What is it that makes the body and the world exists for you? It is awareness. Mind is this entire universe in which you, me and others and everything that you, me and others know exists. The whole universe which contains you, me and others is mental; therefore it is mind.
The universe is mere mirage or illusion created out of the self, which is the soul. One has to analyze the mind through deeper thinking. Then only he becomes aware of the fact that, the mind is not confined to the body; because the mind is the whole universe. The universe appears as mind and the mind appears as waking and dream. And waking or dream disappears as deep sleep. This fact has to be investigated and assimilated first.
If the mind is whole universe and the universe is in the soul, which is the true self; what is there to claim as mine when there is nothing beside the soul, which is in the form of consciousness; when whatever is, is the true self or the consciousness. Consciousness converted in to waking or dream. And waking or dream is converted into deep sleep. Thus the substance of the three states is one and the same. Thus the substance itself is witness of the three states. Therefore, the substance and witness are one in essence. The essence is consciousness. The consciousness is the ultimate truth.
Thus, whatever is claimed as me and mine is meaningless from the ultimate point of view because there is no second thing exists other then consciousness.
Consciousness is everything, then there is nothing exist other then consciousness. Lectures limit consciousness. If one wants to overcome the physical conditioning of consciousness, then he has to realize the fact that, self is not physical but it is formless soul, which is in the form of consciousness. So there is room for duality in reality, therefore the birth, life, death and world are mere illusion created out of consciousness.
Having renounced the three states [illusion] mentally, one perceives the ultimate truth, through non-dual wisdom. Whatever prevails without the three states is the ultimate truth.