This can be done only by entering the void of empty thought and being merged into its stillness. Because the Mind transcends the objective world, it transcends the manyness of this world. In it there is "no-thing." The dream-world is really a projection of the dreamer's mind. He is the subject and it is the object. But when he awakes the world vanishes. Where has it gone? It could only have gone back into his mind, for it is there that it originally arose. But this is something intangible, a veritable void. In the same way the external world as an object of thought is during this first stage deliberately retracted into the Mind-Void.
-- Notebooks Category 23: Advanced Contemplation > Chapter 8: The Void As Contemplative Experience > # 82