Mostly as a result of meditation, but sometimes during an unexpected glimpse, a mystical experience of an unusual kind may develop. He feels transparent to the Overself; its light passes into and through him. He then finds that his ordinary condition was as if a thick wall surrounded him, devoid of windows and topped by a thick roof, a condition of imprisonment in limitation and ordinariness. But now the walls turn to glass, their density is miraculously gone, he is not only open to the light streaming in but lets it pass on, irradiating the world around.
-- Notebooks Category 22: Inspiration and the Overself > Chapter 6: Experiencing a Glimpse > # 166