Science fiction (often shortened to Sci-Fi or SF) is a genre of speculative fiction, typically dealing with imaginative concepts such as advanced science and technology, space exploration, time travel, and extraterrestrial life. Science fiction often explores the potential consequences of scientific and other innovations, and has been called a "literature of ideas".
"Science fiction" is difficult to define, as it includes a wide range of subgenres and themes. James Blish wrote: "Wells used the term originally to cover what we would today call ‘hard’ science fiction, in which a conscientious attempt to be faithful to already known facts (as of the date of writing) was the substrate on which the story was to be built, and if the story was also to contain a miracle, it ought at least not to contain a whole arsenal of them."
Isaac Asimov said: "Science fiction can be defined as that branch of literature which deals with the reaction of human beings to changes in science and technology." According to Robert A. Heinlein, "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."
Lester del Rey wrote, "Even the devoted aficionado or fan—has a hard time trying to explain what science fiction is", and that the reason for there not being a "full satisfactory definition" is that "there are no easily delineated limits to science fiction." Author and editor Damon Knight summed up the difficulty, saying "science fiction is what we point to when we say it", while author Mark C. Glassy argues that the definition of science fiction is like the definition of pornography: you do not know what it is, but you know it when you see it.
Sense of Wonder
Science fiction is often said to generate a "sense of wonder." Science fiction editor and critic David Hartwell writes: "Science fiction’s appeal lies in combination of the rational, the believable, with the miraculous. It is an appeal to the sense of wonder." Carl Sagan said: "One of the great benefits of science fiction is that it can convey bits and pieces, hints and phrases, of knowledge unknown or inaccessible to the reader ... works you ponder over as the water is running out of the bathtub or as you walk through the woods in an early winter snowfall." Isaac Asimov in 1967 commenting on the changes then occurring in SF wrote: "And because today’s real life so resembles day-before-yesterday’s fantasy, the old-time fans are restless. Deep within, whether they admit it or not, is a feeling of disappointment and even outrage that the outer world has invaded their private domain. They feel the loss of a 'sense of wonder' because what was once truly confined to 'wonder' has now become prosaic and mundane."
As Protest Literature
Science fiction has sometimes been used as a means of social protest. James Cameron’s film Avatar was intended as a protest against imperialism, and specifically against the European colonization of the Americas. Its images were used by, among others, Palestinians in their protest against Israel.
Robots, artificial humans, human clones, intelligent computers, and their possible conflicts with humans has been a major theme of science fiction since the publication of Frankenstein. Some critics have seen this as reflecting authors’ concerns over the social alienation seen in modern society.
Feminist science fiction poses questions about social issues such as how society constructs gender roles, the role reproduction plays in defining gender and the unequal political and personal power of men over women. Some of the most notable feminist science fiction works have illustrated these themes using utopias to explore a society in which gender differences or gender power imbalances do not exist, or dystopias to explore worlds in which gender inequalities are intensified, thus asserting a need for feminist work to continue.
Libertarian science fiction focuses on the politics and the social order implied by right libertarian philosophies with an emphasis on individualism and private property, and in some cases anti-statism. Climate fiction, or "cli-fi" deals with issues concerning climate change and global warming. University courses on literature and environmental issues may include climate change fiction in their syllabi, as well as it being discussed by the media, outside of SF fandom.
Comic science fiction often satirizes and criticizes present-day society, as well as sometimes making fun of the conventions and clichés of serious science fiction.
Science Fiction has historically been sub-divided between hard science fiction and soft science fiction – with the division centering on the feasibility of the science central to the story. However, this distinction has come under increasing scrutiny in the 21st century. Authors including Tade Thompson and Jeff VanderMeer have pointed out that stories that focus explicitly on physics, astronomy, mathematics, and engineering tend to be considered "hard", while stories that focus on botany, mycology, zoology or the social sciences tend to be categorized as, "soft," regardless of the relative rigor of the science.
Max Gladstone defined hard SF as being, "SF where the math works," but pointed out that this ends up with stories that seem, "weirdly dated," as scientific paradigms shift over time. Aliette de Bodard argued that there was a risk in the categorization that authors' work would be dismissed as not being, "proper," SF. Michael Swanwick dismissed the traditional definition of hard SF altogether, instead saying that it was defined by characters striving to solve problems, "in the right way – with determination, a touch of stoicism, and the consciousness that the universe is not on his or her side."
Ursula K. Leguin took a more traditional view on the difference between "hard" and "soft" SF but arrived at a divergent value-judgment from the one implied by de Bodard, saying, "The "hard" science fiction writers dismiss everything except, well, physics, astronomy, and maybe chemistry. Biology, sociology, anthropology—that's not science to them, that's soft stuff. They're not that interested in what human beings do, really. But I am. I draw on the social sciences a great deal."
Science fiction elements can include:
• Temporal settings in the future, or in alternative histories.
• Spatial settings or scenes in outer space, on other worlds, in subterranean earth, or in parallel universes.
• Aspects of biology in fiction such as aliens, mutants, and enhanced humans.
• Speculative or predicted technology such as brain-computer interface, bioengineering, superintelligent computers and robots, ray guns and other advanced weapons.
• Undiscovered scientific possibilities such as teleportation, time travel, and faster-than-light travel or communication.
• New and different political and social systems and situations, including utopian, dystopian, post-apocalyptic, or post-scarcity.
• Future history and evolution of humans on earth or on other planets.
• Paranormal abilities such as mind control, telepathy, and telekinesis.