The sages found a clue: in dreamless sleep, the observing self detaches itself not only from the body but from the mind. “As a tethered bird grows tired of flying about in vain to find a place of rest and settles down at last on its own perch, so the mind,” like the body, “settles down to rest” in dreamless sleep – an observation in harmony with current research, which suggests that in this state the autonomic nervous system is repaired.
