Manduka Upanishad has no assumptions, whatever. It is an honest and a bold inquiry into truth. It rises above scripture.+

Sage Goudpada: he was the first historic Sage known to us to give a rational exposition of Advaita. He says that whatever is seen, whether external or internal, whether by the ordinary persons or yogis is unreal.

Non-causality is of the highest importance; that is why Sage Goudpada puts it at the end of his book and devotes 100 slokas to it whereas the other subjects get less than 50 slokas.

Manduka Upanishad has no assumptions, whatever. It is an honest and bold inquiry into truth. It rises above scripture.

Manduka Upanishad is not meant for all, as it is based entirely on the reasoning. Hence, only a few will be able to understand and assimilate it.

Manduka Upanishad:~

Atman is the highest Reality and its opposite: Note the word "and". Reality and illusion together make Brahman: nothing can be left out.  Page 51.

Brahman must be realized in the waking state when all objects are present in consciousness, otherwise, it is nonsense. Page 65: v.10.

"Sleep does not exist In Turiya”: This emphatically disproves the mystic use of sleep as an analogy for Brahman. Page 69.

This means that objects do not disappear, they are there, and yet they are non-dual. Disillusionment is not the same as appearance. Page 74. v. 17:

The essential message of Manduka is that the whole world, whatever is seen is only imagined.  Points out that even though it is harder for them, still women can attain Brahman just as men. Page 351

"From their notion": Everybody has his own imagination about facts and starts from that, instead of discarding his personal idea and looking at the fact. Page 333. V. 83 

"Soundless and of infinite sounds"; means both the waking and sleep world must be known, both objects and non-objects must be understood before the truth of Brahman is realized. Page 96. v. 29:

Manduka shows how one opinion may be used to contradict another so that both may be thrown away. Opinions are not for philosophy; they are as Ashtavakra says, merely thoughts; it wants the truth.

With deep sleep and anesthesia, you have non-duality, but no Gnana. Therefore,  there must be discrimination along with non-duality. Otherwise, sleeping dogs would be Gnanis. ~ (P.219)

Existence means existence in the sense of the Drik. When you reduce everything to consciousness, Drik, Gnana, or even Mind, giving up all imaginations in truth it is unborn. You see a man's body comes and goes, but that is not the same as seeing him come and go, which you can never do. P.300. V.45.

Sage Goudpada 's 3^rd chapter is devoted to proving the existence of Atman in order to distinguish it from the changeable objects in this world, but in the final 4th chapter P.33, verse 83, he discards that position and rejects even the idea of Atmanic existence. He then declares we may assert nothing about it. Not even existence or nonexistence i.e. silence alone is demanded by the truth. :~Santthosh Kumaar