Bhashya
सर्वमेतत् तार्किकैः सह सामञ्जस्यकल्पनया रमणीयंपश्यन्ति, न उपनिषत्सिद्धान्तं सर्वन्यायविरोधं च पश्य-मयस्यैव एतानि रूपाणि कस्मान्न भवन्ति, विज्ञानमयस्यापिप्रकृतत्वात्, 'तस्य' इति च प्रकृतोपादानात्- नैवम्,विज्ञानमयस्य अरूपित्वेन विजिज्ञापयिषितत्वात्; यदि हितस्यैव विज्ञानमयस्य एतानि माहारजनादीनि रूपाणि स्युः,तस्यैव 'नेति नेति' इत्यनाख्येयरूपतया आदेशो न स्यात् ।ननु अन्यस्यैव असावादेशः, न तु विज्ञानमयस्येति- न,षष्ठान्ते उपसंहारात्- 'विज्ञातारमरे केन विजानीयात्' इतिविज्ञानमयं प्रस्तुत्य 'स एष नेति नेति'- इति; 'विज्ञाप-यिष्यामि' इति च प्रतिज्ञाया अर्थवत्त्वात्- यदि च विज्ञान-मयस्यैव असंव्यवहार्यमात्मस्वरूपं ज्ञापयितुमिष्टं स्यात् प्रध्व-स्तसर्वोपाधिविशेषम्, तत इयं प्रतिज्ञा अर्थवती स्यात्- येनअसौ ज्ञापितो जानात्यात्मानमेव अहं ब्रह्मास्मीति, शास्त्रनिष्ठांप्राप्नोति, न बिभेति कुतश्चन; अथ पुनः अन्यो विज्ञानमयः,अन्यः 'नेति नेति' इति व्यपदिश्यते- तदा अन्यददो ब्रह्मअन्योऽहमस्मीति विपर्ययो गृहीतः स्यात्, न 'आत्मानमे-वावेदहं ब्रह्मास्मि' इति ।तस्मात् 'तस्य हैतस्य' इतिलिङ्गपुरुषस्यैव एतानि रूपाणि ।सत्यस्य च सत्ये परमात्म-स्वरूपे वक्तव्ये निरवशेषं सत्यं वक्तव्यम्; सत्यस्य च विशे-षरूपाणि वासनाः; तासामिमानि रूपाण्युच्यन्ते ॥
In plain words
They find this reconciliation with the logicians very pleasing — but they don't notice that it breaks with what the Upaniṣad actually concludes, and with reason itself. Someone might object: why couldn't these very forms — the saffron cloth and the rest — belong to the vijñānamaya, the conscious self, since it's the vijñānamaya that's under discussion here, and the word 'his' clearly points back to it? The answer is no. The whole point of teaching about the vijñānamaya is to reveal it as formless. If these describable forms really belonged to it, then the teaching 'not this, not this' — which only makes sense for something beyond all description — couldn't apply to it at all. Someone might push further: maybe 'not this, not this' points to something else, not the vijñānamaya. But no — the passage's own conclusion settles it. It introduces the vijñānamaya with the question, 'By what could you ever know the knower?' — and answers, 'he is this: not this, not this.' And the earlier promise, 'I will reveal this to you,' would mean nothing unless it were a promise about the vijñānamaya itself. If what's meant is to reveal the vijñānamaya's own nature — untouched by everyday dealings, stripped of every last trace of adopted identity — then that promise finally makes sense. Through it, a person comes to know: 'I am nothing but the Self, I am Brahman' — and stands firmly on the ground the scripture gives, afraid of nothing, from any quarter. But if the vijñānamaya were one thing and 'not this, not this' pointed to something else, we'd end up with exactly the wrong idea: 'Brahman is one thing, and I am another' — instead of 'I have known the Self itself: I am Brahman.' So the phrase 'his, of this one' refers only to the person identified with the subtle body — these forms belong to him alone. And when it comes time to speak of the truth behind the truth — the real nature of the Supreme Self — the whole truth has to be told, nothing held back. The particular shapes the ordinary truth takes are exactly these latent impressions. And it's these very forms that are being described here.
Close to the Sanskrit
All this they regard as agreeable, together with the logicians, by a contrived reconciliation; they do not see the Upaniṣadic conclusion and the opposition to all reasoning [that this involves]. [Objection:] Why should these forms not belong to the vijñānamaya itself, since the vijñānamaya too is the topic under discussion, and because of the taking-up of the word 'tasya' referring to what is under discussion? [Reply:] Not so — because the vijñānamaya, by virtue of its formlessness, is that which is intended to be made known precisely as formless. For if these forms beginning with the saffron-cloth belonged to that very vijñānamaya, then the teaching 'not this, not this' regarding it, by virtue of its indescribable nature, would not hold. [Objection:] But surely that designation belongs to something else entirely, not to the vijñānamaya. [Reply:] No — because of the concluding summation at the end of the sixth chapter: having introduced the vijñānamaya with 'By what, O friend, could one know the knower,' it concludes 'he is this: not this, not this'; and because the promise 'I shall make known' would otherwise be meaningless. And if it were intended to make known the vijñānamaya's own true nature — not subject to transactional dealing, with every particular condition-adjunct utterly destroyed — then this promise would be meaningful, by which, once informed, he knows 'I am the Self alone, I am Brahman,' attains steadfastness in the scripture, and fears nothing from anywhere. But if, on the other hand, the vijñānamaya were one thing and 'not this, not this' were designated of another, then the inverted notion would be adopted: 'that Brahman is one thing, I am another' — not 'I have realized the Self itself: I am Brahman.' Therefore the phrase 'tasya haitasya' refers to the liṅga-puruṣa alone; these forms belong to him alone. And when the truth of the truth — the true nature of the Supreme Self — is to be told, the truth must be told in full; and the particular forms of that empirical truth are the vāsanās; of these, these forms are being described.