Total loss of visual connection with reality. The senses cease to function in the normal way. Total loss of ego. Merging with space, other objects, or the universe. The loss of reality becomes so severe that it defies explanation. The earlier levels are relatively easy to explain in terms of measureable changes in perception and thought patterns. This level is different in that the actual universe within which things are normally perceived, ceases to exist! Satori enlightenment (and other such labels).