Spirit self
The spirit self, the higher self of the human being in the narrower sense, which inspires him as a genius, is that element of the human being which is formed by the conscious work of the individual "I" on the human astral body. It is also called manas (skrt.) or karana sharira in the theosophical tradition. In order to develop the spirit self and consciously enter the spiritual world, absolute impartiality is necessary, which is especially trained by the fifth subsidiary exercise.
„The spirit self is a revelation of the spiritual world within the “I,” just as from the other side sensations are a revelation of the physical world within the “I.” In what is red, green, light, dark, hard, soft, warm, cold one recognizes the revelations of the corporeal world. In what is true and good are to be found the revelations of the spiritual world. In the same sense in which the revelation of the corporeal world is called sensation, let the revelation of the spiritual be called intuition ...
There could be no color sensations without physical eyes, and there could be no intuitions without the higher thinking of the spirit self. As little as sensation creates the plant in which color appears does intuition create the spiritual realities about which it is merely giving knowledge.“