Science fiction is notoriously difficult to define, but Fredrick Pohl’s definition is one of the lovelier ones.
“Does the story tell me something worth knowing, that I had not known before, about the relationship between man and technology? Does it enlighten me on some area of science where I had been in the dark? Does it open a new horizon for my thinking? Does it lead me to think new kinds of thoughts, that I would not otherwise perhaps have thought at all? Does it suggest possibilities about the alternative possible future courses my world can take? Does it illuminate events and trends of today, by showing me where they may lead tomorrow? Does it give me a fresh and objective point of view on my own world and culture, perhaps by letting me see it through the eyes of a different kind of creature entirely, from a planet light-years away? — These qualities are not only among those which make science fiction good, they are what make it unique. Be it never so beautifully written, a story is not a good science fiction story unless it rates high in at least some of these aspects. The content of the story is as valid a criterion as the style.”