All guru propagated wisdom is are based on dualistic perspective and orthodox point of view whereas Sage Sankara's Advaitic wisdom is based on non-dualistic perspective and on also on rational standpoint.+

 Many took second-hand knowledge propagated by Gurudom as a fact without thinking and reasoning and stuck up without reaching nowhere.

All guru propagated wisdom is are based on dualistic perspective and orthodox point of view whereas Sage Sankara's Advaitic wisdom is based on non-dualistic perspective and on also on rational standpoint. 

Sage Sankara: ~ 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.

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.

First, the seeker must inquire into the nature of the three states to realize the three states are one in essence. One has to observe everything in the three states because all three states are one in essence and that essence is consciousness (Soul or Atman) Atman is Brahman or God in truth.

The seeker should not shut his eyes to the nature of the three states, because they are a mere mirage created out of consciousness.

Form, time, and space are one in essence. That essence is consciousness. Consciousness is the ultimate truth or Brahman. Brahman is God.

Brahman cannot be described, because description implies distinction. Brahman cannot be distinguished from any other than Soul, the Self.

The three states have no independent existence. The Soul which is present in the form of consciousness alone has real existence. The three states are a mere illusion created out of consciousness.

A Gnani sees only unity in diversity, just like a goldsmith estimating the gold in various items of jewelry sees only gold.

When one identifies the Self with the form then only the form, time and space are present. But when one transcends form, time, and space the duality never remain as reality: ~ Santthosh Kumaar