ABSTRACT
Mantras represent a cosmic non-linguistic language that creates a connection to the reality that lies beyond language. The mantra encountered most often in the Upanisads is om. The syllable om is absent from the Rgveda, but is referred to as the pranava ("reverberation"), a name later often used for it, in the Taittiriya Samhita. The Katha Upanisad, like the Taittiriya Upanisad, identifies om with brahman itself, while the Mandukya Upanisad divides the syllable up into four parts and uses the fourfold om as the starting point for elaborating on the idea of the four states of the atman: wakefulness, sleep, dreamless sleep, and a mystical state beyond all these. The fourth state, associated with the deepest possible insight into reality, is here identified with the syllable om in its entirety. In the Samaveda Upanisads, textual authority is occasionally located outside the Vedic tradition itself, in the "speech" of animals, or the crackling of the fire.
