The best science fiction worlds feel inevitable. Not because they’re familiar, but because they’re coherent. Pick one impossible thing—teleportation, immortality, telepathy—and trace every consequence. The world builds itself from that single change.
Change too much and it falls apart. The reader stops believing.
The Credibility Problem
When a science fiction world has teleportation and telepathy and time travel and magic crystals, you start to notice the seams. The writer is just adding whatever feels convenient for the plot. The world loses internal logic. It stops feeling real because nothing holds it together.
The single change is what creates credibility. It forces the author to think through implications. If everyone can teleport, what happens to cities? To borders? To privacy? To crime? To relationships? The one thing ripples outward, reshaping everything it touches in ways that feel inevitable.
That discipline is generative. It creates the world.
Playing With One Change
I’ve been doing this lately with product ideas. Pick one change and follow it. What if just one element was different?
No database. Everything in the browser. No cloud, local only!
Each one reshapes what’s possible. “No database” pushes you toward local-first, toward what can live in memory, toward sync without a source of truth. “Everything in the browser” surfaces URL encoding, WebAssembly, service workers—a completely different architecture.
The change propagates. That’s the point.
Why One Thing Matters
Without that singular change, you follow well-worn patterns. Use a database because that’s what you do. Put it in the cloud because everyone does. The solutions are familiar because nothing pushes you to reconsider.
Change too many things at once and you’re just listing preferences. “I want it fast and beautiful and cheap and flexible and simple.” Those aren’t changes. They’re wishes.
But change one foundational element—one thing that affects everything else—and your brain has to leave the path. You’re world-building. The single change isn’t a limitation—it’s permission to think differently.
The If If If
The questions are cheap: if if if. But following one all the way through is hard. It means resisting the urge to compromise, to add just one more exception, to let the change slip when it gets uncomfortable.
Good science fiction stays disciplined. It picks one impossible thing and makes everything else follow. The world feels real because it’s consistent, because the author did the work of thinking through implications instead of just inventing conveniences.
Good product design can work the same way. Pick one change that matters. Follow it to its conclusion. See what world it builds.
