Bhagvan Buddha, Sage Sankara and Sage Goudpada have declared non-dualistic or Advaitic truth centuries back.+

Swami Vivekananda aptly described Sage Sankara’s Advaita as the fairest flower of philosophy that any country in any age has produced.

The Advaitic truth is a rational or scientific truth declared by the Sages of truth centuries back, but unfortunately, the original essence of the rational Advaita is lost mainly, because of orthodox adulteration and add-ons, which is based on the ego (waking entity), which is the false self within the false experience (waking).

The seeker has to first indulge in deeper self-search without scriptures and understand and assimilate the Advaitic truth, which leads to self-awareness. Thus, soulcentric thinking, reasoning, and judgment are very much necessary in pursuit of truth.

Sage  Gaudapada:~ The non-dual Atman is realized when the individual self (jiva) is awakened from its ignorance. Atman is unborn, dreamless, sleepless, and motionless and is beyond duality. It is cognition at its purest. It is Brahman- Ayam Atma Brahma, this Atma is that Brahma; Thus epitomizing the core of Upanishad teachings.

Blavatsky says that Sage Sankara’s wisdom will remain a dead letter to most Hindus for ages to come. (SD 1:271-2).

***

Many believe spirituality and religion are considered interconnected, but it is not so. Religion is based on the false self (ego or body or you) and it is limited to the false experience (universe), while spirituality transcends race, religion, gender, language nationality, and universe.  Spirituality is based on the soul, the innermost self. From the standpoint of the soul, the innermost self the universe in which we exist is merely an illusion.  

Remember:~

People who think the ‘I’ or ‘I AM’ as the 'Self' are caught up in the web of duality, and they experience the illusory world in which they exist as reality.    

As the waking entity or ego becomes more and more inward-turned, it becomes gradually free from experiencing the duality as reality.  

When the soul, the 'Self' becomes freed from all the obstruction by fully eliminating the ignorance it remains in its own awareness.  

When the Soul, the Self remains in its own awareness amid duality then the duality is merely an illusion created out of the soul, which is present in the form of consciousness.

So long the Soul, the  'Self' identifies itself with the waking entity (ego or the waking entity) it remains in ignorance of its formless nondual true nature. Therefore, it is necessary to realize the fact that, the ‘Self’ is neither the waking entity (you) nor the ‘Self’ is a dream entity but the Self is the  Soul,  the Self, which witnesses the coming and going of the three states.

Just as the sun is the direct cause of the daylight, so without the Self-knowledge no emancipation can be had. Compared to all other forms of discipline Self-knowledge is the only direct means of freedom from experiencing the illusory world as a reality.

Only when the Advaitic wisdom dawns, the Soul, the  Self can remain in its own awareness in the midst of duality. 

Remember:~

Bhagavan Buddha, Sage Sankara, and Sage Goudpada have declared non-dualistic or Advaitic truth centuries back,  but one has to reach the destination with scientific (rational) investigation, not through punditry or intellectuality. Until one mentally reaches a conclusion, the conviction will not arise. 

Without firm conviction, wisdom will not dawn. Therefore, there is a need to know consciousness is real and all else is a myth, which Sri, Sankara declared as the world is a myth Brahman alone is real.

That alone is called the ultimate truth or Brahman, which is a fact that can never be changed under any circumstances. One must make an effort to know the ultimate truth. The Soul is there always in the form of consciousness. 

Everyone has got it, there is nothing new to be acquired; only they have to be sharp enough to grasp understand, and assimilate it when told about it. But there is a difference between understanding and realization.

An effort is required for this understanding only, whereas once understood no special effort is needed to remember his understanding: until then he only has an idea of the Soul, he only partially understands it. But once he thoroughly grasps what it is and that all these things are Soul, he will then constantly find it present everywhere without further effort, because he will perceive the ultimate truth by understanding, even in the midst of worldly existence.

When there is only one thing that is the Soul, then there is nothing to change, nothing to appear or disappear; when one speaks of remembering or forgetting the Soul that implies he believes in the existence of something else, i.e. a second thing, which is to be remembered. That would show he does not know that all is one. But knowing it, there is no second, consequently no intermittent perception of the soul, but a permanent effortless understanding and assimilation that it alone is.

When one gets a glimpse of truth he has to try to repeat it many times to establish it.  The Soul, the innermost self must raise itself by the Soul, the  Self.

The difference between physical truth and spiritual truth, the former can evolve or change; the latter is ultimate and final. 

Remember:~

Sage Sankara ’says:~ "Kuruthe Ganga sahar gamanam Vratha paripal mathva dhanam. Gyana Vihine.Sarva Mathene.”~Gnana is common to all religions. There is nothing like One Gnana for a Hindu and another for a Christian.

The entire philosophy of Sage Sankara can be summed up in the following statement:-

Brahma Satyam, jaganmithya, jivobrahmaivanaparah: - Brahman alone is real; the world is non-real and the individual Self is essentially not different from Brahman.

This is the quintessence of Sage Sankara’s metaphysics.

The consciousness is the one single reality or Brahman. The individual self is a reality within the duality. There is no individual in the realm of the nondual reality.

Sage Sankara says:~ One alone exists, and the rest is all superimposition on that One, due to ignorance.

Through a systematic inquiry into the nature of the mind, which is present in the form of the universe, one arrives at the position that the soul, the innermost self, which is present in the form of consciousness, is the ultimate truth or Brahman.

The Soul, the innermost self is constant and, therefore, real, while the phenomena constituting the universe are constantly changing and, therefore, unreal. The final conclusion is that the form, time, and space or the universe are one in essence. That essence is consciousness. Thus, no second thing exists other than consciousness.

The seeker of truth has to take into account all three states of our existence, which are waking, dream, and deep sleep ~ in waking or dream one experiences duality, and in deep sleep, there is only non-duality. To obtain a complete picture of our existential reality, we need to include evidence from all three states. This is the phenomenology of consciousness.

The consciousness is one only, without a second. One experiences the manifold universe ignorance ~ led illusion “covers" the One and "projects" the Many. The illusion is the veil on consciousness. In truth, only One, non-dual Reality is all there is. consciousness is all-pervasive. It is intrinsically Real, self-effulgent, infinite, undifferentiated Pure.

When the Soul, the Self, wakes up to its own formless nondual true nature, ignorance ceases, and the illusion, which is present in the form duality never again experienced as reality.

The show of the illusory duality, however, continues, as before. Only our identification with a particular actor's role is gone forever because the Self is in its own awareness.

Self-awareness is Brahmic Bliss! This state is already ours always in deep sleep in a "general" way. When the Self-Knowledge dawns then one is awake to it in a "special" way in the midst of duality.

Atman=Brahman or the Self, capture the essence of the immanent (Self) and the transcendent (Brahman) Reality. Humanity has not yet conceived a more lofty conception of its position in the universe.

Advaita only means the negation of duality. The soul, which is present in the form of consciousness, is the ultimate truth or Brahman. The consciousness is the cause of the origin, maintenance, and withdrawal of the universe is Advaita (i.e. non-dual), which means that the consciousness transcends all conceptions, positive and negative. Nothing positive can ever be imagined or said about it.

The consciousness is existence absolute, awareness absolute. Existence absolute means that consciousness is not unreal or non-existent. And it is not the unconsciousness. Nothing positive can be stated about consciousness.:~Santthosh Kumaar