Sage Sri, Sankara affirmed a progression of points of view depending on the stage of one’s practice.
“From the standpoint of the waking entity the universe is a reality from the standpoint of the soul, the innermost self, the universe is mere illusion created out of consciousness. When wisdom dawns then one realizes the whole universe is consciousness. The dualistic view is possible only in ignorance. At the dawn of Self-knowledge or Brahma Gnana or Atma Gnana there is only non-dualistic view in the midst of duality because the whole universe is consciousness. Thus all the contents of the universe are also consciousness. Thus form, time and space are mere illusion created out of consciousness. If the form time and space are consciousness than the experience birth, life and death also consciousness..
To get Self- Realization or freedom no qualification is actually needed. It is possible to have the realization of the non-dual truth here, in this very life.
The universe appears as waking, dream (duality) and disappears as deep sleep (non-duality). Gaining the knowledge of the knower of the three states, is the only way one can transcend the triad of states. To gain this knowledge by perfectly analyzing the very states of dream and sleep in the waking to benefit from the states rather than becoming victims of the states.
A Gnani knows that the enjoyment of desires within the waking also is as unreal as in the dream, because he is fully aware of the fact that, the self is neither the waking entity, nor the dream entity but self that which witnesses the three states. Thus, the universe, which appears as waking or dream is mere illusion created out of consciousness, which is the substance and witness of the three states.
The pain and pleasure are part of the waking or dream. The waking or dream is an object to the true self, which is consciousness.
When awake, one should, first picture to himself vividly what he has seen in a dream and then carefully and constantly think over the conditions of dreaming and wakefulness and analyze and realize the fact that the witness of the three states is formless and part. The witness is nothing to do with the individual happenings within the universe, which appears as waking or dream. The dream entity and dream universe is nothing to do with the waking entity. The waking entity and the waking universe is nothing to do with dream entity. In deep sleep the witness remains without the waking or dream experience. In waking alone experience the waking entity is aware of the dream or deep sleep experiences but the waking entity was absent in dream or deep sleep. Thus one which is aware of the three states is neither the waking entity not the dream entity because the deeper inquiry revels the fact that the self is not physical but self is formless consciousness. The one which witnesses the waking or dream is not the form but it is the formless, because the form is limited to the waking or dream. Thus the witness is that which witness the waking or dream experience as a whole without the physical apparatus.
The seeker must observe deeply and find out the essential similarity of the dream and waking experience. He should realize the fact that, the witness of the three states is formless and apart. He should then give up the notion of the reality of the waking experience, same way he gives up the dream realities, when waking takes place and cease to be attached to both waking or dream, by holding mentally the formless witness as real and eternal.