Science fiction is a genre of speculative fiction dealing with imaginative concepts such as futuristic settings, futuristic science and technology, space travel, time travel, faster than light travel, parallel universes and extraterrestrial life. Science fiction often explores the potential consequences of scientific and other innovations, and has been called a "literature of ideas."〔 It usually eschews the supernatural, and unlike the related genre of fantasy, historically science fiction stories were intended to have at least a faint grounding in science-based fact or theory at the time the story was created, but this connection has become tenuous or non-existent in much of science fiction.〔http://www.loa.org/sciencefiction/introduction.jsp〕〔http://web.mit.edu/comm-forum/papers/jenkins_mi.html〕〔http://misabuckley.com/does-the-science-in-science-fiction-matter/〕
Science fiction is difficult to define, as it includes a wide range of subgenres and themes. Author and editor Damon Knight summed up the difficulty, saying "science fiction is what we point to when we say it",〔 a definition echoed by author Mark C. Glassy, who 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.〔
Hugo Gernsback, who was one of the first in using the term "science fiction", described his vision of the genre: "By 'scientifiction' I mean the Jules Verne, H. G. Wells and Edgar Allan Poe type of story—a charming romance intermingled with scientific fact and prophetic vision."〔Hugo Gernsback. "A New Sort of Magazine", Amazing Stories, Vol. 1, No. 1 (April 1926), p. 3.〕
In 1970 William Atheling Jr. wrote about the English term "science fiction": "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."〔James Blish, More Issues at Hand, Advent: Publishers, 1970. P. 99.〕〔Jesse Sheidlower, Dictionary citations for the term «hard science fiction». Jessesword.com. Last modified 6 July 2008.〕
According to science fiction writer 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."〔 Rod Serling's definition is "fantasy is the impossible made probable. Science fiction is the improbable made possible."〔 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."〔
Science fiction is largely based on writing rationally about alternative possible worlds or futures.〔 It is similar to, but differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically established or scientifically postulated physical laws (though some elements in a story might still be pure imaginative speculation).
The settings for science fiction are often contrary to those of consensus reality, but most science fiction relies on a considerable degree of suspension of disbelief, which is facilitated in the reader's mind by potential scientific explanations or solutions to various fictional elements. Science fiction elements include:
* A time setting in the future, in alternative timelines, or in a historical past that contradicts known facts of history or the archaeological record.
* A spatial setting or scenes in outer space (e.g. spaceflight), on other worlds, or on subterranean earth.〔
* Characters that include aliens, mutants, androids, or humanoid robots and other types of characters arising from a future human evolution.
* Futuristic or plausible technology such as ray guns, teleportation machines, and humanoid computers.〔
* Scientific principles that are new or that contradict accepted physical laws, for example time travel, wormholes, or faster-than-light travel or communication.
* New and different political or social systems, e.g. dystopian, post-scarcity, or post-apocalyptic.〔
* Paranormal abilities such as mind control, telepathy, telekinesis, and teleportation.
* Other universes or dimensions and travel between them.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』