"Where there is a duality, as it were, there one sees another; there one smells another; there one tastes another; there one speaks to another. . . But where everything has become just one's own self, then whereby and whom would one see? Then whereby and whom would one smell? then whereby and whom would one speak? then whereby and whom would one hear? then whereby and whom would one think? then whereby and whom would one touch? then whereby and whom would one understand?"
- Brihadaranyaka Upanishad (2.4.14)
"My connection with the body and its parts is dissolved. My perceptive organs are discarded. Thus leaving my material form and bidding farewell to my knowledge, I become one with the Great Pervader. This I call sitting and forgetting all things."
(~ 4th century BC)