A great deal of speculative fiction takes place in a "secondary world"--a make-believe reality that shares enough traits with the real world to tell a meaningful story, but is different enough to raise questions the real world couldn't broach or simply magical enough to inspire awe. Developing deep, cohesive worlds that, though unreal, feel real is a challenge that nearly every writer of speculative fiction will encounter in their career--whether they are writing high fantasy, space opera, cyberpunk, or post-apocalyptic Earth-based fiction.
These last few weeks, I've been building a pair of new worlds of my own: a fantasy realm, and a space opera universe. But to do this, I didn't set myself down with a huge piece of paper and start drawing detailed maps, or begin researching potentially habitable planets and star systems throughout the known universe. In fact, I didn't take a macro view of the situation at all. All I did was write one short story--then another, and another, and another.
Some writers might be scared of tackling their secondary worlds this way. What if in one story you create a piece of technology or a magical system that becomes inconsistent or undesirable in terms of your later work? What if the actions, titles, capabilities, or knowledge of a character or collective compromises secrets or myths you wish to make use of further down the road? What if a city appears where once there was an ocean? These worries can quickly pile up, and force a writer to sit down with a very long piece of paper with which to create a timeline, and a very large piece of paper with which to create maps, charts, and genealogical trees.
For some people, that might be the right way to approach the task. But there are a slew of fantastic things about discovering your secondary world rather than describing it, things that result, I believe, in deeper and more authentic worlds over all.
First of all, the macro approach tends to obscure the truly interesting details of a fantasy world or a spacefaring future. In any story, it is usually far more important what characters think of the world they live in, and how they react to it, than the actual components of that world. And since you, the writer, don't live in your secondary world, there is humongous benefit to be reaped by simply throwing some device or event at your characters, rather than plotting out every conceivable ramification for a piece of technology or fluke of magic. You'll get to see what that unobtainium means to the man who mines it and the woman who turns it into spaceship hulls, rather than the admiral who simply wonders how long that hull can hold out against the alien weapons.
Not only does this develop better stories; it develops better worlds. I've discovered things about my fantasy realm and the people that inhabit it that I never would have realized by pure abstraction. Bread is delicious, and I could conceivably describe the most delicious marble rye imaginable; but bread doesn't rise without yeast. In world building, those microorganisms are your peddlers, your footsoldiers, your craftspeople and your wise-women. Although they appear to be worth very little when you take the long view of a world, without them your world would seem, at closer range, to be full of holes.
A few simple ground rules can give you massive flexibility in creating a world, make it super fun, and leave you stress-free to enjoy the task of writing. For example:
1. Write within eternal timelines: Timelines don't need to be literally eternal; the framework of my space opera, for example, occurs within a ten-thousand year period. But even this range offers me humongous flexibility when it comes to technology, information, political processes, war and peace, planets and living space, economies, the work force, and all the rest. If I write a story and later figure out I don't like some apparently integral aspect of it, well, no problem: that was an integral aspect of the universe four-thousand years ago. The maximizing aspect of this rule is the maxim: nobody cares what date it is.
2. Big names, little worlds: Don't even think about the Chosen One, the Dark Lord, the Apocalypse, or Genesis. Writing about these massive subjects will actually constrict the size of your world, because you will from the outset have defined its outer boundaries. Save these humongous topics for your magnum opus. The inverse of this imperative is: little people, big worlds. The minutiae of regular peoples' lives are infinitely more interesting than the grandiose schemes of gods, prophets and heroes--even in fantasy worlds.
3. Explore, don't claim: Voyage across your world like you don't know what's there yet. Every time you set out, try to find new land. You'll be more interested in your writing, your world will develop more depth, and you'll write better stories as a result. The complement of this idea is: destroy, destroy, destroy. People don't romanticize cultures like the Incas and the Celts because they're our neighbors.
Writing short stories to discover your worlds is a great way to build them. It requires less work on your part as a writer, it will be more fun (i.e., because you'll be writing and not planning what to write), and by following a few basic ground rules you can develop a secondary-world where every aspect of society and reality is thoroughly real, and not just the backdrop to your heroes' epic designs. If you move into the world of the grandiose too early, you risk mythologizing your world--and destroying its reality--by ignoring the little people, places, events and beliefs that make it up.