Sage Goudapada: ~ “Whatever is seen, whether external or internal, whether by the ordinary persons or yogis is unreal".+

Sage Goudapada's rational exposition of Advaita: ~ “Whatever is seen, whether external or internal, whether by the ordinary persons or yogis is unreal”.

Thus, whatever is seen, known, believed, and experienced as a person is a reality within the waking experience (duality) but the waking experience (duality) itself’ is merely an illusion.

To say the universe is an illusion without first examining it and inquiring into its nature thoroughly is to delude oneself. This world is common to every one of us; therefore the seeker of truth must begin his inquiry with it. It is only after he has inquired into the nature of the objective world, he realizes the universe which through ignorance appears as of diverse forms, is nothing else but the Soul which is present in the form of consciousness is absolutely free from all the limitations of human thought.

Those who assert the world is not an illusion because they are unaware of the fact that, the world is the reality within the illusion (waking). And they are frightened to consider the world an illusion. Without considering the world as an illusion, it is impossible to acquire ‘Self-knowledge or Brahma Gnana or Atma Gnana.

Sage Sankara: ~ VC~.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.

After verifying through deeper inquiry if one finds the world is the reality within the illusion then he cannot again say the world is not an illusion.

If one is frightened to accept the world is an illusion (waking) then he is unfit to acquire Self-knowledge or Brahma Gnana or Atma Gnana. Those who are stuck with the reality of the world are stuck with the reality of the individual experiences of birth, life, and death, which take place within the unreal world. Thus the pursuit of truth is for those who have the courage to accept reality as it is, that is the reality without form, time, and space.

When you finally realize the ‘‘Self’ ‘is not you but the  Self is the Soul then you will realize the world in which you exist is merely an illusion created out of the Soul. The Soul is present in the form of consciousness.

Thus, you, your experience of birth, life, death, and the world are merely an illusion created out of the consciousness, the consciousness is the ultimate truth or Brahman or God in truth.

The world is both real and unreal. It is real because it is a manifestation of consciousness, but is unreal, in the sense, that it is not absolute and eternal like consciousness itself.

People's approach is more practical, and they stuck with the reality of the world, they take it as real. That is why all the confusion. 

In Self-awareness-- the witness and witnessed are one in essence. That essence is consciousness. There is no second thing that exists other than consciousness.
Thus, whatever is seen, known, believed, and experienced as a person is a reality within the waking experience (duality) but the waking experience (duality) itself is merely an illusion.

A person, who stamped his foot on the ground to refute to show the world, is real, ignores that in the dream he would do exactly the same--stamp his dream foot on the ground and assert it to be real.

Remember: ~

Sage Sankara: ~ “VC~ All this universe which through ignorance appears as of diverse forms, is nothing else but Brahman (Consciousness) which is absolutely free from all the limitations of human thought.

The universe is the product of ignorance. Ignorance is present in the form of the ‘I’.

Sage Sankara says:~ VC-47 All the effects of ignorance, root, and branch, are burnt down by the fire of knowledge, which arises from discrimination between these two—the Self and the non-Self.

Till you think you are an individual separate from the world and the world existed prior to you and you are born in it afterward ignorance will prevail as a reality. Till ignorance is there the universe prevails as reality.

Sage Sankara says: ~ “The exercise in discrimination between real and unreal and renunciation of the false is real meditation, then why you are indulging in other types of meditation.

Perfect understanding and realization of ‘what is what’ leads to Self-awareness. By holding onto theories one remains in the realm of duality. 

You have to mentally go on dropping what is not the truth through deeper Self-search. Finally when you become aware of the fact that, your ego, your body, and the world are one in essence then there is Self-awareness in the midst of duality. : ~ Santthosh Kumaar