To realize ultimate truth or brahman , seeker has to first know the fact that, ‘I’ is not the self. ‘I’ is mind and Mind is the universe. Universe appears as waking or dream and disappears as deep sleep. The one which appears as waking or dream and disappears as the deep sleep is the formless soul or consciousness , the innermost self. the three states are mere mirage created out of the soul, which is in the form of consciousness. The consciousness is the formless substance and witness of the three states. The soul or consciousness is the innermost self. The truth will start unfold itself, when one learns to view and judge the truth, on the base the soul or consciousness , which is the innermost self.
The man and his world are mere appearances because they are within the appearance of waking or dream. These appearances appear as waking or dream. The whole appearance of waking or dream is mind. Because when the mind is there then only the waking or dream is present. Absent of mind absent of appearance. Absent of appearance absent of duality or diversity. Absent of diversity there is only unity. Thus, the truth pursuit is a journey from diversity to unity.
The experience of diversity is created out of single stuff that is the formless consciousness. Thus all the forms and shapes within the waking or dream is created out of single stuff. In deep sleep there is no diversity. The one which is aware of the appearance and disappearance of the experience of diversity is formless.
Seeker has to reflect upon the nature of the self, which is Consciousness as distinct from the physical existence. Thus the consciousness , the inner most Reality, is seen behind appearance.