Early in his commentary (bhasya) on the Brahma Sutras of Badarayana, Shankaracarya, the greatest sage of the Advaita Vedanta, offers a theory about the Brahman-world relation, and our knowledge of it.
The second of 555 sutras reads as follows: “(Brahman is that) from which the origin, &c. (i.e. the origin, subsistence, and dissolution) of this (world proceed)” (1.1.2). Shankara comments, “The full sense of the Sûtra therefore is: That omniscient, omnipotent cause from which proceed the origin, subsistence, and dissolution of this world–which world is differentiated by names and forms, contains many agents and enjoyers, is the abode of the fruits of actions, these fruits having their definite places, times, and causes, and the nature of whose arrangement cannot even be conceived by the mind,–that cause, we say, is Brahman…The origin, &c. of a world possessing the attributes stated above cannot possibly proceed from anything else but a Lord possessing the stated qualities,” though Shankara insists that neither he nor the Sutra is proving this by reason, but in fact is simply commenting on “Scripture” (the Upanishads) (1.1.2).
He grants that, in principle, “inference also, being an instrument of right knowledge in so far as it does not contradict the Vedânta-texts, is not to be excluded as a means of confirming the meaning ascertained,” but that in this case, “as Brahman is not an object of the senses, it has no connection with those other means of knowledge. For the senses have, according to their nature, only external things for their objects, not Brahman. If Brahman were an object of the senses, we might perceive that the world is connected with Brahman as its effect; but as the effect only (i.e. the world) is perceived, it is impossible to decide (through perception) whether it is connected with Brahman or something else” (1.1.2).
Shankara here rejects so-called “cosmological” (or a posteriori) proofs for the existence of God (assuming, for the moment, some kind of equivalence between Brahman- and God-talk), using arguments similar to those that Kant would later deploy in the Antinomies of Pure Reason in the first Critique. (Both take it that “cause-talk” is meaningful only within the world, and can’t in any meaningful sense be applied to the world as a whole.) Since such proofs fail, we must conclude that “the Sûtra under discussion is not meant to propound inference (as the means of knowing Brahman), but rather to set forth a Vedânta-text” (1.1.2). Here, he goes beyond the critique of inferences from the world to Brahman, and argues that, since the world possesses no (so to speak) Anknupfungspunkt with Brahman, we can only grasp its mode of dependence on Brahman by way of special revelation — in this case, the Upanishads.
Francis Clooney summarizes this passage as follows: “By itself the sutra appears to describe Brahman in terms general enough to allow for inference, and opens the way to such reasoning. Shankara accordingly declares that only Brahman, the Lord, can be an adequate source for the complex and varied world we observe around us…But then, one might argue, if Brahman is in fact the cause of this observable world, one should be able to draw an inference from the world, the effect, regarding Brahman as cause…Shankara rejects this inference, though he has no problem with its conclusion. He insists that there is a unique textual basis for saving knowledge; UMS [= the Brahma Sutras] 1.1.2 does not mean that Brahman is a source that can be inferred; rather, it tells us that the word ‘Brahman’ is designated to the useful name of what we learn from the upanishadic texts” (Theology after Vedanta, 97-98).
As I said at the top: so far, so Barthian!