Where does Adi Shankaracharya explain the meanings of "Shruti" and "Smriti"?

Question

I came across this quote of Shankaracharya:

Shankarāchārya says, "Shruti is a means of direct perception [in the sphere of transcendent knowledge], since, in order to be an authority it is necessarily independent of all other authorities; while Smriti plays a part that is analogous to induction, in that it derives its authority from an authority other than itself."

What's the source of this quote?

Edit: I want the source from Shankara's works. Because the author has claimed that Shankara has said this. I want to verify this.

I'm also interested in scholarly content* that compares the authority of Shruti and Smriti. Does Smriti have less authority or the same authority in comparison with shruti?

Answer 1

The classification of scripture into Sruti (heard, revealed; i.e. Vedas, as the Vedas are revealed from God directly) and Smriti (written by men) is much earlier than Shankaracharya. Shankaracharya is not the one that made the classification. One of the earliest references is Manu Smriti. Manu writes in 2.10:

But my Sruti (revelation) is meant the Veda, and by Smriti (tradition) the Institutes of the sacred law; those two must not be called into question in any matter, since from those two the sacred law [dharma] shone forth.

In his commentary to Brahma Sutras verse 1.2.25 Shankaracharya says (Swami Vireswarananda translator, available here - https://www.wisdomlib.org/hinduism/book/brahma-sutras):

The Smritis are interpretations of Sruti texts. So when a doubt arises as to the meaning of a Sruti the former may be consulted to throw light on the subject...

And in Brahma Sutras 2.1.1, the Brahma Sutra text itself refutes Smritis that are not based on Sruti.