“But mans head is being generated by the whole universe.
It also is an image, an effigy of space. The reason why it is round on top is, because its shaped in the likeness of outer space.
All of the starry sky acts upon the skull. This is not a fantastic idea.” (Rudolf Steiner)
Source: Rudolf Steiner, “On health and illness”. Second lecture in Dornach, October 24th, 1922. GA348, page 53