Waking, dreaming, deep sleep, and turya (the fourth state, which is the state of enlightenment). In general, all Western science starts from the reference of a waking state of consciousness. Here, sleep and dreams have appeared as psycho­physical phenomena to be analyzed from the standpoint of the waking consciousness. All the other states—dream, deep sleep, etc.—are analyzed from this perspective. Advaita Vedanta affirms that the waking consciousness is just a relative, not absolute, point of reference. The waking state is not the ultimate, absolute reality. The dream and deep sleep states are a second and third dimension of Pure Consciousness. Thus, we can more easily understand the relative character of wakefulness. Here Pure Consciousness, as revealed in turya, is the real continuous reference.