Non-dualistic truth is supreme truth; all dualistic systems hold false self as real self and false experience as reality

Non-dualistic truth is supreme truth; 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 Dualists 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.  

Mind is in an experience. Mind appears as waking or dream [duality] and disappears as deep sleep (non-duality). Man and his world are within the waking or dream.  The waking experience is parallel dream. And dream is parallel waking experience.  Thus trying to experience the truth as an individual is total impossibility.  Thus the people who are trying to experience the self as in individual are in hallucination because self is not an individual it is universal. Self which is consciousness pervades in everything and everywhere in all the three states. Thus the people who are expounding knowledge that self can be experienced as an individual are playing with the feelings and sentiments of the people and make them hallucinate and keep them permanently in the grip of hallucination.  The truth has to be mentally traced and grasped, understood assimilated and realized by deeper self-search because it is hidden within the three states but it is beyond the three states.

That is why Sage Sri, Sankara indicated 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.

Seeker of truth has to direct realization of the true self, through deeper, inquiry, analysis and reasoning   and avoid losing precious time and effort loosing himself in philosophical studies.