This is a work of fiction. Still, given an infinite number of possible worlds, it must be true on one of them. And if a story set in an infinite number of possible worlds is true in one of them, then it must be true in all of them. So maybe, it's not as fictional as we think.
Neil Gaiman, Michael Reaves (2013). “Interworld (Interworld, Book 1)”, p.4, HarperCollins UK