The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
53. Some (maintain the non-existence) of a (separate) Self, on account of the existence (of the Self) where a body is (only).
At present we will prove the existence of a Self different from the body in order to establish thereby the qualification (of the Self) for bondage and release. For if there were no Self different from the body, there would be no room for injunctions that have the other world for their result; nor could it be taught of anybody that Brahman is his Self.--But, an objection is raised, already in the first pâda which stands at the head of this Sâstra (i.e. the first pâda of the Pûrva Mîmâmsâ-sûtras) there has been declared the existence of a Self which is different from the body and hence capable of enjoying the fruits taught by the Sâstra.--True, this has been declared there by the author of the bhâshya, but there is in that place no Sûtra about the existence of the Self. Here, on the other hand, the Sûtrakâra himself establishes the existence of the Self after having disposed of a preliminary objection. And from hence the teacher Sabara Svâmin has taken the matter for his discussion of the point in the chapter treating of the means of right knowledge. For the same reason the reverend Upavarsha remarks in the first tantra--where an opportunity offers itself for the discussion of the existence of the Self--'We will discuss this in the Sârîraka,' and allows the matter to rest there. Here, where we are engaged in an inquiry into the pious meditations which are matter of injunction, a discussion of the existence of the Self is introduced in order to show that the whole Sâstra depends thereon.
Moreover, in the preceding adhikarana we have shown that passages may be exempted from the influence of the leading subject-matter, and that for that reason the fire-altars
built of mind and so on subserve the purpose of man (not of the sacrifice). In consequence thereof there naturally arises the question who that man is whose purposes the different fire-altars subserve, and in reply to it the existence of a Self which is separate from the body is affirmed.--The first Sûtra embodies an objection against that doctrine; according to the principle that a final refutation of objections stated in the beginning effects a stronger conviction of the truth of the doctrine whose establishment is aimed at.
Here now some materialists (lokâyatika), who see the Self in the body only, are of opinion that a Self separate from the body does not exist; assume that consciousness (kaitanya), although not observed in earth and the other external elements--either single or combined--may yet appear in them when transformed into the shape of a body, so that consciousness springs from them; and thus maintain that knowledge is analogous to intoxicating quality (which arises when certain materials are mixed in certain proportions), and that man is only a body qualified by consciousness. There is thus, according to them, no Self separate from the body and capable of going to the heavenly world or obtaining release, through which consciousness is in the body; but the body alone is what is conscious, is the Self. For this assertion they allege the reason stated in the Sûtra, 'On account of its existence where a body is.' For wherever something exists if some other thing exists, and does not exist if that other thing does not exist, we determine the former thing to be a mere quality of the latter; light and heat, e.g. we determine to be qualities of fire. And as life, movement, consciousness, remembrance and so on--which by the upholders of an independent Self are considered qualities of that Self--are observed only within bodies and not outside bodies, and as an abode of those qualities, different from the body, cannot be proved, it follows that they must be qualities of the body only. The Self therefore is not different from the body.--To this conclusion the next Sûtra replies.