The final goal of all the seekers on the Advaitic path is the realization of the nameless formless and featureless “tat” (That), “like It really is,” free from the distortions and aberrations introduced by the perceptual apparatus (the normal ‘vision’) we are accustomed to in our day-to-day life. Many a seeker, though very endowed, intelligent and well-read in scriptures, often finds it difficult to discern between one’s own true intuitive grasp of the Ultimate Advaitic Truth and mere intellectual decipherment of the verbal content of the teaching. Bhagavad-Gita highlights this fact eminently when it says:
मनुष्याणां सहस्रेषु कश्चिद्यतति सिद्धये ।
यततामपि सिद्धानां कश्चिन्मां वेत्ति तत्त्वतः ॥ — 7.3, BG.
Meaning: Among thousands of men, one perchance strives for Perfection; even among those who strive and are perfect, only one perchance knows “me” (i.e. Pure Consciousness) in “true essence” ( तत्त्वतः ).
Shankara explains the meaning of the word ( तत्त्वतः ) as “like It Is” ( यथावत् ) i.e. in Reality, in Its essence. From this we can deduce that one who intuits the ineffable Reality in Its essence, like It is, is the tattvadarshI ( तत्त्वदर्शी ). S/he is the true Seer ( द्रष्ट ) of “That” which the 2.4.5, brihadAraNyaka Upanishad exhorts us to find through “listening to, reflecting on what is heard, and by deep contemplative meditation.
आत्मा वा अरे * द्रष्टव्यः * श्रोतव्यो मन्तव्यो निदिध्यासितव्यो मैत्रेय्यात्मनो वा अरे दर्शनेन श्रवणेन मत्या विज्ञानेनेदं सर्वं विदितम् ॥ — 2.4.5, B.U.
Meaning: The Self, my dear, should be * realized * – should be heard of, reflected on and meditated upon. (Translation: Swami Madhavananda).
Bhagavad-Gita explains tattvadarshI in the Second Chapter to be:
नासतो विद्यते भावो नाभावो विद्यते सतः ।
उभयोरपि दृष्टोऽन्तस्त्वनयोस्तत्त्वदर्शिभिः ॥ — 2.16, BG.
Meaning: Of the unreal there is no Being; the Real has no nonexistence. But the nature of both these, indeed, has been realized by the seers of Truth (तत्त्वदर्शी ).
Shankara clarifies further:
एवम् आत्मानात्मनोः सदसतोः उभयोरपि दृष्टः उपलब्धः अन्तो निर्णयः सत् सदेव असत् असदेवेति, तु अनयोः यथोक्तयोः तत्त्वदर्शिभिः । तदिति सर्वनाम, सर्वं च ब्रह्म, तस्य नाम तदिति, तद्भावः तत्त्वम् , ब्रह्मणो याथात्म्यम् । तत् द्रष्टुं शीलं येषां ते तत्त्वदर्शिनः, तैः तत्त्वदर्शिभिः । — Shankara at 2.16, BGB.
Meaning: The nature, the conclusion (regarding the nature of the Real and the unreal) that the Real is verily real, and the unreal is verily unreal; of both these indeed, of the Self and the non-Self, of the Real and the unreal, as explained above; (dRShTah), has been realized thus; (tattva-darshibhih), by the seers of Truth.
‘tat‘ is a pronoun (sarvanAma, lit. name of all) which can be used with regard to all. And all is brahman. And Its name is ‘tat.’ The abstraction of ‘tat’ is tattva, the true nature of brahman. Those who are apt to realize this are tattva-darshinah, seers of Truth. (Trans: Swami Gambhirananda).
In order to give us a feel of who is NOT a tattvadarshI (अ – तत्त्वदर्शी ), Shankara writes at 2.38, Gaudapada kArikA on mANDUkya as follows;
तत्त्वमाध्यात्मिकं दृष्ट्वा तत्त्वं दृष्ट्वा तु बाह्यतः ।
तत्त्वीभूतस्तदारामस्तत्त्वादप्रच्युतो भवेत् ॥ — 2.38, GK.
Meaning: Examining the Reality in the context of the individual and in the external world, one should become identified with the Reality, should have his delight in Reality, and should not deviate from Reality.
यथा अतत्त्वदर्शी कश्चित्तमात्मत्वेन प्रतिपन्नश्चित्तचलनमनु चलितमात्मानं मन्यमानः तत्त्वाच्चलितं देहादिभूतमात्मानं कदाचिन्मन्यते प्रच्युतोऽहमात्मतत्त्वादिदानीमिति, समाहिते तु मनसि कदाचित्तत्त्वभूतं प्रसन्नमात्मानं मन्यते इदानीमस्मि तत्त्वीभूत इति ;
न तथा आत्मविद्भवेत् , आत्मन एकरूपत्वात् , स्वरूपप्रच्यवनासम्भवाच्च । सदैव ब्रह्मास्मीत्यप्रच्युतो भवेत्तत्त्वात् , सदा अप्रच्युतात्मतत्त्वदर्शनो भवेदित्यभिप्रायः ; शुनि चैव श्वपाके च’ (5.18, BG) ‘समं सर्वेषु भूतेषु’ (13.27, BG) इत्यादिस्मृतेः ॥ — Shankara at 2.38, GK.
Meaning: (One should) have one’s delight only in the Self, and not in anything external like one lacking in realization, who accepts the mind as the Self, and thinks the Self to be changing in accordance with the changes of the mind, or at times accepts the body etc. to be the Self and thinks, “I am now alienated from Reality, that is the Self,” and when at times the mind become concentrated, who thinks himself to be united with Reality and in peace under the belief, “I am now identified with Reality.”
The Knower of the Self should not be like that, because, the nature of the Self is ever the same and it is impossible for anything to change its nature; and one should be forever apracyutah, unwavering from Reality, under the conviction, “I am brahman,” that is to say, he should ever have the Consciousness of Reality that the Self, in accordance with such smRti texts as “(The enlightened man) views equally a dog or an outcast” (5.18, BG), “He sees who sees the Supreme Lord) existing equally in all beings (13.27, BG). (Trans: Swami Gambhirananda).
Advaita Vedanta holds a tattvadarshI very highly because only s/he can be a competent and effective teacher of the Non-dual message of Oneness. Bhagavad-Gita says:
तद्विद्धि प्रणिपातेन परिप्रश्नेन सेवया ।
उपदेक्ष्यन्ति ते ज्ञानं ज्ञानिनस्तत्त्वदर्शिनः ॥ — 4.34, BG.
Meaning: Know this by (total body) prostration, by enquiry, by service; those men of Wisdom, who have realized the Truth, will teach thee wisdom.
Shankara emphasizes the point of a tattvadarshi only being (chosen to be) the teacher as he writes;
ज्ञानवन्तोऽपि केचित् यथावत् तत्त्वदर्शनशीलाः, अपरे न ; अतो विशिनष्टि तत्त्वदर्शिनः इति । ये सम्यग्दर्शिनः तैः उपदिष्टं ज्ञानं कार्यक्षमं भवति नेतरत् इति भगवतो मतम् ॥ — Shankara at 4.34, BG.
Meaning: Some only, but not all, know as well as realize the truth. By this the Lord means to say that that Knowledge alone which is imparted by those who have realized the truth and no other knowledge can prove effective.
kaTha Upanishad gives further support:
न नरेणावरेण प्रोक्त एष सुविज्ञेयो बहुधा चिन्त्यमानः ।
अनन्यप्रोक्ते गतिरत्र नास्ति अणीयान्ह्यतर्क्यमणुप्रमाणात् ॥ — 1.2.8, kaTha Upa.
Meaning: The Self is not certainly adequately known when spoken of by an inferior person; for It is thought of variously. When taught by one who has become identified with It, there is no further cognition with regards to It. For, It is beyond argumentation, being subtler even than the atomic quantity. (Trans: Swami Gambhirananda).
Shankara observes at this mantra: “When the Self is spoken of by a teacher who has become identified with brahman that he speaks of, there is no non-comprehension or non-realization. To this hearer, the realization, “I am That (Self),” does come, just as it did in the case of the teacher. This is the idea.
Summing up the various issues, Shankara succinctly defines who a tattvadarshI is in his introduction to the Chapter 4 of Gaudapada kArikA. He says:
ज्ञानज्ञेयज्ञातृभेदरहितं परमार्थतत्त्वदर्शन … | Shankara at 4.1, GK.
Meaning: (One who has realized) the Ultimate Reality, characterized by the identity of the knower, knowledge and the object of knowledge. (Trans: Swami Nikhilananda).