It’s really quite simple. What makes a story fall into one genre (Fantasy) versus another (Sci-Fi) is a continuum of imagined time, usually as defined by technology and faith systems. In the former, belief is limited to supernatural concepts, allowing space for the banished world of magic, spirits, and the like, the ghosts that still haunt the glass house of our atheism.
Yet in the end, the story is about relationships, how characters interact. And in both cases, the suspension of the present’s rules, with all their mundane demands, means interactions and emotions leap into the foreground.
That’s why I love working in this genre so much. It’s not disbelief that gets suspended; it’s belief that gets unleashed, for all good Fantasies have rules. They have maps–and maps’ margins are fractured and distorted–but their topologies abide by rules, like non-Euclidean geometries, say. Wiping away technology’s frills and the details of everyday life–no one has a to do list in Fantasies, do they?–clears the path for other thoughts, ones that have a distinct order that draws heavily on our past. Perhaps even on something akin to ancestral memory.