The self is neither form, nor time, nor space. In order to grasp and assimilate the ultimate truth one has to know the witness of all these.
The self is seeking itself within the illusion. In ignorance it is unaware of its true nature. Until it holds itself as a person perceiving this world, which is a pitfall that has to be avoided by perfect understanding led by deeper inquiry, analysis and reasoning. All accumulated wealth of scriptural knowledge has to be dropped only then, one will be able to overcome the all the obstacles and able to grasp the nondual truth in lesser time and effort.
The pursuit of truth is a mental journey. Deeper inquiry, analysis and reasoning makes one aware of what truth is and what is untruth and only then the subconscious will be able to reject the untruth after knowing, what is Truth. Whatever prevails after rejecting the untruth mentally is the ultimate truth.
The universe, individual experience of birth, life and death, thoughts, words, pain and pleasure are part and parcel of the illusion. One has to overcome illusion by knowing the self in truth. The birth, life, death and universe are nothing to with the self, which is in the form of consciousness. But egocentric orthodox scriptural knowledge will not allow accepting anything other than their egocentric knowledge.
The path of orthodoxy is not straight. Their conduct based practices and concepts based on imagination mixing dual and nondualistic ideologies and indulging in Non-Vedic activities are great obstacles in pursuit of truth. Thus, shunning all of them is necessary for those who want the ultimate truth or wisdom.
Illusion contains the truth but without any things, forms and names. If seeker aspires for self-knowledge he has to shun the three states mentally by realizing the three states are mere mirage and realize the self as the formless substance and witness, of these three states. The formless substance and witness is the soul, which is in the form of the consciousness. Thus, consciousness alone is real and eternal. Therefore, one has to know the three states as mere mirage. The mirage contains his body and his experience of the world. And realize the mirage as consciousness because mirage is erupted out of consciousness to bring unity in diversity. The diversity is mere mirage created out of single stuff, which is consciousness. Thus everything is consciousness.
VlSHNUVARDHANA, the King of the Hoysalas, was a Vaishnavite and was greatly incensed at the doctrine taught by Sankaracharya that everything here below is an illusion. He wanted to teach the exponent of this doctrine a lesson. So he invited the then Sankaracharya to his palace. That holy man went there and stoutly maintained that everything in this world was illusion. The king had arranged to let loose an infuriated elephant against Sankaracharya. The beast rushed at Sankaracharya who took to a precipitate flight to save himself.
'Oh, Venerable Sir,' shouted the king, 'why do you run so fast seeing that the elephant is only an illusion?'
'Oh, king,' said Sankaracharya in his course of his flight, 'my running too is an illusion. Everything in this world is an illusion.’
Thus searching the truth in illusion with the illusory self, within the illusory experience, has to be illusion. The illusion is created, and sustained, and finally dissolves as Spirit, which is Soul/Self. Since, there is no second thing other than the Spirit or consciousness; the Spirit itself is God/ Brahman/Christ. This conviction can be derived only from deeper inquiry, analysis and reasoning.