Belief in the existence of the "spiritual essence" of an immortal soul has infused human thought and history. Still, most of today's scientists remain materialists who believe that only the physical world is real. Today's topic pits the scientific materialists against those who believe in the concept of "dualism," which requires some nonphysical component -- call it a "soul" -- to transform the human brain into the human mind. Joining host Robert Lawrence Kuhn are neuropsychologist Warren Brown; parapsychologist Dean Radin; philosopher of mind John Searle; transpersonal psychologist and parapsychologist Charles Tart; and theoretical physicist Fred Alan Wolf.