We are meditating on something which will not arise and disappear, as ideas do and as material forms do, on something which is not ephemeral. Because that which vanishes contradicts its own arisal, we seek for that which does not contradict itself. Hence this kind of meditation which brings contemplation into action, sleep into wakefulness, has been called by the ancients "The Yoga of the Uncontradictable."
-- Notebooks Category 23: Advanced Contemplation > Chapter 8: The Void As Contemplative Experience > # 178
-- Perspectives > Chapter 23: Advanced Contemplation > # 43