Advaita (non-duality) and dvaita (duality) is the state of the Soul, the Self.+

Advaita (non-duality) and dvaita (duality) is the state of the Soul, the innermost  Self. It is not some intellectual theory. Orthodox Advaitins believe the Atman (Soul) is Brahman, and the world is an illusion. Religious dvaitins believe, the body as the Self, they believe the world is a reality, and they believe in creator and creation theory.   

In India Advaita and Dvita is mere a religious tradition, which they inherited from their ancestors. No one questions their validity because it is considered blasphemy to question any guru and god-men or pundits.

 People who are attached to their religious code of conduct and trying to preach Advaita, that is mixing the individual life, and the concept of God, and all mixed up hotchpotch religious doctrine and feed the seeking minds, are themselves not aware of the fact that the individuality and the worldly life is part of the illusion.

The Buddha must have verified religion, the Vedas, and the concept of God and found them inadequate and useless in the pursuit of truth and rejected them and he got enlightened without the aid of religion, the Vedas, and the concept of God. 

After studying and going through all the rigorous training from the religious scholars in the Theosophical Society, J.K was confused about all these, and when he started verifying with deeper introspection, he found everything was priest-crafted hotchpotch ideologies. Thus, he refused to become the world guru, rejected it, and walked out and condemned the priestcraft.  

In Orthodox Advaita, they accept karma theory.  If they accept the karma theory, one will not be able to reach the nondual destination. 

If one accepts karma theory then it is impossible to treat the world as an illusion. All the pundits’ explanation of karma theory carries no weight in the realm of truth because if karma is accepted they are accepting the false self (ego or body) as the true Self and false experience (universe or waking) as a reality.

Sage Sankara says:~ Karma is not competent to remove ignorance, for it is not opposed to it. It does not matter in what way we characterize ignorance, whether as the absence of knowledge or as doubt, or as erroneous knowledge. It is always removable by knowledge, but not by action in any of its forms, for there is no contradiction between ignorance and karma. (Commentary on   Brah.3-3-1 )

Birth, life, and death are part of the waking experience, which is merely an illusion from the standpoint of the true self.  It is no use of saying that, we are not born, we do not die because we all were born and we all are going to die. However, birth, life, and death are part of the illusion, which comes and goes as the waking experience.  The formless witness of the three states is real, which is our identity has no birth and death. That is why self-knowledge is nothing to do with the religious-based Advaita, which is based on non-Vedic beliefs.  :~Santthosh Kumaar