What is the difference between sleep-thought and waking-thought? Perhaps dream-thought is intermediate. since dreams occur during REM sleep which is less deep; so dream-thought could give us a clue to deep sleep thought.

Dream thought is less directed, more free, but more chaotic than waking thought. Therefore deep sleep thought might be still more chaotic and free: unobserved, unconscious, but active in the dim cavern of the night. Awakening wipes it out by shocking it with the dazzling light of consciousness.

Who has not felt a momentary twinge of regret at this loss, as the gossamer thread of night thought vanish into nothingness each morning? It is like a snowflake melting. Every snowflake is beautiful and unique – no two are ever alike, just as two human beings are never identical. But in the heat of the sun, each ordered, uniquely valuable snowflake melts into a shapeless liquid drop like any other. “Ice to ice, water to water” is like “ashes to ashes, dust to dust”.

Awakening is like dying to our night-time selves. We are all split personalities. our day self and our night self. It is like the story my mother used to read to me when I was a child about the young bride whose soul was in the willow tree outside her bedroom window each night. (Her husband was distressed by this. and cut down the willow; but as he did so, his sleeping bride gave a deep sigh and died.) While our day self and our night self can perhaps talk to each other in the depth of the mind-brain which we cannot plumb, they know very little about each other at the surface of our being where the sun shines. We consciously know only half of our being.