Even though it intends to be constrained and succinct –and actually accomplishes it–, the entry on “Definitions of Science Fiction” in Clute and Langford’s Enciclopedia of Science Fiction (SFE) consists of nearly three thousand words. Defining Science Fiction is clearly not an easy task. Sci-Fi is a slippery genre and there are as many definitions of it as there are interests, or critics, or agendas. Hugo Gernsback, for instance, defined it as a “romance intermingled with scientific fact and prophetic vision”; Darko Suvin, as any text that meets the necessary conditions of ‘estrangement’ and ‘cognition’; James Gunn as the “literature of change”; Urusla K. Le Guin as a metaphor that draws from “all the sciences and technology”, Brian Aldiss as a genre that is “no more written for scientists than ghost stories are for ghosts”… The definitions are almost endless. In fact, as Paul Kincaid recounts in “On the Origins of Genre”, Gary K. Wolfe in his 1986 Critical Terms for Science Fiction: A Glossary and Guide to Scolarship came to include up to thirty-three different definitions of the concept. This wide spectrum has eventually led to exhausted –but not less rich– definitions such as Damon Knight’s “science fiction is what we point to when we say it”.

If I were to contribute to this array of definitions I would define Sci-Fi as the most realist of the non-realist genres. Distancing itself from realism, it teams up with myth, the fantastic and the marvelous in the design of an alternative world, different from the one inhabited by the ‘imagineur’. But what eventually sets apart Sci-Fi from the other non-realist genres is the fundamental realism that governs its visionary and “liar” worlds. In other words, what differentiates them, is the way each genre “imagines”: while fantasy’s (or myth’s) imagination is wild and unlimited, Sci-Fi’s is restricted and constrained. Fantasy manufactures its own conventions entirely and makes them a natural (and uncontested) condition of the imagined reality (i.e. characters can fly because they can). Science fiction, on the other hand, maintains the laws that govern the everyday world, if it breaks them, it is usually alongside an explanation (i.e. characters can fly because they have a jetpack). That is, fantasy creates its own world and laws; science fiction accepts the world and its laws within a non-realist environment. So, while realism intends to shows the world as it is, and fantasy parts from it altogether; science fiction, as John Clute puts it, works “to make the incredible seem plausible and familiar”.