*The people at "TV Tropes" have so much cult jargon that they're in a conceptual world all their own.
Wander in there, you might never come out
1. Science in Genre Only: The work is unambiguously set in the literary genre of Science Fiction, but scientific it is not. Applied Phlebotinum is the rule of the day, often of the Nonsensoleum kind, Green Rocks gain New Powers as the Plot Demands, and both Bellisario's Maxim and the MST3K Mantra apply. Works like Futurama, Star Wars, Tengen Toppa Gurren Lagann, The DC and Marvel universes,note and The Hitchhiker's Guide to the Galaxy fall in this class.
2. World of Phlebotinum: The universe is full of Applied Phlebotinum with more to be found behind every star, but the Phlebotinum is dealt with in a 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 E. E. “Doc” Smith's Lensman series, Neon Genesis Evangelion, Star Trek: The Original Series, and StarCraft fall in this category.
A subclass of this class (arguably 2.5 on the scale) contains stories that are generally sound, except the physics aren't our own. Plot aside, they are often a philosophical exploration of a concept no longer considered true (such as Aristotelian physics), or never considered true in the first place (e.g. two spatial dimensions instead of three, like Flatland). Some of Arthur C. Clarke's stories fall here. However, given the overlap with fantasy, it can prove tricky to even classify a story as SF.
3. Physics Plus: Stories in this class once again have multiple forms of Applied Phlebotinum, but in contrast to the prior class, the author aims to justify these creations with real and invented natural laws — and these creations and others from the same laws will turn up again and again in new contexts. Works like Schlock Mercenary, David Weber's Honor Harrington series, David Brin's Uplift series, and Battlestar Galactica (2003) fall in this class. Most Real Robot shows fall somewhere between Classes 2 and 3.
4. One Big Lie: 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 Cities in Flight stories fall squarely into this category, courtesy of the "Dirac Equations" leading to the "spindizzy motor" and instantaneous communication. Most works in Alan Dean Foster's Humanx Commonwealth series, the Ad Astra board games and Robert A. Heinlein's Farnham's Freehold fall in this category, as do many of Vernor Vinge's books.
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 FTL Travel), but for which the device is not a major element of the plot. Many Hal Clement novels (e.g. Mission of Gravity, Close to Critical) and Freefall fall within the subclass.
5. Speculative Science: Stories in which there is no "big lie" — the science of the tale is (or was) genuine speculative science or engineering, and the goal of the author to make as few errors with respect to known fact as possible. The first two books in Robert L. Forward's Rocheworld series and Robert A. Heinlein's The Moon Is a Harsh Mistress fall in this class.
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.) Gattaca, Planetes, Transhuman Space and the more Speculative Fiction works of Jules Verne fall in this subclass.
Real Life (aka Fiction in Genre Only): A Shared Universe which spawned its own genre, known as
6. "Non-Fiction". Despite the various problems noted at Reality Is Unrealistic, it is almost universally agreed that there is no other universe known so thoroughly worked out from established scientific principles. The Apollo Program, World War II, and Woodstock fall in this class.
Alternative Ti
