Sage Sankara’s whole teaching can be summed up into one sentence:- There is nothing else but Brahman.+

Sage Sankara says:~ 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

But how does one have that realization? That is where Advaita and Advaita Vedanta diverge.

Sage Sankara goes on to say: ~A sickness of not cured by saying the word “medicine.” You must take the medicine. Liberation does not come by merely saying the word “Brahman.” Brahman must be experienced. Until you allow this apparent universe to dissolve from your consciousness until you have experienced Brahman, how can you find liberation just by saying the word Brahman? The result is merely noise. Until a man has destroyed his enemies and taken possession of the splendor and wealth of the kingdom, he cannot become a king by simply saying “I am a king.”

A buried treasure is not uncovered by merely uttering the words: “Come forth.” You must follow the right directions, dig, remove the stones and earth from above it, and then make it your own. In the same way, the pure truth of the Atman, which is buried under Maya and the effects of Maya, can be reached by meditation, contemplation, and other spiritual disciplines but never by subtle arguments. 

Ignorance will not vanish without Advaitic wisdom. It is not you who has to get rid of ignorance, because you and you and your experience of the world are the product of ignorance. The Soul, the Self is in ignorance of its own true nature. 

Only through Self-knowledge or Brahma Gnana or Atma Gnana, the Soul, the Self, awake from its sleep of ignorance.  When the soul remains in its own awareness of its own true nature, there is no division in the soul or consciousness, there is unity in diversity. 

Sage Sankara’s whole wisdom can be summed up into one sentence:- ‘There is nothing else but Brahman. He says that Absolute Existence, Absolute Knowledge and Absolute Bliss is Real. The universe is not real. He says that Brahma and Atman are one. The ultimate and the Absolute Truth is the Self, which is one though appearing as many in different individuals. The individual has no reality. Only the Self is real; the rest, mental and physical are but passing appearances.

Sage   Sankara: ~  "Though I wear these robes of a Sanyasin, it is only for the sake of bread." (Select Works of Sage Sri, Sankara" also his commentary on Brihad)

Sage   Sankara:~  The Gnani "should pass through life", not run away from life, and should take a middle course between seeking worldly honor and worldly abasement. ( Chap.3.4.50; Sankara's commentary to Brahma Sutras)

Genuine philosophy must be independent of religion, that in Sage Sankara himself the Saguna Brahman or a personal God is only a part of the phenomenal (if not illusory) world and the Nirguna Brahman is the only reality and has nothing to do with religion. 

The main hurdle in his way of thinking is the fact that Sage Sri, Sankara did not claim to be an original thinker at all, and his philosophy took the form of commentaries on the generality of scriptures, particularly the Upanishads and the Gita. 

Sage  Sankara was an independent thinker. His philosophy has not been taken seriously by many in India because most of the followers of Sage Sankara are religious orthodox.

It is that philosophy in India was for centuries more an exposition of the ancient classics than the independent thought of individual thinkers as in ancient Greece or modern Europe and America.

Sage Sankara and  Sage  Gaudapada are independent thinkers other schools of Indian philosophy are mere theologies. Advaitic philosophy is real philosophy. The dualistic philosophy cannot escape the charge of dogmatism.

Intelligence and thought, do not apply to Advaitism, intelligence and thought are based on a false self (waking entity) within the false experience (waking).   The whole Advaitic philosophy is an attempt to transcend the limitations of intelligence and thought.

The two points of view A Gnani is not cut off from the experience of practical life within the practical world because Advaitic truth is neither realism nor idealism; it is beyond both these.

Sage Sankara said:~Talk as much philosophy as you like, worship as many gods as you please, observe ceremonies and sing devotional hymns, but the liberation will never come, even after a hundred aeons, without realizing the Oneness.

Philosophy does not begin with the ultimate truth. The ultimate truth has to be proved, not assumed. Hence, so-called philosophers who take Brahman for granted are not philosophers at all.

Lots of Advaitin scholars will teach that all is yourself, but none of them can show that this is so, none has analyzed it scientifically, and none can prove it. Rational proof is required so that one arrives at knowing the ultimate truth or Brahman i.e. Gnana.  Theirs is mere dogma, parrotism, and repetition of what they read in scripture.  Authoritarianism merely assumes as true what another says, but what has yet to be proved.

Sage Sankara endeavored toward establishing the Vedic religion and overthrowing Buddhism. But even he was not able to avoid the influence of Buddhism. The influence of the revolutionary atmosphere of Buddhism has reappeared in the Advaita of Sage Sankara. His inability to revive the Vedic religion that flourished before the Buddhist revolution in its pure form is discernible.:~Santthosh Kumaar