Terry used the Discworld to explain many of his own Ideas. He also ported a fair amount of Ideas proposed by others in our world into his universe.
The list below contains the ones I felt compelled to pull out of the book series. It is in chronological order by book and within each book.
Each idea is presented here only once as found in the book in which Terry first discussed it. If something significant about the idea is added in a later book, I’ll add to the description given in the earlier book.
Since there are relatively few such Ideas (compared to Persons, Places, and Things), I don’t intend to do any more with this list than what you see here. If I change my mind later, this paragraph will change with it.
Ideas in The Colour of Magic
Big Bang Hypothesis vs Steady Gait Theory – Two competing Ideas about how the Great A’Tuin moves through space. Neither may be correct.
Hogswatchnight – The last night of the year when the Hogfather does his thing.
Law of Conservation of Reality – “The effort needed to achieve a goal should be the same regardless of the means used.”
The Eight Great Spells – Seven are still in The Octavo; one is in Rincewind’s brain. No one knows what they are or what they do. That’s probably a good thing.
Mage Wars – Early in the Disc’s existence, these cause the Gods to be banished to Dunmanifestin, man to be re-created in smaller form, and wild magic to be sucked out of the Disc. And something more of significance.
Time, Non-Existence of – From Greicha the First (deceased but ruling) of Wyrmberg: “Imagine every moment being at one and the same time a distant memory and a nasty surprise….”
Seminal Ideas in The Light Fantastic
Librarian, Creation of – “The room had been part of the library until the magic had drifted through, violently reassembling the possibility particles of everything in its path. … And several of the wizards later swore that the small sad orang outang sitting in the middle of it all looked very much like the head librarian.”
Rite of AshkEnte – Summoning Death either by an elaborate ceremony, if there’s time, or something quite basic, if there’s not.
Thaum – The basic unit of magical strength. Often prefaced with prefixes like kilo- and mega-.
Tourism – According to Twoflower, the Disc’s inaugural Tourist: “I often don’t know where my Luggage is, that’s what being a tourist is all about.”
Multiple Universes – Often called (in other works) the Multiverse. According to the shopkeeper of one of those shops when asked what he would do next: “Oh, go to some other universe, there’s plenty around.”
Far Side of Darkness – Terry often goes through an idea to its other side or far side. He does so here with Darkness to create The Light Fantastic.
New Ideas in Equal Rites
Borrowing – When a witch gets into the mind of an animal (or the occasional University) and sees the Discworld through it.
Headology – Why a witch’s appearance and manners are more than they seem, according to Granny Weatherwax.
Metterfors – Granny’s term for metaphors. These aren’t particular to Equal Rites, but I decided to use them to create my main review of said novel. Thus I turned them into a 7A-part series of articles as listed below.
- How to Write Like Terry Pratchett: Similes and Metaphors in Equal Rites
- Writing Like Terry, Metterfors, Part 2
- Terry’s Metterfors, Part 3
- Metaphors in Equal Rites, Part 4
- Equal Rites Metaphors, Part 5 – What’s Not to Like?
- More Metaphors in Equal Rites, Part 6
- Penultimate Studies in the Metaphors of Equal Rites, Part 7
- Metterfors in Equal Rites, Part 7A, the Last
Hogswatch Day – The first day of the year in Discworld. In the roundworld, it would be both Christmas Day and New Years Day.
New Ideas in Mort
Hogswatch Eve – Virtually the same as Hogswatch Night. The equivalent of Christmas Eve in the roundworld.
Schism of the Turnwise Ones – Something to do with pizza and a jihad that caused the death of 25,000. Probably best not to ask.
New Ideas In Sourcery
Eve of Small Gods – When a new Archchancellor of Unseen University is “elected”.
All-Wadi Imperturbability Championship – The current holder is normally one tough dude. Normally.
Year of the Hyena – In force during the course of Sourcery.
Soul Cake Tuesday – At times celebrated on Thursday or even Friday. Involves trickle-treating at night. (See Reaper Man below.)
New Idea in Wyrd Sisters
Sumtin, Philosophical system of – According to the Fool, Zen is a sub-sect of this Turnwise Klatch system. Who’s to argue?
New Ideas in Pyramids
Year of the Engaging Sloth – During which the Thieves’ Guild declared a General Strike. The actual crime level doubled.
Smoking Mirror, Secret rituals of the – In which we learn of Nesh. Other rituals from Pyramids could be included here but are not.
Year of the Cycle of Cephnet – Imagined by Teppic while falling asleep. So it might not be real.
Century of the Cobra – During the time of Teppic.
Century of the Fruitbat – Not during the time of Teppic.
Troll’s Head – A tavern in Ankh-Morpork whose customers aspire to become the dregs of humanity.
New Ideas in Guards! Guards!
Grune – Seventh month of the Common Year. Between June and August. This being the time of change when the sun doth rise on the Right when facing the Hub.
Knurd – The state of not being drunk that goes beyond sobriety.
New Ideas in Eric
None. In fact, the only idea (by my definition, which is the only one that counts here) mentioned is the Rite of Ashkente.
New Ideas in Moving Pictures
Nothing to speak of here either, unless you count Holy Wood itself.
New Ideas in Reaper Man
Finally something new again. Actually, most are quite old as they are time-related.
Year of the Intimidating Porpoise – When old ‘Scratcher’ Hocksole Went Away.
Century of the Dragonfly – In which a ruler of Ankh-Morpork had tried to tell the wizards what to do.
Year of the Impromptu Stoat – Per the Farmer’s Almanac and Seed Catalogue, on June 15, 150 yrs. since, a Man killed by Freak shower of Goulash in Quirm.
Soul Cake Night – On which the young may go trickle-treating.
Year of the Significant Triangle – Year in which Windle Poons was born.
Century of the Three Lice – Century in which Windle Poons was born.
Year of the Notional Serpent – Year in which Windle Poons died.*
*This was within the Century of the Fruitbat.
New Ideas in Witches Abroad
Fat Lunchtime / Fat Tuesday / Mardi Gras – All 3 are noted in Witches Abroad. Fat Lunchtime is probably how folks usually referred to the carnival.
Path of The Scorpion – Devised by Grand Master Lobsang Dibbler (who is almost a contradiction in naming rights) and studied by Magrat Garlick.
Way of Mrs Cosmopolite – Discussed in one of the longest footnotes in the Discworld novels.
Year of the Revolving Crab – During which Compte Guy de Yoyo discovered the 2nd largest waterfall on the Disc.
Yen Buddhism – Yen Buddhists are the richest sect in the universe. Since money is a great evil, they take it (the money) upon themselves so you don’t have to.
Samedi Nuit Morte / Dead Night – Literally, Saturday Night Death. When Fat Lunchtime was celebrated in Genua.
New Ideas in Small Gods
Nine Fundamental Aphorisms – What Brutha knew to repeat when confronted with impure thoughts and demons.
Year of the Lenient Vegetable – In which Brother Kreeblephor converted a demon by the power of reason alone.
Year of the Astounded Beetle – In which, Brutha (nearly 3 years old) on Grune 3 saw Citadel cents.
New Ideas in Lords and Ladies
General Theory of L-Space – L-Space, being short for Library-Space, suggests that the contents of books as yet unwritten can be deduced from books now in existence.
Trousers of Time – At circle time (and perhaps other times), when the walls between this and that are thinner, then the universe can be sent careening down a different leg of the Trousers.
Blind Pig Tuesday – The approximate date on which the witches, notably Magrat, returned to Lancre from Genua.
New Ideas in Men at Arms
Silicon Anti-Defamation League – In deference to same, Vetinari required the Watch to add more species. Thus, Cuddy, Detritus, and Angua became Lance-Constables.
Troll New Year – Only of significance to trolls, unless you happen to live near one.
Battle of Koom Valley Day – Ask your favorite troll or dwarf about it, unless one is near the other.
Oggham – Ancient language of the Oggs who have been around (Lancre) for a very long time.
Battle of Crumhorn – Bloody Stupid Johnson created an arch (pocket-sized) in its memory.
Auguste – Month between Grune and Spune. Also blandly spelled August by those who don’t really care.
New Ideas in Soul Music
Breccia – Troll crime syndicate led by Chrysoprase.
Eisteddfod – Festival in Llamedos for poets, musicians, etc.
Ggroohauga – Trollish for “music made from rocks.”
Divisibility Paradox – Developed by Noxeuse. Demonstrates the impossibility of falling off a log.
New Ideas in Interesting Times
Heisenberg*’s Uncertainty Principle – Per Ponder Stibbons, related to teleportation, the object sent “is reduced to a thaumic particle and is therefore the subject of an eventually fatal dichotomy: it can either know what it is or where it is going, but not both.”
Battle of Koom Valley – Legendary scuffle between trolls and dwarves.
Flume’s Third Equation – During teleportation, predicts that an extra node can appear at a point equidistant to the original two under the proper conditions.
Turffe’s Law – During teleportation, sees to it that distortion (as predicted in Flume’s Third Equation) would stabilize in such a way as to create three separate points, each moving a roughly equal mass one jump around the triangle (that has three right angles).
*Wizard Sangrit Heisenberg.
New Ideas in Maskerade
Spune – Month between August and Sektober. Good time to gather scumble apples. (Months similar to those of the roundworld will not be mentioned here.)
Year of the Insulted Goat – One wonders what someone did to insult it.
New Ideas in Feet of Clay
Ankh-Morpork Historical Re-creation Society / Peeled Nuts – Nobby, as a member, got to play the role of King Lorenzo the Kind.
Battle of Ankh-Morpork – A civil war that lasted a little over 9 hours in the month of Grune in the year 432. No one actually won, other than the ravens.
Campaign for Equal Heights (for Dwarfs) – Mostly run by humans. That about says it all.
Century of the Rat – Was thought by Doc Pseudopolis, president of the Gamblers’ Guild, to be the 100 years soon to follow the Century of the Fruitbat. It turned out to be the Century of the Anchovy, so maybe he was just guessing.