The one which witnesses the appearance and disappearance is not ‘I’ because the ‘I’ appears and disappears.+

The ‘I’ appears on its own it perishes on its own.  The ‘I’ is not the cause of the appearance and disappearance because the ‘I’ itself is the appearance.  

The ‘Self’ not ‘I’, but the ‘Self’ is the Soul, which is present in the form of consciousness.

The one which witnesses the appearance and disappearance is not ‘I’ because the ‘I’ appears and disappears.  

The one which is aware of the appearance and disappearance ‘I’ is the Soul, which is present in the form of consciousness.    

Realize, ‘what is this ‘I’ is supposed to be in actuality’ and what is hidden by the ‘I’ will be revealed.

If you realize the ‘Self ‘not the ‘I’ but the Soul then whatever is hidden by the ‘I’   will be revealed.

Realizing the Soul is not the ‘I’ but the Soul is the Self, is Self –realization.

That is why Bhagavad Gita: ~ The permanent is always there, only the transient ‘I’ comes and goes. (2.18)

The ‘I’ hides the Soul, the Self, which is present in the form of consciousness. 

People think the ‘I’ without the body is the Self. The seeker has to understand the fact that ‘I’ is not the Self, but the witness of the ‘I’ is the true Self, which is eternal. 

That is why Ashtavakra Gita 16:10:~ If you desire liberation, but you still say 'I'  if you feel the ‘Self’ is the ‘I’, you are not a wise man or a seeker. You are simply a man who suffers. 

People are stuck with the reality of the ‘I’, which they take it as real because some Gurus have propagated the Self is the ‘I’. There is no need to convince such a mindset. The seeker of truth accepts only the truth nothing but the truth. 

Perfect understanding and assimilation of ‘what is what’ lead to Advaitic Self-awareness. : ~ Santthosh Kumaar