This is all the maximum explanation Science could provide biologically on Sleeping?Slumber apart from making loud noises about the Brain needing rest, the body recharging during sleep.
Psychologists as usual try everything under the sun for explaining away Sleep.
Sigmund Freud says it is the repressed desires expressing themselves , Jung states it is the Human personality asserting itself in Sleep.
Behaviorist say, well, it is Behavior!
But the main question has not been answered.
What happens during Sleep and what is dreaming and deep sleep?
Buddhist Schools speak of the Etheric body, Astral Body..
Rene Descartes the Great Rationalist( Philosophical term , not to be confused with the self-styled rationalist jokers like Karunanidhi and Kamal Hassan) proves the Existence of God the External World and Mind.
While describing the process of enquiry he says he can not trust his senses for they are not always right.
He can not others words as the truth for he does not know whether they can be relied upon.
As he goes on in this vein he exclaims,
” Am I awake or Dreaming, May be It Real world I was experiencing when I was dreaming and this world might be a Dream.