SF is rife with tropes (say that quickly a few times).
In mainstream literature, a trope is a figure of speech: metaphor, simile, irony, or the like. Words used other than literally. In SF, a trope—at least as I understand the usage—is more: science used other than literally. Think of it as a willing-suspension-of-disbelief contract between author and reader.
Readers are clearly open to such contracts. Look at popular SF, both literary and media. Look at SF conventions—what con doesn’t have a panel on fictional devices like faster-than-light (FTL) travel?
Why does our genre need its own tropes? Because science can get in the way of a good story. Combine the light-speed limit with the astronomical observations that suggest it is vanishingly unlikely humans share our solar system with intelligent aliens. After enough tales with decades- or generations-long interstellar treks, many of us decided to ignore travel details and get on with the story. (While we could always begin stories after the travel has ended, without faster-than-light travel, such interstellar stories would remain pinned within a single solar system.) The ability to zip between solar systems really opens up plot possibilities.
Time travel, of course, is another popular SF trope. Without time travel, we chop about thirteen billion years from the prospective domain of our stories. Without time travel, we cannot combine SF with the historical-fiction genre.
Not many posts ago I called myself a hard-SF author. You may be wondering how I reconcile that description with the “bad science” of FTL, time travel, and other SFnal tropes. Some of you will be familiar with the Mundane SF movement that rejects such tropes. Mundane SF sticks with near-Earth, near-future stories rooted in today’s science.
I’m not of the Mundane SF camp for two reasons. First, sometimes I want to tell a story just because—I hope—it’s a good story. I’m happy to use a mechanism beyond conventional science in the furtherance of entertainment if the mechanism does not flat-out contradict good science.
That said, I have self-imposed limits. Rule one: no more than one trope per story, because credulity stretches only so far. Rule two: the trope (say, time travel) must follow its own set of rules and constraints, used consistently and with meaningful consequences throughout the story. I try to use tropes as speculative science, not magic.
And the other reason I’m willing to go beyond known science? Humility. Thinking back on scientific advances since, say, 1900—like heavier-than-air flight, quantum mechanics (QM), relativity, molecular biology, and digital computing—I refuse to believe that today’s scientists know all the universe’s possibilities.
Take FTL travel. Yes, relativity has been confirmed time and again. That said, relativity has never been reconciled with quantum mechanics, which also has been confirmed time and again. Something very basic eludes us. Here are three ways we might get to FTL travel:
- String theory is an attempt—not yet past the playing-with-numbers stage, and still lacking testable predictions—to reconcile QM with relativity. If string theory has merit, it expands the number of dimensions in the universe. Maybe one or more of those dimensions offers us a shortcut.
- Our entire universe may be a four-dimensional piece of a higher-dimensional multiverse—if so, there may be shortcuts available through other universes.
- Or take cosmic inflation: it solves issues with Big Bang theory but lacks a theoretical justification of its own. A variable speed of light, at least during the early universe, eliminates the need for inflation theory. If light speed was different in the early universe, maybe it can be made locally different now.
With those possibilities as legitimate physics topics, I see no reason to surrender my hard-SF union card in order to use FTL in stories.
Time travel offends our sense of cause and effect—but maybe the universe doesn’t insist on cause and effect. Quantum mechanics is, at its roots, acausal. That’s why, for example, no one can predict when a given uranium-238 nucleus will spit out an alpha particle. Physics defaults to discussing the probabilities. (Then again, what about QM doesn’t violate our sense of how the world works?) And it’s not like a physicist can tell you what time is, or why we feel it flows in one direction. For me, it’s premature to declare time travel impossible.
My personal blog has a long-running, randomly scheduled series of related posts: Trope-ing the light fantastic. Those posts have looked at the cases for and against FTL, time travel, artificial intelligence, telepathy, universal translators, life-sign detectors, and alien abductions.
I’ll leave you with the first of Arthur C. Clarke’s laws of prediction: “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”
EDWARD M. LERNER worked in high tech for thirty years, as everything from engineer to senior VP. He writes near-future techno-thrillers, most recently Fools’ Experiments and Small Miracles, and far-future space epics like the Fleet of Worlds series with colleague Larry Niven. Ed blogs regularly at SF and Nonsense.