When one realizes the fact that , the thinker of the thoughts are one is essence, than one do get consciousness or Brahman

When formless witness witnesses the waking experience and its attention is fixed to the waking experience, which is an object to it, than it is in ignorance of its formless non-dual true nature and it is in forgetfulness of its own formless non-dual true nature. Same thing is applied to the dream. But when formless witness is free from waking and dream it is in its formless non-dual true nature, which identified as deep sleep in the waking experience, which is the state of ignorance.   Till waking entity traces the formless witness mentally and realizes it itself is not the self but the formless witness, which is in the form of consciousness is the true self, the wisdom will not dawn.  

When one puts aside the imagination and has the thinker-- what does he get with thinking—he can get only a thought. Meditation is only an effort of the ego within the illusion; it is imagination based on the false self; the consciousness remaining the same with or without ideas.

When one is absorbed in thinking of anything, he forgets the subject, which consciousness the innermost self, that which witnesses all the coming and going of the three states in succession.

One may think for hundred hours continuously but it is all thoughts, hence not consciousness. When one realizes the fact that ,  the thinker of the thoughts are one is essence,  than one do get consciousness or Brahman , the knower, the formless witness of the three states. Consciousness the innermost self is the eternal.

One has to get rid of his doubts, But that did not mean, simply go and believe everything he is told. The doubt is to be got rid of "by the sword of wisdom.