Central to the teachings in the Upanishads is the focus on the enunciation of mortal vs. immortal. Amid all the changes manifested in the dynamic universe lies something that is unchanging and everlasting. This essence of eternity is identified as Brahman, the ultimate source. This Brahman is also the abiding atma in individual beings, as claimed by the sages.
Chandogya Upanishad propounds the philosophy behind the Mahavakya ‘Tat Tvam Asi’ (That art Thou). Sri Mani Dravid Sastrigal referred to the story of Svetaketu’s enlightenment while explaining this cosmic truth during a discourse. Uddalaka is unhappy that the knowledge gained by his son even after receiving 12 years of Vedic instructions from his mentors is inadequate. He questions Svetaketu whether he had requested his teachers for the knowledge by which the unhearable, the unperceivable and the unknowable can be revealed. Perplexed, Svetaketu answers in the negative, adding his venerable teachers themselves may be ignorant of this truth. He sincerely pleads with his father to enlighten him further.
The father elucidates with simple examples drawn from day-to-day life. For making any object, the prime requirements are the raw material, the tool and the maker. It is well known that items made of mud are not different from the mud, nor are the objects fashioned out of gold different from gold. In the case of the universe, Brahman is the material, the instrument and the maker. The entire creation is no different from the all-pervading Brahman. “The bees gather juices from many flowering plants and trees and make honey. The merged juices now do not know from what flowers they severally came. Similarly, all creatures, when merged in the one Existence, do not know that they are merged in Him and come from Him.”
Uddalaka adds: “In the beginning, there was Existence alone; that is one only, without a second. He thought ‘Let me be many and let me grow forth.’ Out of Himself, He thus projected the universe. He entered into every being and every thing. All that is has its self in Him alone. He is the Self. And that, Svetaketu, That art Thou.” The prapancham is the manifestation of Brahman wherein all have their source.