Bhāṣya
नित्यश्च आत्मा, सदकारणवत्त्वात् परमाणुवत् ; सन् आत्मा, अहमस्मीति प्रतीतेः ।अकारणवांश्च ; न हि अस्य कारणं वस्तु प्रत्यक्षादिभिरुपलभ्यते, नापि श्रूयते ; किं तु त्रैलोक्यैककारणता हि आत्मनः श्रूयते ‘तस्माद्वा एतस्मादात्मन आकाशः सम्भूतः’ इत्यादिश्रुतिभ्यः ।न त्वात्मनोऽपि कारणान्तरम् ।अतः सदकारणवत्त्वात् नित्य आत्मेति सिद्धम् ।तस्मात् साधूक्तं नित्यबोधस्वरूपमिति ।तत्रैव दृष्टान्तमाह — अग्न्युष्णवदिति ।यथा उष्णत्वमग्नेर्न व्यतिरिच्यते ।व्यतिरेके हि कदाचिदग्नेरन्यत्राप्युपलभ्येत — यथा पुरुषाद्दण्डादि ; न चैवमस्ति ; तस्मादग्निस्वरूपमेव अग्नेरुष्णत्वम् ।एवमात्मनोऽपि चैतन्यं स्वरूपमेवेत्यर्थः ।तथा च उक्तम् — ‘निरंशत्वाद्विभुत्वाच्च तथानश्वरभावतः ।ब्रह्मव्योम्नोर्न भेदोऽस्ति चैतन्यं ब्रह्मणोऽधिकम्’ इति ।यच्चोक्तं मनश्चक्षुरादीनां प्रवृत्तौ किमर्थमधिष्ठाता इष्यते, स्वयमेव कस्मान्न प्रवर्तन्ते इति, तत्राह — अबोधात्मकानीति ।हेतुगर्भमिदं विशेषणम् ; अतश्च अयमर्थः सेत्स्यति — अबोधात्मकत्वात् अचेतनत्वाच्च घटादिवच्चेतनमधिष्ठातारमाश्रित्यैव प्रवर्तन्त इति ।तदचेतनत्वं चैषां तज्ज्ञेयत्वात् घटादिवदिति ।श्रुतिरपि ‘नान्योऽतोऽस्ति द्रष्टा’ इत्यादिना आत्मव्यतिरिक्तस्य चेतनत्वं प्रतिषेधति ।अतो युक्तमुक्तं चेतनमात्मानमाश्रित्य प्रवर्तन्त इति ।निष्कम्पं निस्तरङ्गं निःसंशयमित्यर्थः ।तथा च श्रुतिः ‘भिद्यते हृदयग्रन्थिश्च्छिद्यन्ते सर्वसंशयाः क्षीयन्ते चास्य कर्माणि तस्मिन्दृष्टे परावरे’ इति ।एकम् अद्वितीयं देवतिर्यङ्मनुष्यादिशरीरेषु एकम् , न तु साङ्ख्यादिपरिकल्पितवत् नानाभूतमित्यर्थः ॥
In plain words
The Self is eternal because it is uncaused, much like space or an atom; its existence is self-revealing, known directly in the intuition 'I am'. It has no antecedent cause, for no instrument of knowledge perceives an origin for it, nor does any scripture declare one. On the contrary, the Vedas declare the Self to be the ultimate cause of the entire universe, as in the text, 'From this very Self, space came forth.' The Self has no higher cause above it. Thus, being real and uncaused, the Self is established as eternal. That is why it is rightly described as being of the nature of pure, eternal awareness. To illustrate this, the text offers an example: just as heat is never separate from fire. If heat were separate, it could sometimes be found independently elsewhere, just as a staff is separate from the person holding it. But no such separation exists; the heat of fire is nothing other than fire itself. In the exact same way, the consciousness of the Self is its very essence. As traditional wisdom declares: 'Because it has no parts, because it is all-pervasive, and because it is indestructible, there is no difference between Brahman and space; consciousness is not something added to Brahman.' When it was asked why the mind and senses require a conscious overseer to function, and why they cannot act on their own, the answer is given: they are devoid of awareness. This very description contains the core reason. The meaning is established: because they are unconscious and inert like a jar, they can only function by depending upon a conscious master. Their insentience is proven by the fact that they are objects known by the Self, just as a jar is known. Scripture likewise denies any independent consciousness outside the Self, declaring, 'There is no other seer.' Therefore, it is entirely correct to say that the senses operate only in dependence upon the conscious Self. This realization is stable, tranquil, and beyond all doubt. As the Upanishad proclaims: 'When the higher and the lower reality is seen, the knots of the heart are untied, all doubts are severed, and one's karmas are dissolved.' It is one, non-dual, shining equally within the bodies of gods, animals, and humans—not fragmented into many separate souls, as various philosophers imagine.
Close to the Sanskrit
Eternal is the Self, because of having no cause, like an atom; being the Self, from the cognition 'I am'. And possessing no cause; for indeed no cause of this entity is perceived by perception and other means, nor is it heard; but the sole causality of the three worlds indeed of the Self is heard from such scriptural passages as 'From this very Self space was produced'. Nor is there any other cause of the Self. Hence, because it is existent and uncaused, the Self is eternal, thus it is established. Therefore it is well said that its nature is eternal awareness. In regard to that itself, he states an example — like the heat of fire. Just as heat does not differ from fire. In separation, indeed, at some time it might be perceived elsewhere — like a stick from a person; and this is not so; therefore the heat of fire is the very nature of fire. Thus the consciousness of the Self is also its very nature, is the meaning. And thus it is said — 'Because of being partless, and because of all-pervasiveness, and likewise from the state of indestructibility, there is no difference between Brahman and space; consciousness is not something additional to Brahman'. And what was said: 'In the functioning of the mind, eyes, and the rest, for what purpose is a controller desired, why do they not function by themselves?', to that he replies — 'Because they are devoid of awareness'. This qualification contains the reason within it; and hence this meaning will be established — that they function solely by depending upon a conscious controller, because of being devoid of awareness and because of being insentient, just like a jar. And their insentience is because they are objects known by that, just like a jar. Scripture also prohibits the sentience of anything other than the Self through statements such as 'There is no other seer than this'. Hence it is aptly said that they function by depending upon a conscious Self. Unshaking, wave-less, free from doubt, is the meaning. And thus scripture: 'The knot of the heart is pierced, all doubts are severed, and his actions perish when the higher and lower is seen'. One, non-dual, one in the bodies of gods, animals, humans, etc., and not manifold as imagined by the Sāṅkhyas and others, is the meaning.