This tremendous equation – “the Self is Brahman” – is the central discovery of the Upanishads. Its most famous formulation is one of the mahavakyas or “great formulae”: Tat tvam asi, “You are That.” “That” is the characteristic way the Upanishads point to a Reality that cannot be described; and “you,” of course, is not the petty, finite personality, but that pure consciousness “which makes the eye see and the mind think”: the Self.
