sa ātmā tvam eva ity upahṛtya sva-antaḥ tva eva anusartuṃ praviśya viśvato vihāya

sa ātmā (that Self) tvam eva (you alone) ity (thus) upahṛtya (having taken, or considered)sva-antaḥ (within yourself) tva eva (you alone) anusartuṃ (to follow)praviśya (having entered) viśvato (on all sides) vihāya (having gone)

Advaita Vedānta (Ādi Śaṅkarācārya): This verse from the Chāndogyopaniṣad is pivotal in establishing the non-dual nature of reality. Shankara, in his commentary on this Upaniṣad, emphasizes that the phrase 'sa ātmā tvam eva' (that Self is you) points directly to the identity of the individual self (ātman) with the ultimate reality (Brahman). This understanding is foundational to Advaita Vedānta's core tenet of non-duality. Shankara's reasoning, as seen in his commentaries, particularly highlights the importance of introspection and self-inquiry (anvichā) as the means to realize this identity. The directive to 'enter into one's own Self' underscores the introspective path to self-realization, suggesting that one must look inward to find the truth of one's nature, which is none other than Brahman itself. This verse, therefore, encapsulates the essence of Shankara's teaching on the brahman-ātman identity, serving as a direct pointer to the non-dual reality that underlies all existence.

Vaiṣṇava tradition (Rāmānujācārya / Madhvācārya): In the Vaiṣṇava tradition, particularly through the lenses of Rāmānujācārya and Madhvācārya, this verse is understood within the framework of qualified non-dualism (Viśiṣṭādvaita) for Rāmānuja, and dualism (Dvaita) for Madhva. Rāmānuja sees the relationship between the jīva (individual soul) and Īśvara (God) as one of inseparable dependence, with the jīva being a part of Īśvara, akin to a body part being part of the body. Thus, the realization 'that Self is you' is an acknowledgment of one's intrinsic connection with the divine, prompting a devotional path towards Īśvara. For Madhva, the distinction between the jīva and Īśvara is absolute, yet this verse encourages the jīva to realize its true nature and relationship with Īśvara, emphasizing surrender and devotion as the means to achieve spiritual liberation. Both interpretations, while differing in their metaphysics, converge on the verse's emphasis on self-realization and the importance of understanding one's true relationship with the ultimate reality.

Neo-Vedānta (Swami Vivekānanda / S. Rādhākrishnan): This verse, with its emphasis on 'taking "thou art that Self" as the thread' and entering into one's own Self, speaks directly to the universal and practical applications of Vedāntic philosophy in contemporary life. Swami Vivekānanda often emphasized the importance of self-realization as the key to unlocking human potential and achieving a sense of unity and harmony among all beings. He saw the identity of the individual self with the universal Self (Brahman) as a call to action, encouraging individuals to look beyond their petty differences and recognize their shared humanity. Similarly, S. Radhakrishnan, in his philosophical works and speeches, underscored the relevance of this Upaniṣadic teaching in fostering a global vision of unity and cooperation. This verse, therefore, is not merely a philosophical dictum but a practical guide for living, urging individuals to explore their inner depths, find their true selves, and in doing so, contribute to the creation of a more compassionate and interconnected world.

More from this source