To understand 'What is what' depends upon the medium through the  observer views it. In fact ,our mental and intellectual conditions will  determine  the three states observed and experienced. A Gnani views the  three states will see it differently from a ignorant viewing the same  three states.  Each one interprets the three states that he sees in term  of his existing knowledge.A  Gnani sees only  consciousness in all the  three states.     If one is seeking truth of his true existence then  there is need to understand, otherwise there is no need to understand  anything. The waking experience is the state of ignorance.  The one who  has the inner urge to know the truth searches  for it, others are  immersed in their practical life within the practical world  . Thus who  has inner urge for him there is a need to reach his destination.
People  who are caught up in intellectuality  think there is no need to do  anything on their own intellectual standpoint, but  one has to  understand, even inaction is also action. All action and inaction are  happening in the state of ignorance. Intellectuality is not wisdom. 
The  'I' is present only when the mind is present. The mind is present only  in waking or dream. The mind is absent when the waking or dream is  absent. the mind is in the form of universe, the universe appears as  waking and dream and disappears as deep sleep.  Limiting the mind to the  physical entity is cause of the the ignorance. Until one thinks the  mind is within the body he will never be able to cross the trashold  duality.   ‘I’ is not the self.   ‘I’ is mere illusion. I Am is the ego.
   Ego is the false entity within the false experience.   There is a need  to know “What is ‘I’? before proceeding in pursuit of truth.  The  deeper inquiry, analysis and reasoning reveal the fact that, ‘I’ is not  limited to the physical entity but to the whole experience of  diversity[universe].  Therefore limiting the ‘I’ to the physical entity  and viewing and judging the truth on base of false physical entity  within the false experience is erroneous. 
The  world is mere illusion/myth. Therefore, the birth, life and death,  which take place within the world, is also illusion.  The belief of god,  the religion and its scriptures are reality within the illusion.   Therefore, trying to get enlightenment on the base of physical entity,  which is limited to the world, will lead one to hallucinated  enlightenment, based on the imagination.
 
The god and guru are part of  the illusory world; therefore the devotee and disciple also are also  part of the illusion. Accepting the birth, life and death as reality, is  accepting the illusion as reality. Accepting illusion as reality is the  cause of the ignorance. Ignorance makes one feel the duality as  reality. The duality makes one feel he is an individual separate from  the world.  This separation makes one feel the birth, life and death as  reality.  The person who bases on the birth, life and death is trying to  find the meaning of life. There is no meaning or purpose of the life,  because the life is mere happening within the illusion.  Thus the karma  based on the physical entity is based on the birth, life and death,  which is part and parcel of the illusion.
All appearance has not appeared to the physical entity, but to the consciousness. Man and the world are mere appearance. That is, the illusion is mere appearance. Thus man cannot be considered as witness, since man and his experience of the world are within the illusion. Thus the witness of the illusion is within the illusion but it is apart from the illusion. It is with is within the illusion as its formless substance and it is apart from the illusion as its formless witness. The formless substance and witness is the consciousness. The consciousness is the true self. Realizing the consciousness as self is Self -Realization. Therefore, the consciousness alone is real and all else is mere illusion. By Learning to view and judge the truth on the base of consciousness as self will lead one to realize the fact that the man and the world are mere illusion.
Therefore, it is necessary to learn to view and judge the truth on the base of consciousness, to understand and assimilate the Self-Knowledge or Brahma Gnana or Atma Gnana . It is the though the consciousness one knows himself as a person and perceives the world. It is the consciousness, which is the author or knower of the three states, not the person who is limited to waking or dream.
A well-directed search will lead one to his non-dual destination. Trying to seek truth on the false entity or ego, one feels he is going round and round. Until one drops all the accumulated dross and stops interprets with his existing accumulated knowledge by holding it as yardstick, it becomes very difficult to understand assimilate and realize the non dual truth.
