Everyone’s inner work leads towards new understanding and realization. When doubts crops up and when one do not get a reasonable reasoning for his doubts from the other source, then only he indulges in his own personal research, and try to investigate, and then only he becomes aware of 'what is truth' and 'what is untruth'. As he goes deeper into the subject so many things will reveal.
What was the religion our ancestors were following prior to the introduction of Advaita by Sage Sri, Sankara and Dwaita by other sages? If Sage Sri, Sankara is the founder of Advaita math in 8th century what was the religion of our ancestors prior Sri, Sankara. It has to be Santana Dharma/Vedic religion.
If one reads the Satyarth Prakash of Maharshi Dayanand Sarswati(1824-1883) a real authenticated authority on Vedas, then he will become aware of the fact Dwaita and Advaita and Vishita Advaita were add-ons to the Sanatan Dharama or Vedic religion. And if he bifurcate all the add-ons from Santana Dharama and then he becomes aware of the fact Advaita was modified by Sri,Sankara on the base of Vedas to uplift the Vedic Dharma which was in the ruins in the clutches of Buddhism to suit the mind set of that time. Thus by bifurcating the add-ons from the Santana Dharma or Vedic religion, he will become aware of the fact that, there was no trace of Advaita prior to 8th Century and Dwaita in later century in Sanatana Dharma or Vedic religion Because present Hinduism is not Sanatana Dharma or Vedic religion.
One will also find all the rituals, worship and customs followed by the present generation also not Vedic based, it is modified add-ons to suit the mind set of that time. When this truth was revealed by the Maharshi Dayananda he was poisoned and killed by the pundiths.
I am not advocating Mahrshi Dayananda or the Santana Dharma, I just saying if one is seeking truth of his true existence, then he has to look beyond religion, concept of god and scriptures and yoga.
One will also trace the dates of oldest Upanishads and also some idea of Braminism and Buddhism and Hinduism as per the historian’s research essay on their origins and interaction –BRAMINISM AND BUDDHISM by Lal Mani Joshi of dept of religious studies Punjab University Patiala. There are many books of the religious historians on this subject; if one is ready to go in deeper research without preconceived ideas he will be able to know, what truth is, and what is untruth. And he will be able to accept the truth and drop all accumulated dross of untruth.
I am not interested in arguing my claims are tenable and trying to impose my idea on others. And also I am not trying to prove whether Buddha is right or Sri, Sankara is wrong. But my only purpose of my personal research is to know, how to realize the nondual truth, which is propounded by the Buddha and Sri,Sankara and Sri, Goudpada? Since present practices are based on conduct and action, and they are based on the false physical self [ego]. What are the fatter and obstacle in realize the non-dual truth? How to overcome the obstacle on the path of non-dual truth?
In Ashtavakara(commentaries on Ashtavakara Gita by Osho) it clearly mentioned that Vedas are not the means to acquire the self-knowledge. Thus it indicates that Advaita is nothing to do with the Vedas.
Dual and non-dual are not religious theories, but the state of the true self. Thus religious dualism and non-dualism and qualified non-dualism is nothing to do with ultimate truth.
When the self(soul or consciousness) is in illusion then it is called duality ( mind or universe). When the self(consciousness) is in its formless non-dual true nature then it is Atman or consciousness or spirit. Since man(waking entity) is false entity within the false experience (waking) he views and judges the worldview on the base of false self, and created all this theories on the base of false self. Therefore, whatever is seen, known, experienced and believed on the false base ( ego or form base), has to be false hood, on the base of the true self ( formless or soul base).
People limit the mind to the physical entity, and thinks the mind is within the physical body. Whereas the physical body, ego, the universe altogether is mind. Mind is an experience, it is not an experincer. Same way as the dream is the mere experience; the waking also is an experience. The whole experience [waking/dream] is an object to the formless subject [witness]. One has to realize the object and subject are one is essence. And that essence is Atman or consciousness or spirit.
Therefore, one has to bifurcate the physicalized Advaita [religious add-ons] which is meant for the mass mind set, who are incapable inquire to verifying their inherited beliefs. But for the seekers truth, to get the pure essence of spiritual Advaita of Sri Sankara and Sri, Goudpada which is based on the formless soul. The path of inquiry, analysis and reasoning on the true base, leads towards the non dual destination. Therefore, there is need to rectify the seeking base from ego base to soul base.
Bhagvan says: this self –inquiry is not the critical study of the scriptures. When the source is reached the ego gets merged into it. The result of self-inquiry is the cure for all the sorrows. It is the highest of all the results. There is nothing greater then it. It only indicates there is no necessity to study the scriptures to acquire self-knowledge or Brahma Gnana or Atma Gnana. (Page-66-practicle guide to know yourself c/e by A.R.N).
Bhagvan says:-
Q by D: Is not necessary to study the Vedas or at least the Prasthanatraya [the Bhagavad Gita,Dasopanishad and Brahma Sutras, all with commentaries]to ensure firm realization?
Bhagwan: No. Do you need all that to see yourself? All that is intellectual wealth, useful in explain doubts and difficulties if others rise them or if you yourself encounter them in the course of thinking. But to attain realzatrtion, all that is not necessary. You want fresh water to drink, but you do not require all the water of the river Ganges to quench your thirst. (Page 111/112 of Practical guide to know yourself c/e by A.R.N).
Therefore all the personal research is for making sure which is the surest and easiest path to acquire self-knowledge, when we are confused with uncertainty which path easier for to acquire non-dual truth or self-knowledge or Brahma Gnana or Atma Gnana.