Without knowing the nature of the universe, it is impossible to know the truth.

Without knowing the nature of the universe(mind), it is impossible to know the truth. It is of no use of trying to find the truth before one understands the nature of the universe. The world which confronts one is also consciousness itself therefore the world in which man exists is a mere mirage created out of consciousness, which is the innermost self. 

If one does not make his induction from facts from the world before him, the world of the five senses, he is only drawing on his imaginations. Then he says “The ‘Self’ is like this, or like that." but it will be only his imagination within the waking experience, which is mere illusion from ultimate standpoint. .

First seeker must inquire into the nature of the physical body i.e. Matter. Second he must inquire into the nature of the mind.

Most of the dualistic sages approach was more practical, and they stuck with the reality of the world, they took it as real. Whereas Sri, Sankara says: one must first know what is before him. If he cannot know that, what else can he know or understand? If he gives up the external world in his inquiry, he cannot get the whole truth.
Sage Sri, Sankara says- VC- 63. Without causing the objective universe to vanish and without knowing the truth of the Self, how is one to achieve Liberation by the mere utterance of the word Brahman? — It would result merely in an effort of speech..

By studying various scriptures one cannot be established in the true self, which is consciousness [soul] unless he drops all accumulated knowledge. Scriptures and yoga are preliminary steps but they are not the means to acquire self-knowledge or non-dual truth.

Getting certainty and irrefutable proof of our true existence without dogmatic assertion and assumption and speculation is the attitude of true seeker. One has to know the self in the truth.

All the study of scriptures and texts and teachings has to be dropped when one becomes aware of the fact that, the self is not physical but self is the soul (consciousness). One must think of always of the soul (consciousness) the witness of the three states; rather than the three states.

One may enjoy work or practice meditation but he will still yarn of that which is beyond all imagination ,all thinking and the objects and in which all the desire are extinguished. The subconscious goal of one’s search can only be non-duality.