Śaṅkaraon Brahma Sūtra 4.2.4

We have ascertained that a thing which has not originated from another is not itself merged in the latter, but only through its functions. A doubt now arises whether, according to the word of scripture, the function of breath is merged in heat, or in the individual soul which is the ruler of the body and senses. —According to the piirvapakshin we must conclude that the breath is merged in heat only, since the scriptural statement allows no room for doubt and we are not entitled to assume something not declared by scripture. The breath under discussion persists ‘in the ruler,’ i.e. the intelligent Self (the individual soul) which possesses nescience, work, and former knowledge as limiting adjuncts; i.e. the function of breath has that for its substratum. —Why so? — ‘On account of (the pra//as) going towards him,’ &c. Another scriptural passage declares that all pra;?as without any difference go to tlie soul, ‘ All the pra//as go to the Self at the time of death when a man is thus going to expire’ (Brl Up. IV, 3, 38). Another passage again specially declares that the pra«a with its five functions follows the individual soul, ‘After him thus departing the pra;?a departs,’ and that the other pra;/as follow that pra;/a, ‘And after the pra;/a thus departing all the other pr^//as depart’ (Br/. Up. IV, 4, 2). And the text, ‘ He is furnished with intelligence ’ (ibid.), by declaring the individual soul to be of intimately intelligent nature, suggests that in it, viz. the soul, the prawa—into which the different organs of knowledge have been merged—has taken its abode. But scripture also says, ‘ The pra«a (is merged) in heat;’ why then make the addition implied in the doctrine that breath is merged in the individual soul? We must make that addition, we reply, because in the process of departure &c. the soul is the chief agent, and because we must pay regard to specifications contained in other scriptural passage^ also. How then do you explain the statement, ‘ Breath is merged in heat?’ To this question the next Slitra replies.