The following list of errata comprises reader-discovered errors of a variety of types. Within each category, errata are listed in the order in which they appear.

Note: Many of these errors contain speculation. Please refer to the discussion page for debates on some of the more contentious topics.

Confirmed errors Edit

The following are the only errors that have been confirmed by their correction in later printings of Anathem.

Editorial errors Edit

The following are misspellings or a relatively contained mistakes that seemingly stem from one or two incorrect words.

Three sacks of Concent of Saunt Edhar Edit

While describing the clock of the Concent of Saunt Edhar, Fraa Erasmas writes about a weight riding up and down on a jackscrew in a hermetically sealed chamber that provides power to the timekeeping mechanism of the clock (and nothing else) while the clock is being wound, or if the clock is not wound and the meteorite weight ends up on the floor (p. 22 of the Harper paperback edition). He goes on to say that the only time the latter had happened was during a plague or during the three Sacks.

However, as the Concent of Saunt Edhar did not yet exist during the First Sack, the clock could not have been running. (This is corroborated by Barb's statement on the first morning of Apert that the shafts that drive the Decenarian gate cannot be made of New Matter, as the Concent of Saunt Edhar was built after the First Sack.)

Use of 'planning' instead of 'planing' Edit

Corlandin says to Erasmas: "I understand that some planning took place in the kitchen?" but it is clear that he should be saying "planing."

Use of 'trucks'Edit

At the Bazian monestary, Erasmas describes a sound he's hearing (which turns out to be Fraa Jad chanting) as sounding like "trucks descending a grade using air brakes." All other references to large motor vehicles use mobes, fetches, or drummons depending on the intended size.

'Yesterday' Edit

When the peregrin party has sufficiently recovered they take a two-hour tour of Ecba. The narration describes the events as having had happened 'yesterday':

Late yesterday, Yul had shattered the calm of the place by starting the engine of Cord's fetch[…]
Since all of Erasmas's possessions are later destroyed there is no way that this record could have actually been written a day after they toured the island.

Cord's fetchEdit

At the fueling station outside Norslof, Gnel arranged for the temporary storage of Cord's fetch, and Cord moves her gear into Yul's fetch. The text is unambiguous that when the peregrin party departs, "Cord's fetch stayed behind."

During Erasmas's recovery period on Orathena, however, "Yul[…]shattered the calm by starting the engine of Cord's fetch." Presumably the vehicle used is actually one of the three vehicles they do have (Yul's fetch, Gnel's fetch, or Gnel's three-wheeler).

Yul talking when he's not thereEdit

When Cell 317 begins training at Elkhazg, some bits of dialogue are attributed to Yul despite his confirmed absence from the scene. These attributions were corrected in later printings.

Use of 'corn'Edit

In most cases the word 'cob' is used in contexts where an English-speaker would say 'corn' or 'maize'. However, on page 799, while testing a surveillance syndev, Raz and Jesry spin a nonsensical story about how they used to make Everything Killer out of "cornstalks and shoelaces."

'P' is for piEdit

In one instance 'p' appears instead of 'pi'.

Mathematical errors Edit

These issues stem from either the misuse of mathematical language or mathematics itself.

Visual representation of the year Edit

Fraa Erasmas claims that one can view the weights of Saunt Edhar's clocks and guess that it's approximately 3689, but in fact there's no indication of it being the fourth millennium. An informed observer would only be able to tell that the year is X689 (i.e. the next millennium is 311 years away).

Striped dragons Edit

During the nerve gas–farting dragon dialogue, the following disagreement occurs:

"Restricting ourselves to nerve-gas-farting dragons, how many colors do you think we could distinguish?"
Opinions varied between eight and a hundred. Tulia thought she could distinguish more, Lio fewer.
"Say ten," Orolo said. "Now, let us allow for striped dragons with alternating colors."
"Then there would be a hundred combinations," I said.
"Ninety," Jesry corrected me. "You can't count red/red and so on".
However, if Jesry is going to be pedantic, he should say "Forty-five" because there is no difference between a red/blue and a blue/red dragons.

Hiding against the sunEdit

When the Daban Urnud's plane-change manœuver is detected by Ala and Erasmas, they note that the sparks were hidden against the sun's disc. This, however, cannot be an significant covert tactic because it would only work for a fraction of Arbrans. The Daban Urnud is orbiting too close to the planet for its antumbra to span all of Arbre, therefore many inhabitants would see the sparks off the sun's disc.

Appearance of the Darban Urnud and polar satellitesEdit

Contrary to the events in the story, it would be very easy to find the Darban Urnud in the sky. With a diameter of 8000 m, it is comparable to the Martian moon Deimos, which is a bit smaller and a bit closer to the planet and similar in brightness. At its maximum distance of 40000 km, it would appear to have about 1/8th the diameter of our moon—easily visble with naked eye. To make finding the Darban Urnud non-trivial, it would have to initially be at least one million km away.

Furthermore, when a satellite in a polar orbit crosses over the pole of a planet, it will cross the pole star only from the perspective of an observer at the pole. A typical polar orbit is 1000 km over the surface. To an observer at 51.3° N, such a satellite will be 8° below the horizon when it crosses the pole. The Darban Urnud, on the other hand, when over the north pole, would be visible from Saunt Edhar but about 6–10° south of (beyond) the pole star. (This is based on the stated altitude of 14000–25000 miles.) Hence the diagrams on pages 257 and 258 are wrong; they could have been made from either the south or the north pole, but not from the concent of Saunt Edhar.

Orb "stacks"Edit

The configuration of the orbs within the Daban Urnud is described inconsistently. In both descriptions orbs are arrayed around a central core. In the original description, four levels of four polar-arrayed orbs are packed as densely as possible by offsetting adjacent levels by τ/8 (45°). In later descriptions, however, the orbs are packed more loosely, without the rotational offset.

Perhaps the columnar version was the one written into early drafts, since it creates a clear hierarchy for the shipboard politics, and the efficient version was a late modification.

Praxic errors Edit

These issues stem from contradictions of physical properties.

Guidestar laser communication Edit

Depending on how the guidestar laser works, one of two assertions is proven false.

  • If the guidestar laser functions as a "line-of-sight" form of communication (i.e. it is invisible from any point not on the line), it could not "sweep" an analemma that is viewable by a single recipient unless they were already moving in the same formation.
  • If the guidestar laser illuminates pockets of the atmosphere, it could "sweep" a shape or message, but it would be visible to any party looking at those pockets of atmosphere.

Badges get a signal in the Faraday cageEdit

The characters confront Zh’vaern in a Faraday cage so that the microphone he is wearing cannot send signals. After a bit of conversation, everyone's emergency badges receive a signal and light up with the evacuation plan. Faraday cages block transmission in both directions, so if the cage worked (and it did, because the Pedestal expressed their anger at being cut off) they couldn't have gotten the signal to evacuate.

Challenges with breathing other narrative oxygen Edit

All of the four Geometer races and the people of Arbre have at least some difficulty breathing the air from other narratives. The explanation is that hemoglobin is particular about the bonding with oxygen. If this is true, the races on the Darban Urnud are doomed, because they have no way to replenish their oxygen supply.

Regardless of how efficient the recycling process is, there will be inevitable losses from opening and closing airlocks, minor leaks, and the inevitable mixing of air between the lobes, the core, and the vertices. Since the air at the next narrative can't be used to replenish the supply, the occupants of the Darban Urnud are doomed to slowly asphyxiate in the presence of plenty of available oxygen.

Rotating the Darban Urnud Edit

The central core with its lobes partially filled with water would a massive angular momentum of its own. Any attempt to turn the Darban Urnud would result in precession caused by the central core. The "railroad" momentum wheels Erasmas mentions would need to be huge to counter that torque.

Narrative errors Edit

Third Sack relics Edit

"Of those, two hundred died on the spot from wounds suffered during the operation. This wedge of granite was their tumulus[…] The rest of the concent fell the next day."

"Amnectrus was cast in bronze but the rifle and the lake of spent shell-casings in which he was immersed were actual relics. p167

It's unlikely that there would have been an opportunity to bury 200 dead or collect spent shell casings before the concent fell. (The rifle, on the other hand, would likely have passed to the Millinerians.)

Cord's knowledge of the sacksEdit

As of the first day of Apert, Cord claims to have no knowledge of the First or Second Sack, but by the tenth day she's embarrassed when Rosk makes casual mention of the Third Sack.

Color of unfocused lightEdit

When Erasmas unwraps the tablet before placing it in Clesthyra's Eye, he says that the unfocused light will be the color of Arbre's sun, but when he finally examines the tablet he describes the initial frames as being blue due to the dominance of the sky.

Spelikon's interest in Erasmas's thoughtsEdit

Fraa Spelikon bases part of his investigation of Orolo on the leaves taken from Fraa Erasmas's niche, which we are told include the same account we are reading (presumably through the end of Erasmas's weeks of isolation). These clearly include Erasmas's thoughts and his conversation with Orolo on the ninth night of Apert,. However, Fraa Spelikon apparently does not know what occurred that night for Erasmas.

The first Provener after Erasmas's VocoEdit

At the start of the meeting in Cord's machine hall, the bells ring Provener, and Erasmas feels "wounded that they'd managed to wind the clock without [his team]." However, the bells are merely summoning the concent to Provener; the clock winding won't begin for several minutes and won't be done for another twenty-minutes after that.

Temporal errorsEdit

The following are issues that stem from conflicting or ambiguous chronology.

The weed war as coverEdit

In the moments preceding Orolo's Anathem, Erasmas's climb through the Fendant Courts escapes scrutiny because his work drawing the weed war is known to Suur Trestinas. However, this moment comes only two weeks days after the weed war was first discussed and well before the spring growing season (the equivalent of February in Earth's northern hemisphere), so it is doubtful that Erasmas would have had enough to draw to spend enough time in this pursuit for it to have become so familiar to the Warden Regulant.

Days in quarantineEdit

At first Erasmas reports sending several days in quarantine after the Visitation, but later describes leaving for Tredegarh at the end of the second day.

Points of ambiguity Edit

The following moments may represent some sort of internal inconsistency but are not verifiable as erroneous.

Use of 'saunt'Edit

Regarding the word 'saunt', the fourth edition of the dictionary states that "Within some traditional orders it is still pronounced "Savant" and obviously the same is probably still true among Millennarians." There is no need for such conjecture since the dictionary is only complied at Millennial aperts. Furthermore, there is little reason to believe that Millennarians would have been exempted from this corruption during the Third Sack since they too (except for those at the three inviolates) were forced into Perigrinage.

Use of 'Earth'Edit

'Earth' is used in idioms throughout Anathem:

  • During Orolo's interview with Artisan Quin, Raz asks "What on earth does that mean?" when Quin says that Artisan Flec's speelycaptor was "too good" to be used in the Mynster.
  • When Cord gives Arsibalt a tampon (for his bloody nose), he asks "What on earth are those?"
  • Arsibalt asks Raz, "Then why on earth did you say them to a total stranger?" to challenge his conversation with Varax the Inquisitor.
  • When Lio considers making gardening his avocation, Raz asks "“But why on earth would you want to?"
  • Following the Voco of Ala, Raz recalls his tenth-night conversation with Varax the Inquisitor and wonders "What on earth did that mean?"
  • "The red-shirted Valer's scream during the battle in Mahsht is described as "unearthly", although "unarbrely" would be more likely on Arbre.
  • During his initial "interview" during Raz's first Plenary at Convox after Inbrase, Fraa Lodoghir asks, "What on earth were you and Orolo doing on the top of the volcano after dark?"
  • Lodoghir, reacting to Jad's proposal that the geometers came from another Narrative, shouts out "What on earth is he going on about?

'Earth' is also used as a reference to the ground and soil:

  • When Erasmas is telling Quin about the first draft of Saunt Orolo's, he describes the materials: "The first draft of everything is going to be wood and earth."
  • "Earthquake" appears at throughout the book.

Finally, 'Earth' is used to refer to the real-cosmos planet:

  • Fraa Paphlagon's speech at the end of the book refers to "our friends from Urnud, Tro, Earth, and Fthos".


Erasmas asks Orolo about the meaning of bottleshakers, and the resulting answer is almost identical to Erasmas's earlier explaination of Flec's behavior. Furthermore, "bottleshaker" seems to get used to describe both the Warden of Heaven and members of his congregation without distinction.

Bulletproof boltEdit

During Apert, Lio shoots his possessions with arrows and bullets to determine their protective properties. However, when Erasmas extricates himself from the arctic chasm, he recalls childhood experiences of reading about uses for the bolt, the chord, and the sphere. The notion that Lio would not already know if his bolt and sphere can stop bullets is absurd within this context.

Gardan's steelyardEdit

A steelyard balances two unequally weighted objects on lever arms of different lengths in order to measure a large unknown mass against a smaller know mass. This does not match the metaphor of weighing two hypotheses against one another and choosing the one that rises.

Barb as a fidEdit

Erasmas decides to take Barb as his fid while cleaning the kitchen one day about a week after the Winter Solstice. That same day he engages Orolo in what becomes the infamous Pink Dragon Dialogue. Orolo ends the post-dialogue conversation by shooing Erasmas off to a lecture, where Erasmas sits down next to Barb and comments that Barb has enhanced his learning over the past six weeks. This is technically possible since it's almost the exact duration since Erasmas's Eliger, but it conflicts with his upsight in the kitchen.

"Real" paperEdit

When the the main characters are first viewing Praxic Age Exoatmospheric Weapons Systems, Erasums inexplicably refers to the medium of the pages as "real paper made in a factory." Other references to paper, however, imply that paper is not uncommon extramuros and is not used intramuros simply because it is inferior to leaves, so it is improbable that Erasmas would chose to use the word 'real'.

Disappearing FermanEdit

Considering that Ferman Beller is one of the main characters on the road from Edhar to Samble, his sudden disappearance is strangely unmarked.

Suur SpryEdit

Upon Erasmas's arrival at Tredegarh, there are two references to a romantic relationship between Erasmas and (presumably) Suur Spry: Fraa Lodoghir attempts to bait Erasmas with a mention of a "girlfriend" at Orithena, and independently Erasmas admits to the reader that he thought of himself as single after Ala's Voco. This seems to hint that in an earlier draft of the the book there was more significant relationship between Erasmas and Spry.

Reasons for going to EcbaEdit

Erasmas tells Lodoghir that his expectation of being Anathematized contributes to his decision to travel to Ecba. This is clearly not true, and the lie seems purposeless as the true motivation is not being hidden.

Avout of TredegarhEdit

There is no explanation for what happened to the (presumably) thousands of avout who were displaced by the Convox.

Messal without microphonesEdit

One of the fundamental benefits of the Messal system of dining is ability of servitors to listen to the conversation, but this would not work well without the audio system in the kitchen that was installed by the Ita specifically for the Convox.

Jules's babblingEdit

Shortly after reaching orbit, Esma says that Jules had been "speaking incoherently of cheese". If Jules had indeed been delirious and babbling, one would expect him to be babbling in French and most likely using the word 'fromage'.

Geography of Saunt Orolo's Edit

The geography during the final chapter seems ambiguous. There are some hints that it may be at the site of the hundred-missile launch, but it would more appropriate for a site named after Orolo to be near Ecba. Erasmas starts near a rod crater, which would be on Ecba, but then has to cross water to get to "the island," which is either Ecba or a never-before-mentioned island.

Relativity Edit

At his unmasking in the last messal Jules describes the concept of spacetime and gives it the name "General Relativity" which Suur Moyra calls "Geometrodynamics". However, much earlier in the story, during the discussion of Praxic Age Exoatmospheric Weapons Systems in Shuf's Dowment, Barb makes a direct reference to relativity and calls it by that name.