The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
21. That which possesses the attributes of invisibility and so on (is Brahman), on account of the declaration of attributes.
Scripture says, 'The higher knowledge is this by which the Indestructible is apprehended. That which cannot be seen nor seized, which is without origin and qualities, without eyes and ears, without hands and feet, the eternal, all-pervading, omnipresent, infinitesimal, that which is imperishable, that it is which the wise regard as the source of all beings' (Mu. Up. I, 1, 5; 6).--Here the doubt arises whether the source of all beings which is spoken of as characterised by invisibility, &c. be the prâdhana, or the embodied soul, or the highest Lord.
We must, the pûrvapakshin says, understand by the source of all beings the non-intelligent prâdhana because (in the passage immediately subsequent to the one quoted) only non-intelligent beings are mentioned as parallel instances. 'As the spider sends forth and draws in its thread, as plants grow on the earth, as from the living man hairs spring forth on the head and the body, thus everything arises here from the Indestructible.--But, it
may be objected, men and spiders which are here quoted as parallel instances are of intelligent nature.--No, the pûrvapakshin replies; for the intelligent being as such is not the source of the threads and the hair, but everybody knows that the non-intelligent body of the spider ruled by intelligence is the source of the threads; and so in the case of man also.--While, moreover, in the case of the preceding Sûtra, the pradhâna hypothesis could not be accepted, because, although some qualities mentioned, such as invisibility and so on, agreed with it, others such as being the seer and the like did not; we have here to do only with attributes such as invisibility which agree with the pradhâna, no attribute of a contrary nature being mentioned.--But the qualities mentioned in the complementary passage (Mu. Up. I, 1, 9), 'He who knows all and perceives all,' do not agree with the non-intelligent pradhâna; how, then, can the source of all beings be interpreted to mean the pradhâna?--To this the pûrvapakshin replies: The passage, 'The higher knowledge is that by which the Indestructible is apprehended, that which cannot be seen,' &c., points, by means of the term 'the Indestructible,' to the source of all beings characterised by invisibility and similar attributes. This same 'Indestructible' is again mentioned later on in the passage, 'It is higher than the high Imperishable.' Now that which in this latter passage is spoken of as higher than the Imperishable may possess the qualities of knowing and perceiving everything, while the pradhâna denoted by the term 'the Imperishable' is the source of all beings.--If, however, the word 'source' (yoni) be taken in the sense of operative cause, we may by 'the source of the beings' understand the embodied Self also, which, by means of merit and demerit, is the cause of the origin of the complex of things.
To this we make the following reply.--That which here is spoken of as the source of all beings, distinguished by such qualities as invisibility and so on, can be the highest Lord only, nothing else.--Whereupon is this conclusion founded?--On the statement of attributes. For the clause, 'He who is all-knowing, all-perceiving,' clearly states an
attribute belonging to the highest Lord only, since the attributes of knowing all and perceiving all cannot be predicated either of the non-intelligent pradhâna or the embodied soul whose power of sight is narrowed by its limiting conditions. To the objection that the qualities of knowing and perceiving all are, in the passage under discussion, attributed to that which is higher than the source of all beings--which latter is denoted by the term 'the Imperishable'--not to the source itself, we reply that this explanation is inadmissible because the source of all beings, which--in the clause, 'From the Indestructible everything here arises'--is designated as the material cause of all created beings, is later on spoken of as all-knowing, and again as the cause of all created beings, viz. in the passage (I, 1, 9), 'From him who knows all and perceives all, whose brooding consists of knowledge, from him is born that Brahman, name, form, and food.' As therefore the Indestructible which forms the general topic of discussion is, owing to the identity of designation, recognised (as being referred to in the later passage also), we understand that it is the same Indestructible to which the attributes of knowing and perceiving all are ascribed.--We further maintain that also the passage, 'Higher than the high Imperishable,' does not refer to any being different from the imperishable source of all beings which is the general topic of discussion. We conclude this from the circumstance that the passage, 'He truly told that knowledge of Brahman through which he knows the imperishable true person,' (I, 2, 13; which passage leads on to the passage about that which is higher than the Imperishable,) merely declares that the imperishable source of all beings, distinguished by invisibility and the like--which formed the subject of the preceding chapter--will be discussed. The reason why that imperishable source is called higher than the high Imperishable, we shall explain under the next Sûtra.--Moreover, two kinds of knowledge are enjoined there (in the Upanishad), a lower and a higher one. Of the lower one it is said that it comprises the Rig-veda and so on, and then the text continues, 'The higher knowledge
is that by which the Indestructible is apprehended.' Here the Indestructible is declared to be the subject of the higher knowledge. If we now were to assume that the Indestructible distinguished by invisibility and like qualities is something different from the highest Lord, the knowledge referring to it would not be the higher one. For the distinction of lower and higher knowledge is made on account of the diversity of their results, the former leading to mere worldly exaltation, the latter to absolute bliss; and nobody would assume absolute bliss to result from the knowledge of the pradhâna.--Moreover, as on the view we are controverting the highest Self would be assumed to be something higher than the imperishable source of all beings, three kinds of knowledge would have to be acknowledged, while the text expressly speaks of two kinds only.--Further, the reference to the knowledge of everything being implied in the knowledge of one thing--which is contained in the passage (I, 1, 3), 'Sir, what is that through which if it is known everything else becomes known?'--is possible only if the allusion is to Brahman the Self of all, and not either to the pradhâna which comprises only what is non-intelligent or to the enjoyer viewed apart from the objects of enjoyment.--The text, moreover, by introducing the knowledge of Brahman as the chief subject-which it does in the passage (I, 1, 1), 'He told the knowledge of Brahman, the foundation of all knowledge, to his eldest son Atharvan'--and by afterwards declaring that out of the two kinds of knowledge, viz. the lower one and the higher one, the higher one leads to the comprehension of the Imperishable, shows that the knowledge of the Imperishable is the knowledge of Brahman. On the other hand, the term 'knowledge of Brahman' would become meaningless if that Imperishable which is to be comprehended by means of it were not Brahman. The lower knowledge of works which comprises the Rig-veda, and so on, is mentioned preliminarily to the knowledge of Brahman for the mere purpose of glorifying the latter; as appears from the passages in which it (the lower knowledge) is spoken of slightingly, such as (I, 2, 7), 'But frail
indeed are those boats, the sacrifices, the eighteen in which this lower ceremonial has been told. Fools who praise this as the highest good are subject again and again to old age and death.' After these slighting remarks the text declares that he who turns away from the lower knowledge is prepared for the highest one (I, 2, 12), 'Let a Brhâmana after he has examined all these worlds which are gained by works acquire freedom from all desires. Nothing that is eternal (not made) can be gained by what is not eternal (made). Let him in order to understand this take fuel in his hand and approach a guru who is learned and dwells entirely in Brahman.'--The remark that, because the earth and other non-intelligent things are adduced as parallel instances, that also which is compared to them, viz. the source of all beings must be non-intelligent, is without foundation, since it is not necessary that two things of which one is compared to the other should be of absolutely the same nature. The things, moreover, to which the source of all beings is compared, viz. the earth and the like, are material, while nobody would assume the source of all beings to be material.--For all these reasons the source of all beings, which possesses the attributes of invisibility and so on, is the highest Lord.