What is accepted without proper enquiry will not lead a person to the final goal.

Advaita Sage, Sri, Sankara' gave religious, ritual or dogmatic instruction to the mass but pure philosophy only to the few who could rise to it. Hence the interpretation of his writings by commentators is often confusing because they mix up the two viewpoints. Thus they may assert that ritual is a means of realizing Brahman, which is absurd.

In commentary to "Brahma Sutras Sri, Sankara writes." "The highest beatitude is not to be attained by Yoga." [Sacred Books of East Series page 298 Vol.1.]   

This Atman cannot be attained through study of the Vedas, nor through intelligence, nor through much learning. He who chooses Atman—by him alone is Ataman attained. It is Atman that reveals to the seeker Its true nature.(3 page 70 upanhsds--by Nikilananda)

It means the truth is beyond scriptures and egocentric intelligence.  Thus in order to grasp, assimilate and realize the non-dualistic truth the seeker to employ soul-centric reasoning faculty. 

That is why Sri, Sankara says in commentary in Vedanta sutra that:-  What is accepted without proper enquiry will not lead a person to the final goal. On the contrary, such acceptance will result only in evil, in something which is detrimental to our spiritual progress.

Thus    Seeker of truth should not believe blindly in traditional orthodox non-duality without verifying all the facts from every angle. One has to reflect through reasoning over and over again without getting tired of the process.