Ashtavakra Gita: ~ It is not the absence of Buddhi (Reason) that can grasp Advaita, but the man who possesses the highest intellect.

When the invisble and unborn Soul, the Self, is a formless, timeless, and spaceless existence, then the body (brain) and the world are merely an illusion. 

The world in which you exist exists only in the domain of form, time, and space.

The world in which you exist ceases without form, time, and space.

The truth- realization is possible only through perfect understanding and assimilation.

The reasoning base has to be rectified from (I) form to formless (I-LESS-Soul) to unfold the mystery of the universe.

When the 'Self' is not you but the invisble Soul, then it is erroneous to judge and reason, and conclude the truth as you.

You are the false self (ego) within the false experience (waking).

Just as the body and the world in a dream are superimposed on the invisble Soul, which is present in the form of consciousness and therefore illusory, so is this body and the world within the waking experience superimposed on the invisble  Soul, the Self, which is present in the form of consciousness.

In deep sleep, the invisble Soul, the Self, remains in its own awareness; it is free from the illusory superimposition of form, time, and space.

Eradicating ignorance completely is necessary. And this is possible only through Self-knowledge or Brahma Gnana or Atma Gnana.

Thus, there is no other road to freedom other than Gnana. There is no other entrance other than except Gnana. Ignorance will vanish only when the nondual wisdom dawns. : ~ Santthosh Kumaar