[S]cience fiction as a form is where theological narrative went after Paradise Lost, and this is undoubtedly true. … The form is often used as a way of acting out the consequences of a theological doctrine. .. Extraterrestrials have taken the place of angels, demons, fairies and saints, though it must be said that this last group is now making a comeback. We want wisdom. We want hope. We want to be good. Therefore we sometimes tell ourselves warning stories that deal with the darker side of some of our other wants.
via The Guardian