In 1953, Isaac Asimov published an article titled "Social Science Fiction" in Modern Science Fiction. In that article he stated that every science fiction plot ultimately falls into one of three categories: Gadget, Adventure, or Social.
- Gadget: The focus of the story is the invention itself: How it comes to be invented, how it works, and / or what it is used for. The invention is the end result of the plot.
- Adventure: The invention is used as a dramatic prop. It may be the solution to a problem, or it may be causing the problem itself, but the main focus is on the caper and how the invention's presence helps or hinders it.
- Social: The focus of the story is on how the presence of the invention affects people's daily lives, whether for good or for ill. The chief distinction between this and the other two types is that the presence of the invention influences the plot rather than causing it or being the goal.
To demonstrate what he meant by each, he used the example of three different late nineteenth century authors all being inspired to write new stories about the automobile, each going in one of three directions:
Or, to paraphrase it briefly:
Adventure sci-fi: Man invents car, gets into a car chase with a villain.
Social sci fi: Man invents car, gets stuck in traffic in the suburbs.
Prior to the rise of John W. Campbell and his Astounding Stories, the vast majority of science fiction fell under either Gadget or Adventure science fiction, with most of the characters being flat and stereotyped (though there were a few exceptions). Campbell wanted good stories, not merely good science; he wanted people to write science fiction that could stand on its own literary merits and seriously examine the consequences of technology on future society. His philosophy influenced authors such as Asimov and Robert A. Heinlein. Asimov, Heinlein, and a few others in turn influenced New Wave Science Fiction of the 1960s and 70s, which leaned heavily—some might say almost exclusively—into the Social (Harlan Ellison, Frank Herbert, and Ursula K. Le Guin being the most prominent examples).
Most modern science fiction stories do not exist exclusively in any one category; they have elements of all three present to some degree or another. However, many clearly place more weight on one emphasis than the other two.
Note that this is not Mohs Scale of Science Fiction Hardness. That is a measure of how closely a premise sticks to real-world scientific theories; this categorizes a story on how it uses that premise, wherever it may fall on the scale.note Also don't confuse this with Asimov's Three Laws of Robotics (though Asimov has written stories of all three types in which those laws are the invention in question—the stories in his collection I, Robot starts with their invention and working out the kinks, moves on to some adventure stories relying on the Laws, and ends up with social science fiction about the impact of Three Laws-compliant AI on society, setting up his Robot novels).
- 20,000 Leagues Under the Sea contains all three: The Nautilus is a technological marvel described in loving detail (some of which haven't stood the test of time, having been extrapolated from what was the cutting-edge of science), allowing the exploration of the seas more closely than any other method, and the implications of a rogue submariner running around sinking British ships in revenge for their colonial mishandlings.