This mysterious experience seems also to have been known to Dionysius the Areopagite. It is definitely an experience terminating the process of meditation, for the mystic can then go no higher and no deeper. It is variously called the Nought in the West and Nirvikalpa Samadhi in the East. Everything in the world vanishes and along with the world goes the personal ego; nothing indeed is left except Consciousness-in-itself. If anything can burrow under the foundation of the ego and unsettle its present and future stability, it is this awesome event.
-- Notebooks Category 23: Advanced Contemplation > Chapter 8: The Void As Contemplative Experience > # 88