Turiya - The Fourth State
The transcendent awareness beyond waking, dreaming, and sleep.
Turiya is not a state but the Self itself - pure consciousness that witnesses all states. It is the background of awareness in which the three states appear and disappear.
Neither inward-turned nor outward-turned consciousness, not knowing, not unknowing - this is the Fourth, the Self.
Turiya is the direct experience of non-dual awareness.
Mandukya Upanishad
Written about in
- What the Upanishads say about the self
The fourth is not another state but what the other three appear in. The Mandukya will only describe it by negatives: not inward, not outward, not knowing, not unknowing.