Mohs Scale of Science Fiction Hardness - Television Tropes & Idioms

alt title(s): Mohs Scale Of Sci Fi Hardness

"Hard" Speculative Fiction is firmly grounded in reality, with few fantastic flights of fancy not justified by Science™.

"Soft" Sci Fi is more flexible on the rules.

The existence of Faster Than Light Travel generally makes a series "softer"; the more restricted or inconvenient FTL becomes, the "harder" the series feels. Space Is An Ocean automatically pushes a show into "soft" territory, while Space Is Noisy makes it feel that way, even if there's a reason. Real Robots are by definition "harder" than Super Robots, although neither of them qualify as truly Hard Sci-Fi. TV tends to be softer than movies, which tend to be softer than books. Stories set Twenty Minutes Into The Future tend to be harder than stories set in The Future, simply because there's less change from the present-day. Human Aliens and Rubber Forehead Aliens are typically "soft"; Absent Aliens and Starfish Aliens are more "hard" options. All of these examples, of course, have loads of exceptions.

A useful rule of thumb might be derived from Jim Kakalios's rule of "miracle exceptions" in his "Physics of Superheroes" articles - while many stories require a willing suspension of disbelief, the best ones may require only one leap of faith from an established scientific principle, or just "one big lie"; the more "exceptions" required, the harder it is to accept the story in real terms. A link to the idea can be found here

Another useful rule of thumb: A character is shown a time machine and asks, "How does it work?" In hard SF the answer will be: "An interesting question. Please have a seat while I bring you up to speed on the latest ideas in quantum theory, after which I will spend a chapter detailing an elaborate, yet plausible-sounding connection between quantum states, the unified field theory, and the means by which the brain stores memory, all tied into theories from both Einstein and Hawking."

In soft SF, the answer to, "How does it work?" will be: "You sit in this seat, set the date you want, and pull that lever."

(Note this is not universally true; you can skip over the details as long as the basic explanation you give doesn't seem to conflict with anything you've established so far.)

The Mundane Manifesto is one attempt to define a set of rules for writing a hard SF story or series, by deliberately forbidding many of the traditional tropes of media Sci-Fi.

"Hardness" is not, however, a simple two-category sorting function, or even a one-dimensional continuum. Many series depart from reality in different ways, and for different reasons. Nevertheless, here's a grossly simplified attempt at a list, from softest to hardest. Don't take it as gospel; just look at the size of the arguments on the discussion page.

Note that this list only tracks Sci Fi series, which are meant to take reality and diverge from it. Fantasy series need not apply, even though many of the softest Space Operas have been accused of being just fantasy stories with spaceships and ray guns. Similarly, a series that revolves around a Black Box is hard to classify until you know what the Black Box is.

Finally, remember that harder is not always a good thing. Some authors try so hard to make a story realistic they forget plot and characterization, and others may try to justify their occasional break from reality with technobabble, although the most famous example's on the soft end. Thus, neither side is truly better than the other, and which side you prefer depends on personal taste and where a person's Willing Suspension Of Disbelief lies.

The name comes from the Mohs scale of mineral hardness

Please note: This list is ranked. That means Soft stuff goes on top, and Hard stuff goes on the bottom. Softer items are closer to the top, while Harder items are further away towards the bottom. So, if you know about a really, really hard work of sci-fi, don't place it under "Hardest"; instead, place it at the very bottom of the list, right above "Hardest".

Softest

MST3K: Stuff happens. Don't think too much how. Characters breathe in space on at least two occasions. Artificially intelligent robots built entirely out of random spare parts. A VW Microbus converted into a spaceship. As the theme song says: "It's just a show. You really should relax."
Futurama: Chock full of every single popular science fiction trope, often with intentionally silly Reverse The Polarity style answers to justify them. Only "harder" than MST 3 K because there's no MST 3 K Mantra in the opening.
The Hitchhiker's Guide To The Galaxy: Packed full of all kinds of bizarre nonsense (one example - the fastest mode of travel through the universe is by bistro. Yes. Bistro. As in "place you eat in" or "second most overworked word in food marketing after new ".), but the stories are fully aware of how absurd it is, and the reader IS encouraged to think about it.
Earthbound: Psychic powers, zombies, a living tent, mind-controlled sentient animals, a dog possessed by a member of the dev team, a cult that worships the color blue, an idol that makes people greedy and an Azathoth clone as a Big Bad. And the sequel is even weirder.
Tengen Toppa Gurren Lagann: Run not by the laws of physics, but by the Rule Of Cool. And HOT BLOOD.
Warhammer 40000: Chainsaw swords, psychic spacemen, undead robots, planet-eating bugs, three-hundred-metre-tall millennia-old walking battle cathedrals, soul-eating space stations and vehicles that travel faster because they're painted red (justified). The primary means of FTL is flying through Hell. In 40k, Rule Of Cool is physics.
Command And Conquer Red Alert series: It starts off with Einstein traveling back in time to assassinate Hitler. By the time we're finished, we have dolphin commandos, psychically-controlled giant squid, electricity-draining UFOs, psychic soldiers that set people on fire with their minds, cloning machines, teleporting commandos who erase their targets from space-time, and bear paratroopers.
Neon Genesis Evangelion: A lot of the Applied Phlebotinum in this series involves branches of biology and engineering that neither exist in real life nor are ever likely to exist. "Metaphysical biology," for example — Doctor Kozo Fuyutsuki's specialty — is kind of like genetics, only it involves human souls instead of genes.
The Lensman novels: A classic pulp SF series, which originated the trope of Space Police armed with incredibly powerful and flexible weapons. Lensmen had intertialess drives, habitable gas giants (with surfaces you could land on)... basically, it was pretty soft even when the first stories were published (in the 1930s), and since then, the march of science has made hash out of most of its assumptions.
Suzumiya Haruhi. The series has already enough problems with Science Fiction Versus Fantasy. Vaguely defined Applied Phlebotinum doesn't help! At least the Time Travel is clearly elaborated.
Freelancer: Space Is An Ocean on its top splendor. The space battles look like World War II air battles, only without the limitation of gravity. And on top of that, the in-game scale is warped enough to have entire planets with a 200 meters atmosphere, and no more than 2 km of diameter. These "softnesses" can be considered Acceptable Breaks From Reality, though, because they actually make the game more playable.
Star Trek Voyager: Ship went so fast that it was everywhere in the universe at once and then the crew 'evolved' into lizards? Yow! (Specifically the episode "Threshold", recapped here.)
Star Wars: Magic is present, though it is not called magic. There are sounds in space. Other than that, everything is pretty solid.
Red Dwarf: Hard to place because, as a comedy, it naturally has many absurd elements, but the Absent Aliens, the fact that it takes time to go places, the way robots are treated and (in earlier series) soft light holograms make it seem a lot harder than most. The novels are harder.
Doctor Who: Varies, being harder and softer at certain points in its extremely long run.
Star Trek The Original Series: Debatable though, many aspects of the show were pretty hard sci-fi when it was created, and only seem strange now after decades of science. Though the setting is stranger than other Star Trek shows, the ships and the technology is much more grounded.
The Halo; some of the technology used by the UNSC is upgraded real-world tech or technology based off predicted future developments, like railguns and AIs. The primary form of FTL are extremely dangerous and unpredictable "Slipspace" drives. Things get a lot wierder with time-and-space-bending Forerunner technology, which is made worse by the comparative wierdness of their tech and flatly refusing to explain how anything works.
Mass Effect: Uses only one form of Applied Phlebotinum :Element Zero, though this affects most of the sci-fi technology. Quite realistically, something as important as eezo and the mass effect fields it generates fundamentally influence most of society, and just about everything else in the setting reflects realistic science, including accurate geography, geology, astrology, physics, alien biology, computing, and military tactics and strategy. Well, not exactly... All the aliens speak English, though this is explained in the Bring Down the Sky DLC as a result of ubiquitous computers and translation software. There are also a few (almost) Rubber Forehead Aliens, with bizarre biology quirks of their own. On the whole, it's a mostly hard with a soft center, like an Everlasting Gobstopper.
The Stargate Verse: Considering the entire premise of the show is that ancient Earth religions were based off of alien snakes that take over your body or little grey men, that Atlantis is really a flying city in another galaxy, and that if you die, you can pop back again good as new after ascending/sleeping in a sarcophagus/being rebuilt by nanobots... it's surprising how hard they can get if they put their minds to it. StargateSG-1 got softer as it progressed, letting mystical concepts like Life Energy, Ascention and the power of belief take center stage.
Command And Conquer Tiberium series: Uses only one form of real Applied Phlebotinum, in the form of the titular Tiberium, but Tiberium itself has all manner of weird properties. By the third installment, though, the Sufficiently Advanced Aliens arrive with all manner of odd and physics-bending technology.
Andromeda: Tries to be harder than Star Trek. Set farther in the future, and teleporters, interstellar radio (they use couriers to deliver mail), and holodecks (they use virtual reality instead) are all still impossible. Rather than hand phasers, they use small tracking bullets, or if they're desparate, plasma bursts, though they can only fire a few shots of those. Also, their main weapons are small missiles traveling near the speed of light the hit with their kinetic energy. Trouble is, a lot less stuff is actually explained, meaning you usually have to take their word for it or make something up yourself whenever they use technology.
Infinite Ryvius: While its Space Is An Ocean (quite literally, in fact), complete with Space Whales, and contains impossible gravity-manipulating Humongous Mecha fights, the series also features relatively realistic Artificial Gravity and remembers to avert such things as Infinite Supplies and Sci Fi Writers Have No Sense Of Scale.
Mobile Suit Gundam: Original series only; the later ones tended to add more fantastic flights of fancy, but the original only had Psychic Powers, Minovsky Particles, and the basic unlikeliness of Humongous Mecha.
The Honor Harrington book series: Space Is An Ocean, but the series demonstrates admirable internal consistency, relies on essentially only one piece of "new" technology (gravity control methods), mostly merely extending other pieces of current technology (medical science, nuclear fusion containment, lasers). Additionally, space combat is very three-dimensional and ship-to-ship engagements are often fought from fractional light-second distances (contrast the traditional Star Trek Starship Standoff).
Macross: Plenty of Humongous Mecha, No Sense Of Scale and ships that pack more than their own weight in missiles. On the other hand, space combat scenes are not particularly fanciful and there are realistic depictions of zero gravity environments, decompression and the like.
Max Headroom: Strongly related to its Twenty Minutes Into The Future premise, though still packed with TV commercials that make people's brains explode.
Eve Online: FTL speeds are possible, but only applicable within a single solar system. Bridging the massive space that separates solar systems requires advanced stargate technology or highly costly specialized equipment that costs even more to use because of fuel limitations. Weapons are fairly realistic, employing relatively justifiable laser technology, magnetic railcannons, missiles, and even good old fashion bang-you're-dead projectile weaponry. The universe is ridiculously huge, much like actual space, with over 5000 unique solar systems, though ships in zero-G have a "Top speed" and decelerate once the engines turn off.
Sid Meiers Alpha Centauri: The Tech Tree expands based on our current understanding of science, the quotes from the in-game characters always make sense, nonsensical Technobabble is almost nonexistent, and a lot of in-game scientific and technological advancements have already been predicted by several writers and scientists. Could have ranked very low in this list if the Psychic Powers didn't look a bit too much like magic.
The Uplift series, by David Brin: Hard science mixed with a lot of Imported Alien Phlebotinum to make one of the 'hardest' of the Space Operas, a sub-genre that is usually very 'soft'.
Freefall: Tends to limit itself to 'theoretically possible but difficult' technologies, such as terraforming, AI and cryogenics. Even artificial gravity is absent (as the name suggests), and FTL travel is portrayed as slow, rare and hideously expensive.
Larry Niven's Known Space stories: Rather than breaking the laws of the universe outright (no Human Aliens here! Er... with one exception), they tend to simply do very unlikely things. An automated colony ship deciding to set up shop on a plateau of habitable land in the upper atmosphere above a Venusian miasma is not technically impossible, but it is pretty unlikely.
HP Lovecraft, by his own admission, preferred to "supplement reality rather than contradict it." His fiction takes a serious look at humanity's true place in the universe, and is full of Eldritch Abominations, Starfish Aliens, and scarily plausible explanations; there's no use of Aliens Speaking English or Rubber Forehead Aliens unless they're played for horror (since neither trope should naturally occur). Lovecraft stories also provide scientific rationales for merfolk, time travel, and the effects of witchcraft (it's really math).
Firefly: No sound in space (except for inside the ion cloud in The Movie, where the sound has a medium to travel through) and no aliens, and a few other things that seem like the writers actually did do the research (such as how nasty stomach wounds are), but there are some things, such as terraforming, temporary cryonics, and space ships that may or may not be viable 500 years from now - though all of them seem to have problems. Terraformed worlds all have "quirks" such as unique diseases that crop up, cryonics can cause a bit of a shock if you come out of it too quickly, spaceships break down easily, etc.. The most improbable feature of the world is probably River's apparent telepathy. The ships also move at the speed of plot, with Whedon waffling back and forth as to whether or not they can travel faster than the speed of light. The ships that left Earth took a "generation" at least to get to the system, but that was presumably generations before the story takes place.
Vernor Vinge's The Peace War, The Ungoverned and Marooned in Realtime: Mostly explore the consequences of a single fictional technology: time-stopping stasis bubbles
Charles Stross's Accelerando series: An Einsteinian universe without FTL but with traversable wormholes, with some handwaving of uploading and computronium. The characters speculate about distant aliens performing a timing channel attack on the computational ultrastructure of space-time itself, and the eventually-weakly-godlike-robot-cat claims to have a Halting Oracle, but that might be intimidation.
Cowboy Bebop: Has no Space Friction (except during dog fights), Artificial Gravity, travel outside this solar systems, and debatably has no FTL Travel. The least realistic things are ships that can easily reach escape velocity, terraforming that appears to use force fields, gates that accelerate ships to what may or may not be FTL, and that this will all happen by the 2070s.
A Miracle Of Science: Basically everything that's used is explained via modern theory, with the exception of a few staples such as FTL. Fairly impressive for a series based around mad scientists running a muck.
Alastair Reynolds' Relevation Space series: Has no FTL travel but does contain several superscience technologies, e.g. the Conjoiner near-lightspeed drive, space/time manipulating weaponry, messages from the future to the past (also the basis for FTL messaging).
Vernor Vinge's Rainbows End: Set Twenty Minutes Into The Future. The most speculative parts concern the existence of certain vulnerabilities in the human brain against information-based attacks.
2001: A Space Odyssey: Unusually among films and TV series with spacefaring, the vacuum of space is actually silent. Oddly enough, this is one of the few cases where the book is softer than the movie, due to going further into the details.
The works of Greg Egan: Tend to include in-depth discussions of physics, maths, computer science and biochemistry in a non-Techno Babble way, and many start from the assumption that, given time, modern science will go the way of Newtonian Physics. He gets bonus points by never using this as a cheap excuse for FTL travel.
The Tintin stories Destination Moon and Explorers on the Moon. Though science has marched on considerably since it was written, at the time it was a very plausible depiction of nuclear energy and space flight.
The movie also named Destination Moon, with screenplay by Robert Heinlein.
Patlabor: What giant, humanoid robots would be like in the real world. All units are awkward to pilot and their abilities are extremely limited. Police-issue labors can brawl with rogue worker mecha but will get utterly trashed by a simple gatling gun. Military labors are few and far between, and common anti-tank weapons are quite effective against them. Pilots need months of training and software assistance to perform well, and so on.
Century City: The science tried to be hard. The plots, on the other hand...
The Andromeda Strain by Michael Crichton: Scientists spend several hundred pages isolating and examining a lethal organism. The film adaptation also does a pretty good job.
Strange Days: A film with one innovation ("playback" of memories via portable superconducting quantum interference devices) and the consequences thereof.
Blue Planet: The hardest RPG released. FTL travel only through wormholes. Cetacean intelligence.
Gattaca: The gamete selection technology portrayed in the movie is a reasonable extrapolation from technology that already exists; indeed, the furthest-out thing in the film is a manned expedition to Titan (and given an entire world population of geniuses, it's not much of a stretch).
Robert L. Forward's Rocheworld setting was quite hard (it should be, he's a physicist), at least before it fell prey to Sequelitis. The only major implausibilities in the first book are alien life and a life-prolonging drug. In the third and later books, the science softens to mush, including finding native coffee beans on the moon of a gas giant circling a red dwarf.
Contact by Carl Sagan: Scientists spend the first third of the book struggling to raise money for the SETI program amid sponsoral skepticism. Once they finally find an alien transmission, they spend the second third deciphering the transmission, considering all the possibilities involved, and thoroughly applying the scientific method, all the while showing the social impact of knowing that we're not alone. It would rank even lower in the list if the last third was not about building borderline Imported Alien Phlebotinum, but it could be softer, because the setting and the clearly established rules actually make the alien device look rather hard.
Planetes: Near-future spaceflight. Its premise is economically infeasible, but the show features detailed orbital mechanics, realistic effects of space on health, diapers under spacesuits, and invisible laser beams. INVISIBLE LASER BEAMS. Only gratuitous In Space Everyone Can See Your Face keeps it from being harder.
Ben Bova's Grand Tour novels: Perfectly credible spaceflight-within-the-Solar-System stories. The only Phlebotinum is nanotechnology, which is at least theoretically possible. Some extraterrestrial life features, but it is plausibly primitive.
Robert L. Forward's Timemaster: probably the only hard science fiction story you'll ever encounter that has time travel at the core of the plot. The only iffy element is a substance with a negative rest mass: although such a material has never been observed, several mainstream theories of physics predict its existence.
Allen Steele's Near Space series. Spaceflight-within-the-Solar-System stories with no Phlebotinum at all, except in the farthest-future setting, A King of Infinite Space, which features reversible cryosuspension and a class of humans genetically engineered to function in space.
The works of Thomas Pynchon. Mr. Pynchon studied engineering physics before WWII, and you can tell.
Real Life: A Shared Universe which spawned its own genre, known as "The Documentary". Real Life has spawned much imitation, and comes close to the hardest end of the scale, but Reality Is Unrealistic.

Hardest

Metagame

« Meta Concepts »

The Moorcock Effect

Main Tropes Index

Troperville

Editing

Tools

Toys