# '''Mohs/WorldOfPhlebotinum:''' The universe is full of AppliedPhlebotinum with more to be found behind every star, but the Phlebotinum is dealt with in a [[MagicAIsMagicA fairly consistent fashion despite its lack of correspondence with reality]] and, in-world, is considered to lie within the realm of scientific inquiry. Works like Creator/EEDocSmith's ''Literature/{{Lensman}}'' series, ''Anime/NeonGenesisEvangelion'', the various ''Franchise/StarTrek'' series, and ''VideoGame/StarCraft'' fall in this category.\\

# '''Mohs/ScienceInGenreOnly:''' The work is unambiguously set in the ''literary genre'' of ScienceFiction, but ''scientific'' it is not. AppliedPhlebotinum is the rule of the day, often of the [[ItRunsOnNonsensoleum Nonsensoleum]] kind, GreenRocks gain NewPowersAsThePlotDemands, and both BellisariosMaxim and the MST3KMantra apply. Works like ''WesternAnimation/{{Futurama}}'', ''Franchise/StarWars'', ''Anime/TengenToppaGurrenLagann'', The Creator/{{DC|Comics}} and Creator/{{Marvel|Comics}} universes,[[note]]although the individual comics of some heroes might fit elsewhere occasionally[[/note]] and ''Franchise/TheHitchhikersGuideToTheGalaxy'' fall in this class.

# '''Mohs/WorldOfPhlebotinum:''' The universe is full of AppliedPhlebotinum with more to be found behind every star, but the Phlebotinum is dealt with in a [[MagicAIsMagicA fairly consistent fashion despite its lack of correspondence with reality]] and, in-world, is considered to lie within the realm of scientific inquiry. Works like Creator/EEDocSmith's ''Literature/{{Lensman}}'' series, ''Anime/NeonGenesisEvangelion'', ''Series/StarTrekTheOriginalSeries'', and ''VideoGame/StarCraft'' fall in this category.\\

* '''In really hard SF:''' "It doesn't. Time travel to the past is impossible."

''Note 5:'' As far as this wiki is concerned, TropesAreTools. "Hard" and "soft" may be considered as denotations of the quality of the story by those who prefer one over the other, but [[Administrivia/RuleOfCautiousEditingJudgement we don't want to hear about it that way]].

''Note 4:'' Sometimes a study hits the news that, if confirmed, would reassign many works on the scale. For example, [[http://www.telegraph.co.uk/news/science/8782895/CERN-scientists-break-the-speed-of-light.html the September 2011 OPERA experiment which measured faster-than-light travel by neutrinos]] might have moved works whose Mohs/OneBigLie was FTLTravel into the Mohs/SpeculativeScience category. There are three reasons to be cautious about doing so: first, because mass media reporting of scientific results is often inaccurate due to the difficulty of presenting technical results to a non-technical audience; second, because revolutionary new results (and results in the ''news'' are generally new) are far more likely to be overturned than they appear (indeed, the OPERA anomaly was [[http://www.sciencemag.org/news/2012/02/breaking-news-error-undoes-faster-light-neutrino-results caused by faulty equipment]]); and third, for purposes of the Scale, the yardstick of scientific plausibility is what the science said ''at the time the work was written'', not what [[ScienceMarchesOn scientists discovered later]]. If the story in question was based on a scientific model that, while now discredited, was widely accepted in its day, it still qualifies as "hard" science fiction because the author [[FairForItsDay did his best]] ''[[FairForItsDay with the information available at the time]]''.

''Note 5:'' As far as this wiki is concerned, TropesAreNotGood and TropesAreNotBad. "Hard" and "soft" may be considered as denotations of the quality of the story by those who prefer one over the other, but [[RuleOfCautiousEditingJudgement we don't want to hear about it that way]].

# '''Mohs/PhysicsPlus:''' Stories in this class once again have multiple forms of AppliedPhlebotinum, but in contrast to the prior class, the author aims to justify these creations with [[ShownTheirWork real]] and [[MinovskyParticle invented]] natural laws -- and these creations and others from the same laws will [[ChekhovsBoomerang turn up again and again in new contexts]]. Works like ''Webcomic/SchlockMercenary'', Creator/DavidWeber's ''Literature/HonorHarrington'' series, David Brin's ''Literature/{{Uplift}}'' series, and ''Series/BattlestarGalactica2003'' fall in this class. Most RealRobot shows fall somewhere between Classes 2 and 3.

This class also includes a subclass (4.5 on the scale) we call ''One Small Fib'', containing stories that include only a single counterfactual device (often FTLTravel), but for which the device is not a major element of the plot. Many Creator/HalClement novels (e.g. ''Literature/MissionOfGravity'', ''Close to Critical'') and ''Webcomic/{{Freefall}}'' fall within the subclass.

A subclass of this (5.5 on the scale) is ''Futurology:'' stories which function almost like a prediction of the future, extrapolating from current technology rather than inventing major new technologies or discoveries. (Naturally, {{Zeerust}} is common in older entries.) ''Film/{{Gattaca}}'', ''Manga/{{Planetes}}'', ''TabletopGame/TranshumanSpace'' and the more SpeculativeFiction works of Creator/JulesVerne fall in this subclass.

''Note 5:'' As far as this wiki is concerned, TropesAreNotGood and TropesAreNotBad. "Hard" and "soft" may be considered as denotations of the quality of the story by those who prefer one over the other. We don't hold to that here.

''Note 3:'' While the term "soft science fiction" is used above as the antonym of "hard science fiction", another common use of the term is to describe ''soft science'' fiction: [[AsimovsThreeKindsOfScienceFiction sociological and psychological]] science fiction. This can, in some cases, make it appropriate to talk about "hard soft science fiction", but doing so is likely to confuse people. By and large, though, science-fiction "hardness" doesn't correlate well with realism in areas such as characterization, views of human nature, or views of human societies. In such areas, some works that barely qualify as SF might be unsparingly realistic… and some of the hardest SF imaginable might deal in out-and-out fantasy.

->''"Imagine a World where Machines can transmit information across long distances. Where carriages are pulled not by horses, but by engines relying on combustion. Imagine a World where electrically powered ships can sail below the surface of the Sea and heavier-than-air vessels sail the skies. Creator/JulesVerne imagined ALL these things.”''
-->-- '''Webvideo/ExtraCredits'''

->''"Imagine a World where Machines can transmit information across long distances. Where carriages are pulled not by horses, but by engines relying on combustion. Imagine a World where electrically powered ships can sail below the surface of the Sea and heavier-than-air vessels sail the skies. Creator\\JulesVerne imagined ALL these things.”''

# '''Mohs/OneBigLie:''' Authors of works in this class invent one (or, at most, a very few) counterfactual physical laws and writes a story that explores the implications of these principles. James Blish's ''CitiesInFlight'' stories fall squarely into this category, courtesy of the "Dirac Equations" leading to the "spindizzy motor" and instantaneous communication. Most works in Creator/AlanDeanFoster's ''Literature/HumanxCommonwealth'' series, the Ad Astra board games and Creator/RobertAHeinlein's ''Literature/FarnhamsFreehold'' fall in this category, as do many of Creator/VernorVinge's books.\\