The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
5. On account of seeing (i. e. thinking being attributed in the Upanishads to the cause of the world; the pradhâna) is not (to be identified with the cause indicated by the Upanishads; for) it is not founded on Scripture.
It is impossible to find room in the Vedânta-texts for the non-intelligent pradhâna, the fiction of the Sânkhyas; because it is not founded on Scripture. How so? Because the quality of seeing, i. e. thinking, is in Scripture ascribed to the cause. For the passage, Kh. Up. VI, 2, (which begins: 'Being only, my dear, this was in the beginning, one only, without a second,' and goes on, 'It thought (saw),
may I be many, may I grow forth. It sent forth fire,') declares that this world differentiated by name and form, which is there denoted by the word 'this,' was before its origination identical with the Self of that which is and that the principle denoted by the term 'the being' (or 'that which is') sent forth fire and the other elements after having thought. The following passage also ('Verily in the beginning all this was Self, one only; there was nothing else blinking whatsoever. He thought, shall I send forth worlds? He sent forth these worlds,' Ait. Âr. II, 4, 1, 2) declares the creation to have had thought for its antecedent. In another passage also (Pr. Up. VI, 3) it is said of the person of sixteen parts, 'He thought, &c. He sent forth Prâna.' By 'seeing' (i.e. the verb 'seeing' exhibited in the Sûtra) is not meant that particular verb only, but any verbs which have a cognate sense; just as the verb 'to sacrifice' is used to denote any kind of offering. Therefore other passages also whose purport it is to intimate that an all-knowing Lord is the cause of the world are to be quoted here, as, for instance, Mu. Up. I,.1, 9, 'From him who perceives all and who knows all, whose brooding consists of knowledge, from him is born that Brahman, name and form and food.'
The argumentation of the Sânkhyas that the pradhâna may be called all-knowing on account of knowledge constituting an attribute of the guna Goodness is inadmissible. For as in the pradhâna-condition the three gunas are in a state of equipoise, knowledge which is a quality of Goodness only is not possible 1. Nor can we admit the explanation that the pradhâna is all-knowing because endowed with the capacity for all knowledge. For if, in the condition of equipoise of the gunas, we term the pradhâna all-knowing with reference to the power of knowledge residing in Goodness, we must likewise term it little-knowing, with reference to the power impeding knowledge which resides in Passion and Darkness.
[paragraph continues] Moreover a modification of Goodness which is not connected with a witnessing (observing) principle (sâkshin) is not called knowledge, and the non-intelligent pradhâna is destitute of such a principle. It is therefore impossible to ascribe to the pradhâna all-knowingness. The case of the Yogins finally does not apply to the point under consideration; for as they possess intelligence, they may, owing to an excess of Goodness in their nature, rise to omniscience 1.--Well then (say those Sânkhyas who believe in the existence of a Lord) let us assume that the pradhâna possesses the quality of knowledge owing to the witnessing principle (the Lord), just as the quality of burning is imparted to an iron ball by fire.--No, we reply; for if this were so, it would be more reasonable to assume that that which is the cause of the pradhâna having the quality of thought i.e. the all-knowing primary Brahman itself is the cause of the world.
The objection that to Brahman also all-knowingness in its primary sense cannot be ascribed because, if the activity of cognition were permanent, Brahman could not be considered as independent with regard to it, we refute as follows. In what way, we ask the Sânkhya, is Brahman's all-knowingness interfered with by a permanent cognitional activity? To maintain that he, who possesses eternal knowledge capable to throw light on all objects, is not all-knowing, is contradictory. If his knowledge were considered non-permanent, he would know sometimes, and sometimes he would not know; from which it would follow indeed that he is not all-knowing. This fault is however avoided if we admit Brahman's knowledge to be permanent.--But, it may be objected, on this latter alternative the knower cannot be designated as independent with reference to the act of knowing.--Why not? we reply; the sun also, although his heat and light are permanent, is nevertheless designated as independent
when we say, 'he burns, he gives light 1.'--But, it will again be objected, we say that the sun burns or gives light when he stands in relation to some object to be heated or illuminated; Brahman, on the other hand, stands, before the creation of the world, in no relation to any object of knowledge. The cases are therefore not parallel.--This objection too, we reply, is not valid; for as a matter of fact we speak of the Sun as an agent, saying 'the sun shines' even without reference to any object illuminated by him, and hence Brahman also may be spoken of as an agent, in such passages as 'it thought,' &c., even without reference to any object of knowledge. If, however, an object is supposed to be required ('knowing' being a transitive verb while 'shining' is intransitive), the texts ascribing thought to Brahman will fit all the better.--What then is that object to which the knowledge of the Lord can refer previously to the origin of the world?--Name and form, we reply, which can be defined neither as being identical with Brahman nor as different from it, unevolved but about to be evolved. For if, as the adherents of the Yoga-sâstra assume, the Yogins have a perceptive knowledge of the past and the future through the favour of the Lord; in what terms shall we have to speak of the eternal cognition of the ever pure Lord himself, whose objects are the creation, subsistence, and dissolution of the world! The objection that Brahman, previously to the origin of the world, is not able to think because it is not connected with a body, &c. does not apply; for Brahman, whose nature is eternal cognition--as the sun's nature is eternal luminousness--
can impossibly stand in need of any instruments of knowledge. The transmigrating soul (samsârin) indeed, which is under the sway of Nescience, &c., may require a body in order that knowledge may arise in it; but not so the Lord, who is free from all impediments of knowledge. The two following Mantras also declare that the Lord does not require a body, and that his knowledge is without any obstructions. 'There is no effect and no instrument known of him, no one is seen like unto him or better; his high power is revealed as manifold, as inherent, acting as knowledge and force.' 'Grasping without hands, hasting without feet, he sees without eyes, he hears without ears. He knows what can be known, but no one knows him; they call him the first, the great person' (Sv. Up. VI, 8; III, 19).
But, to raise a new objection, there exists no transmigrating soul different from the Lord and obstructed by impediments of knowledge; for Sruti expressly declares that 'there is no other seer but he; there is no other knower but he' (Bri. Up. Ill, 7, 23). How then can it be said that the origination of knowledge in the transmigrating soul depends on a body, while it does not do so in the case of the Lord?--True, we reply. There is in reality no transmigrating soul different from the Lord. Still the connexion (of the Lord) with limiting adjuncts, consisting of bodies and so on, is assumed, just as we assume the ether to enter into connexion with divers limiting adjuncts such as jars, pots, caves, and the like. And just as in consequence of connexion of the latter kind such conceptions and terms as 'the hollow (space) of a jar,' &c. are generally current, although the space inside a jar is not really different from universal space, and just as in consequence thereof there generally prevails the false notion that there are different spaces such as the space of a jar and so on; so there prevails likewise the false notion that the Lord and the transmigrating soul are different; a notion due to the non-discrimination of the (unreal) connexion of the soul with the limiting conditions, consisting of the body and so on. That the Self, although in reality the only existence, imparts the quality of Selfhood to bodies and the like
which are Not-Self is a matter of observation, and is due to mere wrong conception, which depends in its turn on antecedent wrong conception. And the consequence of the soul thus involving itself in the transmigratory state is that its thought depends on a body and the like.
The averment that the pradhâna, because consisting of several elements, can, like clay and similar substances, occupy the place of a cause while the uncompounded Brahman cannot do so, is refuted by the fact of the pradhâna not basing on Scripture. That, moreover, it is possible to establish by argumentation the causality of Brahman, but not of the pradhâna and similar principles, the Sûtrakâra will set forth in the second Adhyâya (II, I, 4, &c.).
Here the Sânkhya comes forward with a new objection. The difficulty stated by you, he says, viz. that the non-intelligent pradhâna cannot be the cause of the world, because thought is ascribed to the latter in the sacred texts, can be got over in another way also, viz. on the ground that non-intelligent things are sometimes figuratively spoken of as intelligent beings. We observe, for instance, that people say of a river-bank about to fall, 'the bank is inclined to fall (pipatishati),' and thus speak of a non-intelligent bank as if it possessed intelligence. So the pradhâna also, although non-intelligent, may, when about to create, be figuratively spoken of as thinking. Just as in ordinary life some intelligent person after having bathed, and dined, and formed the purpose of driving in the afternoon to his village, necessarily acts according to his purpose, so the pradhâna also acts by the necessity of its own nature, when transforming itself into the so-called great principle and the subsequent forms of evolution; it may therefore figuratively be spoken of as intelligent.--But what reason have you for setting aside the primary meaning of the word 'thought' and for taking it in a figurative sense?--The observation, the Sânkhya replies, that fire and water also are figuratively spoken of as intelligent beings in the two following scriptural passages, 'That fire thought; that water thought' (Kh. Up. VI, 2, 3; 4). We therefrom conclude that thought is to be taken in a figurative sense there
also where Being (Sat) is the agent, because it is mentioned in a chapter where (thought) is generally taken in a figurative sense 1.
To this argumentation of the Sânkhya the next Sutra replies:
48:1 Knowledge can arise only where Goodness is predominant, not where the three qualities mutually counterbalance one another.
49:1 The excess of Sattva in the Yogin would not enable him to rise to omniscience if he did not possess an intelligent principle independent of Sattva.
50:1 Ânanda Giri comments as follows: paroktânupapattim nirasitum prikkhati idam iti. Prakrityarthâbhâvât pratyayârthâbhâvâd vâ brahmano sarvagñateti prasnam eva prakatayati katham iti. Prathamam pratyâha yasyeti. Uktam vyatirekadvârâ vivrinoti anityatve hîti. Dvîtiyam sankate gñâneti. Svato nityasyâpi gñânasya tattadarthâvakkhinnasya kâryatvât tatra svâtantryam pratyayârtho brahmanah sidhyatîty âha.--The knowledge of Brahman is eternal, and in so far Brahman is not independent with regard to it, but it is independent with regard to each particular act of knowledge; the verbal affix in 'gânâti' indicating the particularity of the act.
53:1 In the second Khanda of the sixth Prapâthaka of the Kh. Up. 'aikshata' is twice used in a figurative sense (with regard to fire and water); it is therefore to be understood figuratively in the third passage also where it occurs.