Like a sewer, science fiction has the quality of whatever is dumped down its drains. To call a sewer a genre of pipe is as useful as calling science fiction a genre of literature, and yet people frequently call themselves "genre writers", and critics speak of "genre fiction"—as if either term disguised the stink in the air.
Taxonomically, science fiction may be a sub-genre of the broad literary genre of "fiction", just as "detective fiction" and "romance fiction" are sub-genres, but the label allows too much of what is happening underneath the problematic words science fiction to slip away unnoticed, unblamed, unscathed. Meanwhile writers, readers, and critics merrily miss an array of points and possibilities.
There was a time when calling science fiction a genre made good sense. Stories, novels, television shows, and movies which were so labeled had a variety of elements in common. The usefulness of science-fiction-as-a-genre ended (at the latest) by the time of the New Wave in the 1960s, and I expect it had stopped being useful somewhere around the first issue of The Magazine of Fantasy and Science Fiction in 1949, which brought a very different sort of esthetic to readers who had previously been reading Astounding, Thrilling Wonder Stories, Planet Stories, and other pulps. Audiences began to split away from each other, and with them went any infallible definition of "science fiction".
To be a genre, something must have clear and identifiable elements that carry across different circumstances and tastes. An old edition of A Handbook to Literature has a usefully conservative definition: "Genre classification implies that there are groups of formal or technical characteristics existing among works of the same 'kind' regardless of time or place of composition, author, or subject matter; and that these characteristics, when they define a particular group of works, are of basic significance in talking about literary art." (200)
Science fiction no longer has enough common characteristics to be any sort of genre other than fiction. Yet, simply to call science fiction "fiction" would be to lose some obvious and important distinctions between science fiction and everything else in the world. Though it's difficult to come up with a satisfying and comprehensive definition of the form, most readers have an intuitive sense of what is or isn't science fiction, and this intuition suggests something separates SF from other forms of writing, even if it may be indefinable.
For the moment, let's call science fiction a "style", a certain way of approaching a narrative. The style itself has broadened over the past half century or so, and the use of SF tropes and techniques in films, TV, comic books, etc. creates a separate audience of its own, while within literary SF, the audience is more varied than it ever has been. Within the main genres of fiction, poetry, and drama, such fragmentation is common and accepted. However, SF editors and critics have often seemed to work hard to define the One True Science Fiction, which, paradoxically, may be the only thing that could kill SF as a distinct style of writing, because it limits possibilities rather than adding to them, forcing science fiction to remain a form the way a sonnet is a form of poetry. The critic who says, "Jonathan Lethem is not an SF writer" has put a nail in the coffin of SF, however it is defined.
In "The Semiology of Silence", the first of his Silent Interviews, Samuel R. Delany proposes that science fiction is a way of reading with a codic system distinct from that of other types of writing, but that analyzing or defining SF based on subject matter is at best an illusion:
Poems often have different subject matter from mundane fiction. Dramas frequently have different subject matter from poems. And films frequently have different subject matter from dramas. But no sophisticated analysis of poetry, fiction, drama, or film would try to present an exhaustive analysis of each field, or its differences from the others, purely in terms of appropriate and inappropriate subject matter—purely in terms of traditional category themes. (28)
Delany's statement is important and insightful, but it is not an exact analogy, because science fiction is, itself, a type of fiction, as well as a type of film, a type of video game, a type of comic book, a type of poem, and even, perhaps, a type of drama, though few plays have ever been labeled as SF. Delany is not fundamentally wrong: with science fiction, subject matter is (or at least should be) secondary to the systems of codes that determine how any given text is interpreted by a reader or viewer.
Hence, the paradox: science fiction functions like a major genre of literature along with fiction, poetry, and drama, but it also functions like a sub-genre of any one of those, and no strict definition of either genre or sub-genre is comprehensive enough to cover what all science fiction is and does.
Describing science fiction's existing subject matter, and labeling existing works as science fiction based on subject matter, is an essentially harmless activity, but defining science fiction by subject matter will lead at best to the ossification of the field, at worst to its destruction as a viable and maturing type of writing.
When describing becomes a form of marketing, it can be harmful or helpful. Harmful to the writer who could have a larger audience without the mixed blessing of being labeled a "science fiction writer", helpful to the writer who would be unpublished, ignored, or condemned without the science fiction community.
Regardless of marketing, defining abstract qualities and using those qualities to prescribe what is or isn't science fiction is a dangerous activity because it attempts to set subject-based boundaries on imagination.
I am, once again, skirting the realm of paradox here.
Let's consider the differences between defining and describing. Aristotle's Poetics is a good place to start. Aristotle described elements of tragedy based on, it seems, a few plays he was familiar with. His proclamations are useful as descriptions of some Greek tragedies, but when Rennaissance and Neoclassical scholars turned Aristotle's descriptions into definitions from which all writers had to work, they restricted authors, blinded audiences to the possibilities of alternative dramatic forms, and sent many myths about what drama and tragedy "should be" seeping down through the ages to corrode the perspectives of generations of writers, critics, and audience members.
Plays survived because writers like Shakespeare were willing to laugh at the rules and definitions created by legislators of taste and decorum.
Poetry is another example. While lacking any single influence as great as Aristotle's influence on drama, poetry has a similar history of rebellion against definition. By the second half of the twentieth century (at the latest) it was impossible to create any single definition of poetry that would encompass everything poets were publishing. The insults hurled between the New Formalists and the L=A=N=G=U=A=G=E Poets in the late 1970s and early '80s were a showy variation on disagreements that had been sprouting up between poets, critics, and general readers of different stripes for decades—disagreements that stemmed from contradictory answers to the question, "What is poetry?"
What has happened to the world of poetry at the end of the twentieth century and beginning of the twenty-first, though, could stand as a sign of optimism for the increasingly fractured world of science fiction. While certainly there remain conservative and liberal readers and writers of poetry, and arguments of course still occur, many younger poets have seized on the freedom to write however they want, without paying much attention to labels and commandments, and without feeling compelled to circulate manifestos. They plunder whatever influences interest them at the moment.
Science fiction began as an interesting cross-breed of the Victorian realistic novel and what could be called "philosophical romance"—stories which used the techniques of realism to convey nonrealistic adventures and ideas. This is the form that almost all SF, from the early days of Amazing until now, has taken. It works, and it was, at least at the beginning, a radical mode of writing for its time, because unlike many fabulist tales of the past, it shunned even the most subtle metafictional tendencies.
The challenge science fiction faces is that its mode of storytelling is one that new technologies have steadily made less and less effective. When such stories are driven by plot, film is a more appealing form for narrative, easily mixing elements of character and image that are more difficult to manipulate through words alone. The veneer of reality that such stories strive to create is the hallmark of popular SF films, which dazzle by making the fantastic look real. The effect of such films is, for many people, more compelling than any written text.
For SF to do what movies can't, critics and readers need to see realism as a choice, one which is appropriate at times, but not the default mode of all storytelling. We need to discover new ways of presenting SF ideas, and we need to understand why we want to present those ideas in the first place. The New Wave was all about this, but the New Wave was killed by Star Wars—suddenly the basic cargo of SF stories had lots of attention, everybody wanted a piece of it, and the formulas that had kept the audience for written SF happy for fifty years lost their luster. The short fiction markets quickly began the decline they are still suffering through, and a true opportunity was lost: short fiction can be extremely experimental with much less risk than novels. Most writers don't spend the same amount of time on a short story that they do on a novel, publishers certainly don't invest the same amount of resources, and neither do readers.
Short fiction in the 1980s got distracted by the inane and meretricious supposed-rivalry between the "cyberpunk" and the "humanist" writers, neither of which had much of anything original to say about the esthetics of stories. The 1990s continued the decline, with magazine circulations reaching all-time lows and the only noticeable discussion of form being yet another definitional one of what is or isn't "hard science fiction".
The only force preventing science fiction from becoming a nostalgic, petrified, and anomalous type of writing was the rise in the late 1990s of various writers who had some sense of a literary world beyond the science fictional and who wanted more freedom of imagination in the stories they wrote and published. Consigned mostly to the smallest of the small presses, these writers formed a community that blossomed as the popularity of the internet rose, allowing easy communication between people of similar tastes and easier access to small press writings via publisher's websites and sites such as Amazon.com and Booksense.
These writers, who have little in common except a desire to write what they want and how they want, have suffered under various labels, but labeling their work as "slipstream" or "New Weird" or "interstitial" is a fundamental contradiction of their purpose, which is essentially anti-definitional. The beauty and brilliance of writers such as Jeffrey Ford, Nalo Hopkinson, Kelly Link, Jeff VanderMeer, and numerous others is that their work has a range of both subject matter and form that transcends any one genre, but that clearly and unequivocally gains energy from certain tropes and motifs of traditional science fiction, fantasy, and horror fiction.
There has been fear from some critics that writers who write anti-definitional stories will destroy science fiction as a form of writing and as a community of writers and readers. Such an opinion stems from a false dichotomy. New art forms do not destroy old art forms, though they may make them less appealing. Narrative poetry became less and less common as the novel gained popularity, because the freer form of the novel allowed more writers to create a wider variety of material which appealed to a wider audience. (Of course, various socio-economic factors, from advances in public education to advances in printing technology, also affected the growth of the novel, just as the social and technological changes of the twentieth century affected the growth of cinema.) The novel is now a less popular art form than film, but that doesn't mean the specific virtues of a novel are no longer desired or relevant. Similarly, we have seen many changes in the popularity of the short story and in the presence of the short story in popular markets.
The question we should ask, then, is what is the place of written science fiction in a culture which has more artistic technologies and forms available to it than did the culture which created and popularized SF? There is no point in saying writers should do this and shouldn't do that—what we need to do, if the genre is to survive as something other than a subset of the main genre of fiction (and whether it should is an entirely different subject), is look at what the possibilities of a certain form are, what the relationship of that form to others is, and what methods are used to bring writers to audiences that will appreciate their work.
Readers and writers have a choice: they can read and encourage writing that adds some of prose's values to primarily traditional narratives, which are better and more appealingly utilized by film; or they can try to read and write works that exploit written prose's strengths: the sensory values of language, intimacy of detail, movement between thought and action, the ability to convey information (history, etc.) easily through exposition, and the ability to use language and narrative structures to suggest patterns that could not be suggested through purely visual or dramatic structures.
Emphasizing such qualities will both threaten and strengthen science fiction, particularly science fiction that seeks the purity of being a genre. Attention to fiction's inherent strengths will make the traditional "literature of ideas" more appealing, because text remains the most effective way of communicating ideas, but such attention will also increase the urge to break boundaries and scuttle conventions. It's easy enough to write a traditional SF story that's not as interesting as a film; it's much harder to write one that tries to do only what prose can do. Such aspirations have had a home in mainstream fiction since its beginning (no science fiction novel has ever played with the perception of time the way Laurence Sterne's Tristram Shandy does), despite the stranglehold realism has held on popular mainstream literature for the past century.
The novel of today should not be the novel of 1865, and science fiction of today should not be science fiction of 1926.