How can we know the Knower
येन रूपं रसं गन्धं शब्दान् स्पर्शाꣳश्च मैथुनान् ।
एतेनैव विजानाति किमत्र परिशिष्यते । एतद्वै तत् ॥ ३॥
yena rūpaṃ rasaṃ gandhaṃ śabdān sparśāgͫśca maithunān .
etenaiva vijānāti kimatra pariśiṣyate . etadvai tat .. 3..
It is through Atman that one knows form, taste, smell, sounds, touches and carnal pleasures. Is there anything that remains unknown to Atman? This, verily, is That.
Commentary:
That, with the help of whose light and awareness one beholds things in perception through the eyes, tastes things through the tongue, smells through the nose, hears through the ears, touches with the skin, and contacts in various ways—with the help of this one thing, all things are known. Having known this, there is nothing more to be known.
“This verily is the answer to your question, Nachiketas,” says Yama. “Here I am giving you the answer to your question, the third boon that you asked, and I am gradually revealing it here in the instruction that I have given to you in these passages. After knowing this, what remains—kim atra pariśiṣyate? This verily is that. This indeed is that which you seek, and here it is before you.”
Swami Vivekananda Says —
…that Reality is the only thing we know, because in and through It we know everything else; and yet we cannot conceive of It. How can we know the Knower? If we knew It, It would not be the knower, but the known; It would be objectified.[Source]