Mind becomes one with consciousness in deep sleep. Mind has emanated from and in consciousness. The individual experiences are reality within the waking or dream. Individuality ceases to exist without the waking or dream. The one which witnesses the dream is not waking entity and one which witnesses the waking is not dream entity. The one which witness the deep sleep experience is neither dream entity not the waking entity. Then what is it that is aware of these three states, which come and go in succession.
It is the consciousness [soul] which is aware of all the three states, which comes and goes in succession. Thus it is the witness of the three states. It is also is the substance of the three states because it pervades in everything and everywhere in all the three states. Thus consciousness is the common essence in dual and nondual experiences. The one, who discovers, understands and assimilates and realizes the essence as ultimate truth becomes free from experiencing the duality as reality. The consciousness exists with or without the duality. The birth, life, death and the world are within the mind or duality. And the consciousness is the formless substance witness of birth, life, death and the world [mind]. Consciousness [soul] is apart from the birth, life, death and the world, because it is not an object within the duality, but the duality [waking or dream] is an object to it. When one becomes aware of the fact that, the formless substance and witness are one in essence, then there is unity in diversity.