The System of the Vedanta according to Badarayana's Brahma-Sutras and Cankara's Commentary c8.s2.t2.4

c8.s2.t2.4

To this we reply: the soul is an eternally intellectual being; this follows from the fact that, as we have proved, it does not originate but is the highest unchangeable Brahman itself, which when disguised by the Upâdhis appears as the individual soul. Now the highest Brahman is as we have proved (chap. IX, 4 above p. 134 ff.) naturally intellectual; consequently to the soul also intellectuality is as essential as heat and light to fire. Yet the organs of perception are not for this reason superfluous; for they are the gates through which the intellect receives the specifically different sense-impressions, e. g. the perception of smells by the sense of smell etc.—If sleepers etc. do not perceive, this is to be explained by the passage: "If he then sees not, yet is he seeing, though he does not see" etc. (above p. 191); i. e., the soul does not then perceive, not because perception is wanting but because the objects are wanting; just as light does not become visible in space, as long as there are no objects to be illuminated (648, 2—649, 13).