The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
8. The bhûman (is Brahman), as the instruction about it is additional to that about the state of deep sleep (i.e. the vital air which remains awake even in the state of deep sleep).
We read (Kh. Up. VII, 23; 24), 'That which is much (bhûman) we must desire to understand.--Sir, I desire to understand it.--Where one sees nothing else, hears nothing else, understands nothing else, that is what is much (bhûman). Where one sees something else, hears something else, understands something else, that is the Little.'--Here the doubt arises whether that which is much is the vital air (prâna) or the highest Self.--Whence the doubt?--The word 'bhûman,' taken by itself, means the state of being much, according to its derivation as taught by Pânini, VI, 4, 158. Hence there is felt the want of a specification showing what constitutes the Self of that muchness. Here there presents itself at first the approximate passage, 'The vital air is more than hope' (Kh. Up. VII, 15, 1), from which we may conclude that the vital air is bhûman.--On the other hand, we meet at the beginning of the chapter, where the general topic is stated, with the following passage, 'I have heard from men like you that he who knows the Self overcomes grief. I am in grief. Do, Sir, help me over this grief of mine;' from which passage it would appear that the bhûman is the highest Self.--Hence there arises a doubt as to which of the two alternatives is to be embraced, and which is to be set aside.
The pûrvapakshin maintains that the bhûman is the vital air, since there is found no further series of questions and answers as to what is more. For while we meet with a series of questions and answers (such as, 'Sir, is there something which is more than a name?'--'Speech is more than name.'--'Is there something which is more than speech?'--' Mind is more than speech'), which extends from name up to vital air, we do not meet with a similar question and answer as to what might be more than vital air (such as, 'Is there something
which is more than vital air?'--'Such and such a thing is more than vital air'). The text rather at first declares at length (in the passage, 'The vital air is more than hope,' &c.) that the vital air is more than all the members of the series from name up to hope; it then acknowledges him who knows the vital air to be an ativâdin, i.e. one who makes a statement surpassing the preceding statements (in the passage, 'Thou art an ativâdin. He may say I am an ativâdin; he need not deny it'); and it thereupon (in the passage, 'But he in reality is an ativâdin who declares something beyond by means of the True' 1),--not leaving off, but rather continuing to refer to the quality of an ativâdin which is founded on the vital air,--proceeds, by means of the series beginning with the True, to lead over to the bhûman; so that we conclude the meaning to be that the vital air is the bhûman.--But, if the bhûman is interpreted to mean the vital air, how have we to explain the passage in which the bhûman is characterised. 'Where one sees nothing else?' &c.--As, the pûrvapakshin replies, in the state of deep sleep we observe a cessation of all activity, such as seeing, &c., on the part of the organs merged in the vital air, the vital air itself may be characterised by a passage such as, 'Where one sees nothing else.' Similarly, another scriptural passage (Pra. Up. IV, 2; 3) describes at first (in the words, 'He does not hear, he does not see,' &c.) the state of deep sleep as characterised by the cessation of the activity of all bodily organs, and then by declaring that in that state the vital air, with its five modifications, remains awake ('The fires of the prânas are awake in that town'), shows the vital air to occupy the principal position in the state of deep sleep.--That passage also, which speaks of the bliss of the bhûman ('The bhûman is bliss,' Kh. Up. VII, 23), can be reconciled with our explanation, because Pra. Up. IV, 6 declares bliss to attach to the state of deep sleep ('Then that god sees no dreams and at that time that happiness arises in his body').--Again, the statement, 'The bhûman is immortality' (Kh. Up. VII, 24, 1), may
likewise refer to the vital air; for another scriptural passage says, 'Prâna is immortality' (Kau. Up. III, 2).--But how can the view according to which the bhûman is the vital air be reconciled with the fact that in the beginning of the chapter the knowledge of the Self is represented as the general topic ('He who knows the Self overcomes grief,' &c.)?--By the Self there referred to, the pûrvapakshin replies, nothing else is meant but the vital air. For the passage, 'The vital air is father, the vital air is mother, the vital air is brother, the vital air is sister, the vital air is teacher, the vital air is Brâhmana' (Kh. Up. VII, 15, 1), represents the vital air as the Self of everything. As, moreover, the passage, 'As the spokes of a wheel rest in the nave, so all this rests in prâna,' declares the prâna to be the Self of all--by means of a comparison with the spokes and the nave of a wheel--the prâna may be conceived under the form of bhûman, i.e. plenitude.--Bhûman, therefore, means the vital air.
To this we make the following reply.--Bhûman can mean the highest Self only, not the vital air.--Why?--'On account of information being given about it, subsequent to bliss.' The word 'bliss' (samprasâda) means the state of deep sleep, as may be concluded, firstly, from the etymology of the word ('In it he, i.e. man, is altogether pleased--samprasîdati')--and, secondly, from the fact of samprasâda being mentioned in the Brihadâranyaka together with the state of dream and the waking state. And as in the state of deep sleep the vital air remains awake, the word 'samprasâda' is employed in the Sûtra to denote the vital air; so that the Sûtra means, 'on account of information being given about the bhûman, subsequently to (the information given about) the vital air.' If the bhûman were the vital air itself, it would be a strange proceeding to make statements about the bhûman in addition to the statements about the vital air. For in the preceding passages also we do not meet, for instance, with a statement about name subsequent to the previous statement about name (i.e. the text does not say 'name is more than name'), but after something has been said about name, a new statement is
made about speech, which is something different from name (i. e. the text says, 'Speech is more than name'), and so on up to the statement about vital air, each subsequent statement referring to something other than the topic of the preceding one. We therefore conclude that the bhûman also, the statement about which follows on the statement about the vital air, is something other than the vital air. But--it may be objected--we meet here neither with a question, such as, 'Is there something more than vital air?' nor with an answer, such as, 'That and that is more than vital air.' How, then, can it be said that the information about the bhûman is given subsequently to the information about the vital air?--Moreover, we see that the circumstance of being an ativâdin, which is exclusively connected with the vital air, is referred to in the subsequent passage (viz. 'But in reality he is an ativâdin who makes a statement surpassing (the preceding statements) by means of the True'). There is thus no information additional to the information about the vital air.--To this objection we reply that it is impossible to maintain that the passage last quoted merely continues the discussion of the quality of being an ativâdin, as connected with the knowledge of the vital air; since the clause, 'He who makes a statement surpassing, &c. by means of the True,' states a specification.--But, the objector resumes, this very statement of a specification may be explained as referring to the vital air. If you ask how, we refer you to an analogous case. If somebody says, 'This Agnihotrin speaks the truth,' the meaning is not that the quality of being an Agnihotrin depends on speaking the truth; that quality rather depends on the (regular performance of the) agnihotra only, and speaking the truth is mentioned merely as a special attribute of that special Agnihotrin. So our passage also ('But in reality he is an ativâdin who makes a statement, &c. by means of the True') does not intimate that the quality of being an ativâdin depends on speaking the truth, but merely expresses that speaking the truth is a special attribute of him who knows the vital air; while the quality of being an ativâdin must be considered to depend on the knowledge of the vital air.--This
objection we rebut by the remark that it involves an abandonment of the direct meaning of the sacred text. For from the text, as it stands, we understand that the quality of being an ativâdin depends on speaking the truth; the sense being: An ativâdin is he who is an ativâdin by means of the True. The passage does not in anyway contain a eulogisation of the knowledge of the vital air. It could be connected with the latter only on the ground of general subject-matter (prakarana) 1; which would involve an abandonment of the direct meaning of the text in favour of prakarana 2.--Moreover, the particle but ('But in reality he is,' &c.), whose purport is to separate (what follows) from the subject-matter of what precedes, would not agree (with the prâna explanation). The following passage also, 'But we must desire to know the True' (VII, 16), which presupposes a new effort, shows that a new topic is going to be entered upon.--For these reasons we have to consider the statement about the ativâdin in the same light as we should consider the remark--made in a conversation which previously had turned on the praise of those who study one Veda--that he who studies the four Vedas is a great Brâhmana; a remark which we should understand to be laudatory of persons different from those who study one Veda, i.e. of those who study all the four Vedas. Nor is there any reason to assume that a new topic can be introduced in the form of question and answer only; for that the matter propounded forms a new topic is sufficiently clear from the circumstance that no connexion can be established between it and the preceding topic. The succession of topics in the chapter under discussion is as follows: Nârada at first listens to the instruction which Sanatkumâra gives him about various matters, the last of which is Prâna, and then becomes silent. Thereupon Sanatkumâra explains to him spontaneously (without being
asked) that the quality of being an ativâdin, if merely based on the knowledge of the vital air--which knowledge has for its object an unreal product,--is devoid of substance, and that he only is an ativâdin who is such by means of the True. By the term 'the True' there is meant the highest Brahman; for Brahman is the Real, and it is called the 'True' in another scriptural passage also, viz. Taitt. Up. II, 1, 'The True, knowledge, infinite is Brahman.' Nârada, thus enlightened, starts a new line of enquiry ('Might I, Sir, become an ativâdin by the True?') and Sanatkumâra then leads him, by a series of instrumental steps, beginning with understanding, up to the knowledge of bhûman. We therefrom conclude that the bhûman is that very True whose explanation had been promised in addition to the (knowledge of the) vital air. We thus see that the instruction about the bhûman is additional to the instruction about the vital air, and bhûman must therefore mean the highest Self, which is different from the vital air. With this interpretation the initial statement, according to which the enquiry into the Self forms the general subject-matter, agrees perfectly well. The assumption, on the other hand (made by the pûrvapakshin), that by the Self we have here to understand the vital air is indefensible. For, in the first place, Self-hood does not belong to the vital air in any non-figurative sense. In the second place, cessation of grief cannot take place apart from the knowledge of the highest Self; for, as another scriptural passage declares, 'There is no other path to go' (Svet. Up. VI, 15). Moreover, after we have read at the outset, 'Do, Sir, lead me over to the other side of grief' (Kh. Up. VII, 1, 3), we meet with the following concluding words (VII, 26, 2), 'To him, after his faults had been rubbed out, the venerable Sanatkumâra showed the other side of darkness.' The term 'darkness' here denotes Nescience, the cause of grief, and so on.--Moreover, if the instruction terminated with the vital air, it would not be said of the latter that it rests on something else. But the brâhmana (Kh. Up. VII, 36, 1) does say, 'The vital air springs from the Self.' Nor can it be objected against this last argument that the concluding
part of the chapter may refer to the highest Self, while, all the same, the bhûman (mentioned in an earlier part of the chapter) may be the vital air. For, from the passage (VII, 24, 1), ('Sir, in what does the bhûman rest? In its own greatness,' &c.), it appears that the bhûman forms the continuous topic up to the end of the chapter.--The quality of being the bhûman--which quality is plenitude--agrees, moreover, best with the highest Self, which is the cause of everything.
163:1 As might be the primâ facie conclusion from the particle 'but' introducing the sentence 'but he in reality,' &c.
166:1 It being maintained that the passage referred to is to be viewed in connexion with the general subject-matter of the preceding past of the chapter.
166:2 And would thus involve a violation of a fundamental principle of the Mîmâmsâ.