There is no such thing as fiction. Who are we to say that alternate realities do not exist?
This is the inspired theme that I use presently in my own fantasy stories of The Morning Star series, and the divine theme that I teach to my aspiring authors across my Story Launching programs.
To write a compelling Science Fiction and or a Fantasy story, authors are coached to write their world as if they are as real as their own believable reality that they reside.
The success of any Sci-Fi and Fantasy Story depends entirely upon the believability of the world they are creating, and this believability begins with the author believing it first.
The preparation and creation of this world, of course, is expanded and expounded upon by the author as the story evolves. And many of these details may never appear in the narrative for the reader. The details of such believable realities are woven and crafted by and for the author ultimately as the book’s foundation.
And only from this believable world do the setting, characters, dialogue, conflict, theme, and story emerge.