Ego cannot be dropped until and unless one realizes what is mind.

Ego cannot be dropped until and unless one realizes 'What is mind?' and 'What is substance of the mind?' and 'What is the source of the mind?'. Ego, body and the world appear together and disappear together. When the mind is there then the ego, body and the world are there. It is not the person, who is the false entity, within the false experience has to drop the falsehood. Only non-dual wisdom frees one from experiencing the duality as reality. 

It is impossible to drop the ego with the ego. The ego is the physical entity which perceives the world within the waking or dream. The true self pervades in everything and everywhere in the world, which exists in the waking or dream as their formless substance and witness.

  The soul, the innermost self  is not an entity or identity within the waking or dream. Thus basing our understanding on the false self will lead us towards falsehood or hallucination. Until we mentally grasp the formless witness of the three states and base our understanding on the true self, it is impossible to assimilate the Self-knowledge or Brahma Gnana or Atma Gnana. 

Only when the formless witness is grasped then only it is possible to realize the fact that the true self is the soul and drop the mirage (three states) mentally. Whatever prevails without the three states is the substance and witness of the three states. The soul, the innermost self  remain with or without the waking/dream. When it is without the waking or dream we call it deep sleep or death. Deep sleep is not the self but the formless knower of the deep sleep is the true self.

Through, physical efforts like yoga, virtues and mediation it is not possible to assimilate the truth. It is mental effort through deeper understanding through inquiry, analysis and reasoning on the base of true self ,one becomes aware the whole universe(diversity or duality) including all it contents are mere illusion created out of spirit or consciousness or soul. Thus there is no second thing exists other then the spirit or consciousness or soul. Thus, the man and his experience of the world (waking)are mere mirage. The dream becomes unreal when waking takes place and waking becomes unreal when the wisdom dawns.

The wisdom does not dawn by practices based on the ego. One has to realize the fact that the ego is not the self, thus whatever is seen, known, believed, accumulated understanding and experienced on the base of ego is bound to be false. Thus, it is necessary to learn to view and judge and conclude the understanding on the formless witness(soul) in order to understand and assimilate the Self-knowledge or Brahma Gnana or Atma Gnana.  .

Seeker on his own has to verify the validity of every claim through deeper inquiry, analysis and reasoning and accept only un-contradictable truth.