When the serious seeker reaches a stage with all his baggage of accumulated knowledge, then uncertainty haunts him. Whether he is right?" Where is the certainty that he is proceeding on the right lines?

Doubts and Confusions arise when the seeker finds the scriptures and yoga are inadequate or useless to quench his spiritual thirst.   Disappointments in religion or yoga or even science implies error or ignorance.

When the serious seeker reaches a stage with all his baggage of accumulated knowledge, then uncertainty haunts him.  Whether he is right?" Where is the certainty that he is proceeding on the right lines?" Thus doubts arise and the inquiring spirit comes and impels to search elsewhere for truth where it will not be possible even to have doubt. The test is therefore in experience. And only in non-duality, where there are no two to argue about views or to have a difference of opinion can such doubtlessness be possible.  Belief depends upon unstable bases whereas certainty depends on proof.

Most think Consciousness usually implies something, thoughts or things, but it is the formless nondual nature of the Ataman or the soul. 

The consciousness exists with or without the matter because without the consciousness the matter ceases to exist because the matter is created out of consciousness.  . It exists as a matter in waking or dream.   And when wisdom dawns it is consciously aware of its formless nondual true nature in the midst of matter, as in deep sleep.

Proof is the main thing in pursuit of truth, "How can God exists without man’s existence?” how can the world exist without man’s existence. Thus man has to exist first to say god and the world exists.  Thus seeker has to verify about his own existence to realize the fact that, all the three states are unreal, on the standpoint of the formless witness, which is the soul, the innermost self.