You are the false self(ego or waking entity) within the false experience(waking) bound by birth, life and death and form, time and space whereas the ‘Self ‘ is birthless and deathless because it is formless.

It is not the body, which is trying to know the truth. Because the body and the world are one in essence. that essence is consciousness.   The consciousness(soul)   is the innermost self.  soul or consciousness is the formless knower of the body including the world. The  formless soul, innermost self is in ignorance of its own true nature within the illusion,which is present in the form of waking experience. thus as waking entity(ego) it is trying to know the truth to free itself from the bondage of illusory experience of birth,life,death and the world.

Till   the waking entity discovers the fact that it itself is not the self it will experience the illusory duality as reality. 

Only when waking entity   becomes aware of the fact that  it itself is not the self but the self is the formless  soul  then it realizes its body, ego and the experience of the world are mere mirage created out of consciousness. 

The mind is not limited to the  waking entity but mind is whole waking experience. Therefore, the man and his experience of the world are within the mind. Therefore, considering the mind as an invisible organ within the physical body is erroneous. Thinking the mind is within the physical body causes ignorance. Therefore, deeper self-search is needed in order to unfold the mystery of the mind or universe. 

It very much necessary for you to realize :- Self is not ‘you’ but the self is that witnesses ‘you and the world’ together without the physical apparatus.  You are the false self(ego or waking entity) within the false experience(waking) bound by birth, life and death and form, time and space whereas the ‘Self ‘ is birthless and deathless because it is formless.  Thus self is not limited to waking state alone because it pervades in everything and everywhere in all the three states.   Thus limiting the ‘self’ to waking entity alone is cause of the ignorance.  

The dream entity (you) and the dream world becomes falsehood when waking takes place. Similarly the waking entity (you) and the waking world become falsehood when wisdom dawns.  Wisdom dawns when waking entity (you) realizes it itself is not the self but the self is that which witnesses the coming and going of the three states.   The witness and the three states are one in essence. That essence is consciousness (Atman). Thus consciousness is ultimate truth or Brahman. Atman is second to none.  

Thus one has to know ‘What is mind? ‘What is the substance of the mind?’  and ‘What is the source of the mind?’ in order to realize the non-dualistic or Advaitic truth.