Sage Sankara:~ "Without knowing and examining the external world, one can’t know the Truth.+

Chandogya Upanishad~ sarvam khalvidam Brahma ~ all this (universe) is verily Brahman. By following back all of the relative appearances in the world, we eventually return to that from which it is all manifest – the non-dual reality (Chandogya Upanishad).  

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. 

Sage Sankara:~  VC~.63 says: "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.

There is no need to study Advaita Vedanta or Buddhism to acquire Self-knowledge or Brahma Gnana or Atma Gnana.  All accumulated knowledge is of no use to realize the Advaitic truth beyond the form, time, and space.

Sage  Sankara says in the commentary in Vedanta, sutra that what is accepted without a proper inquiry will not lead a person to the final goal. On the contrary, such acceptance will result only in evil, in something which is detrimental to our spiritual progress

There is no need to study Advaita Vedanta to realize the Advaitic truth beyond form, time, and space. Advaita is not a theory or a philosophy. Advaita is the nature of the Soul, the innermost Self.  There is no need for any theory or philosophy or scriptures to acquire Self-knowledge. Only a perfect understanding of ‘what is what’ is needed.

There is no need to buy books of Sage Sankara in order to acquire Self-knowledge. A perfect understanding of 'what is what' is needed. Nothing else is a need other than realizing the fact that, the form, time, and space are one in essence and that essence is the Soul, which is present in the form of consciousness in order to get the  Advaitic  Self-awareness.

Self-knowledge cannot be attained by the study of the scriptures and intellectual understanding or by bookish knowledge.  Therefore, there is no use in studying the scriptures and other scriptures in order to acquire non-dual wisdom.  That is why Buddha rejected the scriptures, and even Sage Sankara indicated that the ultimate truth lies beyond religion,  the concept of God, and the scriptures.

Fortunate is the one who does not lose themselves in the labyrinths of philosophy. Fortunato is the man who does not lose himself in the labyrinths of philosophy but goes straight to the source from the universe arise.

There is only one Reality to be known, the same for all seekers, but the ways to it, are hidden by the religion.  Self-discovery is the only way, towards the non-dualistic absolute without any religious doctrines, which will help the seekers to unfold the mystery of the illusion in which we all are searching for the truth of our true existence.

Sage Sankara said:~Neither by the practice of yoga nor philosophy, nor by good works, nor by learning, does liberation come, but only through the realization that Atman and Brahman are one in no other way. (1) VivekaChudamani v 56, pg 25

The citations from scriptures are not proof.  The ultimate truth has to be proved without the scriptures.  The ultimate truth is the universal truth and it does not belong to any religion.  Religion causes diversity in unity, whereas, the ultimate truth brings unity in diversity. 

That is why Sage Sankara himself says: ~ VC 59. The study of the Scriptures is useless so long as the highest Truth is unknown, and it is equally useless when the highest Truth has already been known.

60. The Scriptures, consisting of many words are a dense forest that merely causes the mind to ramble. Hence, men of wisdom should earnestly set about knowing the true nature of the Self.

61. For one who has been bitten by the serpent of Ignorance, the only remedy is the knowledge of Brahman. Of what avail are the Vedas and (other) Scriptures, Mantras (sacred formulae), and medicines to such a one?

It is not that one should pore over the ancient scriptures.  There is no need to study first, and then realize. One has to realize first, then only he will know ‘what is the truth?’ and ‘what is untruth’. One has to make his discoveries through the process of rational thinking.

That is why Sage Sankara says:~ V C:~65- As a treasure hidden underground requires (for its extraction) competent instruction, excavation, the removal of stones and other such things lying above it and (finally) grasping, but never come out by being (merely) called out by name, so the transparent Truth of the Self, which is hidden by Maya and its effects, is to be attained through the instructions of a knower of Brahman, followed by reflection, meditation and so forth, but not through perverted arguments.

He who has not rectified his reasoning base from the ‘I’(form) base to Soul (formless) base and one who does not have the intense urge to know the non-dualistic or Advaitic truth,  and who is not tranquil and subdued and whose mind is not receptive, cannot acquire Self-Knowledge or Brahma Gnana or Atma Gnana. 

When we realize the form, time and space are one, in essence, then it leads to Advaitic  Self-awareness.  In Self-awareness,   even though there is diversity,  there is unity in diversity, because everything is created of the same stuff. That stuff is consciousness. There is no second thing that exists other than consciousness.  

Remember: ~

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

 That is why Sage Sankara says: ~ VC-63-Without causing the objective universe to vanish and without knowing the truth of the ‘Self’ how is one to achieve Liberation by the mere utterance of the word Brahman? — It would result merely in an effort of speech.

Ignorance will never vanish without Advaitic wisdom.  The ignorance will not vanish without inquiring into the nature of the universe. 

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.

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.

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

All is consciousness. The whole universe is consciousness. From consciousness, the universe comes. When the universe disappears, the consciousness still remains without form, time, and space.:~  Santthosh Kumaar