M. C. Escher remarked in his essay “The Impossible” that “Whoever wants to portray something that does not exist has to obey certain rules.” The majority of science fiction stories are not plausible extrapolations upon our current situation, using available information; rather they are Escheresque impossible objects which use the principles of science in much the same way that Escher used rules of geometric symmetry—the rules give form to the impossible imaginative content.

Sf allows us to understand and experience our past, present, and future, in terms of an imagined future. Like the conventions of perspective in drawing, which allow us to extrapolate railroads from two convergent lines crossed by a lot of parellel line segments, the conventions of sf allow us to imagine a physical world beyond the frame of the scenes described. All sf about the future, no matter how rigorously constructed, must build its future from fragments of the past and present; the futures we construct are as much a part of the present as we ourselves are; although they will never really be the future, they can represent it.

Physical law tells us that many things are impossible given existing technology, but the ever-expanding frontier of scientific knowledge shows us how to do many things of which we would never have dreamed. Writing stories within the rules of the universe as we know it and yet discovering fantastic possibilities of new ways of life is the central endeavor of the hard sf writer. Sf writers prefer to give us truth, rather than reality. Sf represents what the future could be like, although we know that the future will look nothing like it. Sf allows us to know about our future, although when we meet it we may not recognize it.

There has been a persistent view that “hard” sf is somehow the core and center of the sf field; that all other sf orbits around this center; and that the characteristic of this core is a particular attitude toward science and technology. What we habitually call “hard” sf is more precisely technophilic sf, an attitude which Poul Anderson described in the 1970s: “Science, technology, material achievement and the rest are basically good. In them lies a necessary if not sufficient condition for the improvement of man’s lot, even his mental and spiritual lot.” He also differentiated the hard sf story from other varieties of sf: “A hard science story bases itself upon real, present-day science or technology and carries these further with a minimum of imaginary forces, materials or laws of nature.” One is more likely to identify a story as “hard” sf—regardless of the amount of actual science it contains—if the narrative voice is pragmatic, deterministic, and matter-of-fact about the many high-tech artifacts among which the story takes place, and if the future (or clearly alternate present or past) in which the protagonist lives is primarily the result of significant technological change from the here-and-now. Through repetition we have come to identify this narrative voice as “futuristic.”

Like utopian fiction, science fiction grew out of the desire to create and predict the possibility of a better world. In sf, this better world will be created and predicted through science and technology: scientific exploration and technological innovation are political acts leading to world salvation. But without the tradition of the folk-tale, sf, should it exist at all, would be a literature of didactic tracts, blueprints for “utopia.” Fortunately, the enlightened, rationalistic, utopian impulse collided with the irrational, romantic, fanciful folk story-telling tradition.

In addition to its connection to the folk-tale, sf has another important connection to pre-literate culture. Before the Reformation, when only the clergy were allowed to read the Bible, the laity looked to religious art not for representations of daily reality, but for revelations of the principles underlying reality—to discover the sacred texts. Sf is the religious art of science. While of course anyone who can read today is as entitled to read scientific texts as they are to read the Bible, the habits of “reading” religious art have carried forward to the way we read sf. We read sf not for representations of our daily lives, but for revelation of the principles behind everyday experience—the cosmic order. As young teenagers we may have read science fiction to learn about science itself. As adults, we probably already know most of the science, perhaps better than many of the authors whose works we read, but science linked to story-telling gives us an emotional experience difficult to replicate while confronting mundane reality alone, without the company of a book.

Since the founding of the science fiction field in the nineteen-twenties, science has been the guiding force of science fiction, and to some extent science fiction has been able to reciprocate. Could there have been a space program without science fiction? While the robots that make cars in Japanese factories bear precious little resemblance to those in I, Robot, they might not now exist were it not for Isaac Asimov and company. Several generations of scientists and engineers have grown up reading sf, learning that there is such thing as science, and if they work hard in school they can play too—science fiction influenced the career choices of such scientists as Carl Sagan and the late Gerald Feinberg. A number of sf readers turned scientist have later in life become science fiction writers: Fred Hoyle, Gene Wolfe, John Cramer, Carl Sagan, Gregory Benford, Robert L. Forward, and Don Kingsbury, just to name a few. Despite this connection between science and sf, the nature of this connection remains largely unexplored.

The early defense of sf emphasized the wonders of science and the sensation that they arouse in the reader—at its best, science fiction tends to be about the emotional experience of discovering what is true, often represented by scientific discoveries of great consequence. In traditional hard sf, the story is to be taken very literally, instisting on it more strongly than any other kind of English-language fiction.

However over the last couple of decades not enough attention has been paid to those virtues that science fiction derives from its unique relationship with science. During this time, the relationship between science and science fiction has been de-emphasized in favor of the relationship between science fiction and Literature. By now a significant portion of the field’s practitioners prefer to call sf “speculative fiction,” because the social position of a “futurist" is more desirable than that of a “science fiction writer." From this view, speculative fiction, which addresses not just the past and present, but also the glorious, mysterious future, is a much broader field than “mainstream” (the sf world’s dismissive term for non-science fiction) set in the currently-known or historically-known world, usually involving only those characters and situations that we conceive of as appropriate to a realistic account. Thus defined, mainstream is a subset of science fiction, and the greats of literature are, intentionally or not, merely speculative fiction writers without much talent for speculation.

Although John W. Campbell promoted this view of sf, stripped of Campbell’s technologically oriented futurism it takes on a different meaning: science is marginalized in favor of social extrapolation. While the prose style of the average science fiction story has improved, many of the best writers have been distracted from the task of working out their own syntheses of science and fiction, and so it goes: out go the paragraphs giving clear evidence that the writer spent all day calculating the nature and quality of eclipses on a planet with five moons, and in come paragraphs of carefully observed description of the protagonist’s moods, signifying the writer’s sincere obeisance to the conservative but currently fashionable belief that all good stories are “character driven.”

Hard sf also interacts with the technologies and accompanying institutions that produce and distribute it. In the twenty years since the death of John W. Campbell, much has happened to obscure his technophilic vision of science fiction. The hard sf attitude became a salable commodity on its own, separable from scientific content. Particularly during the Reagan years, “hard sf” evolved into right wing power fantasies about military hardware, tales of men killing things with big machines, fantasies that had very little to do with scientific thought or theory.

In that era, the majority of the most talented younger sf writers were quite uninterested in writing about science, precisely because what was generally perceived as hard sf was rapidly degenerating into political allegory. In the midst of this, many writers were still writing good hard sf: Isaac Asimov, Arthur C. Clarke, Charles Sheffield, Joe Haldeman, Donald Kingsbury, Gregory Benford, Greg Bear, Paul Preuss, and Joan Slonsczewski. Simultaneously, certain of the cyberpunk writers, Bruce Sterling, William Gibson, and Rudy Rucker, were bending certain tropes of hard sf to their postmodern project. A number of good hard sf stories have appeared in the past few years by such writers as Geoffrey Landis, Connie Willis, George Alec Effinger, and Lois McMaster Bujold.

The 1983 Eaton Conference on hard science fiction conference brought together literary critics and “writer/scientists” Robert L. Forward, David Brin, Gregory Benford. They discussed many aspects of the affect of hard science fiction, but judging by the published proceedings of the conference, some basic connections between science and fiction remained obscure.

Having served on panels on hard sf at conventions, I had noticed certain rhetorical patterns in the claims hard sf writers made for hard sf. Whenever possible, they minimize the differences between very hard science fiction and science itself. For example, David Brin, in his essay “Running Out of Speculative Niches: A Crisis for Hard SF?” astutely observes that in a hard sf story, “‘science” itself ... is a major character” (p. 8). He goes on to describe how something rather like peer review transpires among hard sf writers. While I acknowledge that this sort of interactive reading occurs among hard sf writers and among writers in other genres and subgenres, the general drift of Brin’s essay in the Eaton Conference Proceedings, and for that matter Forward’s, entitled “When Science Writes the Fiction,” and Benford’s, entitled “Is There a Technological Fix for the Human Condition?”, is that science and hard sf are very similar. This perception of the similarity of science and hard sf is manifest in Beford’s definition of hard sf in that essay:

My miniumum definition of hard sf demands that it highly prize fidelity to the physical facts of the universe, while constructing a new objective “reality” within a fictional matrix. It is not enough to merely use science as integral to the narrative… Sf must use science in a specualtive fashion. The physical sciences are the most capable of detailed prediction (and thus falsification by experiment), so they are perceived in fiction as more reliable indicators of future possibilities, or stable grounds for orderly speculation.

But, as mathematician Henri Poincaré pointed out, only a small of minority of the human race experiences mathematics pleasurably. So, while mathematics is the bones holding up the scientific animal, the science must be “de-boned” before it can be used in fiction, because the majority of readers, even hard sf readers, will tolerate very few equations in a work of fiction. Even the anthology Mathenauts, edited by Rudy Rucker, contains, to my count, only four equations, and of those, none are beyond the ken of a high school freshman.

Although some hard sf writers take the same attitude as Leonardo Da Vinci, who claimed in his essay “On Painting and Science” that “No human inquiry can call itself a true science if it is not confirmed by mathematical proofs,” and expect that the scientifically literate reader will whip out her calculator and discover that all the math behind appearances works out, as often as not it doesn’t. In this sense science and hard sf are very different.

Hard science fiction is a lively and diverse literature that attempts to get at the power and wonder of science, to articulate the sensation of discovering the true and the real. Stories like “The Singing Diamond” by Robert Forward and “Surface Tension by James Blish hit the reader with a shot-gun blast of ideas; at the right moment, under the right circumstances, reading a story like that can capture the feeling of making a major discovery.

Hard science fiction is about the aesthetics of knowledge, even knowledge of the most disturbing, overwhelming kind—that which is bigger than one’s loving or hating it. In Philip Latham’s “The Xi Effect,” Edgar Allen Poe’s “Descent in the Maelstrom,” and Arthur C. Clarke’s “Transit of Earth” this knowledge is deadly, but its revelation is numinous. Hard sf is at its core beyond questions of optimism and pessimism, beyond questions of technology and application. Hard sf recognizes wonder as the finest human emotion.

As most sf readers already know, hard sf has an identifiable feel, a particular kind of narrative voice, the right attitude. This attitude is respectful of the principles underlying the practice of science, not unlike the reverence one should display when entering the chapel. A rationalist cosmology accompanies this attitude: a cosmology based on the belief that the literal facts of a situation are more important than any interpretation. The anti-mysticism of hard sf is a point of pride for sf writers (and scientists of similar mindset) who see science as a replacement for religion and superstition.

In his essay on metaphor, entitled “On Truth and Falsity in their Extramoral Sense,” the philosopher Friederich Nietzsche describes what he feels to be the literal, factual, non-metaphorical situation of humanity, which might easily serve as a description of the hard sf cosmography:

In some remote corner of the universe, effused into innumerable solar-systems, there was once a star upon which clever animals invented cognition. It was the haughtiest, most mendacious moment in the history of this world, but yet only a moment. After Nature had taken breath awhile the star congealed and the clever animals had to die.

The lifespan of our sun is but the briefest moment in the history of the universe; everything we value will vanish soon unless we spread ourselves across the universe, or unless there have been, are, or will be other intelligent life forms out there. Hard sf writers try to find a way out of this dilemma. Hard sf uses the rules of a deterministic universe to show us that our fate not yet sealed. As Hal Clement remarked in conversation, in hard sf, the universe itself is the antagonist.

Hard sf’s problem-solving attitude toward our inevitable extinction has three corollaries: (1) no precondition of viable intelligent life is irreplaceable, given enough scientific knowledge, (2) the replacement of things needed to sustain life is necessary, desirable, and promotes the long-term survival of our species, (3) the scientific should replace the unscientific. Nietzsche’s pronouncement that “the clever animals had to die” is a depressing thought for the realist; but for the hard sf rationalist, it is an exciting challenge! Hard sf’s strong connection to physics—one of the last systems of classical idealism to retain its intellectual validity—allows hard sf to continute to take on the most all-encompassing aspect of the human condition, our survival as a species. The technophilic wing of the science fiction community treasures the thought that because of our interest in and enthusiasm for technological innovation, we may just be the next stage of human evolution. This notion leads to one of hard sf's paradoxes: if our faith in science replaces religious faith, science is coopted into becoming a religion, which, of course, would be unscientific. The work of Arthur C. Clarke best shows the tension between science and religion within hard sf: some editions of his novel Childhood’s End carried the disclaimer that the opinions in the book were “not those of the author.” His Christmas hard sf story “The Star” also shows this tension: the story “explains” the Star of Bethlehem in hard sf terms, a scientific and technological notion replaces a religious one; yet, were it not for Christianity, this replacement would lack meaning.

The primacy of the sense of wonder in science fiction poses a direct challenge to religion: does the wonder of science and the natural world as expreienced through science fiction replace religious awe? It is perhaps no coincidence that a similar controversy has emerged in the New Age movement over whether or not true enlightenment can be attained through the use of meditation machines— are electric revelations authentic? If not, how can we tell the difference?

The idea that in the future better and more scientific things will replace all the things we currently need and use—a cosmic belief in an ever-improving standard of living—constitute what I call the replacement principle of sf. Robert Heinlein’s “It’s Great to Be Back” expresses this idea in strong terms: a family returning to Earth after years on of living on the Moon discovers that their nostalgia for the lushness of Earth and the richness of its societies was misguided sentimentality. Frederick Pohl’s “Day Million” describes a society in which most of what we know has been replaced by something more futuristic, but he makes less attempt at salesmanship. While atomic light bulbs no longer seem like such a good idea, the notion of living in an L5 colony, traveling to another planet, and communicating with an extraterrestrial intelligence still enchant us. If “slow glass” as described in Bob Shaw’s “Light of Other Days” were commercially available, many of us would buy it. And we remain fascinated by such technologies as cloning (see Ursula K. Le Guin’s “Nine Lives”) and time travel (see Ian Watson’s “Very Slow Time Machine”). The big ideas of hard science fiction are more ambitious than the creation of any single device. Hard science fiction shows us many alternate places to live: space stations, other planets, undersea communities, and so on: hard science fiction takes the position that we should have the knowledge and technology to create, from the building blocks of the universe, everything we need to have rich and happy lives, so as to end our child-like dependence on the Earth and what nature gives us.

Though some hard sf writers claim that their future worlds and situations never violate physical law, and therefore just might happen, most sf scenarios are at least implausible, often wildly so, and many are outright impossible. The long-standing controversy over whether sf writers should use faster-than-light travel in their stories exposes the various conflicting demands upon the writer: because of sf’s utopian goal of saving humanity from extinction, it is a game that must be played by the rules; it will do no good to beg for favors from the uncaring universe. Eliminating FTL from possibility does rather limit our options: we’re all dressed up with no place to go. And yet, we must become a self-made species, become the fittest, so we can survive the inevitable death of our sun.