Role of Reasoning in Vedanta

Vedānta certainly uses reasoning, but it does not treat Brahman as something produced or arrived at by reasoning alone.

The method can appear discursive and analytical. But the pramāṇa is śruti.

And the recognition is immediate.

This is the important distinction between independent philosophical speculation (only observation and dependent logic) and śruti-anugṛhīta tarka, reasoning guided by the Upaniṣads.

Ordinary reasoning tries to reach truth through conceptual analysis, inference, or intellectual construction. Vedāntic reasoning functions differently. It operates within the vision unfolded by the Upaniṣads, and its purpose is not to “discover” Brahman as some unknown object, but to remove mistaken identification.

Take pañca kośa viveka for example. It is analytical in method, but revelatory in function. 

The inquiry negates identification with the body, prāṇa, mind, intellect, and even ānandamaya. But this negation is not meant to infer some distant metaphysical entity called Brahman. Rather, it helps reveal the ever-present sākṣī, the self-revealing consciousness that was never absent.

In that sense, the Self is never newly cognized. It is always present as the very consciousness because of which every experience, thought, and act of reasoning is known.

(bodham bodham prati viditam)

What is “fresh/novel” is only the recognition through śruti, that this already self-evident “I” is not the finite jīva, but Brahman itself.

(Think Mahāvākyā)

So the shift is not from “not knowing the Self” to “knowing the Self” as though the Self were an object newly discovered.

Rather, it is from: “I am this limited body-mind individual” 

to

 “This very self-revealing consciousness is Brahman.”

Thus, the Self is ever evident.

The error is misidentification.

Śruti removes the error.

Vedantic reasoning assists by helping the mind assimilate the vision of śruti.