Seeker has to analyze three states [object] and formless witness [subject] analysis to bifurcate the object from the subject and know that, the three states are an object to the formless subject, which is consciousness.
Science is based on individuality not on the whole existence. Science considers the world as a part and tries to unfold the mystery individual object. Scientific views are based on the physical witness or ego. Thus science treats the object as subject [body or –ego], whereas the subject is hidden within the object. The science, which demands physical proof, cannot cross the threshold of physicality. Since the subject cannot be obtained from laboratory the mental journey is the only process to know the mystery behind the mind ,which is in the form of universe.
Until one thinks he is an individual and world is apart from him, it is impossible to unfold the mystery of the universe as a whole, which appears as waking or dream. Therefore, the mind has to be inquired into.
Dream gives a strong hint that the waking experience also illusion. Since dream is experience as a whole, which indicate the dream entity and the dream world are within the dream, likewise the waking entity and the waking world are within the waking experience. Thus the one, which witnesses the three states, is neither the waking entity not the dream entity. Deep sleeps indicates that the substance and witness of experience of duality can remain with or without the waking and dream.
The psychology cannot transport seeker beyond physicality. The psychology is based on the physical self or ego. It cannot go beyond duality.
Without the idea of illusion, it is very difficult to explain and understand and bifurcate and assimilate and realize the non-dual reality.
If one thinks only as a person he thinks within the scope of the Waking experience. Therefore, his thinking is within the Waking experience. Therefore, it is impossible to unfold the reality on the physical based inquiry.
The ‘self ’ not limited neither to the waking entity not to the dream entity but it pervades all the three states. The ‘I’ appears in the form of ‘mind. The mind is in the form of the universe. And universe appears as waking or dream. The self is not an entity or identity or a thing in the universe but it pervades all the three states as their formless substance and that formless substance itself is the witness of the three states. Therefore, the seeker has to trace the formless witness of the three states in order to realize the self is neither the waking entity nor the dream entity but the formless soul ,which is in the form of consciousness.
One has to learn to view and judge on the base of the soul to unfold the mystery of the mind. The idea of illusion serves as stepping stone towards the truth.
One has to start inquiring on what standpoint the universe is an illusion. The chain of inquiry through reasoning proceeds until the he reaches the substance of the universe,which is in the form of the mind. As he goes deeper and deeper the truth starts reveling itself.