In ages of crude, primordial cultures, man thought he could come to know a second real world in dreams: this is the origin of all metaphysics. Without dreams man would have found no occasion to divide the world. The separation into body and soul is also connected to the oldest views about dreams, as is the assumption of a spiritual apparition5 that is, the origin of all belief in ghosts, and probably also in gods. "The dead man lives on, because he appears to the living man in dreams." So man concluded formerly, throughout many thousands of years.