The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut [1896] at sacred-texts.com
53. (Should it be said that distinction of pleasure, pain, &c., results) from (difference of) place; we say no, on account of the (Self's) being within (all things).
Here it might be objected that, although all Selfs are all-pervading, yet their conjunction with the internal organ which is seated in the body must take place in that part of each Self which is limited by the body; and that thus there may result from difference of locality a limitative distinction of resolutions, &c., of the adrishta, and of pleasure and pain.--This also, we reply, is not possible 'on account of the being within.' For, as being equally infinite, all Selfs are within all bodies. Thus the Vaiseshikas have no right whatever to assume any part of the Self to be limited by the body. And if they do assume such a part of the Self which in reality is without any parts, that part because merely assumptive will be incapable of limiting a real effect. Moreover, it is impossible to limit the body which originates in proximity to all (omnipresent) Selfs to one particular Self to the exclusion of all others. Moreover, on the doctrine of limitation due
to difference of place, it would follow that sometimes two Selfs enjoying the same pleasure or pain might effect their fruition by one and the same body, since it may happen that the unseen principle of two Selfs occupies the same place. For we may observe, e.g. that after Devadatta's body has moved away from a certain spot in which Devadatta had enjoyed a certain amount of pleasure or pain, and the body of Yagñadatta has moved into that very same place, Yagñadatta enjoys an equal amount of pleasure or pain; a thing which (on the theory discussed) could not happen if the unseen principles of the two men did not occupy the same place. From the doctrine that the unseen principles occupy fixed places it would, moreover, follow that no enjoyment of the heavenly world, &c. can take place; for the adrishta is effected in definite places such as e.g. the body of a Brâhmana, and the enjoyment of the heavenly world is bound to a definite different place.--It further 1 is impossible to maintain that there exist many all-pervading Selfs 2, as there are no parallel instances. Mention if you can a plurality of other things occupying the same place!--You will perhaps bring forward colour and so on 3. But we refuse to accept that instance as parallel, because colour, &c., although non-different in so far as they are attributes of one substance, yet differ through their essential characteristics. On the other hand there is no difference of characteristics between your (alleged) many Selfs. If you say that a difference of characteristics can be established on the ground of the ultimate special differences (of all substances), we point out that you implicate yourself in a logical circle as the assumption of difference of characteristics and the assumption of ultimate differences presuppose each other.
[paragraph continues] Should you adduce as parallel instances the all-pervadingness of ether, &c. (the '&c.' implying place and time), we reply that their all-pervadingness is not proved for him who holds the doctrine of Brahman and looks upon ether and so on as mere effects.
All which establishes the conclusion that the only doctrine not open to any objections is the doctrine of the unity of the Self.
72:1 And this is an attack on the basis of the position of the Sâṅkhyas as well as of the Vaiseshikas.
72:2 Which being equally omnipresent would all occupy the same space.
72:3 Many attributes such as colour, smell, touch, &c. reside in one place as belonging to one material object.