Western scientists describe the various stages of sleep. Yet they are looking at sleep from outside and do not know how to correlate the stages with the movement of consciousness during sleep. They recite facts based on observation and brain wave activity and pronounce that one is experiencing waking, transition to sleep, REM sleep in the dream state, or deep sleep. We must ask, however, what is the status of consciousness during sleep. Where does the awareness go? What is it that sleeps and what is the purpose of sleep?
The subjective experience of most individuals is one of unconsciousness. When they are asleep, their waking personality is absent. Even in dream, they may or may not actively identify themselves as ‘actors’ in the dream space. Assuming they identify their ego-personality as the ‘I’ in the dream-state, they do not always act according to the outer personality in the waking state, so we cannot say conclusively that the sleeper is expressing the personality of the waking individual.
Sri Aurobindo provides insight into the status of consciousness during sleep and he also correlates the stages of sleep with the action of consciousness in other realms or planes of awareness.
Sri Aurobindo writes: “In sleep one very commonly passes from consciousness to deeper consciousness in a long succession until one reaches the psychic and rests there or else from higher to higher consciousness until one reaches rest in some silence and peace. The few minutes one passes in this rest are the real sleep which restores, — if one does not get it, there is only a half rest. It is when you come near to either of these domains of rest that you begin to see these higher kinds of dreams.”
“A long unbroken sleep is necessary because there are just ten minutes of the whole into which one enters into a true rest — a sort of Sachchidananda immobility of consciousness — and that it is which really restores the system. The rest of the time is spent first in travelling through various states of consciousness towards that and then coming out of it back towards the waking state. This fact of the ten minutes true rest has been noted by medical men, but of course they know nothing about Sachchidananda!”
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, Chapter 10, Difficulties in Transforming the Nature, Sleep, pp 311-314