Science is a way of thinking about reality that takes its objectivity for granted. Fiction is a way of describing reality that assumes the subjectivity of experience—for every fiction, a different way of seeing things, a different reality. The two words together contradict each other. A thing cannot be both "science" and "fiction" at the same time, any more than it can be both "reality" and "fiction."
We don't talk about "reality fiction"; we talk about "realistic fiction," literature that seems real even though we know it is fictional. But despite numerous attempts to change the name, we do talk about "science fiction." I suspect the name evokes the central paradox of the genre; science fiction pretends to take the objectivity of the world it describes for granted, yet clearly does not describe the objective world as we know it to be. It is "scientific," but clearly unrealistic.
People who dislike science fiction see it as an unrealistic literature of escape, a shallowminded distraction from the serious consideration of things as they are. Those who like science fiction insist it is really about the world we live in—at most an allegorical representation of reality, at least logical extrapolation based upon and commenting on things as they are. But good science fiction is neither an escape from reality nor a description of it; and Darko Suvin is wise enough never to forget that. He sees science fiction as "a developed oxymoron, a realistic irreality," and he presents a definition of it that accounts both for its science and for its fiction.
That is not to say that he accounts for these things clearly. Suvin is two verbose things at the same time—a theoretical literary critic and a Marxist. His vague Marxist jargon takes over when his vague critical jargon gives out, and Metamorphoses of Science Fiction is filled with silly words like "Situationality" and "hermeneutic" and "seriation levels." Suvin calls science fiction a literature of "cognitive estrangement"; the language he uses in his book is estranging enough that it might itself be considered science fiction.
Translated into real English, however, Suvin's ideas turn out to be interesting. "Cognitive estrangement" is the "factual reporting of fictions." For Suvin, this has the significant effect of separating or "estranging" us from our usual assumptions about reality. "Estrangement" is Suvin's version of Bertold Brecht's "Verfremdung," usually translated as "alienation." Brecht was talking about describing familiar things as if they were unfamiliar; not quite logically, Suvin borrows the phrase to comment on how science fiction describes unfamiliar things as if they were familiar. But for Suvin the final effect is the same; by Brechtian distancing or by the unfamiliarity of science fictional worlds, we are estranged from our assumptions about reality and forced to question them.
Suvin emphasizes estrangement for two reasons. The first is political. As a Marxist, he sees science fiction as a literature of revolt, "a genre showing how 'things could be different.'" The second is only a little less political. As a Marxist scholar, Suvin wants to reinvent literary history in Marxist terms—to show how science fiction has actually existed for centuries, but that little is known about it because it has always expressed the aspirations of the masses. Consequently, it "has been a suppressed and neglected, often materially and most always ideologically persecuted tradition." Much of Suvin's book is a fascinating but unpersuasive remaking of history, which shows how the forces of history influenced More's science fiction novel Utopia and Swift's science fiction novel Gulliver's Travels and Blake's science fiction poem The Four Zoas and Shelley's science fiction epic Prometheus Unbound.
I do not find this persuasive. Just because some obscure fellow living in Lower Thuringia in 1593 invented a primitive something to hang his trousers on that we can now see to be a precursor of the modern toilet-tissue holder does not make that invention the only important event of 1593; nor does our ignorance of the inventor mean that knowledge of his invention was suppressed by a bourgeosie afraid of the revolutionary implications of convenient toilet paper. And just because Darko Suvin sees similarities...