Chapter XXI: Know Thyself
Our inquiries have led us to a picture of man as a sensible-supersensible organism composed of three dynamic aggregates - physical, etheric, astral. As three rungs of a spiritual ladder they point to a fourth, which represents that particular power in man by which he distinguishes himself from all other beings in nature. For what makes man differ from all these is that he is not only fitted, as they are, with a once-for-all given mode of spiritual-physical existence peculiar to himself, but that he is endowed with the possibility of transforming his existence by dint of his free will - that indeed his manhood is based on this capacity for self-willed Becoming.
To this fourth principle in man we can give no better name than that which every human being can apply to himself alone and to no other, and which no other can apply to him. This is the name, I. In truth, we describe man in his entirety only if we ascribe to him, in addition to a physical, etheric and astral body, the possession of an I (Ego).
While through Imagination man comes to know of his ether-body as part of his make-up, and correspondingly through Inspiration of his astral body, and thereby recognizes himself as participant in the supersensible forces of the universe, it is through Intuition that he grows into full awareness of his I as a spirit-being among spirit-beings -
God-begotten, God-companioned,
for ever God-ward striving.