The Mandukya Upanishad analyzes consciousness through four states. Jagrat (waking) is ordinary awareness of external world through senses—most people identify completely with this state. Swapna (dreaming) reveals consciousness creating entire worlds without external input—the dream-tiger chasing you seems absolutely real until awakening. This demonstrates consciousness's creative power. Sushupti (deep sleep) lacks both external objects and mental content, yet upon waking we report "I slept well" and "I knew nothing"—indicating consciousness persisted as witness even to absence of content. Most philosophies stop here, but Advaita recognizes a fourth state: Turiya (the Fourth), pure consciousness underlying and pervading the other three like thread through pearls. Turiya is not another state to be achieved but the background awareness within which waking, dreaming, and sleeping arise and subside. In deep meditation or through grace, this Turiya consciousness is recognized as one's true nature—ever-present, unchanging, self-luminous awareness that is Brahman itself. Liberation is not entering Turiya but recognizing you never left it; identification with changing states was the illusion.