"Theorum" is a word invented by UsefulNotes/RichardDawkins in his 2010 book ''The Greatest Show On Earth'' as a synonym for "scientific theory," to differentiate "theory" from its usage as a synonym for "hypothesis." [[note]]This differs from the much older world "theorem" which means, essentially, the same thing. Dawkins pronounces his word the-or-um (rhymes with decorum).[[/note]]
A theorum is a scientific theory, but not just ''any'' scientific theory. While any real scientific theory has to be supported by at least ''some'' research, a theorum is a core knowledge that is supported by massive evidence and supports our basic understanding of how the universe works.
Four classic theorums are Gravity, Evolution, Heliocentrism (in the sense that the Earth revolves around the Sun rather than vice versa, not in the sense that the Sun is the center of the universe) and Round Earth (in the sense that the Earth is not flat, not in the Creator/TerryPratchett sense that the world is flat but indeed round rather than [[http://www.rogermwilcox.com/square_earth.html square]]).
The word theorum was coined in 2009, for the purpose of distinguishing between different kinds of theories. The thing is that the word "theory" can be used in three very different ways.
* We have the layman term "theory", which can be quite synonymous with "wild guess" or with the scientific term "hypothesis".
* We have the scientific term "theory", which requires actual research and a good argument for why the theory is valid. However, these theories come and go and regularly replace each other as new-and-improved theories turn out to be better than the old ones.
* Finally, we have the theorums, which get expanded over time rather than replaced. A lot has happened since the days of Newton, and many different theories regarding gravity have come and gone. But this doesn't mean that gravity itself is outdated: No, on the contrary, it gets stronger with each new calibration.
Discarding a theory is only reasonable when the research supporting it gets replaced with more accurate research. Thus, it doesn't take much to overthrow a wild guess. Any scrap of evidence is enough, and without evidence, any other wild guess is equally valid anyway. Overthrowing a regular scientific theory is more complicated, but might still be easy: Simply make a better theory and gather better evidence. Overthrowing a theorum, however, well.... In fiction, the ''easiest'' way to do that is usually to prove that reality itself is a conspiracy or that the entire mainstream scientific community is in on the same AncientConspiracy. While it does happen that a theorum gets disproven and eventually put on history's discard pile in RealLife, this is very rare and usually means a huge paradigm shift, such as when our civilization abandoned the geocentric worldview in favor of the heliocentric.
In fiction, theorums are generally much more fun to mess around with than general theories are. A character dismissing string theory is boring and pointless unless you are making a highly specialized science-nerd joke or similar. A character dismissing gravity ''as such'', now that's much more interesting!
Not to be confused with a theorem, which is a mathematical truth proven from axioms and other theorems.
!!Tropes where a theorum can be messed with by a character, TheVerse itself, or both:
* CloudCuckoolander (An unique perspective on any theorum goes a long way to show that this character lives in his own little world.)
* EarthIsYoung (astronomy, evolution, geology, and so on.)
* FlatEarthAtheist (for comical effect, such a character is likely to believe in ideas that are theorums in RealLife but is very obviously untrue in TheVerse.)
* GravityIsAHarshMistress (gravity)
* GravityIsOnlyATheory (primarily gravity, secondarily any theorum other than evolution - some of the examples are ''indirectly'' about evolution, however.)
* HollywoodScience (any theorum)
* IRejectYourReality (theorum shmeorum)
* ScienceIsBad (the theorum is not only wrong, it is fundamentally evil)
* ScienceIsWrong (any theorum)
* StrawLoser (What better way to give a character a total lack of credibility than to let him believe that the earth is flat or whatever?)
* WindmillPolitical (any theorum)
!!Useful Notes relating to the concept of theorum:
* [[http://rationalwiki.org/wiki/Theorum rationalwiki.org/wiki/Theorum]]
* [[http://www.tompainesghost.com/2009/09/theorum-of-evolution_28.html Thomas Paine's Ghost]]
* [[http://www.amazon.com/Greatest-Show-Earth-Evidence-Evolution/dp/1416594795/ref=sr_1_2?s=books&ie=UTF8&qid=1297599268&sr=1-2 The Greatest Show on Earth]] - the book that coined the word.