It is not possible to explain intellectually how sensations of the physical world are converted into ideas, how the leap-over from nervous vibrations into consciousness occurs, and how a neurosis becomes a psychosis. No one has ever explained this, nor will any scientist ever succeed in doing so. Truth alone can dispose of this poser by pointing out that sensations never really occur, but that the Self merely projects ideas of them; just as a man sees a mirage and mistakes it for real water merely by his mental projection, so people regard the world as real when they are merely transferring their own mental ideas to the world.
-- Notebooks Category 21: Mentalism > Chapter 2: The World As Mental > # 78
-- Perspectives > Chapter 21: Mentalism > # 35