The mind has its origin in consciousness/soul. The three states are dependent on consciousness [soul] for their existence. During the deep sleep the waking and dream merges with consciousness. There is no second thing other than consciousness in its true nature. Hence it is non dual.
Consciousness [soul] is of the nature of knowing. Man, world and his belief of god depend on mind for their existence and mind depends on consciousness for its existence. If the reality of world bothers one and he is not ready to accept its illusory nature then he has to first inquire into the nature of the mind by inquiring “What is ‘I’?, then realize the fact that ‘I’ is not limited to physical entity alone but to the whole mind ,which appears and disappears as waking or dream.
By trying to know the truth as person, kicking the universe behind, it is impossible to acquire self-knowledge. Till one knows the consciousness [soul] one has only the mind [man + universe]. If one is unable to consider the world as illusion then it is realism. By considering the world as reality one is accepting the matter as reality. By accepting the matter as reality one will remain believing the birth, life and death as reality.
One has to realize the fact that, the matter [mind or universe] is dependent on consciousness for its existence. It cannot exist without the consciousness. The consciousness is the substance and witness of the matter [mind or universe]. Thus, substance and witness is one in essence, which is consciousness.
Holding the body and universe as reality, is holding the ignorance as reality. Holding the ignorance as reality is holding the illusion as reality. Holding the illusion as reality is holding the unreality as reality. Thus non-dual truth is impossible for those who believe in realism, because they have accepted untruth as ultimate truth.
The one which has the capacity to know is not the body but consciousness. The consciousness knows the body and the world together. Man and his universe co- exist within the mind. The Mind exists within the consciousness. Thus mind is body and the world together. The knower of the mind, which appears as waking or dream and disappears as deep sleep is consciousness or soul.
One mistake body to be matter everything else as mind. But analysis shows the mind itself is the matter. Without the mind there is no matter. Whatever exists without the matter is real and ultimate and it is consciousness. When everything is consciousness then there is no second thing other then consciousness. Therefore on the standpoint of consciousness as self, everything is consciousness and diversity is mere mirage created out of consciousness. Hence man and world are mere illusion on the standpoint of the consciousness, which ultimate truth.
People are conditioned to view and judge the worldview on the stand point of the false self or ego. They can only understand what they are thought by their by parental grooming, religion societal ethics, accumulated knowledge and circumstances of life. They cannot think beyond physicality.
The seeker of truth is one who is ready verify and has courage to accept and reject the truth when he finds out what is truth and what is untruth. The meek will stick to their inherited conditioning remain experiencing duality as reality.
Pursuit of truth is not suited for religionists, realists and yogis who believe in conceptual god. Because religious idea of god, world, heaven, hell, sin karma, ceases to exist as real when one becomes aware of the non dual truth.
Seekers who are ready to accept only truth have to indulge in the pursuit of truth. And people who are satisfied with their faith and belief and accepted truth must continue without disturbing their present outfit.