recognized when a comparison is made between men of different stages of evolution. Take for instance the uneducated savage and the average European, and compare these again with a lofty idealist. Each one of them has the faculty of saying to himself “I” for the “body of the ego” is existent in each of them. But the uncivilized savage gives way with this “I” to his passions, his impulses and appetites, almost like an animal. The more highly developed man allows himself to follow certain inclinations and desires, others he checks or suppresses. The idealist has formed, in addition to the original inclinations and passions, others that are higher. This is all due to the fact that the “ego” has been at work on the other principles of the human being. And it is precisely the mission of the “ego” to ennoble and purify the other principles by its own power. So the lower principles, under the influence of the “ego,” have become more or less changed within a man who has surmounted the conditions in which the outer world has placed him. Take the case of the man who is just raising himself above the level of the animal—when his “ego” flashes out he still resembles the animal with regard to his lower principles. His etheric or vital body is solely the medium of the living constructive forces of growth and propagation. His astral body only gives expression to such impulses, desires and passions as are stimulated by his outer nature. All the time that the man is struggling on through successive lives, or incarnations, from this degree of culture to an ever higher evolution, his ego is remodelling the other principles. In this way the astral body becomes the medium of purified pleasurable and unpleasurable sensations, refined desires and longings. And the etheric, or vital body, also transforms itself. It becomes the vehicle of habits, of permanent inclinations of temperament and of memory. A man whose ego has not yet influenced his vital body has no remembrance of the experiences he undergoes. He lives just as he has been brought up by Nature. The whole development of civilisation expresses itself for man in this working of the ego upon the subordinate principles. This working penetrates even to the physical body. Under the influence of the ego, the physiognomy, the gestures and movements, the whole appearance of the physical body, change.