It is very difficult to talk to people about ultimate truth or Brahman because everyone thinks he knows the ultimate truth or Brahman. This- I know business is dangerous. And whatever his reached conclusion is second hand stuff. Therefore, accepting accumulated knowledge without verification will lead the seekers to hallucinated realization based on the ego. One may have some flashes of truth when someone tries to indicate it through fewer words. But it takes nearer to truth not realization.
Upanishads say :~ "He who thinks he knows, does not know." This means that to know anything implies a second, an object of knowledge, hence duality, i.e. no Gnana.
Second-hand knowledge of the self-gathered from books or gurus can never emancipate a man until its truth is rightly investigated and applied; only direct realization will do that. Realise yourself, turning the mind inward. : ~Tripura Rahasya, 18: 89
The pursuit of truth is a mental journey. Deeper self-search makes one aware of what the truth is and what is untruth and the subconscious will be able to reject the untruth after knowing, what is Truth. Whatever prevails after rejecting the untruth is the ultimate truth.
Sage Sri, Sankara believed that those of superior intelligence, have no need of this idea of divine causality, and can therefore dispense with Sruti and arrive at the truth of Non-Dualism by pure reason.
Sage Sri, Sankara says:- VC-58. Loud speech consisting of a shower of words, the skill in expounding the Scriptures, and likewise erudition - these merely bring on a little personal enjoyment to the scholar, but are no good for Liberation.
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 which merely causes the mind to ramble. Hence men of wisdom should earnestly set about knowing the true nature of the Self.
Without the scriptures one has to move ahead in his pursuit of truth.
Sri, Sankara says:- VC-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 comes 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.
66. Therefore the wise should, as in the case of disease and the like, personally strive by all the means in their power to be free from the bondage of repeated births and deaths.
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.
Peoples approach is more practical, and they stuck with the reality of the world, they take it as real. That is why all the confusion.
The soul, the innermost self is indivisible and perfect like Space itself, when it is free from identification with the three states, which are the products of its own ignorance.
In self-awareness-- the witness and witnessed are one in essence. That essence is consciousness. There is no second thing exists other than consciousness.
Thus whatever seen, known, believed and experienced as a person is a reality within the waking experience but waking experience itself is mere illusion.
The soul, which is present in the form of consciousness, is the innermost self. Consciousness is the witness that experiences the action, the actor, and the world of separate things. It is like a light that illuminates everything in a theatre, revealing the master of ceremonies, the guests, and the dancers with complete impartiality. Even when they all depart, the light shines to reveal their absence.
What is not consciousness (formless) in the experience of diversity [waking or universe]? The waking and the dream cease to exist without consciousness. The seeker, the seeking and the destination all are one in essence.
There is only need to realize the whole universe in which we exist is created out of the soul or consciousness, the innermost self. On the standpoint innermost self, the universe is mere illusion created out of consciousness. Thus on the ultimate standpoint, no second thing exists other than consciousness. Thus, the consciousness is the ultimate truth or Brahman.