The story that I'm trying to write at the moment is going to be a post-apocalyptic type of story. The universe was ripped in half by a sort of weapon. As a result the world is deteriorating and the laws of nature are able to be bent if not completely broken. This poses the question; What sort of things should I consider while I get the setting ready? More importantly; What would be considered believable? What wouldn't? I also feel that maybe I should get the plot developed before I make decisions on this. What do you think?
All I can suggest is that you make a note of any rules you create along the way and ensure you stick to them. There's nothing worse than reading about how the gravity of the planet has increased and then in the last scene having the hero make a seven foot jump across a falling chasm. Anything is believable as long as it doesn't go against the rules of the universe you create.
Personally, I prefer science-fiction stories where the writer has focused just as much (or even more) on the science-part as the fiction-part. If your story takes place on Earth, I would prefer that everything in the story is plausible. Think about Star Trek, for instance. Sure they fly all over the universe, use all sorts of weird technology and all that, but most of the things they do can in theory be possible to do for real. There's a bit 'in theory' here, but still. Flying across the universe? Sure, if we can find a good enough power-source. Phasers? Already been made, though not as advanced as the one they are using. Still, the prototype works, so it can be done. Com-badges? We have better ones even today. Teleporting? Well, I didn't say 'everything' was possible. But you get the idea. If we look at Star Wars instead, it's just fantasy. Lightsabers can 'in theory' be possible, but it would require a power-source far better than anything we have today, and it would be very tricky to put it all together. AT-ATs and AT-STs? Fully possible, but pointless. Making a robot walk on two or four legs is too risky. If one leg trips, the whole thing collapses. It would be much better and more practical to put it on wheels, like a car or tank. Death Star? In theory it's possible... but think about it. The pyramids took 30 years to make, and it's a small tomb. How long would it take to build an entire planet? And one that functions as a battlestation on top of it? We're talking centuries, at least. So it's possible, but insanely expensive, and no one who started building it would be see even the half done thing. Even dog fights in space is almost impossible for real. Finding each other in the air above the planet can be tricky, but in space? You could fly around for days in the same area and not find each other, much less fight. Combat like in Star Trek might work with the phasers, proton torpedoes and so on, but dog fights like in Star Wars is not really possible. The point is I would prefer you solve things like this first. Instead of thinking 'this could be cool', maybe think 'this could be cool if it's possible' and do some research. Of course, it depends on what kind of book you are writing and who you are writing it for. If it's just a fantasy story set on Earth, go crazy. But if it's sci-fi, don't forget the sci-part.
What is believable is exactly equal to what you can convince the reader to believe. It is a function of your abilities as a writer, or as a bullshitter. I recommend you don't screw around too much with the laws of physics. Those laws hold true over the universe we can perceive with our most powerful instruments. Itr's extremely unlikely that any disaster that could befall this tiny speck of rock out of the untold trillions of objects in the observable universe is going to profoundly affect the laws of physics. Anything that does will likely make that fragile balance of biochemistry called life impossible.
I was thinking that I would make it more fantasy than sci-fi. My plot divice would be that whatever caused the universe to split, it would cause a "reset" if you will. Making it sci-fi would require a lot more research and finding loop holes in the laws of nature and that might make it more fun to write. plus any good fiction comes with a little bullshit as maybe it won't be as difficult as I imagined.
Yeah, I'd go with a strong surrealist edge if I were you. Even a minor change to most of our laws of physics make human life impossible in short order, which makes for an extremely brief and gory story. But if you just get across the idea that 'things we take for granted as the foundation of reality are coming apart' then you have the basis for an exploration of madness, doom and existence that could potentially be quite interesting. Just today I was thinking about something similar, a story where fog descends on the world that makes it gradually harder to see but also seems to eat away at the persistent existence and interconnectedness of physical objects, leaving people confused and isolated. I'd say that sort of thing was still 'science fiction' because it takes a premise and explores it faithfully - story at the service of an idea, rather than ideas at the service of the story, which tends to be a defining characteristic of true fantasy. That's how I see it anyway, people have different definitions, I suppose genre doesn't really matter too much in the end.
Thank you everyone! I was able to use the helpful tips here to set up the initial plot and setting of this story.