The Oxford Handbook of Spontaneous Thought: Mind-Wandering, Creativity, and Dreaming

Where do spontaneous thoughts come from? It may be surprising that the seemingly straightforward answers "from the mind" or "from the brain" are in fact an incredibly recent understanding of the origins of spontaneous thought. For nearly all of human history, our thoughts - especially the most sudden, insightful, and important - were almost universally ascribed to divine or other external sources. Only in the past few centuries have we truly taken responsibility for their own mental content...