Consciousnes is called Chit. The Stilling of the thought waves is the goal of Yoga. At this level, your mind, the brain waves reach the Alpha level and Gamma is just behind it( as of now in Science). Hinduism goes further by stating that Thuriya can not be explained and one gets submerged in Consciousness which an attribute of Brahman, the Reality.
Sometimes I dream that I write and on waking up I find it is untrue and that I have been dreaming. Now I am writing this post. How can I be certain now that this activity is not being done while asleep? This action of writing now may be a dream and I may wake up. This is a problem not solved by Philosophy. Hinduism describes four states of Being. Jagrat, the waking state. Swapna, the dreaming state,
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.
Sleep and Dreams, are the two states of which we know precious little. Sigmund Freud, in his attempt to interpret the Dreams, has set up a system of Psychiatry, blames every one for their actions but themselves. He had interpreted Dreams only as an expression of Sex and depressed desires. Jung professed 'Freud conceived the unconscious solely as a repository of repressed emotions and desires. Jung agreed with Freud's model of the unconscious, what Jung called the "personal unconscious", but he also proposed the existence of a second, far deeper form of the unconscious underlying the personal one. This was the collective unconscious, where thearchetypes themselves resided, represented in mythology by a lake or other body of water, and in some cases a jug or other container. Freud had actually mentioned a collective level of psychic functioning but saw it primarily as an appendix to the rest of the psyche' Then we have many Behavioral Psychologists. These scholars saw Mind as a Blind seeing An Elephant" seeing a part and interpreting it to suit them. Patanjali goes to the basics. Since we do not remember anything in sleep, is Sleep 'Absence of Thoughts?' He says NO.
Hinduism has rituals and procedures laid down for Daily activities. These instructions start from brushing the Teeth to going to Bed at night. Hinduism forbids sleeping during The Day. One such interesting fact is about Sleeping. In which Direction should one have his Head ! 'Head to point the in His Home, To West in close Relatives Home(like In Laws,brothers are considered to be of the same house hold even if they live separately, where as sister is considered to belong to another Household), Towards the North at all times, And Never pointing towards the South" We are aware that the Earth has a Magnetic Field, North and South Poles. The East is Hot. So because of the Heat Current passes from The East to The West. The Right side of this current(North) creates Positive Current. And The Left side (South), the Negative Current. Human Body. specifically the Red Corpuscles have Iron and hey have the properties of being made into a Magnet. Head has Positive Current while the Feet , Negative Current. When one sleeps with one's Head in the North, Feet pointing out at the South we go against the Natural flow of Current and Magnetism and we will be disturbed in Sleep and Health is likely to be hit. When you sleep with head pointing out to South and Feet to North, you will be in Harmony with the Natural Flow of Current in The Earth's ElectroMagnetic Field. This helps you sleep better and is Healthy.