"For after all, if we get out of the superficial life-death-sleep classification to follow an essential classification of the universe, we see that from top to bottom (if there is such a thing as top and bottom) this universe is nothing else but a continuum of consciousness-force or, as Sri Aurobindo says, a gradation of PLANES OF CONSCIOUSNESS which range UNINTERUPTEDEDLY from pure MATTER to pure SPIRIT - subtle Physical, Vital, Mental, Supramental (we may use other words if we like, another terminology, but the fact remains the same) - and that everything takes place in the midst of these planes our life and our sleep and our death; there is nowhere to go outside this and not only is everything located there but everything coexists there, without separation."
"Life, death, sleep are simply different STATIONS of the consciousness amidst this same gradation. When we are awake, we receive mental or vital vibrations which are translated into certain symbols, other ways of seeing, understanding or living the same reality. In all these instances, the key of our existence, here or elsewhere, is always our capacity of consciousness; if we are unconscious in our life, we shall be unconscious in every other ways death will be truly a death and sleep truly a torpor.
"To become aware of these various degrees of reality is then our fundamental task; and we have done this work integrally, the lines of artificial demarcation which separate our diverse modes of living will crumble and we shall pass without break or without a gap in the consciousness from life to sleep to death; or, more precisely, there will not longer be death or sleep as we understand it but various ways of perceiving continuously the total Reality, and perhaps finally an integral consciousness which will perceive everything simultaneously. Our evolution is not over. Death is not a denial of Life but a process of Life." From "Adventure in Consciousness or Aurobindo" by Sat Prem