Once, in the ancient wisdom of the Kaṭha Upaniṣad, it is taught that the self-born Creator has directed the senses outward, causing people to look only to the world outside and not within themselves. Yet, a rare wise person, longing for immortality, turns their gaze inward and discovers the inner Self. Most people, like children, chase after outward desires and become entangled in the vast net of death. But the wise, knowing the secret of immortality, do not seek the permanent among impermanent things in this world. It is through the Self alone that one perceives form, taste, smell, sound, touch, and pleasure; what remains unperceived is nothing but this very Self—it is That. The one who observes both the end of dreaming and the end of waking, and knows the great, all-pervading Self, does not grieve. Whoever knows this Self—the enjoyer of sweetness, the living soul close at hand, the lord of the past and the future—has no fear of anything. This is That. He who existed before ascetic practice and before the waters, who enters the secret place and abides there, whom all beings perceive—this is That. That which, as the goddess Aditi, composed of divinity, arises with the breath, enters the secret place and abides there, and is brought forth by all beings—this is That. Hidden in the woods is Jātavedas, cherished like an embryo by pregnant women; day by day, Agni is praised by those who are awake and offer oblations. This is That. From whom the sun rises and into whom it sets, in whom all the gods are established—none goes beyond That. This is That. Whatever is here is there; whatever is there is here. Those who see difference here go from death to death. This truth is to be attained only by the mind; in reality, there is no diversity at all. Those who see difference here go from death to death. The Person, of the size of a thumb, stands within the Self, the lord of what was and what will be; he does not shrink from anything. This is That. The Person, of the size of a thumb, like a flame without smoke, the lord of what was and what will be—he is today, he is tomorrow. This is That. Just as water poured on a rugged mountain runs off in various directions, so too, seeing duties as separate, one follows them accordingly. But as pure water poured into pure water becomes just so, so the Self of the knower who knows becomes, O Gautama. In the city with eleven gates, the unborn, with crooked mind, having established himself, does not grieve; being liberated, he is freed. This is That. The swan dwelling in purity, the Vasu abiding in the mid-region, the hotṛ on the altar, the guest in the house, dwelling among men, in the noble, in the right, in the sky, born of water, born of cows, born of truth, born of mountains—truth, the great. He raises the breath upward and sends the downward breath back; all the gods worship the dwarf seated in the middle. As this embodied one is released from the body as the body falls away—what remains here? This is That. No mortal lives by breath or by the downward breath; they live by another, on whom these two depend. Listen, Gautama, I will declare to you this ancient, secret Brahman, and how, upon reaching death, the Self becomes. Some embodied beings enter a womb for the sake of a body; others go into stationary forms, according to their deeds and knowledge. That Person who, creating desire after desire, remains awake among those who sleep—he alone is the pure one, he is Brahman, he is called the immortal; upon him all worlds rest, and none goes beyond him. This is That. As fire, one alone, having entered the world, takes on a form corresponding to every form, so too the inner Self of all beings, one alone, takes on a form corresponding to every form, both within and without. As wind, one alone, having entered the world, takes on a form corresponding to every form, so too the inner Self of all beings, one alone, takes on a form corresponding to every form, both within and without. As the sun, the eye of the whole world, is not tainted by external faults seen by the eye, so too the inner Self of all beings, one alone, is not tainted by the sorrows of the world, being beyond them. The one ruler, the inner Self of all beings, who makes the one form manifold—those wise ones who perceive him established in themselves, for them is eternal happiness, not for others. The eternal among non-eternal things, the conscious among the conscious, the one who grants desires to the many—those wise ones who perceive him established in themselves, for them is eternal peace, not for others. They think of That as this—indescribable, supreme bliss. How indeed may I know it? Does it shine or does it not shine? There the sun does not shine, nor the moon and stars; lightning does not shine, how then this fire? That shining, all else shines after it; by its light, all this shines. With roots above and branches below, this eternal aśvattha tree—he alone is the pure one, he is Brahman, he is called the immortal; upon him all worlds rest, and none goes beyond him. This is That. Whatever is here, this whole world, moves as sent forth by prāṇa; a great terror, a raised thunderbolt—those who know this become immortal. From fear of him, fire burns; from fear, the sun shines; from fear, Indra, Vāyu, and Death as the fifth, run their course. If one is unable to know him here, before the body falls away, then one becomes fit for embodiment in the worlds of creation. As in a mirror, so in the Self; as in a dream, so in the world of ancestors; as in water, so in the world of gandharvas; as in shadow and sunlight, so in the world of Brahman. He who knows the distinctness of the senses, their rising and setting, and their separate origin—such a wise one does not grieve. Beyond the senses is the mind; beyond the mind is the higher intellect; beyond the intellect is the great Self; beyond the great is the unmanifest. Beyond the unmanifest is the Person, all-pervading and without marks; knowing him, a living being is freed and attains immortality. His form does not stand within sight; no one sees him with the eye. He is grasped by the heart, by thought, by the mind. Those who know this become immortal. When the five senses, together with the mind, come to rest, and the intellect does not stir, they call that the highest state.