20. On account of (its) passing out, moving and returning.
The Self is not omnipresent, but on the contrary, of atomic size (anu).— How is this known?—Since Scripture says that it passes out, goes and returns. Its passing out is described in the following passage 'by that light this Self departs, either through the eye, or through the skull, or through other parts of the body' (Bri. Up. IV, 4, 2). Its going in the following text 'all those who pass away out of this world go to the moon,' and its returning in the text 'from that world he comes again into this world, for action.' All this going, and so on, cannot be reconciled with the soul being present everywhere.
21. And on account of the latter two (being effected) through the Self.
The 'and' has affirming power. The 'passing out' might somehow be reconciled with a non-moving Self (such as the omnipresent Self would be) if it were taken in the sense of the Self separating from the body; but for the going and returning no analogous explanation is possible. They, therefore, must be taken as effected by the Self itself (which, then, cannot be omnipresent and non-moving).
22. If it be said that (the soul) is not atomic, on account of scriptural statement of (what is) not that; we say no, on account of the other one being the topic.
The passage 'He who is within the heart, surrounded by the Prânas, the person consisting of knowledge' (Bri. Up. IV, 3, 7) introduces as the topic of discussion the personal Self, and further on in the same chapter we read 'the unborn Self, the great one' (IV, 4, 22). The personal Self, being expressly called great, cannot, therefore, be atomic!—Not so, we reply. 'Since the other one is the topic.' In the second text quoted that Self which is other than the personal Self—i.e. the highest Self (prâjña) constitutes the topic. In the beginning of the chapter, indeed, the individual Self is introduced, but later on, between the two texts quoted, the instruction begins to concern itself with the highest Self, 'he by whom there is known the Self of intelligence' (pratibuddha âtmâ; IV, 4, 13). It is this latter Self which, in 22 is called great, not the individual Self.
23. And on account of the very word, and of measure.
Scripture directly applies the word 'anu' to the individual Self, 'By thought is to be known that atomic Self into which Breath has entered fivefold' (Mu. Up. III, 1, 9).—By the term 'unmâna' in the Sûtra we have to understand measurement by selection of comparative instances. Scripture declares the minuteness of the individual Self by reference to things which are like atoms in size, 'The individual soul is to be known as part of the hundredth part of the point of a hair divided a hundred times, and yet it is to be infinite' (Svet. Up. V, 9); 'that lower one is seen of the measure of the point of a goad' (V, 8). For these reasons also the individual Self must be viewed as atomic.—But this conflicts with the fact that sensation extends over the whole body!—This objection the next Sûtra refutes by means of an analogous instance.
24. There is no contradiction, as in the case of sandal-ointment.
As a drop of sandal-ointment, although applied to one spot of the body only, yet produces a refreshing sensation extending over the whole body; thus the Self also, although dwelling in one part of the body only, is conscious of sensations taking place in any part of the body.