Jouvet was the first to localize the trigger zone for REM sleep and dreaming in the brain stem. In this book he provides a neurobiological and psychological analysis of sleep and dreaming. According to his findings, a dream is the vehicle employed by an organism to cancel or archive the day's experiences on the basis of a genetic program. Dreaming is a process that absorbs a lot of energy.
This theory would also solve the dualism between hereditary and acquired features. An hereditary component is activated daily to decide how new data must be acquired.