Definitions of SF

• SF - the "definition" used at the FSFwiki
• "science fiction, fantasy, magic realism, horror, surrealism, le fantastique, myth and legend, fantastical storytelling, and any other writing beyond the strictly realistic", the definition used by the Sunburst Award
• "A handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method. [S]trike out the word 'future' it can apply to all and not just almost all SF." -- Robert A. Heinlein, "Science Fiction: Its Nature, Faults and Virtues" in The Science Fiction Novel: Imagination and Social Criticism, Advent: Publishers, 1959.
• "A good science fiction story is a story about human beings, with a human problem, and a human solution, that would not have happened at all without its science content." Theodore Sturgeon, quoted in James Blish, More Issues at Hand: Critical Studies in Contemporary Science Fiction (Advent Publishers, 1970)
• "Speculative fiction is one of those nebulous terms that everyone defines differently. You could say speculative fiction stories are those that haven't happened yet and might never happen if we limit ourselves to the known rules of our reality. A narrower view might say it's science fiction where some or all of the science has been replaced with less constraining elements, such as magic, horror or unexplained weirdness. I just say 'SF' for short." Jayne Fenn, personal bio (last visited 2009/03/09)
• comparing various fabulist genres to fairy tales: "Not quite like ancient myths, which use nymphs and satyrs to explain recurring natural phenomena; nor like fables, whose timeless moral lessons are parlayed through the escapades of animal characters; nor like legends, which exude the pungent aromas of one particular locale and its history, fairy tales are stories spun into gold at the wooden wheel of a miller’s daughter: stories made to summon wonder, horror, enchantment—and not necessarily anything more. Uncanny in the purest sense of the word, which is to say, both bizarre and familiar at once, they are meant to be told, not read, and they truly possess an inexhaustible power. Children hold on tight, turn pale, close their eyes, and beg for more."
• "Science fiction is the characteristic literary genre of the century. It is the genre that stands in opposition to literary modernism." -- David G. Hartwell, Introduction, The Science Fiction Century
• Isaac Asimov: "Isaac Asimov memorably identified the three major types of science fiction as 'What if,' 'If only,' and 'If this goes on.'" "Indeed, Asimov himself was fond of classifying science fiction into three types of stories: What if . . . If only . . . and If this goes on . . . . What if we could genetically engineer life forms? If only we had computers that could fit into our pockets. If current ecological trends continue, what will the planet look like?"