Non-dualistic or Advaitic truth is supreme truth and ultimate truth or Brahman; all dualistic systems hold false self as real self and false experience as reality.

Non-dualistic or Advaitic  truth is supreme truth and ultimate truth or Brahman; all dualistic systems hold false self as real self and false experience as reality.  Non- dualistic wisdom is culmination of all systems including theistic non-duality.   The true non-dualist will not quarrel and argue with any theoretical philosophy because he is fully aware of the fact that, this orthodox theistic non-dualistic scholars or pundits like Dualist sages could not distinguish between ‘I’ and ‘formless witness.’ The 'I' was the witness. Their highest was the Jiva. One is so much attached to the 'I' that he do not want to think that 'I' does not exist. Again one is unable to detach the ‘I’ from the Real witness.  

No  need to study the scriptures in order to acquire Self-Knowledge or Brahma Gnana or Atma Gnana  . One has to self-search the truth and realize it without the scriptures. And then when he reads the scriptures he becomes aware the scriptures are also saying the same thing but everything is misinterpreted.   

That is why Sri, Sankara says in VivekaChudamani   :- 

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.

61. For one who has been bitten by the serpent of Ignorance, the only remedy is the knowledge of Brahman. Of what avail are the Vedas and (other) Scriptures, Mantras (sacred formulae) and medicines to such a one?

62. A disease does not leave off if one simply utter the name of the medicine, without taking it; (similarly) without direct realisation one cannot be liberated by the mere utterance of the word Brahman.

There is nothing more rational, more intelligible and more un-dogmatic insights of Sri, Sankara, is to drop all the theistic non-duality or Advaita which is meant for those who are incapable and not receptive to realize the ultimate truth or Brahman. – FORMLESS PATH