The Advaita taught by Sage Sri Sankara is a rigorous, absolute one. According to Sage Sri Sankara, whatever is, is Brahman. Brahman itself is absolutely homogeneous. All difference and plurality are illusory.
Sage Sri, Sankara gave out what was of most use to the greatest number of people. Therefore, in the commentaries on the Upanishads, such as the famous Mundaka, he gave the highest nondual message of the identity of Atman and Brahman, revitalizing the philosophy and practice of Advaita, while in the commentaries on the Brahmasutra he gave a lesser teaching, posting both higher and lower Maya and higher and lower Brahman (Ishvara) to explain creation for those of lesser intellects until they were ready for the highest truth.
Sage Sri, Sankara was very careful with his choice of semantic analysis and use of words - taught at different levels of doctrine at different times as the situation warranted. Sage Sri, Sankara first came to the attention of Sage Sri, Goudpada when his own Guru brought him to the Himalayas to present his Advaita writings to the
great Sage, who encouraged his further endeavors.
The Advaitic formula, to be successively realized, is: “The world is unreal; Brahman is real; the world is Brahman.” This is the vision of non-duality. Sage Sri, Sankara affirmed a progression of points of view depending on the stage of one’s practice.
“From the standpoint of the waking entity the universe is a reality from the standpoint of the Soul, the innermost Self, the universe is mere illusion created out of consciousness. When wisdom
one realizes the whole universe is consciousness. The dualistic view is possible only in ignorance. At the dawn of Self-knowledge or Brahma Gnana or Atma Gnana, there is only non-dualistic view in the midst of duality because the whole universe is consciousness. Thus, all the contents of the universe are also the consciousness. Thus form, time and space are mere an illusion created out of consciousness. If the form time and space are consciousness than the experience of the birth, life and death also consciousness. dawns then
The universe is
verily the consciousness. Without realizing ‘what is this Mind?' it impossible to get self- realization. The universe is not different from the Mind because the universe is the mind itself. The mind is not different from the Soul because the mind is the dualistic illusion created out of the Soul, which is present in the form of the consciousness.
Thus, the universe is nothing but the consciousness. The universe is unreal because it is not absolute and eternal like the consciousness.
It is impossible for any human being to challenge successfully the Advaitic position, as Sage Sri, Sankara says.
Sage Sri, Sankara asks his opponents "How do you know there are separate individual Souls? Have you seen the Soul of a man? You can only say that you have seen different bodies. To say more is to misuse language. Therefore, I call you liars unless you give proof, which is impossible.
A man who describes Sage Sri, Sankara's wisdom as negative (because of his Neti, Neti) does not know that this is applied only to the world of the Seen, the critic ignorantly believes that it is also applied to the Seer. Advaita never negates the Seer, only the Seen