[MannoFr]

Sankara: Your last suggestion is untenable, for mere mantric efficacy can be postulated only in the case of sounds like 'Hum, Phat' , etc. , which cannot convey any meaning at all. Now taking your other objections and granting the correctness of your first position that the Vedas must teach us something which we do not know already, the Upanishads are certainly of authority as they us the existence of God. God may be an existent Being but we do not know HIM to be existent: and, to teach us that, the Upanishads are necessary. Even if we know by any other means of knowledge that God exists, the Upanishads are of authority when they teach us a new fact that God and Self are identical, example 'Thou art That' in the teachings of Uddalaka to Svetaketu.

Mandana: They do not teach us any such identity. Why not understand the sentence as mere praise? The Self is said to be God, only as a piece of glorification of the individual Self, the performer of sacrifices.

Sankara: The difficutly is that the sacrifices find no mention in the context and we will be confusing two altogether distinct contexts if we give any such interpretation to the sentence.

Mandana: We may interpret the sentence as importing a command to contemplate on the individual Self as Brahman, just as in other places the sun, air, food etc are so directed to be contemplated upon as Brahman. If this interpretation is accepted, the other ingredient that I mentioned as necessary to clothe any statement with authority, namely, relatability to some action, is also secured.