Rudolf Steiner, Berlin, November 23, 1919:
"External minerality is heavy. But that which gives us, for instance, the possibility of developing the soul element — I do not refer here to intelligence — that which makes us capable of developing soul qualities is not bound to gravity but to its opposite, to what is called the levity of fluids. I have on other occasions described to you how our brain swims in the cerebral fluid. If this were not so, the blood corpuscles contained in it would be crushed. You know from your lessons in physics that Archimedes, sitting in his bath, discovered that he became lighter, and he was so pleased about this that he called out his famous “Eureka!” In regard to our soul, we do not live by being pulled downward, but by being pulled upward. Not by our brain being heavy, but by our brain being lighter through its swimming in the cerebral fluid do we live physically. We live by means of what draws us away from the earth."
Related post: https://martyrion.blogspot.com/2019/03/all-flesh-is-grass.html
Source: https://wn.rsarchive.org/Lectures/Dates/19191123p01.html