Consciousness is the knower of all

The first two mantra presented how an inward turning mind is helping a sādhaka to own up to the nature of the self. Inward-turning mind does not mean giving up everything; shutting down the organs. Even though our senses are open for worldly transactions, we should not get lost in them. Our primary goal is to own up to our inner self - pratyagātmā, by which we will stop searching fulfilment in anything else. The next mantra explains further about the nature of this inner self, by owning which, the life of becoming will come to an end.

yena rūpam rasam gandham śabdān sparśāmśca maithunān |

etenaiva vijānāti kimatra pariśiṣyate |

etad vai tat ||2.1.3||

By this (ātmā) alone one knows color, taste, smell, sounds, touches, and conjugal pleasures. What remains here (to be known by ātmā)? This is indeed that.

yena etenaiva - by which ātmā (of the nature of consciousness) alone, vijānāti - every living being knows clearly about rūpam rasam gandham śabdān sparśāmśca maithunān - form, taste, smell, sound, touch, and experience born of contact with another human being. Śruti nicely classifies the world of an infinite number of objects into five categories: form, taste, smell, sound, touch, and human interactions as maithunām (interactions between one person with another person). Through senses, one experiences everything in this world, but the ability to know is not belong to the senses; it belongs to ātmā. It meant to say that consciousness ātmā exists preceding perception/experience as the knower, where the existence/knowledge of any given thing takes place. Without a knower, there is no known object, since the existence of a given thing is proved only if it is known by the knower. Thus, everything is known only by consciousness ātmā.

Therefore kimatra pariśiṣyate - what does remain in this world which is unknown to the self? Nothing exists that is not known by the consciousness self. When something is said to exist, the existence itself proves the knower of the existence. This consciousness is the knower of all, distinct from everything that is known. Anything that I know is negated as anātmā.

etad vai tat - this innermost self (which illumines everything) is indeed that ātmā which was asked by naciketa, which even devatā doesn’t understand, which is different from dharma-adharma, which is the highest nature of Vishnu.