Speculative fiction is based on what if. All it takes is one small question to begin the process. What if?
It’s after that – the process of building the then what‘s that really builds the world from the writer’s mind. The then what‘s nail down the particulars. After that, a story shines through.
But don’t think I’m advocating a story about a thing- stories are about people. The character must change; that is the beauty of story.