The Advaita (nonduality) is hidden by the Dvaita (duality). Advaita is the Soul, which is present in the form of consciousness. Dvaita is the universe (I).+

The Advaita (nonduality) is hidden by the Dvaita (duality). Advaita (non-duality) is the Soul, which is present in the form of consciousness. Dvaita (duality)  is the universe (I). 

Advaita is basically a denial; it is literally the negation of the Dvaita. That means whatever remains by negating the universe by realizing the universe is created out of single clay and that clay is the Soul, which is present in the form of consciousness.  Consciousness is the cause of the universe and it, itself is uncaused.

Some Gurus say that duality is a thought without knowing what duality is and what is nonduality.

But remember:~

The thoughts, thinker, and the world are within the dualistic illusion or Maya.  By getting rid of the thoughts the illusion will not vanish because thoughts are not the cause of the illusion.  The illusion is the product of ignorance. 

Until ignorance is there the illusion is experienced as a reality.  Getting rid of ignorance is the only way. 

Thoughts and thinkers and the world in which we exist are nothing, but a dualistic illusion or Maya created out of single clay and the Single clay is the Soul, the Self, which is present in the form of consciousness.  

The one who realizes the truth hidden by the illusion transcends from the illusion to Advaitic reality in the midst of the illusion by realizing that form, time and space are one in essence. 

The thinker and his thoughts and his experience of the world are within the dualistic illusion or Maya.  The dualistic illusion is present when a waking experience or dream is present.  

The waking experience is a parallel dream and a dream is parallel waking.  The dualistic illusion is created out of a single stuff. That single stuff is the Soul, which is present in the form of consciousness.  

Remember:~  

If one thinks its mere disappearance in yogic Samadhi is the ultimate truth or Brahman, then he would get it in deep sleep.  Thus, the yogic Samadhi is not the Advaitic wisdom. Thoughtlessness is not Advaitic wisdom. 

Thoughtlessness is not wisdom. The thinker, thoughts, and the world are part of the illusion. The thought will not arise without form, time, and space. The form, time, and space will not arise without the mind.  

The mind ceases to exist without the Soul which is in the form of the spirit. Therefore, there is a need to know the Self is not limited to the physical entity (you), but it pervades everything and everywhere in the experience of diversity (waking or dream).  

Deep sleep is the state of thoughtlessness, silence, wordlessness, silence but it is not considered as a state of oneness because anyone can take a sleeping pill and will be able to get the state of oneness. 

Thus, trying to imitate the state of oneness in duality by observing silence, thoughtlessness, and wordlessness or by yogic Samadhi or surrendering to the physical Guru, the Advaitic wisdom will not dawn. 

Without the Advaitic wisdom, ignorance will not vanish. Getting rid of ignorance through wisdom is the only way to realize the ultimate truth or Brahman.   

Remember:~

Where is the dream world when the waking takes place? Where is the waking world in which you exist when the dream is going on?

The dream people and dream world disappear when the waking reappears, then what substance, this waking and the dream and the deep sleep are made of?

What is it that was aware of this coming and going of the three states?

What is it that becomes the waking experience?

What is it that becomes the dream?

What is it that remains without waking or dream in deep sleep?

~ The Soul, which is present in the form of consciousness, becomes the waking experience (duality). It is the Soul that becomes the dream and it is the Soul that remains without waking or dream in deep sleep (nonduality).

All the three states are created out of single stuff. The Seer of the Seen (three states) is one in essence. So, there is no second thing that exists other than the Soul, which is present in the form of consciousness. Rest in consciousness by realizing everything is consciousness. : ~ Santthosh Kumaar