[[quoteright:331:http://static.tvtropes.org/pmwiki/pub/images/2608432235_51f3eabb6d.jpg]]

->''"Our opponent is an alien starship packed with atomic bombs. We have a protractor."''
-->--'''Fraa Erasmas'''

''Anathem'' is a novel by Creator/NealStephenson about a world where monastic orders called "maths" isolate themselves from the rest of the world to study science, mathematics, and philosophy. When members of one of these maths make a surprising discovery, it's up to them to re-enter the "sæcular world" and use their skills to investigate and deal with the potentially global ramifications.

Like many of Neal Stephenson's other books he [[ShownTheirWork Shows His Work]] with several appendices of [[InstructionalDialogue Socratic dialogues]] and at least a cursory understanding of geometry and platonic philosophy being helpful. Like ''Literature/{{Cryptonomicon}}'', the book isn't really about the plot; just as ''Literature/{{Cryptonomicon}}'' was really about cryptology and ''Literature/TheBaroqueCycle'' was really about modern economics, ''Anathem'' is really about Platonic epistemology. Applied ''and weaponized'' Platonic epistemology.
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!!Tropes used:

* AerithAndBob: Erasmas, Orolo, Arsibalt, and [[spoiler: Jules Verne, who is descended from our Earth]].
* AfterTheEnd: The calendar sets the year 0 at the Reconstitution, which occurred shortly after the Terrible Events, a near-extinction level nuclear/nanotechnological war. This was more than ''3500 years ago.'' See also ScavengerWorld.
* AllThereInTheManual: The glossary and the appendices.
* AmbiguousDisorder: Barb
* AuthorFilibuster: And ''how.''
* BadassGrandpa: [[spoiler:Fraa Jad.]]
* BatmanGambit: Fraa Lodoghir suggests that all the events of the book occurred because [[spoiler: the Thousanders]] wanted to end the subjugation of the mathic world by the sæcular, and so, [[spoiler: right before the Third Sack, they used their Incanting praxis to call alien beings from various parallel universes to come to Arbre and create the existential crisis that enabled this to happen.]] However, given the way [[spoiler: the Thousanders are able to observe and manipulate different Narratives]], for them it might have been a XanatosGambit.
* BelligerentSexualTension: [[spoiler:Fraa Erasmas and Suur Ala.]]
* BizarreAlienBiology: The aliens can marginally breathe Arbran air and cannot digest the food, because [[spoiler:they are from other universes where the atoms are shaped a little differently, making them all chemically incompatible with one another.]]
* BookEnds: We are introduced to Erasmas as he is serving as "amanuensis" (recorder, or maybe witness) for a conversation between Fraa Orolo and an artisan from outside. The end has him acting as amanuensis again, in a very different context.
* CallARabbitASmeerp: Many ''technologies'' and ''cultural references'' have been renamed - for instance, cell phones are "jeejahs", Arbre's version of the net is called the "ret" (starting from "reticule" instead of "network"), scientists are called "theors" and martial arts are called "vale-lore" or "vlor". [[spoiler:Quite thoroughly justified, seeing as Arbre is within a chain of [[AlternateDimension Hylaean Theoric Worlds]]. These are similar to one another by definition, and one of them contains Earth, with rabbits and Socrates and Occam's Razor, as opposed to smeerps and Thelenes and Gardan's Steelyard.]]
* CallASmeerpARabbit: With living creatures, as Stephenson says in the introduction that he has, for instance, chosen to refer to Arbran vegetables which are similar but not identical to carrots simply as "carrots."
* ChekhovsGun: More accurately, Chekhov's [[spoiler:sextant]], sphere, bolt, chord, [[spoiler:ForgottenSuperweapon, oxygen, and soup]].
* {{Cloudcuckoolander}}: Barb/Fraa Tavener.
* CoolAndUnusualPunishment: A common punishment is to have avout memorize chapters in "The Book." Each chapter is more challenging than the last. While one chapter is simply memorizing the numbers in Pi, others are subtly ''wrong'' in their internal logic ({{nursery rhyme}}s that don't ''quite'' rhyme correctly, for example), making them difficult and taxing to memorize. Legend says only three people ever completed the twelfth chapter, and they all ended up completely insane. The punishment is purely optional, however. Avout can choose to simply leave the mathic world instead of submit to punishment.
* CutHimselfShaving
* {{Doorstopper}}: It used to be the picture on that page for a reason.
* DyingDream: [[spoiler:Weaponized by Fraa Jad to deliver a warning/threat to the Geometers.]]
* DeathFromAbove: Rodding. Very simple. Drop a large dense rod from orbit. Works [[IncendiaryExponent really well]] if you aim at [[spoiler:a dormant volcano]]. Boom. Repeat.
* DoomsdayDevice: Everything Killers are pill-sized neutron bombs that kill everything within a mile and can be placed just about anywhere. The World Burner is also ExactlyWhatItSaysOnTheTin.
* EngagingConversation: More like an Engaging Email. [[spoiler:Fraa Erasmus]] proposes to spend the rest of his life with [[spoiler:Suur Ala]], though their romantic relationship up to that point had been to make out once.
* {{Feelies}}: the advanced review copy came with a CD of mathematical chants that the characters sing throughout the book.
* FishOutOfWater: The avout in the sæcular world.
* FiveManBand: Raz's group in the early part of the novel forms a perfect FiveManBand.
** TheHero: Fraa Erasmas
** TheLancer: Fraa Jesry
** TheSmartGuy: Fraa Arsibalt
** TheBigGuy: Fraa Lio
** TheChick: Suur Tulia
* FunetikAksent: [[spoiler:Jules' GratuitousFrench, justified as Erasmas has never heard French before and is just taking wild guesses as to the spelling.]]
* GeniusBruiser: Fraa Lio and all the avout of the Ringing Vale. In fact, all of Erasmas' group are big, muscular guys who were selected for the heavy labor of winding the clock.
* GratuitousFrench: [[spoiler:Jules speaks some, and the others don't understand him, going as far as calling rockets "monyafeeks" after misunderstanding his outburst upon seeing one.]]
* GettingCrapPastTheRadar: Early on, after he gets jumped, Cord stops Arsibalt's nosebleed with what are clearly tampons. She calls them "blood soaker-uppers"
* HanlonsRazor, and its corollary, continually apply to Sæcular society over thousands of years.
* HeroicSacrifice: [[spoiler: Fraa Orolo]], and also [[spoiler: Fraa Jad (sort of).]]
* InfoDump: Like all Neal Stephenson novels, ''Anathem'' contains many of them.
* KangarooCourt: Erasmus is forced to partake in a public interview much like a trial to explain and defend his actions. His interlocutor is heavily against him and poses all of his questions to in an effort to make Erasmus look foolish. Erasmus immediately realizes that he'll have to draw on all his powers of argumentation to get out of the interview unscathed.
* LiteraryAgentHypothesis: In-universe, ''Anathem'' is written down by its main character and narrator, Fraa Erasmas. Overlaps with RecursiveCanon, as described below.
* ALongTimeAgoInAGalaxyFarFarAway: [[spoiler: at first; it later turns out to be TheMultiverse, with one of the other dimensions very clearly specified to be near-future Earth.]]
* LostSuperweapon: [[spoiler: World Burner and Everything Killers, oh and the ability to manipulate the multiverse with nothing more than a little chanting.]]
* [[MagicFromTechnology Magic From Praxis]]: Many legends developed around the Incanters, who were supposedly able to alter reality by chanting. However, [[spoiler: many clues imply that their power is actually a praxis the Millenarians developed. Fraa Erasmus saw (sort of...) Fraa Jad using what was probably the actual device, which looked like a fancy jeejah. It does appear that chanting is how Fraa Jad controlled it, which explains how the legend of the Incanters arose]].
* MindScrew: Plotwise, the book is fairly straightforward, until [[spoiler:Erasmas and Fraa Jad board the alien spaceship]], at which point multiple timelines/universes get involved and it's anyone's guess what the hell is going on. It gets better by the conclusion, though.
* TheMultiverse, thoroughly [[{{Deconstruction}} deconstructed]].
* MorphWeapon
* MountainMan: Yul, as a near-future-tech incarnation of this trope.
* MyNaymeIs: Erasmas, Lio, and Tulia are bastardized from the real-world names Erasmus, Leo, and Talia.
* NanoMachines, or rather, [[spoiler:the femtotechnology of Newmatter]].
* ObliviousToLove: Fraa Erasmus has no idea that [[spoiler: Suur Ala]] is into him until she grows visibly despondent at his obliviousness. [[spoiler: However, knowing Ala, she might very well have manipulated that whole situation just to sidestep his BelligerentSexualTension.]]
* OrionDrive: a spacecraft that travels between different dimensions and uses an Orion-style propulsion system. This ship, the ''Daban Urnud'', is discovered by observing the nuclear explosions used to modify its orbit.
* PersecutedIntellectuals: Mathematicians (called "Avout") are confined to monasteries (called "Maths"), and only allowed contact with the outside world once per year, decade, century or millennium. On three occasions the Maths were invaded because the Avout invented technologies considered too dangerous ("new matter", genetic engineering, and [[spoiler: magic]]).
* QuantumMechanicsCanDoAnything: Orolo's exposition on "Saunt Grod's Machines" suggests that Saunt Grod found a way to use quantum effects to realize a nondeterministic TM[[note]]no, what's called a "quantum circuit" or "quantum Turing machine" by RealLife academics is (probably) not this powerful, with NP and QBP generally thought, albeit not proven, to each contain sets not in the other[[/note]]; Jad's [[spoiler:farewell message]] to Erasmas all but confirms that millenarians have access to this application.
* ReallySevenHundredYearsOld: [[spoiler:Fraa Jad and, it is hinted, at least some of the Thousanders of the Three Inviolate maths, due to a praxis (read: technology) that allows them to be able to live around their stores of nuclear waste.]] Involves [[http://en.wikipedia.org/wiki/Quantum_suicide_and_immortality quantum immortality]].
* RecursiveCanon: In addition to the LiteraryAgentHypothesis being in use, earlier chapters of the book are discovered by concent officials at one point in the story, and they directly quote parts of the story as evidence in a hearing, which, of course, is written down in the book...
* RedShirt: The Valers avert this in Mahsht. Bonus points for doing it while actually wearing red shirts.
* RejectionRitual: The eponymous anathem ritual is performed when avout leave their order.
* RelationshipUpgrade: Justified and Averted. Avouts are required to publicly register their liasons, so as to avoid gossip in the maths. However, before [[spoiler:Fraa Erasmus and Suur Ala]] could register their liason, [[spoiler:Ala]] was evoked.
* RockBeatsLaser: (see page quote). Works until [[spoiler: both sides break out the femtotechnology, planet burners, and everything killers]].
* RubberForeheadAliens: The people on the ship look human, but slightly different in a way that Erasmas can't quite describe. This is because [[spoiler:they're humans from [[TheMultiverse the universe next door]]]]
* SchizoTech: Justified.
* ScavengerWorld: Played with and justified. Arbre has been at a relatively high level of technological development (on and off) for at least four thousand years. Background events suggest that the natural resources of the planet are almost completely depleted. The cars are powered by a processed fuel that originates in genetically engineered trees, and strip-mining abandoned cities for raw materials is a major industry. Several key pieces of high technology are built from designs that are hundreds or thousands of years old. This includes [[spoiler: the space suits.]]
* ScrewPolitenessImASenior
* ShoutOut: One of the Iconographies the sæcular world sometimes associates with the avouts invokes Franchise/StarTrek. Another Iconography involves Franchise/{{Superman}}.
* ShowWithinAShow
* ShownTheirWork: a given for Neal Stephenson novels. Three appendices provide intricately-constructed mathematical underpinnings for plot events or, occasionally, just some exposition. The credits for the book are voluminous and kept online for ease of update.
* SomedayThisWillComeInHandy
* StrawmanPolitical: Poor Fraa Lodoghir, who exists for the sole purpose of asking stupid questions on behalf of [[StrawmanU the Procian school of thought.]] Perhaps the first recorded instance of a Strawman Quantum Theorist. [[spoiler: Although his final conversation with Erasmas suggests this was ObfuscatingStupidity and he knew precisely what Fraa Jad was capable of and did.]]
* TakeMyHand
* TomatoSurprise: [[spoiler:Jules Verne Durand]].
* TranslationConvention: The book is [[LiteraryAgentHypothesis written by its protagonist/narrator]] in Orth; it's just presented to us in English for our benefit. Nearly all dialogue is actually in Orth, with some small parts in Fluccish, though both languages are presented to us in English. The only actual Orth we get to see consists of character/place names. [[spoiler:Also, when one character who speaks French shows up, his French is written in a FunetikAksent, as the narrator has no idea how French is supposed to be spelled]].
* UncannyVillage: [[spoiler:Orithena appears to be a Concent but is subtly different]].
* UnreliableNarrator: [[spoiler: It's not that he's lying, it's just that the records on hand prove him wrong...]]
* WarriorMonk: The avout of the Ringing Vale study athletics and martial arts, which is consequently called "vale lore" or "vlor." They study it with a scientific bent rather than a religious one. Avout outside of the vale, such as Lio, also study vlor.
* WhamLine: [[spoiler:"'In my world,' said Zh’vaern, 'we call it a Faraday cage.'"]]
* WrenchWench: Cord is a mechanic.
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