The seeker has to find out ‘what is it’ that’ becomes the waking or dream (duality) and ‘what is it’ that becomes the deep sleep (nonduality).+

Burn down the ignorance with the fire of Self-knowledge or Brahma Gnana or Atma Gnana. Self-knowledge or Brahma Gnana or Atma Gnana is knowledge of the Soul. Realizing the ‘Self ‘is not the ‘I’ but the Self is the Soul, the witness of the ‘I’ with a firm conviction leads to Self-awareness. 

You think the ‘Self is the ‘I’ and ‘I’, is within the body. You are mistaking the ‘Soul, the ‘Self ‘for the ‘I’, which appears and disappears.  This is the great stumbling block of the Gurus who propagated the ‘I’-centric teaching.

These Gurus think that when the ego is not, nothing remains.  You must realize you are the ego.  You are the false self within the false experience.

You (the ego), body and the world appear together and disappear together.  Therefore, you cannot get rid of the ego alone because your body and the world also appeared along with the ego.  

It is foolish to venture to get rid of the ego alone.  Therefore, it is necessary for the seeker to realize ‘what is what’ in order to discover the truth, which is hidden by the ‘I’. 

The ‘I’ is not different from the mind. 

The mind is not different from the universe. 

The universe is not different from the waking. 

Without the ‘I’ there is neither the mind nor the universe nor the waking.

The universe is verily consciousness. Without realizing ‘what is the Mind? it impossible to get Self-realization. The universe is not different from the mind because the universe is the mind itself. The mind is not different from the Soul because the mind is the dualistic illusion created out of the Soul, which is present in the form of consciousness.  

Thus, the universe is nothing but consciousness. The universe is unreal because it is not absolute and eternal like consciousness. 

It is impossible for any human being to challenge successfully the Advaitic position, as Sage  Sankara says. 

Sage Sankara asks his opponents "How do you know there are separate individual Souls? Have you seen the Soul of a man? You can only say that you have seen different bodies. To say more is to misuse language. Therefore, I call you liars unless you give proof, which is impossible. 

You and your experience of the world disappear when waking experience disappears. 

The waking experience disappears in deep sleep.

The dream disappears when waking takes place.

There is neither the waking nor the dream in deep sleep.

The seeker has to find out ‘what is it’ that’ becomes the waking or dream (duality) and ‘what is it’ that becomes the deep sleep (nonduality). 

The one that becomes dual (waking or dream) and that one that becomes nondual (deep sleep) is the formless Soul, which is present in the form of consciousness. 

The Soul is the  ‘Self’. In the realm of the Soul, diversity has no value because there is unity in diversity in consciousness. 

All three states are made of single stuff. Realizing that single Stuff, which is the Soul is ‘Self’-knowledge or Brahma Gnana or Atma Gnana. 

If the Soul is the  ‘Self’ then the world in which you exist is merely an illusion. The world is a reality on the base of the ego (you), which is the false ‘Self’ within the false experience. 

The illusory world in which you exist is the product of ignorance. When ignorance vanishes the unreal nature of the world in which you exist is exposed. In the same way, the unreal nature of the dream was exposed when waking takes place. Ignorance vanishes when Advaitic wisdom dawns. 

Perfect understanding of ‘what is ‘what’ helps the seeker to remove all the obstacles, which is blocking our realization.

That is why Sage Sankara Says: ~ V.63~ "Without knowing and examining the external world, one can’t know the truth, as the idea that the external world exists, won't go. It can go only by an inquiry into the nature of the external world. 

The Soul, the  ‘Self’ revels ‘what is real’ and ‘what is unreal” when the seeker is receptive and ready. 

It takes time for the subconscious to gain speed; it takes time for the Soul to awake, and it takes time for the Soul which has been in the sleep of ignorance to wake up to its own awareness. :~ Santthosh Kumaar