The seeker, who aspires after liberation, has to shun the experience of duality as illusion and accepts its formless substance, which is Consciousness /Soul as ultimate truth.
The truth is neither in Waking nor in dream nor in deep sleep but it is hidden as their formless substance and witness, which is consciousness/soul. The Soul/Consciousness is ultimate reality.
Inquiry and reasoning reveals:
Duality ceases to exist on the stand point of soul as self. Therefore it is not possible for the external changes. The experience diversity is different or non-different from the soul/spirit, because it is created out of it. This is most important. To grasp this, compare with the dream where the objects are different or non-different from the witness. The dream appears as whole. The witness, which is aware of the dream is also aware of the waking and deep sleep experiences.
The whole experience of duality is one unit whether it is waking or dream. If there is duality, then it is mind or ‘I’. Therefore, whatever visible is visible only to the substance of the mind that is Soul/Spirit? Absent of the Waking is absent of duality. When Soul /Self remain in its formless non-dual true nature, it is non-dual reality.
Deep sleep reminds and teaches the Seeker that it is possible to have the state where there is no duality, means no birth, no life and death, no pleasure and no pain, no fear, no wants and no needs. There is no doubts and confusion, no question to answer.
The question can be asked where the imagination is possible, that is only in illusion. Deep sleep is the second less state. The mind is at its rest and still in deep sleep. This stillness of the mind is possible only when one realizes the fact that self is not physical but spirit.
Once the seeker consciously becomes aware of the formless substance and witness of the mind is the soul/spirit then the mind becomes still and the duality vanishes and remains in its second less state of its existence. This realization of its second less state is freedom.
By taking the deep sleep experience as illustration for non-duality. However, sleep is not the goal. It is given as analogy to show that the duality or mind disappears in deep sleep.
The freedom from duality is possible in this very moment, here and now if the Seeker fact that the self is not physical but it is the spirit. Spirit is the substance and the witness of the three states.
Seeker has to train himself by constant reflecting on the formless substance and witness in order to rectify his reasoning base from form to formless. All doubts and confusion created by duality vanishes when one is able to view the worldview from the ultimate standpoint.
Awareness of Soul/Self must be found in the Waking experience. The analogy of deep sleep is to indicate that deep sleep is the last gate to be passed before reaching the soul, which is the true self.
Deep sleep is definitely not the condition of the Awakened Mind. Otherwise it would keep returning to deep sleep in order to recover its wisdom. Deep sleep and Samadhi gives idea of non-dual experience alone, whilst waking experience gives the idea of non-dual plus duality. Hence, the soul is ever-present in the midst of the Waking life as its witness and substance.
The Seeker by knowing that the Deep sleep gives non-dual experience is not enough. It must be known and realized in the Waking experience. That is the Seeker has to discover it in the midst of the waking experience by deeper inquiry and reasoning into the nature of the mind and trace back the formless witness of the three states. Then only he will be able to realize self/soul.
The knower of the three states, which rises and subsides, is the Soul/Self. The Seeker has to train himself to overcome his conditioning of viewing and judging the world on the base physical self. By rectifying his reasoning base from physical to spirit will help him to understand, assimilate the Self-Knowledge.
Just as dream sinks, back to the substance from which it is made of and rises back as waking experience, same way the Waking experience also is created out of the same formless substance. The substance and witness of both Waking and dream is one and non-dual. The dream becomes unreal when waking takes place same waking becomes unreal when one becomes aware of the fact that the self is not physical.
The physical self and the world within the dream are unreal. Same way the physical self and the world of the waking is unreal when one becomes aware of the fact that the true self is the spirit/soul.
The spirit/soul can stay with or without the experience of duality/mind. The illustration is Deep Sleep. One has to observe the rising and subsiding of the experience of duality/mind. When there is no duality then it remains as Soul/Spirit.
the physical self /ego is present, only in experience of duality ,therefore, it is erroneous to take the authorship as physical self/ego and view and judge the truth on the base of physical self.
How the experience of duality [mind] becomes non-duality [soul]. The illustration of deep sleep is used, before one enters the deep sleep, it witnessed the experience of duality [waking/dream], that subsided, where did it subside. Therefore, it is only an illusory experience created out of the formless Knower. In deep sleep there was only the formless knower of the three states. Therefore, the formless witness can remain with or without the duality, but the duality cannot exist without the formless witness.