FORBIDDEN PLANET was the first big-budget science fiction movie, and the only one for over a decade. It is loosely based on Shakespeare's
The Tempest, the story of Prospero the Sorcerer and his daughter Miranda, who are alone on an island until a storm brings their former countrymen to them. Robby the Robot is the obedient Ariel. And the Id is the powerful and angry Caliban. The gadgets and special effects seem almost quaint to us now, but the movie is still fun to watch for younger children and it still raises some important questions for older ones.
The Id, of course, is named for Freud's famous concept of the id, the instincts and impulses of the unconscious mind. Morbius says that he and his wife survived because they were the only ones who loved the planet and wanted to stay, that the monster was created from the fears and jealousies of the other colonists. The implication (more explicit in portions cut from the film), is that Morbius' jealousy when Alta falls in love with Adams brings the Id's destructiveness out again. In a way, this movie is more a way of exploring unconscious feelings we all harbor than it is speculation about life in the future or on other planets.