“The interpretation of dreams is the royal road to a knowledge of the unconscious activities of the mind,” Freud argued in his influential treatise the interpretation of dreams in 1900. “The earth is heavy and opaque without dreams,” Anais Nin wrote in her dairy  in 1940. “In the olden days, people believed that our dreams were full of clues about the future,” Alain de Botton told a little kid who wanted to know about dreaming. But what, exactly, are dreams and why do we have them? Modern psychology has given us a fair amount of insight on the creative purpose of day dreaming , but — aside from Rosalind Cartwright’s compelling research on how dreams and REM sleep mediate our negative emotions — the studyreams has largely stagnated since Freud day                                                                          .