Tat Tvam Asi
Tat Tvam Asi (Sanskrit: तत् त्वम् असि or तत्त्वमसि), a Sanskrit sentence, translated variously as "That art thou," "That thou art," "Thou art that," "You are that," or "That you are," is one of the Mahāvākyas (Grand Pronouncements) in Vedantic Sanatana Dharma. It originally occurs in the Chandogya Upanishad 6.8.7, in the dialogue between Uddalaka and his son Śvetaketu; it appears at the end of a section, and is repeated at the end of the subsequent sections as a refrain. The meaning of this saying is that the Self - in its original, pure, primordial state - is wholly or partially identifiable or identical with the Ultimate Reality that is the ground and origin of all phenomena.
Major Vedantic schools offer different interpretations of the phrase:
- Advaita - absolute equality of 'tat', the Ultimate Reality, Brahman, and 'tvam', the Self, Atman.
- Shuddhadvaita - oneness in "essence" between 'tat' and individual self; but 'tat' is the whole and self is a part.
- Vishishtadvaita - identity of individual self as a part of the whole which is 'tat', Brahman.
- Dvaitadvaita - equal non-difference and difference between the individual self as a part of the whole which is 'tat'.
- Dvaita†† of Madhvacharya - “Sa atmaa-tat tvam asi” in Sanskrit is actually “Sa atma-atat tvam asi” or “Atman, thou art not that”. In refutation of Mayavada (Mayavada sata dushani), text 6, 'tat tvam asi" is translated as "you are a servant of the Supreme (Vishnu)"
- Acintya Bheda Abheda - inconceivable oneness and difference between individual self as a part of the whole which is 'tat'.
††Note: We find pumlinga Sabdās such as Brahman, Ātman, Rājan, Śarman, Varman appearing as Brahmā, Ātmā, Rajā, Varmā, Śarmā in Vishnu Sahasranaamam. Whenever the word "Brahmā" appears, it actually means "Brahman." Similarly, Ātmā means Ātman, Śarmā means Śarman, etc. Even in Sandhya Vandanam, whose mantras are essentially a part of Veda, in the Invocation(Āvāhanam) of Gāyātrī it comes as Brahmaa Śiraha(ब्रह्माशिरः). It does not mean that the mantra means Brahmaa Aśiraha (ब्रह्म+अशिरः); it actually means Brahman Śiraha (ब्रह्मन्+शिरः).
In Advaita 
||This section is written like a personal reflection or opinion essay rather than an encyclopedic description of the subject. (July 2012)|
Tat tvam asi is the Mahāvākya (Grand Pronouncement) from Chandogya Upanishad. The Advaita school of Shankara assigns a fundamental importance to this Mahāvākya and three others of the same kind from three other Upanishads. This is actually a statement meted out by Sage Aruni to Shvetaketu, his son. It says literally 'That thou are'. In other words that Brahman which is the common Reality behind everything in the cosmos is the same as the essential Divinity, namely the Atman, within you. It is this identity which is the grand finale of Upanishadic teaching, according to Advaita. The realisation of this arises only by an intuitive experience and is totally different from any objective experience. It cannot be inferred from some other bit of knowledge. To comprehend the meaning an analysis of the three words in the pronouncement is needed.
Who is this 'Thou'? 
'Thou' stands for the inherent substratum in each one of us without which our very existence is out of question. Certainly it is not the body, mind, the senses, or anything that we call ours. It is the innermost Self, stripped of all egoistic tendencies. It is Ātman.
The entity indicated by the word 'That' according to the notation used in the Vedas, is Brahman, the transcendent Reality which is beyond everything that is finite, everything that is conceived or thought about. You cannot give a full analogy to it and that is why the Vedas say words cannot describe it. It cannot even be imagined because when there is nothing else other than Brahman it has to be beyond space and time. We can imagine space without earth,water, fire and air. But it is next to impossible to imagine something outside space. Space is the most subtle of the five elemental fundamentals. As we proceed from the grossest to the subtle, that is, from earth to water, to fire, to air, and to space the negation of each grosser matter is possible to be imagined within the framework of the more subtle one. But once we reach the fifth one, namely space or Ākāsha, the negation of that and the conception of something beyond, where even the space is merged into something more subtle, is not for the finite mind. The Vedas therefore declare the existence of this entity and call it 'sat' (existence), also known as Brahman.
This and That 
The Ātman or the innermost core of our self seems to have an individuality of its own. So, in saying that it is the same as the unqualified Brahman in the Infinite Cosmos, we seem to be identifying two things: one that is unlimited and unconditioned, and one that is limited and conditioned. Whenever someone says, for instance, that the person B whom you are meeting just now is the same as the person A whom you saw twenty years ago at such and such a place, what is actually meant is not the identity of the dresses of the two personalities of A and B, nor of the features (those of B may be totally different from A), but of the essential person behind the names. So whenever such an identity is talked about we have to throw away certain aspects which are temporarily distinctive or indicative in both and cling on only to those essentials without which they are not what they are. B and A may have distinct professions, may have different names, may have different attitudes towards you or towards a certain issue, or may have an additional identity, exemplified by, say, having different passports—but still they are the same, is what is being asserted by the statement 'B is the same as A'.
Brahman minus its Māyā and Ātman minus its avidyā are identical 
In the same way, when Brahman and Atman are identified by this Mahāvākya, we have to discard those inessential qualities that are only indicative (and therefore extraneous), choosing only to explore what commonality or essentiality there is in them that is being identified. Brahman is the primordial Cause of this Universe. But this is a predication of Brahman and so is extraneous to the identity about which we are speaking. The Self, or Ātman, appears to be limited by an individuality which keeps it under the spell of ignorance; this is extraneous to the essentiality of the Ātman. So what is being identified is Brahman, minus its feature of being the Cause of this Universe and Ātman minus its limitations of ignorance-cum-delusion. That these two are the same is the content of the statement 'Tat tvam asi'. The cosmic Māyā is what makes Brahman the cause of this Universe. The individual avidyā (ignorance) is what makes the Ātman circumscribed and delimited. So the Mahāvākya says that Brahman minus its Māyā and Atman minus its avidyā are identical.
In Vishishtadvaita 
The Vedas form the fundamental source text for everything in Hinduism. Each of the four Vedas has metaphysical speculations, known as Upanishads, at the end. Among the various discussions in these Upanishads there are mahavakyas (Grand pronouncements), which are of foundational import and deep significance. Tat tvam asi (meaning, That Thou Art) is one such. This is from Chandogya Upanishad. Different schools of philosophy interpret such fundamental statements in significantly different ways, so as to be consistent with their own philosophical thought. Below is the interpretation of the Vishishtadvaita school.
Objections to the Advaita interpretation 
The proclamation of Śankaracarya 'Tat Tvam Asi' is correct that both Ātmā and Paramātmā are sat-cit-ānanda, meaning qualitative unity of the Soul and God. However Ātmā, being localized Paramātmā consequently has localized consciousness. Paramātma, being the reservoir of Ātmā, is situated within every heart. Therefore 'Tat Tvam Asi' falls short to understand that the Soul is not equal to the Absolute Truth in all respects. For example, as a single drop of water has the same qualities as an ocean of water, so has our consciousness the qualities of God's consciousness but is proportionally subordinate. Furthermore, if Ātmā and Paramātmā were indeed one and the same, it would be possible for any ordinary person to claim omnipotence, omniscience, and omnipresence in equivalence to God. Scientifically we know this to be false. Shankara however does not claim the person is God, but that the person is unreal, so no contradictions with science.
According to Advaita, there are 3 orders of reality:
1. paramarthika satyam (absolute reality) 2. vyavaharika satyam (empirical reality) 3. pratibhasika satyam (subjective reality)
"I salute that Govinda who is the extreme limit of happiness, Who is pretty, cause of causes, primeval, without beginning and a form of time, Who danced again and again on the head of serpent Kaliya in the river Yamuna, Who is black in colour, ever present in time and destroys the evil effects of Kali, And who is the cause of the march of time from the past to the future." -Adi Sankara Bhagwat Pada
Ramanuja on the Mahavakya 
In the expression 'Blue Lotus' for example, the two attributes of 'blueness' and 'lotus nature' both inhere in a common substratum without losing their individuality. Such subsistence of many attributes in a common substratum is the correct apposition (samānādhikaranya), rather than the mere apposition as propounded by the advaita school. Direct meanings of the expressions should be taken, simultaneously fulfilling the conditions of Samānādhikaranya.
Meaning of the Mahavakya 
The mighty Iswara, who is the indweller in the cosmic Body is also the indweller in every Jiva. Every Jiva individually is the body of Isvara, just as the Cosmos as a whole is. The 'Tat' of the statement refers to Iswara who resides in the Cosmic Body and the 'Tvam' refers to the same Iswara who indwells the Jiva and has got the Jiva as the body. All the bodies, the Cosmic and the individual, are held in adjectival relationship (aprthak-siddhi) in the one Isvara. Tat Tvam Asi declares that oneness of Isvara.
In Dvaita 
The argument that AtmA+atat(आत्मा+अतत् ) cannot happen just as brahmaa + ashiraha(ब्रह्मा+अशिरः) cannot is not valid. In the word brahmārpanam (ब्रह्मार्पणम्), it cannot be split as brahma+ rpanam (ब्रह्मा+ र्पणम्), but it can only be brahma+ arpanam (ब्रह्मा+अर्पणम्). One cannot even argue that since rpanam is meaningless, it has to be arpanam. The argument that AtmA+atat(आत्मा+अतत् ) cannot happen is baseless, just as brahma+arpanam (ब्रह्मा+अर्पणम्) cannot happen is also baseless. AtmA+atat(आत्मा+अतत् ) means Atman+atat(आत्मन्+अतत् ).
Atman, That and Thou 
When Uddalaka is having dialog with his son Shvetaketu, if he is saying “O Atman, that thou art”, what are these words referring to? Since “Atman” is addressing, “thou” must also refer to Atman. If “thou” points to the Supreme inner self, then the statement simply means “O Supreme inner self, you, the Supreme inner self is that, Supreme inner self”. This simply becomes a redundant statement that is trivially true. There are only two ways the triviality can go. One is Atman refers to individual self and that refers to Supreme inner self and negating their selfsameness is the purport. “O Individual self, you are not that Supreme inner self.” The second way is to note that in Vedic grammar, the Nominative case is representative of other cases. In Accusative case sense, it means that the very object and purpose of an Individual self is Supreme self. In Instrumental case it means that the Supreme inner self or the Lord is instrumental for every action of Individual self. In Dative case, it means the very goal of Individual self is to reach the Supreme inner self. In Ablative case, it means the very origin of Individual self is the Supreme Self. It also means that Individual self is eternally dependent on Supreme self. In Genitive case, it means that Individual self does not own anything as everything belongs to Supreme self. The individual self itself belongs to Supreme self. In Locative case it means the Individual self is located in Supreme self and thus always seeking support for the very existence. Thus in every which way, the eternal dependence is indicated.
Who decides what are Mahavakyas 
Who determines as to what are Mahavakyas or Grand Pronouncements? Everyone can go with his own selection of statements and pronounce that these are Mahavakyas. Even a bigger issue is that if these Mahavakyas contradict other statements in Vedic literature, how can the trust ever be placed in vedic literature itself, since that is tantamount to saying that the vedic literature contains self-contradicting bunch of statements that are not much more than some blabbering by some nomads. Note the explicit statements in Mundaka Upanishad 3.1.1 and Shvetashvatara Upanishad 3.6.6 like -
dvaa suparnaa sayujaa sakhaayaa samaanam vRiksham parishasvajaate | tayoranyah pippalam svaadvattyanashnannanyo abhicaakashiiti ||
The individual self and Supreme self are compared to two birds – they stay on the same tree, one constantly consuming the delicious fruits (and still never satisfied), and the other does not consume anything and yet eternally satisfied.
There are several statements, which describe greatness of Supreme self and pitiable state of individual self. The works like Gita and puraanas further stress this fact.
Context and examples 
Now when Shvetaketu completes his studies and comes home and shows his arrogance, that is when his father Uddalaka starts this dialog. His instructions must include something that takes away his arrogance. That being the case, why would the father address the son and tell him that the Individual self of Shvetaketu is same as the Supreme self? No philosopher would equate the dress or the physical body to either the individual self or Supreme self. On the same token, one must not also equate the Individual self with the Supreme self. The Supreme self is not dependent on cosmic Maya to perform His actions like creation nor can He become a victim of avidya(ignorance) that can degenerate Him to the level of Individual self.
Further, the nine examples that are given by Uddalaka to Shvetaketu speak of the differences and dependency and thus removing any scope for interpretation of identity in that statement.
Avadhuta Gita 
Sanskrit in Devanagari:
तत्त्वमस्यादिवाक्येन स्वात्मा हि प्रतिपादितः ।
नेति नेति श्रुतिर्ब्रूयादनृतं पाञ्चभौतिकम् ।। २५।।
tattvamasyādivākyena svātmā hi pratipāditaḥ /
neti neti śrutirbrūyādanṛtaṁ pāñcabhautikam //25//
By such sentences as "That thou art," our own Self is affirmed. Of that which is untrue and composed of the five elements - the Sruti (scripture) says, "Not this, not this."
- Raphael, Edwin (1992). The pathway of non-duality, Advaitavada: an approach to some key-points of Gaudapada's Asparśavāda and Śaṁkara's Advaita Vedanta by means of a series of questions answered by an Asparśin. Iia: Philosophy Series. Motilal Banarsidass. ISBN 81-208-0929-7, ISBN 978-81-208-0929-1. Source:  (accessed: Tuesday April 27, 2010), p.Back Cover