Several of the irrational elements of 20,000 Leagues Under the Sea seemed more outrageous in the 19th century they do now. However, the novel continues to encapsulate the fantasy and science fiction genres because of its willingness to expand the boundary of what is real. Interestingly, 20,000 Leagues Under the Sea did not stretch those boundaries much further than hard science has. On the other hand, novels such as the ones in the Twilight series are more squarely fantastical. Barring any major scientific discoveries, vampires and shape-shifters simply do not exist. Such elements of the absolutely impossible serve various literary functions. For instance, in New Moon Stephanie Meyer uses vampires and shape-shifters to develop the central character, a human being. As in Frankenstein, the impossible becomes the best means to explore human motivations, dreams, desires, and weaknesses.

Moreover, the fantasy elements are not inherently good or evil in New Moon. Whereas in 20,000 Leagues Under the Sea, creatures like the giant squid are one-dimensional, in New Moon, the vampires are complex and multi-faceted characters. The vampires are so close to being human that they enable a frank exploration of the human psyche without being restricted to the mundane issues that people face in their daily lives. Readers relate as much to the vampires as to the human characters.

In New Moon, the vampires have the potential to enlighten and harm Bella in ways that ordinary humans could not do. The vampires offer Bella a chance ot be special and unique -- a means to set Bella apart from the human race. Themes like belonging can be explored...

Ultimately Bella must choose what world she belongs to, and that personal journey is at the core of New Moon.
As someone who appreciates historical fiction and biographical material more than science fiction and fantasy, the otherworldly elements of fantasy sometimes seem superfluous to me. I do not think that elements of the impossible are needed to relay deep existential issues. I also believe that the real world presents enough problems and challenges that fantasy ones can even seem trivial in comparison. At the same time, I have come to understand the difference of using fantasy as a literary technique vs. capitalizing on what the real world has to offer. Fantasy enables the use of metaphor, and the metaphors used in fantasy and science fiction permit the themes of the novel to become universal. This is probably one of the reasons why fantasy and science fiction can inspire reluctant readers.

Reluctant readers might also discover a sense of wonder and enjoyment in fantasy and science fiction that is impossible to create using the imagery and settings of everyday life. If reading partly serves as an escape from reality, then it makes sense that science fiction and fantasy have become so popular. A reluctant reader who encounters a work of realistic fiction might wonder why they should spend their time reading about events that are boring or mundane. Fantasy, on the other hand, offers readers images like vampires and giant squids.

As Chadbourn points out, the more rational the world gets, the more we need fantasy to inspire us. It is possible that the human brain simply craves imagination. Realism can only take the mind so far in its exploration of literary themes. With fantasy, anything…