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Guest Editorial

Disciplined Daydreaming: The Role of Ideas in Science and Science Fiction

by Robert Scherrer

I’m the luckiest guy in the world—my day job is science fiction. I work in theoretical astrophysics—more specifically, in cosmology. So I get to come up with new speculations about the Universe, work out the implications, and write scientific papers explaining my ideas. When I began writing science fiction much later in my professional life, I noticed interesting parallels between the process of generating new ideas for my research and assembling ideas for science fiction stories.

Science fiction has been called “the literature of ideas,” and there’s no doubt that new ideas play a central role within it. Similarly, scientists are constantly developing novel theories to explain new experimental results. But both fields operate under strict ground rules for what is allowed in the way of speculation and what is considered out of bounds. In that sense, science and science fiction are both forms of “disciplined daydreaming.”

What do scientists actually do? In the classic model of science, they conduct experiments to investigate some aspect of the physical world and develop a “model” or “theory” to explain the results of these experiments. Then they make predictions based on this theory and perform more experiments to test these predictions. If the new experiments disagree with the predictions of the theory, it goes straight in the trashcan. But even if the experiments agree with the theory, it’s not proven to be correct, but only allowed to survive until the next experiment.

In practice, this is an idealized model. We scientists are human, and it’s not unheard of for a scientist to hold tight to a favorite theory (particularly one he has proposed himself) even when the experimental evidence against it has become overwhelming. And the author of a particular theory might not be quite so intent on disproving it as the textbook portrayal of science suggests. However, other scientists will certainly be happy to step in and do the job. So even if the idealized model of science is not always an entirely accurate portrayal of the way that individual scientists operate, it does describe how science progresses within the scientific community as a whole.

I’ve made a distinction between theory and experiment, but the various branches of science are organized differently in that regard. Because physics is the oldest of the sciences1 (dating back to the seventeenth century) it has had more time to develop, leading to a clear distinction between scientists who do experiments (experimentalists) and scientists who develop theories to explain them (theorists). In the world of chemistry, there are certainly people who would describe themselves as theorists, but they are a distinct minority. And theoretical biology is just getting off the ground. This doesn’t mean that chemists and biologists don’t develop theories to explain their results—it’s just that the same person often performs the experiment and proposes the theory to explain it.

I would argue that the scientific endeavor closest to the process of developing new ideas for science fiction is the work of theoretical physics (which coincidentally happens to be my own occupation). But the label “theoretical physics” covers a variety of activities. A theoretical physicist might compare theoretical models directly with experimental data. Or, further removed from the experimental end of things, a theorist might engage in “model building,” attempting to construct a comprehensive framework to explain a whole set of experimental data. And finally, at the most speculative end, is what I’ll call “what if?” theoretical physics: postulating a completely new idea and seeing where it leads.

Some of the greatest advances in physics have arisen from “what if?” questions. What if the speed of light is always the same, so that no matter how fast you move, you can never “catch up” with a ray of light? Albert Einstein showed that this idea leads to the theory of relativity. What if energy isn’t continuous, like the water you pour from a jug, but is only produced in discrete “droplets” that can’t be subdivided? This insight led Max Planck to develop quantum mechanics.

It sounds simple: Just come up with a new idea, develop a theory around it, and collect your Nobel Prize. In reality, it’s more difficult. First of all, any new idea has to agree with known experimental results. Experiment is the acid test of science, and inventing theories that are already contradicted by past experiments is a waste of time. But I would go even further and argue that any new idea can’t get too far out in front of the current edifice of science. Even though relativity and quantum mechanics are often portrayed as “revolutions” in physics, neither of them started from scratch. Both theories made use of the concepts of energy, momentum, time, and space that had formed the basis of physics for the previous three hundred years. They just approached these concepts in new ways.

The restriction that science cannot get too far out in front of its existing edifice of knowledge has some interesting consequences. For one thing, it imposes a speed limit on the progress of science—theory can’t get too far ahead of experiment. One of my colleagues in cosmology once said, “You can only invoke the tooth fairy once.” He meant that a theory could introduce one speculative new idea, but no more than one. If you invoke multiple tooth fairies, even if you are correct, no one will believe you.

For example, suppose I built a time machine and traveled back to the nineteenth century. A normal person would use his knowledge of the past to make enormous amounts of money, acquire great power, and rule the world. However, as a scientist my goal would be to steal someone else’s great discovery from the future and claim it as my own. Unfortunately, the only major discovery I can remember is the theory of how the Sun shines, which was one of the major mysteries of nineteenth century science. I proceed to explain my theory to my new colleague, Lord Kelvin, who believed (incorrectly) that the Sun was powered by gravitational collapse:

Me: So you see, the Sun is powered by the fusion of nuclei.

Kelvin: And what are nuclei?

Me: The nucleus lies at the center of every atom.

Kelvin: Really? So these are the fundamental constituents of the atom?

Me: Well, actually, the nucleus is made of other particles, called neutrons and protons.

Kelvin: I see. Very interesting. And how does this so-called “fusion” occur?

Me: Protons collide, and one of them changes into a neutron.

Kelvin: The proton can change into a neutron? I thought these were fundamental constituents.

Me: Well, they are sort of fundamental. They’re actually made of quarks.

Kelvin: Quarks?

Me: That doesn’t matter. The important thing is that the weak interaction can turn a proton into neutron.

Kelvin: What interaction?

Me: Never mind. The main idea is that matter is converted into energy.

Kelvin: But matter is conserved. So is energy.

Me: Well, actually matter and energy are really two forms of the same thing, and . . .

*   *   *

By this time, Lord Kelvin would have thrown me out of his office! The problem is that the true explanation of how the Sun shines requires so many different layers of development beyond Lord Kelvin’s physics (the internal structure of the atom, the discovery of the weak interaction, the equivalence of matter and energy) that it would be essentially impossible for me to explain it to Lord Kelvin. The need to embed new theories within the existing framework of science simply limits the number of new theoretical ideas that can be introduced at any one time.

However, there is one modern counterexample to my claim: a theory that has leaped far ahead of the rest of physics, without any experimental feedback. It’s called string theory. The jury is still out on the final fate of string theory: Will it be the final theory of everything, or an intellectual dead end? It will be interesting to see how this particular experiment in the sociology of science turns out.

GuestEditDD1While new ideas in theoretical physics cannot get too far outside the current scientific framework, any new theory has to go beyond what is already known, or it adds nothing to the body of knowledge. A theorist is always trying to hit the “sweet spot” between boring on the one hand and crazy on the other. And this is one of the hardest skills to teach new research students: how to find that sweet spot in their own work.

But what about science fiction? It also involves the introduction of new ideas, but only under well-established ground rules and within well-constrained boundaries. And just as in the case of science, the trick is to be original enough to be interesting, but not so far out on a limb as to slide into fantasy.

As in the case of science, the introduction of new ideas in science fiction is not arbitrary—science fiction follows its own set of constraints and rules. New ideas introduced into a science fiction story do not need to be rigorously scientific (if they were rigorously scientific, the writer would be doing science!) but they normally involve a plausible extrapolation of known science or some sort of scientific rationalization. For instance, in Poul Anderson’s Brain Wave, life on earth evolved while our Solar System was situated in a region of space that slowed down the speed of nerve impulses. As the novel opens, the Solar System has just moved out of this damping field and the nervous system of every living thing has speeded up, producing a universal intellectual leap. Is this valid science? No, there is no known field or force that would have this effect. And yet the explanation is a reasonable extrapolation of known science.

Note that it’s not enough for a new idea to “sound like” science. That just leads to technobabble, characteristic of a famous television show whose name I will not mention. What is more important is that the idea reflect a scientific approach—it has to “be like” science, and not just sound like it.

This means that only naturalistic explanations are acceptable in science fiction, and this puts a boundary between science fiction and fantasy. If I postulate a virus that is transmitted by the bite of infected person, and which causes photophobia and a need for increased iron intake, I am writing science fiction. If I invoke vampires, it’s fantasy. A novel incorporating a large reptile that synthesizes hydrogen in its digestive system and ignites it by striking its teeth together to generate sparks is clearly science fiction. A dragon is fantasy. The boundary between science fiction and fantasy is not always clear-cut, leading to many arguments and border skirmishes, but that’s a battle best left for another day.

Even fantasy literature itself operates under a (much looser) set of constraints. While supernatural events are allowed, without any explanation or apology, normal rules of logic and psychological consistency still apply. The train of events must be coherent, and the characters must display understandable motivations. Indeed, the range of character psychology is often less broad in fantasy than it is in science fiction (aliens are usually much more “alien” in their thoughts and motivations than elves or wizards). This “realistic” fantasy really took hold in the wake of J.R.R. Tolkien. There is an older tradition of “dream-like” fantasy, characterized by some of the works of, e.g., E.T.A. Hoffmann and Nikolai Gogol. This tradition lives on largely in the world of horror fiction, in which the world really does not make any sense.

So science fiction inhabits the territory between fantasy, on the one hand, and mainstream literature on the other. Introduce too many unjustified assumptions into your story, and you’ve drifted out of science fiction and into the realm of fantasy. But a story that makes no assumptions beyond known science is mainstream literature.

When writers introduce new ideas in science fiction, they usually explain or rationalize them in some way. This process is limited by the fact that the new idea in question is not actually scientifically valid (or else it would be science rather than fiction), but some explanation is normally provided by the author. This explanation cannot be too detailed or it slows down the story. And the more detailed the explanation, the more obvious it becomes that the idea is a fake—it isn’t actually correct science. So the author must walk a fine line between giving too much explanation and not enough.

GuestEditDD2However, some very implausible ideas have become so much a part of the fabric of science fiction that they can be introduced without any justification whatsoever. These include faster-than-light travel and time travel, probably the two most scientifically implausible ideas in all of science fiction. When H.G. Wells introduced time travel in The Time Machine, his narrator gave a detailed explanation of time as the fourth dimension, and he carefully explained how it should be possible to travel along this dimension as easily as along the other three. Wells had to give us this explanation—he was providing the first science fictional treatment of time travel. But a modern author would simply toss in a time machine and let it rip. At the beginning of the Foundation trilogy, Isaac Asimov digressed on the nature of hyperspace, explaining why it allows for travel between distant stars. Nowadays a space traveler would simply jump into subspace or switch on the hyperdrive with a wave of the hand and no further explanation.

Just as in theoretical physics, many of the strongest science fiction novels and stories use the “what if?” approach. What if a planet orbited multiple stars, so that the Sun never set (until it finally did)? Exploring the consequences of this idea led Isaac Asimov to the classic story, “Nightfall.” What if all living things on Earth suddenly experienced increased intelligence, so that humans became superhuman intellectually, but animals developed human intelligence? As we saw, this simple idea is the core of Poul Anderson’s Brainwave. And what if a supercomputer allowed Tibetan monks to enumerate all of the names of God, bringing an end to the Universe? This idea allowed Arthur C. Clarke to write “The Nine Billion Names of God.”

Note that all of these stories invoke the tooth fairy only once. This is particularly necessary when the “what if?” idea pushes the bounds of scientific plausibility. For example, everything in “The Nine Billion Names of God” is scientifically reasonable except for one absurd idea: that the Universe would end once the names of God are enumerated. But the fact that the idea is introduced only at the very end, and in such a matter-of-fact tone, helps this particular “tooth fairy” to do its job.

In the end, then, the process of developing new scientific theories and the creation of new ideas in science fiction both require the creator to go beyond established fact, but to do so within a fairly rigid system of rules and constraints. But there are also some major differences in the way that these “new ideas” are incorporated in science versus science fiction.

Even if science fiction is the “literature of ideas,” the role of ideas in science fiction is actually secondary to the importance of the writing itself. When I began writing science fiction, I would occasionally encounter the following proposition from a colleague: “Hey, I have this great idea. Why don’t you write the story, and we’ll share the credit.” But while good ideas are important, the writing and presentation of the idea and its incorporation into an interesting plot with compelling characters are much more central. The exposition of a new idea by itself is not enough to form a science fiction story. If it did, then many of the most famous works of science fiction would consist of just a single line:

The Lathe of Heaven, by Ursula K. Le Guin: Your dreams can come true—literally!

“The Star,” by Arthur C. Clarke: The Star of Bethlehem was a supernova that destroyed an advanced civilization. Oops!

And, of course, “To Serve Man,” by Damon Knight: It’s a cookbook!

Science fiction needs a plot and interesting characters to keep the reader engaged—a new idea by itself is almost always insufficient to maintain interest. (This is a particular trap for scientists like me when we start trying to write science fiction—instead of a science fiction story, we end up with a speculative science article). As Frederik Pohl said, “A good science fiction story should be able to predict not the automobile but the traffic jam.” Pohl is arguing here that new technology is not nearly as interesting as the social consequences of that technology. However, I would suggest that even the latter does not make a story—what is important is how human beings react to these social consequences. So a good science fiction should predict not the car, not the traffic jam, but the guy who jumps out of his car to take a sledgehammer to the other cars because he can’t stand the traffic anymore.

The place of ideas in scientific research is quite different. When I taught quantum mechanics, I would occasionally mention to the class that the greatest unsolved problem in physics is the unification of quantum mechanics and general relativity—“and if anyone has a good idea about this, let me know and I’ll help you write it up.” This joke is the exact opposite of the offer by my colleagues to share credit for a science fiction story. And it relies on the fact that in science, the idea is central, and the writing is a necessary but minor exercise. This fact occasionally generates friction between beginning graduate students and their Ph.D. advisors. An advisor will present the graduate student with an idea for a solution to a research problem. The student will go off and develop the idea, performing detailed calculations along the way, and then write up the final results. So why does the advisor even deserve to be listed on the paper? Because in science, the idea is essential, the development of the idea is secondary, and writing is tertiary, exactly the opposite of the role these activities play in science fiction.

Do scientists trying to write science fiction have any special advantages? I would argue that they do, but not the advantages that most people assume. Because the writing styles in the two fields are so dissimilar, a scientist first has to overcome all of the bad writing habits that he or she learned when writing scientific papers. Imagine squeezing all of the juice from a lemon—the desiccated husk is a good metaphor for the writing style of a scientific paper. The passive voice reigns supreme: not “I performed this experiment,” but “the experiment was performed by the author.” Scientists qualify every claim: a result is “fairly accurate” or “possibly implied by the data” or “somewhat plausible.” These are nonstarters when it comes to writing fiction or popular-level nonfiction. Even as I write these words, I am fighting the impulse to (slightly) qualify my claims and (perhaps) take a (somewhat) more tentative approach. But as can (clearly) be seen, this article was written by the author in a more conversational and active voice.

Also, I have found it harder to write about my own field of research, precisely because I know it too well and have a natural tendency to apply much higher standards as to what is plausible. I’ve only written one story based on my own research field of cosmology (“Extra Innings,” Analog, Nov. 2004). I’ve found it easier to write about scientific fields that I know much less about, so that I am not constantly second-guessing what is scientifically accurate. In this case, ignorance (or at least a little ignorance) really is bliss.

On the other hand, there are some clear advantages for scientists hoping to write science fiction. A very mundane advantage is the possession of basic writing skills, including punctuation and grammar. High school students often ask what classes they should take if they want to pursue a scientific career. I always tell them that in addition to studying as much science and mathematics as possible, they should take the most demanding possible English classes. This is not what they want to hear, but being able to write fluently and quickly is an exceptionally useful skill in a scientific career.

Scientists have also mastered the ability to extrapolate new ideas from a basis of known facts, a core activity in writing science fiction. And scientists can also be more realistic in writing about the process of doing science, since they’ve experienced it directly. (Gregory Benford, a research scientist himself, gives an outstanding portrayal of this process in his classic novel, Timescape).

Now if you’ll excuse me, I have to get back to my day job: I have some serious daydreaming to do.



1   Astronomy and mathematics are actually older, but astronomy for all practical purposes has become a branch of physics, while mathematics does not follow the experiment/theory model and is therefore not a branch of science, despite being indispensable to scientific progress. (A famous book by Eric Temple Bell described mathematics as “Queen and Servant of Science.”)

Robert Scherrer is a physics professor at Vanderbilt University, specializing in cosmology.  Over the past few years he has been particularly interested in the nature of the dark energy that drives the accelerated expansion of the universe.  He teaches a course on science and science fiction at Vanderbilt and blogs sporadically at

Copyright © 2019 Robert Scherrer

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