Reality is One Endless change without, and at the heart of all the changes, an abiding reality - Brahman. Endless change within, and at the heart of the change an abiding reality - Atman. Does it mean then that there are two realities? No, answered the rishis, Brahman and Atman are one and the same. They recognized one Atman, one inmost individual being, as the Brahman, the inmost being of universal Nature and of all her phenomena. And they summed up this amazing affirmation in the words, Tat Tvam Asi - That thou art. The identity of Atman and Brahman was a vital part of the wisdom known to the rishis from time immemorial. This dictum is found nearly everywhere in the Upanisads, either stated or implied. It has been presented simply and attractively in the story of Svetaketu, found in Chandogya Upanisad. Story of Svetaketu Svetaketu, when he was twelve years old, was told by his father, Uthalaka Aruni that it was time for him to go and seek a teacher and study. And that nobody in their family remained a brahmin in name alone, without knowing the Vedas. Thereupon Svetaketu went to a teacher and studied for twelve years. After learning all the Vedas, he returned home full of pride in his learning. Sensing his conceit, his father said to him; "Svetaketu, did you ask of your teachers for that knowledge by which we hear the unhearable, perceive the unperceivable, and know the unknowable?" Svetaketu was unable to comprehend such a one. So Uthalaka explained; "By knowing one lump of clay, all things made of clay are known, the difference between them being only in name and form, the truth being they are all clay. And by knowing one nugget of gold, all things wrought out of gold are known, the difference again being name and form only. Exactly so, is that knowledge, knowing which we know all." Svetaketu said that perhaps his teachers were not in possession of such a knowledge and that was why he was not taught that. He then requested his father to impart that to him. 'So be it', said Uthalaka. "In the beginning there was Existence, one without a second. Some say that in the beginning there was nonexistence only, and out of that was the universe born. But how could existence be born out of nonexistence? No, my son, in the beginning there was existence alone; one only without a second. He, the One, thought to Himself, 'let me be many, let me grow forth'. Thus out of himself He projected the universe; and having projected the universe, He entered into every being and everything. So all that is, has its self in Him alone. He is the truth. He is the subtle essence of all. He is the Self. And That art Thou, Svetaketu." On Svetaketu wanting to know more, Uthalaka continued: "As the bees make honey by gathering nectar from many plants and trees, and as the nectar reduced to one honey, do not know from which plant they came, similarly all creatures when they are merged in that one Existence, whether in dreamless sleep or death, know nothing of their past or present state because of the ignorance enveloping them. They do not know that they came from Him and that they are merged in Him." "Whatever creature they be, whether a lion or a tiger, boar or a worm, gnat or a mosquito, they are still the same when they come back from a dreamless sleep. All these have their self in Him. He is the truth. He is the subtle essence of all. He is the Self. And That art Thou, Svetaketu." " The rivers in the east flow eastward, the rivers in the west flow westward, and all enter the seas. From sea to sea they pass, the clouds lifting them to the sky as vapour and sending them down as rain. And as the rivers, when they are united with the sea do not know whether they are this river or that, likewise all creatures, when they come back from Brahman, know not whence they came. All these beings have their self in Him alone. He is the truth. He is the subtle essence of all. He is the Self. And That art Thou, Svetaketu." "If one were to strike once at the root of this large tree, it would bleed, but live. If one were to strike at the stem, it would bleed, but live. If it is struck at the top, it would bleed, but live. Pervaded by the living Self, the tree stands firm, and takes its food. But if the Self were to depart from a branch, then it withers; if It were to depart from another, that branch withers; If the Self were to depart from the whole tree, then the whole tree would wither. Likewise, know this: The body dies when the Self leaves the body, but the Self dies not. All that is, have their Self in Him alone. He is the truth. He is the subtle essence of all. He is the Self. And That art Thou, Svetaketu." Uthalaka asked Svetaketu to bring a fruit from the nyagrodha (Banyan) tree and asked him to split it and tell him what he saw inside. He said he saw the minute seeds, and again was asked to split a seed and see what was inside. Svetaketu was unable to see anything clearly. Then Uthalaka said: "You are unable to see the subtle essence inside. In it is the whole of a nyagrodha tree. That which is the subtle essence, in that have all things their existence. That is the truth. That is the Self. And That art Thou Svetaketu." Uthalaka asked Svetaketu to put some salt in water. Svetaketu did as bidden. The next morning the father asked the son to bring to him the salt. Svetaketu could not, as the salt had dissolved in the water. He was then asked to sip the water. Svetaketu tasted it and said it was salty. Then Uthalaka said; "Though you do not see the salt, it was there then, it is there now. Similarly, though you do not see Brahman in the body, He is indeed there. That which is the subtle essence, in that have all things their existence. That is the truth. That is the Self. And That art Thou, Svetaketu." Thus in this story we find the identity of Atman and Brahman being explicitly and repeatedly emphasized. 'That art Thou' is a Mahavakya belonging to Chandogya Upanisad of Sama Veda. Mahavakyas are the precise utterances wherein you find the whole teaching of the Upanisads summed up!