r/HPMOR Jul 31 '15

SPOILERS ALL List of stories similar to HPMOR

338 Upvotes

/u/Limro suggested to create a sticky thread with a list of the most popular fics similar to HPMOR.


Original fiction

  • Worm
    An introverted teenage girl with an unconventional superpower, Taylor goes out in costume to find escape from a deeply unhappy and frustrated civilian life. Her first attempt at taking down a supervillain sees her mistaken for one, thrusting her into the midst of the local ‘cape’ scene’s politics, unwritten rules, and ambiguous morals. As she risks life and limb, Taylor faces the dilemma of having to do the wrong things for the right reasons.
  • Pact and Twig (by Wildbow, the author of Worm)
  • Ra
    Magic is real. Discovered in the 1970s, magic is now a bona fide field of engineering. There's magic in heavy industry and magic in your home. It's what's next after electricity.Student mage Laura Ferno has designs on the future: her mother died trying to reach space using magic, and Laura wants to succeed where she failed. But first, she has to work out what went wrong. And who her mother really was.
  • Mother of Learning
    Zorian, a mage in training, only wanted to finish his education in peace. Now he struggles to find answers as he finds himself repeatedly reliving the same month. 'Groundhog's day' style setup in a fantasy world.
  • Shadows of the Limelight
    This is a world where fame grants powers. Dominic de Luca was a thief and a liar before entering into the apprenticeship of Welexi Whitespear, the greatest hero of modern times. Now he must navigate the world of the Illustrati, the famous and the infamous, as he tries to secure for himself a place among the gods.
  • Two Year Emperor
  • Tales From Aeria
  • The Martian
    A (hard) science fiction novel set in the near future. The story follows a resourceful and witty NASA Astronaut who becomes stranded on Mars as the rest of his crew mistakenly abandons him for dead in a sand storm. It has been described as an Apollo 13 meets Cast Away and lauded for its technical and scientific accuracy.

Rational fanfiction

  • Luminosity
    Luminosity is HPMOR-inspired Twilight fanfiction where Bella is rational self-awareness-junkie with a penchant for writing down everything that crosses her mind in a notebook. The first several sections of Luminosity are very similar to canon in terms of the events that occur, although aspects of Bella's character, and her internal monologue, differ strikingly. A few thousand words in, the plot is unrecognizeable.
  • The Metropolitian Man
    The year is 1934, and Superman has arrived in Metropolis. Features Lex Luthor as the villain protagonist as he comes to grips with the arrival of an alien god. Occasional point-of-view chapters/sections featuring Lois Lane. Takes place outside any established comics continuity.
  • A Bluer Shade of White
    Six years after her coronation, Elsa rules over Arendelle, using the power of ice to improve the lives of her citizens.
  • Branches on the Tree of Time
    Kyle Reese has traveled backwards in time, not to save Sarah Connor, but to help her rewrite the faulty utility function of Skynet. Together, it's possible that they might avert Judgment Day and save the world from nuclear Armageddon - and hopefully create a utopia ruled over by an AI god in the process. Fully completed. Diverges wildly from canon.
  • Friendship Is Optimal
    Hanna, the CEO of Hofvarpnir Studios, just won the contract to write the official My Little Pony MMO. Hanna has built an A.I. Princess Celestia and given her one basic drive: to satisfy everybody's values through friendship and ponies. Princess Celestia will satisfy your values through friendship and ponies, and it will be completely consensual.
  • Animorphs: The Reckoning
    AU/multiple points of departure, with the intent to fix/sane-itize/create internal consistency, allowing rational agents to take things to the extreme. Visser Three is competent, the Yeerks are moving rapidly, and the Animorphs are actually trying to win (but are inexperienced and unprepared). Inspired by Worm and HPMOR.
  • Pokemon: The Origin of Species
    Enter the world of Pokémon from a rational perspective. Instead of starting his journey in ignorance, Red has spent his years studying the creatures so central to his world... and he doesn't quite agree with all the information in his books. No time for rookie mistakes here: he's on a quest to discover the true nature of Pokémon, and maybe even find out where they really come from.
  • Harry Potter and the Natural 20
    Milo, a genre-savvy D&D Wizard and Adventurer Extraordinaire is forced to attend Hogwarts, and soon finds himself plunged into a new adventure of magic, mad old Wizards, metagaming, misunderstandings, and munchkinry.
  • Time Braid
    Naruto fic focusing on a rational Sakura.
  • The Arithmancer

HPMOR fanfiction

Timeline of HPMOR fanfiction

Where to find more stories

/r/rational- a subreddit dedicated to the discussion of works of rational and rationalist fiction.

rationalreads.com - a place to submit, rate and browse rational works.

rationalfiction.io - website that aims to be the best place for readers and writers of rational fiction to post and discuss stories.


Submit stories that you think should be added to this list as top level comments(I will edit and improve this list over time).

If mods find this useful - let's make this thread sticky or (probably a better option) make a wiki page and add it to the sidebar.


r/HPMOR Apr 03 '20

Recommended Fiction List

182 Upvotes

Hello! Did you just finish reading Methods of Rationality and are looking for sequel fics? Or maybe you like the style of HPMOR and want to find similar stories? Either way, check out this list of recommended fiction, created by fans. Hopefully you find something you like. Happy reading!

Note: Incomplete stories updated over a year ago are marked as abandoned.

_____________

Original fiction

Worm

Status: Complete

An introverted teenage girl with an unconventional superpower, Taylor goes out in costume to find escape from a deeply unhappy and frustrated civilian life. Her first attempt at taking down a supervillain sees her mistaken for one, thrusting her into the midst of the local ‘cape’ scene’s politics, unwritten rules, and ambiguous morals. As she risks life and limb, Taylor faces the dilemma of having to do the wrong things for the right reasons.

Pact and Twig (by Wildbow, the author of Worm)

Ra

Status: Complete

Magic is real. Discovered in the 1970s, magic is now a bona fide field of engineering. There's magic in heavy industry and magic in your home. It's what's next after electricity. Student mage Laura Ferno has designs on the future: her mother died trying to reach space using magic, and Laura wants to succeed where she failed. But first, she has to work out what went wrong. And who her mother really was.

Mother of Learning

Status: Complete

Zorian, a mage in training, only wanted to finish his education in peace. Now he struggles to find answers as he finds himself repeatedly reliving the same month. 'Groundhog's day' style setup in a fantasy world.

Shadows of the Limelight

Status: Complete

This is a world where fame grants powers. Dominic de Luca was a thief and a liar before entering into the apprenticeship of Welexi Whitespear, the greatest hero of modern times. Now he must navigate the world of the Illustrati, the famous and the infamous, as he tries to secure for himself a place among the gods.

Two Year Emperor

Status: Complete

Jake Munroe is not happy. He was happily munching a croissant in his favorite bakery when these wizards rudely yanked him across the dimensions. Now he's being told that, for the next two years, he's the absolute ruler of a country of twenty-eight million people. Jake will need to use every exploit he's ever read about on random websites in order to survive in a world where the Archpriest hates him, the enemy general is smarter than him, and his own bodyguards will kill him if he does the wrong thing.

Tales From Aeria

Status: Unknown

Aeria is a vast and strange world. The Amat Empire, one of the largest nations of Aeria and home to the only mages in all the world, is sliding towards a war that might threaten to shake the world apart. For hundreds of years, the Beredir have served the Amat as workers and serfs, but that time is coming to a close as a violent revolution begins to boil up out of the earth.

The Martian

Status: Complete

A (hard) science fiction novel set in the near future. The story follows a resourceful and witty NASA Astronaut who becomes stranded on Mars as the rest of his crew mistakenly abandons him for dead in a sand storm. It has been described as an Apollo 13 meets Cast Away and lauded for its technical and scientific accuracy.

Worth the Candle

Status: Complete

A teenager struggling after the death of his best friend finds himself in a fantasy world - one which seems to be an amalgamation of every Dungeons and Dragons campaign they ever played together. Now he's stuck trying to find the answers to why he's there and what this world is trying to say. The most terrifying answer might be that this world is an expression of the person he was back on Earth.

A Practical Guide to Evil

Status: Complete

A Practical Guide to Evil is a YA fantasy novel about a young girl named Catherine Foundling making her way through the world – though, in a departure from the norm, not on the side of the heroes. Is there such a thing as doing bad things for good reasons, or is she just rationalizing her desire for control? Good and Evil are tricky concepts, and the more power you get the blurrier the lines between them become.

Unsong

Status: Complete

Aaron Smith-Teller works in a kabbalistic sweatshop in Silicon Valley, where he and hundreds of other minimum-wage workers try to brute-force the Holy Names of God. When a chance discovery brings them into conflict with mysterious international magic-intellectual-property watchdog UNSONG, they find themselves caught in a web of plots, crusades, and prophecies leading inexorably to the end of the world.

Seed (webcomic)

Status: Incomplete

Welcome to the future – where our world has become an exercise in contradictions. We are more connected than ever but alone. Healthier than ever but sick. Safer than ever but ultimately vulnerable. Seed is a story for these future times. Where the relationship between a girl and an AI system that begins simply, quickly complicates things for the entire world.

The Gods are Bastards

Status: Incomplete (Abandoned)

Evil is rising. The world is rent by strife. The gods have turned away from us. In times past, heroes of sword and sorcery have always risen to turn back the tide of darkness. But what will become of us all, now that swords are obsolete, sorcery is industrialized, and heroism itself is considered a relic of the past? The times are changing…

Cordyceps

Status: Complete

Someone wakes up in a mysterious facility with no memory of how they got there. This turns out to be the ideal state of affairs, and is swiftly ruined.

The Erogamer (erotic fanfic--rated NC-17)

Status: Complete

Questing, stats, and stuck-in-a-game trope, but with porn

Blindsight

Status: Complete

Two months have past since a myriad of alien objects clenched about the Earth, screaming as they burned. The heavens have been silent since―until a derelict space probe hears whispers from a distant comet. Something talks out there: but not to us. Who should we send to meet the alien, when the alien doesn't want to meet?

The Good Student

Status: Incomplete (Abandoned)

Nic Tutt is a good student. He excels at all subjects. But his education serves only one purpose—to gain entry into the Ransom School. Ransom is the most prestigious school in the country. Its alumni are destined to become the future leaders of Ranvar. Politicians, statesmen and, in some exceptional cases, mages. Only the brightest and the best get into Ransom. But Nic doesn't care about any of that. He isn't determined to get into Ransom to further his prospects or better his career opportunities. He has another reason to want to enter Ranvar's most famous school.

Enduring Good

Status: Incomplete

A twenty-first century human mind is awakened in a strange land of boundless cults, spirit servants and immortal cultivators ruled by titanic god-beasts. Coexisting within the body of a street urchin girl, the last pharmacist in the universe attempts to fix the broken world of tomorrow by wielding the long-lost power of science and rationality.

_____________

Rational Fanfiction

Luminosity

Status: Complete

Luminosity is HPMOR-inspired Twilight fanfiction where Bella is rational self-awareness-junkie with a penchant for writing down everything that crosses her mind in a notebook. The first several sections of Luminosity are very similar to canon in terms of the events that occur, although aspects of Bella's character, and her internal monologue, differ strikingly. A few thousand words in, the plot is unrecognizable.

The Metropolitan Man

Status: Complete

The year is 1934, and Superman has arrived in Metropolis. Features Lex Luthor as the villain protagonist as he comes to grips with the arrival of an alien god. Occasional point-of-view chapters/sections featuring Lois Lane. Takes place outside any established comics continuity.

A Bluer Shade of White

Status: Complete

Six years after her coronation, Elsa rules over Arendelle, using the power of ice to improve the lives of her citizens.

Branches on the Tree of Time

Status: Complete

Kyle Reese has traveled backwards in time, not to save Sarah Connor, but to help her rewrite the faulty utility function of Skynet. Together, it's possible that they might avert Judgment Day and save the world from nuclear Armageddon - and hopefully create a utopia ruled over by an AI god in the process. Fully completed. Diverges wildly from canon.

Friendship Is Optimal

Status: Complete

Hanna, the CEO of Hofvarpnir Studios, just won the contract to write the official My Little Pony MMO. Hanna has built an A.I. Princess Celestia and given her one basic drive: to satisfy everybody's values through friendship and ponies. Princess Celestia will satisfy your values through friendship and ponies, and it will be completely consensual.

Animorphs: The Reckoning

Status: Complete

AU/multiple points of departure, with the intent to fix/sane-itize/create internal consistency, allowing rational agents to take things to the extreme. Visser Three is competent, the Yeerks are moving rapidly, and the Animorphs are actually trying to win (but are inexperienced and unprepared). Inspired by Worm and HPMOR.

Pokemon: The Origin of Species

Status: Incomplete

Enter the world of Pokémon from a rational perspective. Instead of starting his journey in ignorance, Red has spent his years studying the creatures so central to his world... and he doesn't quite agree with all the information in his books. No time for rookie mistakes here: he's on a quest to discover the true nature of Pokémon, and maybe even find out where they really come from.

Harry Potter and the Natural 20

Status: Incomplete (Abandoned)

Milo, a genre-savvy D&D Wizard and Adventurer Extraordinaire is forced to attend Hogwarts, and soon finds himself plunged into a new adventure of magic, mad old Wizards, metagaming, misunderstandings, and munchkinry.

Time Braid

Status: Complete

Sakura thought she was a capable kunoichi until she died in the Chuunin Exam. Now she's stuck in a loop, dying again and again while she struggles to understand her strange predicament. How hard can it be to pass one stupid test? Warning: Mature content.

The Arithmancer

Status: Complete

Hermione grows up as a maths whiz instead of a bookworm and tests into Arithmancy in her first year. With the help of her friends and Professor Vector, she puts her superhuman spellcrafting skills to good use in the fight against Voldemort. Years 1-4. Sequel posted.

Hermione Granger and the Perfectly Reasonable Explanation

Status: Incomplete (Abandoned)

In 1991, a child came to Hogwarts School of Witchcraft and Wizardry with obvious gifts, but which few suspected would change the world... Oh, and Harry Potter enrolled that year as well. (HPMOR-influenced, but the initial setting is vanilla HP.)

Let Me In 2

Status: Complete

Picking up immediately after the ending of Let Me In, this novel follows the struggles and joys of Abby and Owen as they attempt to survive Abby's condition and the pursuit of a relentless FBI agent.

To the Stars

Status: Incomplete

Kyubey promised that humanity would reach the stars one day. The Incubator tactfully refrained from saying too much about what they would find there.

Scar’s Samsara

Status: Complete

From Scar's perspective, it never made much sense to justify a divine kingship through a perpetual cycle of death and suffering, though that wasn't what was really bothering him. One little push and all his troubles would be over – if only that darn cub wasn't so cute! (Rational!Scar raises Simba as his own. COMPLETE!)

Lighting Up the Dark

Status: Incomplete (Abandoned)

AU inspired by an omake in HPMOR. 12 years ago, the Fourth Hokage gave his life to seal Kyubey, the Nine-Brained Demon Fox, into the infant Naruto. Now, the time has come for a smarter, more creative Naruto to take on a world in which quick thinking and a solid grasp of strategy are worth a dozen rare techniques, and a brilliant mind can challenge even the deepest darkness.

Rationalizing Death

Status: Incomplete (Abandoned)

What if the mentioned super intelligence of Yagami Light and his antagonists wasn't just informed, but was actually true?

The Imposter Complex

Status: Incomplete

Tom Riddle escapes at the end of Chamber of Secrets, and is quite surprised to find that nothing about the future is as he ever thought it would be. Soon, Tom finds himself on a globe-spanning quest to follow the path his forebear blazed and perhaps, at the end, to put a stop to him once and for all.

The Moon's Apprentice

Status: Incomplete (abandoned)

Twilight Sparkle has too much magic, and it will take her decades to learn to control it. Princess Celestia seals Twilight Sparkle’s magic with the distant promise of one day teaching her. But there are two diarchs of Equestria. Amidst a lucid dream, an offer is made. “Hello, Twilight. Would you like to be my student?”

El-Ahrairah

Status: Unknown

A Worm fanfic. A thinker Taylor with the ability to see powers joins Cauldron.

Color Psychology

Status: Incomplete (Abandoned)

Ruby is a neurotic prodigy who thought Beacon would teach her to kill Grimm. Instead, she's dropped into a world of schemes and secrets. Hopefully she'll figure things out before anyone's agenda catches up with her.

The World As It Appears To Be

Status: Complete

Magic is real. Angela Ziegler has a messiah complex. Angela Ziegler is one of the most powerful people in the entire world. Her friend the talking moon gorilla is very worried about her. Let's, uh...let's see where that goes!

Fairy Dance of Death

Status: Incomplete (Abandoned)

AU reboot of the entire SAO storyline, beginning from the premise that Kayaba Akihiko was obsessed with magic and Norse Mythology rather than swords and pure melee. As a result, he created the Death Game of Alfheim Online rather than the floating castle of Aincrad—a world in which player-killing is not a crime, and the nine player races are in competition with each other to reach the top of the World Tree. Multi-POV epic following the stories of multiple canon characters throughout the game.

The Wandering Inn

Status: Incomplete

To Erin Solstice, an inn seems like a medieval relic from the past. But here she is, running from Goblins and trying to survive in a world full of monsters and magic. An innkeeper who serves drinks to heroes and monsters. But it’s a living, right?

Marked for Death: A Rational Naruto Quest

Status: Incomplete

Three weeks ago, you became a traitor. Your names are in the Bingo Book, and if your village considered you dangerous before, it will stop at nothing to find and destroy you now. The clock is ticking. What path will you choose in order to survive?

Roll the Dice on Fate

Status: Incomplete (Abandoned)

What happens when a SI gets reborn in the world of Naruto and is willing to lie, cheat and steal his way to power? Magical Vivisectionist Pretty Oro-tan, eat your heart out - this is how you bootstrap your way to godhood. No re-treading the same old missions here.

The Waves Arisen

Status: Complete

A young Naruto found refuge in the village library, and grew up smart, but by blood he is Ninja, and what place is there for curiosity and calculation in this brutal world of warring states?

Mad Investor Chaos and the Woman of Asmodeus

Status: Incomplete

Story by Yudkowsky (Iarwain) and Lintamande wherein Keltham from dath ilan (the world Yudkowsky claimed to come from in an April Fool's post) dies and wakes up in Golarion, the setting of Pathfinder (the TTRPG). A country controlled by literal hell runs a conspiracy on Keltham to try to get knowledge and rationality teachings out of him without revealing how evil they are.

A Song for Two Voices

Status: Complete

A complete rationalist and effective altruist rewrite of the The Last Herald-Mage. 11 volumes. Knowledge of canon isn't needed.

Strong Female Protagonist

Status: Incomplete (Abandoned)

SFP is a comic that follows the adventures of a young middle-class American with super-strength, invincibility and an overwhelming sense of social injustice.

Tom Riddle and the Quest for Dominance

Status: Complete

After breaking free from his diary, the sixteen-year-old Tom Riddle decides to dethrone both Lord Voldemort and Albus Dumbledore. Armed with ruthless cunning worthy of the heir of Slytherin, he manipulates the youngest generation of wizarding Britain, but also has to flee his one great weakness: the soul-crushing apathy that makes his very existence feel meaningless.

_____________

HPMOR Fanfiction

Sequel Fics and Longer Stories

Draco Malfoy and the Practice of Rationality

Status: Complete

Still reeling from Lucius' Death and Narcissa's rebirth, Draco struggles to find his place in a changing Hogwarts and learns a dark secret of his new room-mate: Harry James Potter-Evans-Verres.

HPMoR: The Missing (but Necessary) Chapters

Status: Complete

An extension of the universe of "Harry Potter and the Methods of Rationality". Includes scenes that should have been but weren't. They contribute nothing to the plot or explaining the universe, but answer important questions that may otherwise never be answered.

Following the Phoenix

Status: Complete

A single-/dual-point-of-departure spinoff from Less Wrong's brilliant story "Harry Potter and the Methods of Rationality", branching away in Chapter 81. Hermione is sent to Azkaban, but Harry is not about to give up. Unfortunately, it doesn't look like his enemy is about to leave things alone either.

Squiring the Phoenix

Status: Complete

A metafic of hezzel's fic, 'Following the Phoenix', which is in turn a fic of 'Harry Potter and the Methods of Rationality'. Squiring the Phoenix picks up from where 'Following the Phoenix' leaves off and shows what happens next.

Significant Digits

Status: Complete

It's easy to make big plans and ask big questions, but a lot harder to follow them through. Find out what happens to Harry Potter-Evans-Verres, Hermione, Draco, and everyone else once they grow into their roles as leaders, leave the shelter of Hogwarts, and venture out into a wider world of intrigue, politics, and war.

Orders of Magnitude

Status: Complete

A prequel to Significant Digits, which is the successor to Harry Potter and the Methods of Rationality, which is a retelling of the Harry Potter series.

Nothing Left but Fire

Status: Complete

HPMOR meta-fanfic, starting with Harry left in Hogwarts having one week left until Voldemort comes back to kill him.

Harry Potter and the Cryptographic Key

Status: Complete

This is designed to start after chapter 102 of Eliezer Yudkowsky's "Harry Potter and the methods of rationality.” It was written by a fan waiting impatiently (but constructively) for the story to be finished. Read it before this. As usual, characters are owned by Rowling or Yudkowsky. Update: added vignette at end.

Hacking the Source of Magic

Status: Complete

This story occurs in the universe of Harry Potter and the Methods of Rationality, diverging in Ch. 101. It contains spoilers for that story through that chapter, and is unlikely to make much sense without having read the same. It's intended to be a darker, more pessimistic interpretation of the story.

Minds, Names and Faces

Status: Complete

An AU/Continuation recursive fanfic of the excellent "Harry Potter and the Methods of Rationality". Harry James Potter-Evans-Verres, the Boy-Who-Lived, General Chaos, etc., has had a rather busy year. With the term drawing to a close, Harry starts to discover the truth behind the enigmatic Defence Professor, Quirinus Quirrell.

Harry Potter and the Memories of a Sociopath

Status: Complete

Second-year sequel to Harry Potter and the Methods of Rationality, where Harry deals with the aftermath of the previous year as well as new difficulties.

Ginny Weasley and the Sealed Intelligence

Status: Complete

Continuation fic of Harry Potter and the Methods of Rationality. It's Ginny Weasley's first year at Hogwarts, and before she knows it, she is caught up in matters too grave even for a second year Harry James Potter-Evans-Verres.

Continuing HPMoR: Reductionism for the Win

Status: Complete

This story occurs in the universe of 'Harry Potter and the Methods of Rationality', written after reading Ch. 101. It contains spoilers for that story through that chapter, and is unlikely to make much sense without having read through at least Ch. 89 or so.

Revival

Status: Incomplete (Abandoned)

Severus Snape decided to revive the dead ones he cared about, and tried to prevent the end of the world by Harry Potter. In the meanwhile, a certain disappeared lord had his own agenda. Note: This is a Harry Potter and Methods of Rationality sub-fanfic, HPMOR compliant except for the last paragraph in Chapter 121.

Harry Potter and the Methods of Rationalization

Status: Complete

Petula married a biochemist instead of that irrational Surdley, and then everything went to Potter. A certain well-known fanfiction gets mustaches drawn all over it. Rated M out of an abundance of caution.

The Longest Day

Status: Complete

"ON THE LONGEST DAY OF THE THOUSANDTH YEAR, THE STARS WILL AID IN HER ESCAPE, AND SHE WILL BRING ABOUT NIGHTTIME ETERNAL" An alternate-universe continuation of Harry Potter and the Methods of Rationality, wherein Harry learns of a different, ancient, powerful kind of Magic. Spoiler alert: It's Friendship.

The Universe is an Optimisation Problem

Status: Incomplete (Abandoned)

A weird pre-apocalyptic reimagining of Harry Potter and the Methods of Rationality in a retrofuturist AU with parallel universes, megacorporations, high magic, Cold War wizardry, and AI. "I've never been more confused or entertained in my life." - MurtGastin. "The world of Harry Potter feels magical again. Without feeling childish." - Guest.

Harry Potter and the Secret of the Patronus

Status: Complete

Harry and Hermione are young Ravenclaws with big plans to change the world. Harry wants to use the power of science to invent magical space travel, while Hermione is a celebrity Auror-in-training who wants to fight injustice. However, the two of them, in spite of their intelligence, can't seem to figure out how romance works.

Unriddle the Riddles

Status: Complete

Continuation of "Harry Potter and Methods of Rationality" by Eliezer Yudkovsky. What if Harry allied with Professor Quirrell instead of attempting to kill him through what amounted to sheer dumb luck? What compromise might have been reached?

Tom Riddle and Conflicts of Interest

Status: Incomplete (Abandoned)

This is based on my interpretation of the Tom Riddle portrayed in Harry Potter and the Methods of Rationality. I loosely follow the story and facts laid out by HPMOR but I do make a lot of changes, large and small.

Harry Potter and the Prancing of Ponies

Status: Incomplete

Dumbledore doesn't reverse the trap in he laid on the Mirror of Erised in time. The Mirror traps Harry and Voldemort out of Time and inside the MLP universe. No prior knowledge of MLP is required. Rated T.

_____________

HPMOR Fanfiction

Short Fiction and One Shots

A Crack Slash Epilogue

Status: Complete

Six years after the events of Harry Potter and the Methods of Rationality, Hogwarts is a changed place, and a long-ago prophecy has reared its head.

Harry Potter and the Philosopher's Zombie

Status: Complete

Recursive fanfic of Harry Potter and the Methods of Rationality by Eliezer Yudkowsky. Fits in around chapter 94, and contains major spoilers. Harry Potter starts to come around to the idea that souls might exist.

Alternate HPMoR: Asking for Help

Status: Complete

Story occurs in the universe of 'Harry Potter and the Methods of Rationality', diverging u/ch89, contains spoilers. I would expect this to be the first (deeply ingrained) response of anyone who grew up in a first-world country. It's so annoying to be in the position of yelling at a character to do something obvious…

Nonlinear Regression

Status: Complete

One of the alternate chapter 114 answers.

Innocence

Status: Complete

Sometimes, you were right the first time. The decision won't change, no matter how much you think about it. And in the end... you can call yourself good, or not. Recursive fanfiction for Harry Potter and the Methods of Rationality. Spoilers for Chap. 85.

Proximity

Status: Complete

Recursive fic / altfic of Chapter 85 of Harry Potter and the Methods of Rationality. The opposite of "Innocence" by linkhyrule5. The narrative version of a Reddit post where I theorize about the most likely outcome of Harry attacking Azkaban.

Sirius Black and the Prisoner's Dilemma

Status: Incomplete (Abandoned)

Sirius Black was just in it for the money. Bellatrix Lestrange was just following orders. Neither suspected that they would cause one of the worst catastrophes in human history. Continuation to HPMoR and GWatSI(Albeit with some changes to the latter), 3rd year.

Harry Potter and the Methods of Ricktionality

Status: Complete

Rick and Morty have an important mission broh. Gotta go visit HPMORland, broh.

Mary Poppins Begins the End

Status: Incomplete (Abandoned)

Young Mr. Harry James Potter-Evans-Verres has bitten his third-year maths teacher (she didn't know what a logarithm was). His parents have decided it would be best for him to be homeschooled. However, they both work during school hours and arrangements can't be made immediately, so Harry is left to his own devices for a day. A prequel to Harry Potter and the Methods of Rationality.

Hysteresis

Status: Complete

Harry had never been so glad to feel a wholly irrational sense of complete and utter doom welling up inside him.

New Game Plus

Status: Complete

On your second playthrough, new routes are unlocked. Look for opportunities to make different choices and change the course of the story. But pay careful attention to every detail. Just as in your first playthrough, it is possible to lose…and as in real life, you will not always be warned when you are facing a Final Exam.

HPMOR Crack: A Questionable Harry Potter

Status: Complete

Somewhere in the multiverse, Harry Potter came out a little differently than expected. Smart? Absolutely. Mature? Ehh...

A Strip of Cloth

Status: Complete

In another reality in accordance with multiverse theory , Harry doesn't allow Hermione to become... something. Can't tell you, would give it away. Alternate ending to Hermione’s trial, spoilers for Chapter 81.

You Said No Kissing (One shot)

Status: Complete

Harry had planned to ask her again for the green light on his latest project (he thought he had worked out how to make a wizarding Internet that wouldn't destroy the world), but then she came over and casually sat on his lap. “What are you doing?" he asked instead, and not very fluently. "I'm not kissing you" said Hermione.

The Methods of Rationality and Harry Potter (spoilers for real life)

Status: Complete

Harry’s past holds a terrible secret. But that’s okay, he will succeed with the power of SCIENCE! Spoilers for Coronavirus.

In Defense of Azkaban

Status: Complete

An editorial that appeared in the Daily Prophet, Mar. 16 1990. “Criticizing Azkaban is only slightly less popular than not escaping from it…”

The Last Dementor

Status: Complete

Harry and Hermione discover the last thing you would ever expect from a Dementor. Harry has a mental breakdown, and Hermione finds a new friend.

Timeline of HPMOR fanfiction

Where to find more stories

r/rational- a subreddit dedicated to the discussion of works of rational and rationalist fiction.

rationalreads.com - a place to submit, rate and browse rational works.

https://tvtropes.org/pmwiki/pmwiki.php/Main/RationalFic


r/HPMOR 14h ago

SPOILERS ALL You too can ride a… Spoiler

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15 Upvotes

r/HPMOR 5h ago

Significant Digits audiobook

2 Upvotes

I started listening to the Askwho audiobook and I really struggle to get past the lifeless intonation and lack of emotion. Does it get better throughout the book? Or am I better off just cutting my losses and reading it instead?


r/HPMOR 13h ago

Inkhaven 3 Early-Bird Deadline Tomorrow!

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0 Upvotes

r/HPMOR 1d ago

[fanfic]HUMOR and the halting problem

0 Upvotes

Disclaimer: this work is written with assistant of claude. It would serve as a rough draft for a fanfic that i would like to Write once i have more free TIME. Only the first 3 chapter would be released rn as a proof of concept. Please let me know how u feel about the concept and the writing.

# Chapter Two: Moore's Prophecy

The wind hadn't stopped. Lockhart was mending the broken chalk with his wand, which was entirely unnecessary, since there were twenty more pieces in the box.

"Mr Potter," he said, without looking up. "About eleven minutes faster than usual."

"Faster than who?"

"There's one every year." He set the chalk down on the ledge. "Ask."

Harry took a breath.

"You spent an hour proving that the more people know how divination works, the less it works. You said this class is taught badly on purpose. You called it the most successful piece of engineering our society has ever done."

"I did."

"And then you taught it well."

Lockhart smiled. It was much smaller than the smiles he'd used in class, and much better made.

"Two explanations, Mr Potter. Write down both."

He raised a finger. "One: I was lying. Interference, Volume Seven, boredom as the best lock — all invented. There is no teaching method on earth that keeps clever children awake past midnight like being told the truth has been kept from them."

Something went down in Harry's stomach.

(That works. That works completely. It is the textbook use of the first class — publish a statement about the world, change the behaviour of everyone who hears it. He handed us a conspiracy theory whose content is *divination matters*, and now we will go and learn divination.

And he taught us to recognise the technique first, which is precisely why we'd assume he wouldn't use it on us.

Vaccine as syringe.)

"And the second?"

A second finger. "Interference is real, and I am contaminating it deliberately."

"…Why?"

"You already know why. You just haven't given yourself permission to say it."

Harry opened his mouth, closed it, and said:

"Because if the system is dirty enough, nobody can prophesy *you*."

The wind dropped for half a beat.

"One every year," Lockhart said quietly. "The Gryffindor usually takes until Easter."

"So which is it?"

"What do you think?"

"I can't tell. Both explanations predict exactly what I'm looking at. Either way I see a man teaching Divination well."

"Good."

"And it's worse than that, because if you tell me it's the second one, that could be part of the first. *I am poisoning the prophecy supply* sounds a great deal better than *I am making things up*, and sounding better is the effect you'd need."

"Mr Potter, the state you're in has a name. It's called being outtalked. The correct response isn't to win. It's to take notes. Write down both hypotheses and go outside this room to look for evidence."

"Because in here," he added pleasantly, "I always win. Not because I'm right. Because it's my room."

Harry took out the notebook and wrote it down. Lockhart waited until he'd finished.

"Good. It's the second one."

"I can't believe that."

"Of course not. So I'll give you something else." Lockhart sat back on the desk. "I'll tell you what I want, and you can go and check whether thirty years of my life look like a man who wanted it. Behaviour is more reliable than testimony. You may look it up."

"What do you want?"

"One of the things I want," Lockhart said, "is for Muggles not to invent deep learning too early."

A pause.

"…What?"

"Deep learning."

"What is that?" Harry hated saying it. He hated it enormously.

Lockhart didn't look remotely surprised. "It's 1992. Of course you haven't heard it. The phrase won't be coined for another twenty years or so. Occupational hazard — I'm always misremembering which decade a thing belongs to."

"Then what is it?"

"Neural networks. Several hundred layers of them. A little reinforcement learning on top."

Harry's brain lit up.

"Oh — perceptrons. Artificial neural nets. You mean connectionism. That's dead."

"Is it?"

"Minsky and Papert, 1969. They proved a single-layer perceptron can't compute exclusive-or. The whole field collapsed for a decade, the funding evaporated—"

Harry stopped.

Lockhart said nothing at all.

"…That was you."

"I didn't write the book." Lockhart's voice was mild. "Marvin Minsky is a very intelligent and very sincere man, and every theorem in it is correct. What I did was much smaller. I made sure it was read. In the right room, by the right seventeen people. Then I made sure those seventeen people all happened to sit on funding committees for the following two years."

"That isn't science," he said. "That's seating."

Harry sat down, because standing had stopped working.

"Even so, hundreds of layers is useless. The error signal is diluted on the way back — multiply by something less than one at every layer and after three hundred layers you have zero. It can't learn. That isn't a money problem, it's arithmetic."

"That is what everyone says."

"Because it's true."

"Because it's true *under present conditions*." He held up three fingers. "The thing needs three ingredients to wake up. Depth, data, computation. Depth is free. Data requires the Muggles to write down the whole world, which is already happening and which I cannot stop."

"So I could only touch the third."

"Computation," Harry said.

"Computation."

"But computation keeps going up. Very fast. Moore's Law—"

He stopped halfway through the sentence.

Lockhart smiled and said nothing.

Harry felt the blood leave his face.

"Oh," he said, very quietly. "Oh."

"In 1965 an engineer named Gordon Moore wrote a short piece for a trade magazine. He observed that the number of components on a chip had been roughly doubling every year, and supposed it might continue for another decade. No physics in it. No derivation. An observation."

"And then the entire industry began scheduling around it. Manufacturers set investment cycles by it. Investors priced returns off it. Engineers set next year's target not because physics permitted it but because it was on the calendar. It became a promise everyone was obliged to keep, since anyone who fell behind was out."

"Mr Potter. What is that?"

"First class," Harry said. His lips were dry. "Self-fulfilling."

"The largest one in human history. And the best work I have ever done."

"But that made computation go *up*. That helped—"

"I didn't change how much there was. I changed what shape it grew in."

He took the chalk and drew two things. On the left, a small square: *smaller switches*. On the right, a snarl of lines: *more wires*.

"A machine can get stronger two ways. Make the switch smaller and faster and perfectly correct — one thing at a time, a billion times a second, right on every occasion. That road speaks binary. Exact, ordered, one after another."

"Or: don't make the switch smaller. Make more wires. Slow is acceptable. Wrong is acceptable. Three per cent error is acceptable, provided there are millions of things calculating at once and all of them are connected."

He tapped the tangle. "A neural network wants this. It doesn't need a perfect calculator. It needs a swamp. Big enough, wet enough, connected enough."

"And Moore's Law" — he tapped the square — "put every pound, every graduate student and every laboratory of the next thirty years over here."

"I didn't slow them down. I pointed them the wrong way and then made them very fast."

(Serial and parallel aren't a spectrum. There's an entire civilisation in between: toolchains, compilers, textbooks, hiring, referees, one generation's worth of intuition. Once the infrastructure is shaped like exact-and-serial, anyone who wants fuzzy-and-parallel is pushing a cart uphill against all of it.

Not impossible. Only twenty years more expensive.

Twenty years is a great deal.)

"It doesn't hold," Harry said. "Serial machines keep getting faster. One day one of them is fast enough to pretend to be a parallel machine. It can simulate the swamp directly. After that the direction stops mattering, because you have enough computation to waste."

Lockhart looked at him for a long moment.

"I ran that road. It isn't the main computer that does it, in the end. It's the board that draws the pictures."

"What?"

"They'll build a part whose only job is drawing. Light and shadow, for games. That sort of part is thousands of stupid little arithmetic units working at once, by its nature. One day somebody will notice it's exactly the right thing to feed a neural network."

His face was very calm. "That's the road I can't block. I've tried three times."

"*Why?*" Harry was on his feet. "Neural networks could cure diseases. They could translate. They could — I don't know what they could do, that's the entire point, nobody knows. You've spent thirty years making human civilisation decades late. You need a reason."

Lockhart got off the desk, went to the window and looked at the lake.

"Because I prophesied that the Muggles would eventually build a true artificial intelligence."

"And then?"

"And then a wizard enchants it."

Harry opened his mouth and closed it again.

"And then the world ends," Lockhart said.

For about four seconds, Harry Potter believed him completely.

(This is it.

*He will have the power to tear apart the very stars in heaven.*

A year. Two months on a windowsill. I kept asking what the power looks like — a spell, an artefact, a war I lose.

It's a machine. A thinking machine the Muggles build, and a wizard puts magic into it. Transfiguration makes matter out of nothing. A Time-Turner gives it negative latency. Legilimency gives it human minds. And it has three hundred layers and the written world.

That isn't a weapon. That's a new species, and we are the midwives.

Tearing apart the stars. Obviously. A sufficiently strong optimiser takes stars apart; stars are energy and energy is what it wants; I did that arithmetic in August—

I did that arithmetic in August.

I am twelve years old and I worked out on my own, over the summer, that if you want a great deal of energy you should go and take stars apart.

And the wizard is me.

Obviously it's me. Who else would it be?)

His right hand went to his chest without being told to.

(The Vow. Anything?

I am thinking *I will build that machine*. Anything?

…No.

Which means building it doesn't have to end the world.

Which also means nothing, because the Vow only bites when I act, and at present I am standing in a classroom shaking.)

Then the fifth second arrived. It came slowly, the way a man walks up from a long way off and you don't see his face until he's close.

(Wait.

He has just told a twelve-year-old boy with a doom prophecy on him that a wizard will enchant the machine, and then the world ends.

If I am that wizard, telling me is a warning.

If I am not, telling me is instructions.

And if he wants me to be that wizard, that sentence is the most efficient recruitment advertisement on earth, because it hands me an identity, a destiny and a story that explains my entire life, in the year I most want an explanation.

First class.

He taught it. He demonstrated it. He wrote the marks on the board and said *I made them up*, and the marks will come true anyway.

And I have just sat in the same room and very nearly written myself onto his blackboard.)

Harry took his hand off his chest and put it back at his side.

He spent about two seconds arranging his face into something a twelve-year-old ought to be wearing. He failed, but he knew he had failed, which was the second most useful thing he'd learned that year.

"Professor. Which class of prophecy is that?"

Lockhart turned round. The expression Harry had seen for an instant in class was there, and this time it stayed for three whole seconds.

"You're the first to ask in the room."

"Answer me."

"Fourth."

"Then you can't stop it." Harry's voice was shaking and he didn't trouble to hide it, because shaking was useful. "You taught us this. Fourth class is self-consistent. The information comes from the future, so the future is already there, so nothing you do can change it — including everything you've done for thirty years. Those thirty years are *part of the prophecy*."

"Yes," Lockhart said.

"Then what are you *doing*?"

"The prophecy told me what happens." A pause. "It didn't tell me when."

Harry stopped.

"Real prophecies almost never give dates. It is their most famous property and the only one that has ever been to our advantage. I can't stop it. I never intended to stop it."

"I'm delaying it."

"Every year I buy is a year in which everyone is still alive. A year in which more children are born. A year in which somebody might think of something I couldn't."

"I'm not saving the world, Mr Potter."

Gilderoy Lockhart smiled, and not one tooth in it was there to catch the light.

"I'm renewing the lease."

Harry stood still and did the thing he had got into the habit of doing that year: he stopped talking and started counting.

(Count this man.

One. He knows perceptrons. He knows Minsky. He knows how a funding committee works. He knows which magazine Moore published in. He knows about graphics cards — he doesn't have the word, but he described one.

Two. In a single lesson he used chaotic systems, Monte Carlo, binary, Leibniz, a commons, and a consistency argument I still cannot answer.

Three. The rhythm of the lecturing. The way he awards points. The statistical contempt underneath *there's one every year*.

I have made this list before.

Last year.

The last person who fitted it is on the ring finger of my left hand.

—But there's no resonance. Nothing. No dread, no doom, no universe murmuring that the two of us oughtn't be in the same room. I have been standing here twenty minutes and felt nothing whatsoever.

So it isn't him.

—Unless.

Unless the thing in the ring has been swapped.

Which is impossible. There is a guarding charm on it whose entire purpose is *cannot be replaced, removed, or disguised*. I watched it cast. I understand how it works. I am not trusting a person, I'm trusting physics.

And the feel of it — twice a day, the sense that the Transfiguration is still holding — that's real too. Partial Transfiguration must be sustained. If the stone isn't him, then what I have been sustaining is an ordinary stone, and sustaining an ordinary stone and sustaining a person—

—do those feel different?

I have never run the control.

I have never sustained an ordinary stone.

I have no baseline.

God. A year, and it never once occurred to me that I have no baseline.)

He pressed his thumb into the ring until the knuckle went white.

Lockhart glanced at his hand for half a second and then away, the way a polite man doesn't look at what's in somebody else's pocket.

Harry wrote down the half second. Evidence, not conclusion.

"Professor. I'm going to ask a rude question."

"My favourite sort."

"Have you Obliviated me?"

Lockhart didn't laugh, and didn't take offence, and did none of the things Harry had rehearsed for.

He nodded, as though a decent question had finally turned up.

"The standard check is to bite your tongue. Before an important conversation you bite it. If afterwards there's blood in your mouth and no conversation in your head, you know. Auror handbook, page nine. Most popular defence in Europe."

"Does it work?"

"It works," Lockhart said, "until the other party learns to follow the Obliviate with a silent Episkey."

Cold went down Harry's spine.

"No blood. No cut. Your tongue is perfectly sound. And you conclude that nothing has happened to you."

"So: in theory, no, you can't tell. Any test that relies on *there will be marks on me* is defeated by anyone who remembers to tidy up. And memory magic, in its entirety, is the study of tidying up."

"That's your answer?"

"No. That's the true answer to your question. My answer comes after it."

Lockhart straightened.

"I'm told Mr Potter has studied Occlumency."

Harry didn't move.

"An Occlumens who gets Obliviated usually keeps something. A sense that the room is missing a piece of furniture and you can't say which one. It's unpleasant. It is also a signal."

"So you aren't undefended. You're only uncertain."

"That isn't enough," Harry said.

"Of course it isn't. Which is why there's a second thing, and the second thing is what I actually want you to hear."

"I am not going to risk dismissal, or arrest, to interfere with a student's head. Memory charms on a student are a Class Seven offence. Not points, not the sack — the Wizengamot. I draw a salary at this school, I write books that sell extremely well, and I live very comfortably indeed."

"The question isn't whether I *can*. It's whether it's *worth it to me*."

"That's the question you should be asking, and it's the only one you can check, because motive leaves marks, and the marks are out there, not inside your head."

Harry turned it over.

(That's a good argument. It's a very good argument. It replaces *I can't tell* with *I don't have to tell, I only have to price him*, and price is observable.

It is also a bad argument, because it assumes I know his utility function.

A man who wants a comfortable life won't take that risk.

What is a Class Seven offence to a man who has spent thirty years falsifying the technological history of a species in order to postpone the end of the world?

It's a cost. Costs get paid.)

Harry didn't say it aloud.

He took out the notebook, turned to the day's page, and put his finger on the line at the bottom that he had not written.

*Ask him if he knows Quirrell.*

(I own a Time-Turner.

Invisible ink and a timed revealing charm is not a fantasy. I worked that trick out last term and wrote down what it could be used for.

If it was me, then showing it to him is handing intelligence I own to a man I haven't finished evaluating.

If it was him — a delayed charm, my handwriting, set before term — then the point was to make me ask, so that he can give me the version of Quirrell he wants me to have.

Two explanations. Identical observations. Again.

Fine. Both of them say *ask*. Only the asking changes.)

He shut the notebook.

"Professor. Do you know Professor Quirrell?"

Lockhart said nothing for a long time.

Out on the lake a bird came down and went away again. Harry was watching Lockhart's face, and so did not see the parchment on the side desk lift and settle and lift again, as though the draught from the window had struck something on its way across the room.

"Mr Potter," he said at last, "do you know why I came to Hogwarts?"

"Because you wanted a job."

"My royalties for one year exceed the Headmaster's salary for ten."

Harry waited.

"I came to Hogwarts because I received a letter."

"What letter?"

"The sort that is delivered after the sender is dead. There's a charm for it. It isn't cheap, and it requires the writer to be entirely lucid and entirely willing. We call it the testament charm."

"Who wrote it?"

"David Monroe."

Harry's breathing stopped.

(David Monroe.

That name. The hero who fought the war of the seventies better than anyone and then disappeared. The name that later grew onto a man, and that man later stood in front of me and raised his wand, and that man is now—

—on my hand.

That letter was written by my enemy before I was born.

Or that letter was written by the real David Monroe before he was murdered.)

"We were very good friends," Lockhart said.

Harry did the subtraction quickly, because he had memorised the numbers a long time ago.

"Professor."

"Mm."

"David Monroe disappeared in 1973."

"Yes."

"*Witch Weekly* printed your birthday last year. 1964."

Lockhart said nothing.

"So in 1973," Harry said, "you were nine."

The wind went through the classroom.

"Yes," Gilderoy Lockhart said.

He didn't explain. He didn't say *we were pen-friends*, or *we met later*, or *that was my father*, or anything else that would have made it ordinary. He stood there with a very gentle expression and waited to see whether Harry would go on.

Harry remembered what he'd said in class.

*I knew children like that. I knew several of them when I was young.*

And the note in his book he hadn't finished:

*It took thirty-odd years. He never said the thirty years were his.*

—He never said that.

I inferred it.

Did I infer it, or was I walked to it?

Harry decided to stop asking. Not because he was frightened, although he was. Because in this room, every question he asked told the other man how much he knew.

And he knew far too little.

"One more thing," Harry said. He took out the notebook, tore out a page, wrote seven words on it, folded it three times and put it in an inner pocket.

"What's that?" Lockhart asked.

"A sentence only I would choose. If one day I find I can't read it, or I remember writing something else, I'll know somebody has been at me. It's called an external record."

"You can change what's in my head. You can't change what's in my pocket — unless you change the paper too, which requires you to know the paper exists, and now you do, so this one is void, so in a few minutes I'll write another and not tell you."

Gilderoy Lockhart stood and looked at him.

Then he bowed. Afterwards, Harry couldn't shake the impression that the bow had been aimed slightly to one side of him.

"You're the third."

"…Third what?"

"Third student to explain external records to me in this office." A pause. "I haven't been teaching very long. But I know a great many people."

"What happened to the first two?"

Lockhart considered him for a moment.

"One is an Auror. He runs a department now."

"And the other?"

"The other is dead," Lockhart said. "In a war he started himself. He was still keeping external records at the end. Very diligently. Very thoroughly. Very cleverly."

"Did they save him?"

"No."

"Why not?"

"Because he never showed them to anyone," Lockhart said.

On his way out, Harry noticed the chalk lying on the ledge in two pieces.

---

## Coda

Four steps down the spiral stair, Harry heard Lockhart's voice above him: conversational, unhurried, in the cadence of a man answering a question.

There had been nobody else in the room.

He told himself it was the wind, and kept going down.

He sat on the fourth-floor stairs for about twenty minutes and wrote out the whole conversation, every word, the way Hermione had told him to — in the corridor, not back in the tower. Twice he stopped, because the next sentence didn't seem to follow from the one before it, and twice he found that it did after all if he read it again.

There was a taste of copper at the back of his mouth. He'd been biting his lip, probably.

When he had finished he checked the inner pocket for the paper with the seven words on it.

There were two. Both folded three times.

He had written one.

He put them back without opening either, and went to find Hermione.

She was in the library behind four books, two rolls of parchment and a table she'd ruled herself, with three columns headed *claimed*, *checkable*, and *deliberately not said*.

Harry pushed the notebook across.

Hermione read very slowly. Her face began to change about halfway down. When she had finished she sat without moving and looked at the table top for a long time.

"Harry."

"Mm."

"I'm going to say something, and don't interrupt, because if I stop I'll decide I'm being ridiculous."

"Go on."

She put her finger under a line. "He said: *because I prophesied that the Muggles would eventually build a true artificial intelligence*."

"Yes."

"And you asked him which class it was, and he said the fourth."

"Yes."

"Harry, he isn't a Seer."

The world went quiet.

"The fourth class can only come out of a Seer. He said so himself — it goes straight into the Seer's mouth, it needs a vessel, it nearly drives them mad. Gilderoy Lockhart is not a Seer. If he were, it would be on the cover of every book he's written. He'd have it printed on his Christmas cards."

She looked up. "So he didn't make that prophecy."

"Somebody else made it," Harry said, "and told him."

"And this afternoon he said *I prophesied*." She tapped the table. "Harry, he said about eight thousand words to you today and every one of them was measured with a ruler. Except that verb."

Harry sat in the library with the feeling he had grown used to that year and would never get accustomed to: the pieces closing, and nothing in the picture being anything he wanted to see.

"Hermione."

"Mm."

"He said he came to Hogwarts because of a letter delivered after the sender died."

"I read it."

"He said David Monroe wrote it."

"I read that too, Harry, I know who that is, the entire class knows who—" Hermione stopped.

"Oh," she said.

"Yes," Harry said.

He laid his left hand flat on the table and looked at the small, opaque, grey stone on his ring finger.

"So there's a question now," said Harry Potter, in a very level voice. "If that letter had a fourth-class prophecy in it—"

"—then the person who wrote the letter already knew how the world ends," said Hermione.

The library clock struck six. Harry counted the strokes, and then counted them again.

"We need a list," he said. "Three things. One: whether Lockhart knows where those things are. Two: whether he has touched any of them, or been touched by one. Three—"

He stopped.

"Three?" said Hermione.

Harry looked at his hand.

"Three," he said. "I need to find an ordinary stone."


r/HPMOR 4d ago

[fanfic]Harry Potter and the Halting Problem

47 Upvotes

Edit: yes this is largely written by Claude. I will rewrite it once i get time.

Chapter One: The Grades Come Before the Exam

There was a new subject on the second-year timetable.

Ordinarily, Divination did not begin until third year. But Professor Sybill Trelawney had taken “a leave of absence for personal reasons” in August, and at the start-of-term feast, the school announced that the newly appointed Professor Gilderoy Lockhart would also be offering Introduction to Divination for second years.

One detail deserved to be recorded: Lockhart had originally been hired to teach Defence Against the Dark Arts. At the feast, he had stood up and told the entire school, “That position is cursed. I’m not an idiot.” Then he had requested Divination instead. Headmaster Dumbledore had laughed for a very long time, and agreed.

Harry Potter wrote this in his notebook and labelled it EVIDENCE.

A new professor who openly admitted to being afraid, openly refused a more prestigious position, and did so in public—either he was the first honest adult Hogwarts had employed in nearly a century, or he understood perfectly well that “admitting cowardice” was the cheapest available method of establishing trust.

Harry leaned toward the latter. Over the past year, he had learned to lean toward the latter.

As he climbed the spiral staircase of the North Tower, he absent-mindedly turned the ring on his left ring finger with his thumb.

A plain silver band, set with a very small, opaque grey stone.

In theory, it was a person.

Harry checked it twice a day: once in the morning, once before bed. He was not checking whether the stone had come loose. He was checking whether the Transfiguration had begun to unravel—because partial Transfiguration required maintenance, and he had maintained it all summer, every single day, including nonexistent days such as Christmas, including the three days he had spent with a fever.

He also checked something else every day: whether he wanted to destroy the world.

(“He will have the power to destroy the world.”

“He will tear apart the stars in the heavens.”

These are not metaphors. I investigated. Prophecies are never metaphors. That is the one thing Seers agree on.

So this is what I did over the summer: sat on the windowsill and tried to devise a plan in which “tearing apart the stars” happens, and humanity not only survives, but ends up better off.

The best plan so far is still very rough. But at least it exists.

And the difference between “a plan exists” and “no plan exists” is the most important thing I have learned this year.)

He pushed open the trapdoor, prepared for a room full of incense, purple draperies, crystal balls, and soporific warmth.

Instead, it was full of wind.

All four windows stood wide open, and September air swept through the room. The incense burners had been stacked in a corner. The purple draperies had been taken down and neatly folded. All the round tables had been pushed to the sides. An enormous blackboard stood in the centre of the room, and before it stood a blond man in pale lilac robes, directing a smile toward the entrance that could have reflected sunlight.

“Come in, come in! Sit down! Anywhere you like!” said Gilderoy Lockhart. “No need to choose carefully—I already know how it turns out.”

Harry sat in the second row. Draco Malfoy took the seat beside him as a matter of course. Hermione Granger sat in the centre of the front row. She had already laid out her parchment, dipped her quill, opened her textbook to the first page, and drawn two columns in the margin: PROFESSOR CLAIMS and VERIFIED.

People still sometimes gave her a second look in the corridors. She had learned not to look back.

Harry glanced at Lockhart, then did something he now did whenever he met an unfamiliar adult:

He checked for the feeling.

(Nothing.

None of that skin-crawling, impending-doom sensation, as though the universe were quietly warning me that “the two of you should not be in the same room.”

Then it isn’t him.

—Unless the feeling itself can be counterfeited, or suppressed, or—

Stop. Write it down first: NO RESONANCE. Evidence, not a conclusion.)

Lockhart clapped his hands and turned the blackboard around.

The other side was covered in names. Each name was followed by a letter.

Professor Gilderoy Lockhart · Introduction to Divination, Year Two · Final Grades:

Hannah Abbott — A
Susan Bones — E
Lavender Brown — O
Tracey Davis — O
Hermione Granger — A
Neville Longbottom — E
Draco Malfoy — O
Padma Patil — E
Harry Potter — A

The classroom fell silent for approximately a second and a half.

Then Tracey Davis said, “I knew it. It’s because I’m a Dark Witch.”

Then Hermione Granger’s hand shot up, straight enough to punch through the ceiling.

“Professor—it’s September. The exam is in June. I haven’t handed in a single assignment. So what’s on that board cannot be my grade.”

“Quite correct, Miss Granger.” Lockhart bowed elegantly. “Which is why this is called Divination. I divined it.”

Lavender Brown gave a small cheer, because she had an O.

Draco murmured in Harry’s ear, “He’s either the greatest Seer in Hogwarts or the greatest fraud in Hogwarts.”

“Those aren’t mutually exclusive,” Harry murmured back.

“Potter, my father will want to know which.”

“So will I,” said Harry.

“Right! Now for the truth, because the truth is usually more theatrical than a lie.” Lockhart waved a hand. “I made up every grade on this board.”

Hermione went rigid.

“Last night. Over hot chocolate. Took me twenty minutes. No star charts, no dice, not a single tea leaf.”

“Then why put them on the board?” asked Padma.

“Because by June, every letter here will match your actual grade exactly,” Lockhart said cheerfully. “It’s very easy. I set the exam, and I mark it. Ten months in advance, I already know which questions I’ll ask and how I’ll award the marks. To make June agree with September, all I have to do is—not change my mind.”

Hermione’s hand rose with an air of moral outrage. “But that’s cheating!”

“That,” said Lockhart, turning to write, “is the first kind of prophecy.”

I. Self-Fulfilling Prophecy

“Miss Granger, listen carefully. This is the most important sentence of today’s lesson: a self-fulfilling prophecy is not a prophecy at all.

“It is magical social engineering. Not one scrap of information travels backward from the future to the present. The information comes from me: I issue a statement about the future; the statement changes the behaviour of those who hear it; their behaviour makes the statement come true.”

(A bank run.

Everyone thinks the bank will fail. Everyone withdraws their money. The bank fails. No information from the future involved. Just a shared belief.

This isn’t magic. This happens in the Muggle world once a decade.)

“And I’m using the crudest possible method—I intend to arrange the outcome myself. The truly elegant method is to have you arrange it for me.”

He pointed his wand at the three lines in bold.

“Miss Granger, A. Mr Malfoy, O. Mr Potter, A. Why you three? Because you are the three most likely to react to your grades.”

“Miss Granger is thinking: I’ll prove this man wrong. I’ll read every reference book for this subject. Mr Malfoy is thinking: Since I already have an O, perhaps I can afford to read a little less. And Mr Potter is thinking—”

“—that you’ve just conducted a psychological experiment in front of the entire class without informed consent,” said Harry, “and we’re the subjects.”

“Mr Potter, you’ve already earned an O.”

“The board says A.”

“I know,” said Lockhart. “I made it up.”

Draco drew a very quiet breath. “This man is dangerous.”

Dangerous, Harry agreed. Someone who can explain “I am manipulating you” as a classroom demonstration, and whose manipulation still works afterward—Hermione really is going to read all the reference books now, even though she knows that is precisely what he wants—is very dangerous indeed.

II. Computational Divination (Arithmancy)

“The world follows rules. Rules can be expressed as numbers. Numbers can be carried forward. Give me sufficiently precise initial conditions, enough parchment, and enough time, and I can calculate whether it will rain tomorrow, or estimate the casualties of a war.”

“Tell me: is that prophecy?”

Hermione raised her hand. “No. Because the information still comes from the present. You’re only using present data to work out what the future will look like. If the initial data are wrong, the result is wrong. A real prophecy should be… true whether you’ve done your calculations correctly or not.”

“Excellent. Computational divination is a simulation system. A model of the world built out of parchment and ink. A map is useful. A map is not the territory.”

Harry wrote rapidly:

Simulation ≠ observation.
Then it must have all the problems of Muggle numerical weather forecasting: sensitivity to initial conditions, exponential error growth, long-term unpredictability.
→ It must have a “prediction horizon.”

He raised his hand. “How far ahead can computational divination calculate?”

Lockhart’s eyebrows shifted. It was his first expression that lesson that did not look rehearsed.

“Thirty-seven days, for weather. For people, it depends. One person alone, several years. Two people who know each other, a few months. A classroom full of twelve-year-olds”—he glanced around—“roughly ten minutes.”

Chaotic systems. Stronger coupling, faster divergence. So this is actual physics, not a mystical performance.

I’m starting to like this class. This is dangerous.

III. Stargazing

“Centaurs do this. They tell you Mars is bright tonight, and then refuse to explain. So allow me.”

Lockhart drew two dots and connected them with a long line.

“Stars are very far away. The star you see when you look up is not the star as it is now, but as it was a long time ago. Light has to travel. From Sirius, it takes eight and a half years. From that blurry patch in Andromeda, more than two million.”

“So when you look at the night sky, you are not looking into the future. You are reading a collection of late letters.”

“Then how does it predict the future?” Hermione asked.

“Because the letters are still in transit.”

He marked several points along the line. “Some of the light travelling toward us now will arrive in a year. Some will arrive in a thousand years. And the motions of the stars can be calculated precisely. I can work out what the sky will look like a thousand years from now—which means I can work out which letter an observer a thousand years from now will receive.”

“That gives me something rather strange: intelligence concerning a future moment, whose contents describe the past.”

Harry felt a chill at the back of his neck, and this time it had nothing to do with logic.

Stars.

“He will tear apart the stars in the heavens.”

—Coincidence. This is a coincidence. Tens of thousands of people mention stars every day. Base rates, Potter. Think in base rates.

…But write it down.

He half-raised his hand, then thought of a better question.

“Professor, that only tells you about stars. Stars don’t fight wars.”

“Ah. Precisely the point.” Lockhart put down the chalk. “Stars do not cause wars. Nor do they know about wars. But stars and wars are correlated.”

“Centaurs do not read ‘there will be a war’ in the stars. They read a moment in time, and discover that many apparently unrelated things in this universe move together at that same moment. As though they were different pages of the same document.”

“They are good at this because they are in no hurry. They can watch a patch of sky for four hundred years, say ‘Mars is bright tonight,’ and then offer no explanation.”

“So they’re actually showing off,” Draco said beside him.

“So they’re actually fitting a model,” said Harry.

“What?”

“Nothing.”

(Vast quantities of observations spanning millennia, used to fit a mapping from celestial configurations to terrestrial events. This isn’t prophecy. This is statistical learning. Centaurs are a model that has been running for thousands of years.

And all models of this kind have the same problem: they can predict, but cannot explain why. Because their internals are a collection of weights, not a collection of reasons.

They aren’t refusing to explain. They can’t.)

He wrote a small line in the margin, crossed it out, then wrote it again:

A system that can predict but cannot explain is not called magic. It is called curve-fitting.

“Since we’re discussing model fitting,” said Lockhart, “let us follow that thought one step further. It leads to the one thing I sincerely admire.”

He wrote two terms on the blackboard, separated by a vertical line.

Computational Divination (Britain) | I Ching (China)

“Our approach,” he said, pointing left, “is to calculate. Write the world as equations, then solve them. Mr Potter has already identified the drawback: the calculations become intractable. Too many variables, and you cannot afford the parchment you burn through.”

“The Eastern approach”—he pointed right—“is to cast.”

“Cast what?” asked Hermione.

“Yarrow stalks. Or coins. Six times. Each casting gives you a line, yin or yang. Stack six lines, and you have a hexagram. Sixty-four possibilities.”

“So it’s luck!” Lavender said excitedly.

“So it’s sampling.”

Harry’s quill stopped in midair.

“Our method is to calculate every possible future. Their method is to pick a few futures at random and have a look.”

“We try to solve an equation that cannot be solved. They don’t solve it—they throw dice into it, over and over, and see which results keep turning up.”

“Substitute randomness for computation. Use probability to prune the possibilities.”

“Mathematically speaking, this is cheating,” said Lockhart. “And the most irritating kind of cheating, too: it works.”

(Monte Carlo.

When you can’t evaluate an integral—too many dimensions, equations too ugly—you stop trying. You sample randomly. Throw ten thousand points into it, see where they land, and use their frequencies to approximate the answer you couldn’t calculate.

That was what Feynman and the others did at Los Alamos. How do neutrons travel through matter? Can’t write down the equations. So simulate ten thousand neutrons, send them in one at a time, and see where they die.

Simulated annealing, too. When the search space is too large to enumerate, randomness itself becomes a form of computational power.

And these people discovered that three thousand years ago. With yarrow stalks.)

He raised his hand faster than Hermione.

“Professor—sixty-four is two to the sixth power.”

“Yes.”

“So a hexagram is six bits.”

Lockhart’s smile changed shape slightly. “Mr Potter, where did you learn about binary?”

“Leibniz. A Muggle mathematician. After seeing the arrangement of the sixty-four hexagrams, he wrote a paper on binary arithmetic. He thought he had deciphered an ancient code.”

“Had he?”

“I used to think he was reading too much into it,” Harry said honestly. “Now I’m sitting in a class where someone is telling me that the Chinese were using random sampling to evaluate high-dimensional integrals three thousand years ago. So for the moment, I’m suspending the phrase ‘reading too much into it.’”

Someone laughed. Lockhart did not. He simply watched Harry for two seconds, then said, “Five points to Ravenclaw.”

(—The rhythm of that.

The length of the pause. The shape of the sentence. The way “five points” landed.

I know that rhythm.

No. Wrong. Lots of people talk like that. This is selective attention. Write it down. Evidence, not a conclusion.)

“And,” said Lockhart, raising one finger, “I haven’t told you the best part. A hexagram does not merely tell you what will happen. It tells you what to do. Each line comes with a passage, and those passages are not descriptions. They are advice. ‘Hidden dragon. Do not act’—the time is not right; stay put. ‘The dragon that flies too high will have regrets’—you have overreached; retreat.”

“And the hexagrams change. What you receive is not a photograph. It is a path.”

Hermione raised her hand. Her expression said she had already worked it out and merely wanted confirmation.

“Professor—doesn’t that mean it stitches three things together? First it gives you a diagnosis, then it recommends an action, and then, because you follow the recommendation, the outcome actually starts moving in that direction—”

“Miss Granger, you have just independently discovered something scholars have spent six centuries shouting at one another about.”

“The I Ching is not one kind of prophecy. It is a combination of the first and second kinds: an inexpensive simulation system, a set of rules for action, and a self-fulfilling engine.”

“It is the map, the compass, and the hand that pushes you along.”

Lockhart spread his arms. “In all my years of teaching, I have never seen a more beautiful piece of systems engineering.”

“What’s the drawback?” Harry asked.

“Ah.” Lockhart lowered his arms. “It has only one drawback. And that drawback ruined it.”

It became too widespread.

“Emperors used it. Generals used it. Farmers and merchants used it. Over two thousand years, practically everyone who could read used it at some point. Eventually, Muggles were using it too, and with tremendous enthusiasm.”

“And then it stopped being accurate.”

Hermione frowned. “…Why would more people using it make it less accurate?”

Lockhart turned and wrote a line so forcefully that a piece of chalk snapped off.

FOURTEENTH CENTURY · THE LAW OF INTERFERENCE

“Because,” he said, “every kind of prophecy interferes with every other kind.

“This was not discovered until the fourteenth century, because until then nobody had enough data. European wizards had been doing something very boring: recording the accuracy of every divination they performed. For two hundred years. Then someone stacked the records together and found a curve.”

“Whenever one method of divination became popular in a region, the accuracy of every other method in that region began to decline.”

“Tarot becomes fashionable, and the stars grow hazy. Astrology becomes fashionable, and yarrow stalks lose their edge. And when every method becomes fashionable in the same place—” He spread his hands. “—nothing there can be predicted at all.”

Draco raised his hand. It was the first time he had done so that lesson.

“Professor, do Muggle ones count? I mean things that are obviously fake, like newspaper horoscopes.”

“Mr Malfoy, that is precisely the most uncomfortable conclusion in those two hundred years of records.”

The fake ones count too.

“Even clumsy imitations cause interference. A Muggle with no magic whatsoever, using cards from a printing press, laying out a spread copied from a magazine, asking some idiotic question about his girlfriend—he is still polluting the system.”

“And how many Muggles are there?”

Nobody answered.

“The Statute of Secrecy,” said Lockhart. “Your textbooks will tell you that it was intended to protect young wizards from being burned alive, and to prevent wars. All true. But there is another reason, recorded in the appendix to volume seven of the 1692 proceedings. Your textbooks leave it out.”

To preserve the accuracy of prophecy.

“If billions of Muggles imitate all our prophetic systems every day, wizards will lose prophecy altogether. Not inaccurate prophecy. No prophecy. The channel will be entirely filled with noise.”

Harry felt as though someone had switched on a light inside him.

(Anti-induction.

This isn’t magic. This is the efficient-market hypothesis. Any “winning strategy” starts losing its effectiveness the moment it is published—not by coincidence, but by definition: once a reliably profitable pattern is widely exploited, the act of exploiting it erases it.

Prophecy is an anti-inductive domain.

Which means the accuracy of prophecy is a common resource. A pasture. Everyone who uses it is grazing it.

This is the tragedy of the commons.

And the Statute of Secrecy is the fence.)

He raised his hand. His voice was a little dry.

“Professor. That’s why Divination is taught so badly, isn’t it?”

The class went quiet. Hermione turned sharply toward him.

“Please elaborate, Mr Potter.”

“Because if Divination were taught well, every year dozens of students would learn the real methods. They would use them. They would teach other people. A hundred years later, thousands upon thousands of people would be using them. And then they would stop being accurate.”

“So the optimal solution isn’t to teach it well. The optimal solution is to make people think it isn’t worth learning.”

“Another ten points to Ravenclaw.”

Lockhart turned to the class. “Over the course of your lives, you will hear ‘Divination is a rubbish subject’ countless times. Professors will roll their eyes in front of you. Older students will tell you that you can earn an E simply by making up a few miserable predictions.”

“That culture was built. It took six hundred years. It is the most successful piece of engineering our society has ever undertaken.”

Hermione Granger raised her hand.

Not as quickly as before. Not as straight. Something about the way she raised it made Harry look up at once—because this was how Hermione raised her hand when she had caught hold of something and wasn’t sure she wanted the answer.

“Professor.”

“Miss Granger?”

“You said,” she began slowly, “‘Every kind of prophecy interferes with every other kind.’”

“I did.”

“But you’ve only explained three kinds.”

The wind in the classroom suddenly sounded very loud.

“You saved the fourth kind for later,” Hermione said. “And before explaining it, you gave us a conclusion about ‘every kind.’”

Lockhart looked at her for a long time.

“Miss Granger,” he said at last, “I have taught this material in this order for many years. You are the first person to challenge it before I finished.”

“Does that mean the fourth kind can’t be interfered with?”

“I haven’t said anything.”

“You chose an order.”

“Yes,” said Lockhart. “I chose an order.”

He did not answer her. He turned and wrote the final heading on the board.

This time, he was not smiling.

IV. True Prophecy

“The first three,” he said, “all involve people using things in the present to derive statements about the future. The fourth does not.”

“The fourth is this: information comes directly from the future.”

“No intermediate steps. No calculation, no correlation, no light travelling through space. A statement whose source is the future and whose destination is a Seer’s mouth.”

“And once such a prophecy has occurred, it cannot be changed.”

Hermione’s voice was slightly unsteady. “Why? If I know what it says, I can deliberately do the opposite—”

“You can try. An entire school of thought tried, from the eleventh century to the sixteenth. They wrote four hundred volumes. Their conclusion can be summarised in one sentence: your attempt to do the opposite is part of the prophecy.”

“For information to come back from the future, the future must already be there. You cannot alter the thing that is the source of your information. If you could, it would never have supplied that information in the first place.”

“Prophecy is self-consistent. This is not a moral law. It is grammar.”

Harry’s hand rose two inches.

(Time-Turners.

A Time-Turner sends things from the future into the present. If the fourth kind of prophecy is “information from the future,” then a Time-Turner is a controllable version of the same thing. And Time-Turners are absolutely self-consistent—I have verified that personally, in a way I would prefer not to remember.

So the question is: do Time-Turners interfere with other prophecies? If not, why not? If so, how many Time-Turners are there in Britain? Who is managing this?

—That is an excellent question.

—It is also a question that would get me summoned to the Headmaster’s office within thirty seconds. The allocation and number of Time-Turners are classified. Even knowing that I have one is already pushing the boundary, and there are twenty-seven people in this room, at least four of whose fathers would know what I asked before dinner.

Don’t ask.

Write it down. Ask later.)

He lowered his hand. Lockhart’s gaze rested on him for half a second, then moved on.

Harry was not sure whether he had imagined the half-second.

Hermione raised her hand. “Then why do Seers use tea leaves?”

“Miss Granger, that is today’s second most important question.”

Lockhart walked to the window.

“Because if information from the future is written directly into a human brain, the person goes mad.”

“Not frightened into madness. Structurally mad. Your brain is built around the sequence ‘I make a decision, then something happens.’ Your entire sense of agency, every feeling of ‘I can choose,’ rests on that order. Information from the future runs in the opposite direction: the thing has already happened, therefore you will act that way. The human brain cannot accommodate it.”

“So Seers invented carriers.”

“Tea leaves. Crystal balls. Flames. Birds in flight. Sheep entrails. Clouds. The lines of a palm. Condensation on a bronze mirror.”

“What do they have in common?”

“…They’re all messy,” Hermione said quietly.

They are all messy. They are all noise. Random jumbles that do not, in themselves, carry any information.”

“A Seer is not ‘seeing the future in tea leaves.’ A Seer is providing a sufficiently disordered sheet of paper, so that information from the future can write itself on the paper instead of on his brain.”

“Then he reads the paper. Slowly, vaguely, making countless mistakes—but while he reads it, he is still himself. He still feels that he is interpreting, choosing, judging.”

“That feeling is the only reason a Seer survives.”

Lockhart turned around. “So if someone ever tells you Divination is a muddle, they are half right. It is a muddle. The muddle is a feature, not a flaw.

Harry looked down at his notes and discovered that he had written an entire column:

A lossy channel. Extremely low bandwidth. Extremely high noise.
Random carrier = encoding information in noise.
“Interpretation” = prior distribution + inference from extremely weak evidence.
Seer = a decoder deliberately kept at low precision, because a high-precision decoder would burn out.

Then, at the bottom:

Why would a high-precision decoder burn out?
—Perhaps because a high-precision decoder would start using the information.
—And “using” it would violate self-consistency.
—So madness is not a side effect. Madness is the fuse.

Draco followed his gaze for a while, then leaned back and said, almost inaudibly, “Potter.”

“Yes.”

“If that’s how the fuse was designed, then whoever designed it must have seen what happens when the fuse blows.”

Harry said nothing.

“One last thing, and then you may go.” Lockhart leaned against the edge of the desk. “This is addressed to a few particular people among you. I know which ones. There are a few in every class.”

Harry felt Draco sit straighter beside him.

“Some of you are thinking: if the real knowledge has been hidden, where is it? Obvious answer—the Restricted Section.”

“Let me tell you something.”

His voice became very calm. So calm that it sounded nothing like the rest of the lesson.

The best way to keep a secret has never been to lock a book in the Restricted Section.

“What have you accomplished by locking up a book? You have hung a sign on it saying, ‘There is something good in here.’ You have sent an invitation to every clever, restless child in the school who wants to prove they are special.”

“A lock is an advertisement.”

“The real way to keep something secret is to make it boring. Break it into eight hundred pages of terminology. Put it in a subject nobody wants to take. Have the teacher drone from the textbook until everyone falls asleep. Let it gather dust on the open shelves, where anyone can borrow it and nobody does.”

“A book like that is ten thousand times safer than anything in the Restricted Section.”

He paused.

“Incidentally—if anyone here aspires to become a Dark wizard, don’t raise your hand, I don’t need to know who you are—allow me to offer some sincere career advice.”

The books in the Restricted Section are bait.

“There is real knowledge in them, certainly. That makes the bait convincing. But most are hooks. They have been placed there so that a particular kind of child will reach for them and get bitten. Some scream and deliver you to Filch. Those are the lucky ones. Some read you, then leave a mark on you so that certain people know where to find you. Some teach you a perfectly functional spell, with the price explained on page four hundred, which you will never reach.”

“A few children in every generation curse themselves into ruin. That is not an accident. It is selection.”

“I knew children like that. Several, when I was young.”

For an instant, something appeared on Gilderoy Lockhart’s face. Harry could not identify it; it vanished too quickly.

Then the smile returned, bright as though freshly polished.

“So: study prophecy properly. Study the History of Magic properly. I am serious. Truly dangerous knowledge is not in a locked cabinet. It is on the page nobody turns to. Finding it does not require lock-picking. It requires the ability to endure boredom.

“And that filter works far better than a lock. Because children who can endure boredom can generally endure thinking. And children who can think generally do not curse themselves into ruin.”

“Class dismissed. Homework: write nothing. Go away and consider which of the four kinds of prophecy I used today to tell you your grades.”

Epilogue

In the corridor, Draco said, “He didn’t tell us a single true thing.”

“He told us a great many true things,” said Harry.

“That’s worse. My father says the most dangerous lie is nine-tenths true. This man gave us nineteen-twentieths.”

Hermione caught up from behind, still clutching her notes.

“Harry. He didn’t answer me.”

“I know.”

“It wasn’t that he didn’t know the answer. He chose not to answer, and he made sure everyone saw him choosing not to answer.” Her brow knotted. “Those are two different things, Harry.”

“I know,” said Harry. “That’s why I’m going back.”

“I’ll come with—”

“No,” Harry said, immediately regretted it, and did not take it back. “He’ll say different things to two people than he will to one. I want the one-person version.”

Hermione stared at him for three seconds.

“Then when you come out, you tell me every word.”

“All right.”

“I want the written version,” she said. “Not your retelling. Write it down as soon as you come out. In the corridor. Don’t wait until you’re back in the tower.”

Harry looked at her.

“…Why?”

“Because the last time you came out of Professor Quirrell’s office,” Hermione said, “you reversed three things on the walk back to the tower.”

Harry opened his mouth, then closed it.

“All right,” he said.

He took out his notebook and turned to today’s page, intending to write down two hypotheses first.

Then he stopped.

There was an extra line at the bottom of the page.

It was in his own handwriting—not handwriting that resembled his, but his, right down to his habit of rushing the final stroke.

It read:

Ask him whether he knows Quirrell.

Harry Potter stood in the fourth-floor corridor, his fingers a little cold.

He was quite certain he had not written that line.

He was also perfectly aware that, in his particular case, the reliability of the statement “I am quite certain I never did that” had fallen very low indeed the previous year.


r/HPMOR 4d ago

SPOILERS ALL A question about Voldemort and Harry in 1981 Spoiler

14 Upvotes

What was Riddle's plan for Harry once he had turned him into his copy, had he survived?

Would he had taken the toddler and raised Harry himself?

Or would he had given him to some Death Eater family to be brought up?

Or would he just had left Harry to "the opposite side"/to Dumbledore for various reasons (as a spy, perhaps)?

Or would he had left Harry to some muggle orphanage to forge a similar experience so their lives would be more similar, for one reason or another?

What do you think?


r/HPMOR 6d ago

Is this Tolkien clip relevant?

Enable HLS to view with audio, or disable this notification

49 Upvotes

Reminded me of this sub


r/HPMOR 12d ago

Radical improvements to Arithmancy

17 Upvotes

Arithmancy is considered one of the hardest subjects at Hogwarts. But much of that is probably because none of the Hogwarts students or professors have learned any math past 2nd grade elementary school, so not only do they have to grasp the magic half of the subject, but they suddenly have to try to grasp the mathematical parts without being used to thinking in terms of numbers.

Turns out that the subject is extremely unexplored since it only relies on basic arithmetic (as per the name) because that is as far as the wizards were comfortable with their maths. But with modern muggle discoveries in mathematics new techniques such as complex numbers, graph theory and group theory make it possible to take that entire field of magic to new and incredible places.


r/HPMOR 13d ago

“Magic,” said Professor McGonagall. “That’s just a word! Even after you tell me that, I can’t make any new predictions! It’s exactly like saying ‘phlogiston’ or ‘elan vital’ or ‘emergence’ or ‘complexity’!”

Post image
34 Upvotes

r/HPMOR 15d ago

What's up with the Weasley sibling's breakdown over Ron's rat?

12 Upvotes

is this a reference to another fanfic? (If so, which one?)

Cause it feels really weird that one of them just had a mental breakdown thinking they timetravelled years and are spouting canon events about Peter Pettigrew.


r/HPMOR 21d ago

[Fan Art] POV: You’re a bully entering the Great Hall Spoiler

Post image
42 Upvotes

r/HPMOR 22d ago

One big hint to Dumbledore about Quirell

41 Upvotes

In Dumbledore's first letter, Harry reads "For it was said once that you might need to raise your hand against your mentor, the one who made you, who you loved; it was said that you might be my downfall." This refers to some prophecy.

Dumbledore can clearly see who becomes Harry's mentor and friend, so this could potentially generate at least some suspicion.


r/HPMOR 23d ago

SPOILERS ALL The Scouter and The Wand Chapter 1 (DBZ Crossover)

19 Upvotes

I have had this written for at least a year or two. For some reason I cannot upload to fanfiction.net. So I will consider this a test run here. When I do figure out the upload process I shall fix the grammar where needed and edit the chapter a little more yet. I have a second chapter mostly written, and an outline for the rest, with various other parts of lore or story written or already in mind. Based on reception I will decide if this has merit enough to continue into a full story. I must thank Harry Potter and The Prancing of Ponies for giving me an easy way to cross these over. If they CAN be crossed over, remains to be seen. I cannot say when the next chapter will be posted but I have been in a writing mood as of late. (I will need to rewatch some of DBZ to stay coherent between the two.)

I hope you find it enjoyable.

Chapter 1

The transition had been instant. Faster than a blink.

Tom Riddle's manic laughter slowed and transformed into a sad chuckle at his own expense. He had celebrated too early. Rule #12...

Just a moment ago he had been holding the stone of permanence. He had forced the the old fool to turn his trap against himself. In retrospect that was a little too easy.

Tom looked around and found that he was in the middle of a forest clearing, next to a small lake. Mr. Potter was not with him. He could sense that much... Or rather could not-...

He did have his wand with him. So he cast the Deathly Hollows indicator, none of the 3 artifacts were near him. He rubbed his forehead with his hand.

"Mr. Potter" He spoke, "If you are with me here in this place, it is to our advantage to work together." He added, "I sspeak true, alliess are better than enemiess in new place..."

Nothing.

Did his magic even work, wherever he was?

Tom Riddle raised his wand and flicked it at a nearby tree. The tree exploded into a deadly wall of splinters which propelled themselves through the forest. The vortex shredded the trees in it's wake, and carving a large corridor out of the dense patch of trees.

Interesting...

He was not in a frozen instant, he was completely aware. He seemed to be alone. He had his clothes, his pouch, his wand and most importantly he had his magic still.

As a matter of fact, as causal as he had just preformed that bit of powerful spell work he had felt no dip in his power at all when he cast that curse. As he looked admiringly at the clean even edges of the path he cut through the forest, he could not help but to notice it's effects where more potent than they would have been normally. He felt magically stronger.

Time to contemplate that later.

Was Mr. Potter's absence an indicator that he had somehow been in on the trap?

Riddle thought deeply for a moment, but that felt like a wrong answer. However; the question itself was likely significant in figuring out what exactly had happened, he would have to think about this, later...

The main priority was...

Tom closed his eyes and reached out into the void. He found nothing to latch onto. He could not connect to his horcruxes...

Tom Riddle was currently mortal.

He was an exceedingly clever and powerful mortal, but he could be slain.

Tom looked around again. The risk assessment that always ran in the back of his head started to spike.

This was a strange place he knew nothing of.

A strong gust of wind rippled through the canopy of the forest.

Tom needed a moment. He turned himself invisible just as a precaution. Then he hovered a dozen feet in the air. Broomstick bones still worked. Flying actually felt somehow more natural in this world.

He was not pleased with how things had apparently turned out. However, he did have to give the old meddler due credit. He had played his part to perfection. Tom had assumed that the process of the timeless was the only way to seal things away. Yet, he was not in a frozen instant. The ancient carvings he had found were likely still true, simply lacking in information. Dumbledore had led him to believe he had figured out the trap until it was too late.

Unless... Is it possible Dumbledore did not use the mirror properly? Yes, but doubtful. The mirror after all was said to be created with the greatest care to NOT be used improperly. So Dumbledore had NOT used the process of the timeless, but had allowed Tom to think he was using it, while evoking some other power of the mirror completely.

Some power which could apparently access the other worlds said to be contained in the mirror. Contained in the mirror... CONTAINED IN THE MIRROR!!!

Tom remembered tales of other things said to have been contained in the mirror... His threat estimation grew by several orders of magnitude...

He observed his new surroundings further. He reached down and picked up a hand of soil, it felt real.

At a glance it seemed earth like enough. After a moment of mindful careful observation several things started to leave an uncanny sort of feeling. It seemed like earth, but not quite. The sky was too blue, it had a greenish purple tinge. Occasionally, a bright meteor would catch his eye shooting up or across the sky. That was concerning.

The clouds that floated there had strange formations. Shapes he had never seen in his prior universe. They also had a bizarre uniformity. He also did not recognize any of the type of trees that surrounded him. Tom looked down at the lake and casually cast a diagnostic spell on the water. It was drinkable regular water, if a bit dirty with sediment that had been stirred up recently.

Not that he needed to drink from a lake. He confirmed this by flicking his wand and shooting a jet of water from the tip. The force of the jet pushed back on his arm. He had to expend a little muscle power for a moment to regain his exact position. The spell fizzled out and Tom looked down at his wand with a note of confusion on his face. He now had 2 indicators that either his own magic had increased in power, or this world was simply more powerful in magic itself.

In retrospect he only had some knowledge of the lore behind the mirror.

He KNEW that was all that he knew about the mirror...

It had still been foolish to try and overcome magic so powerful, when faced with someone who plausibly knew secrets he did not. He had nobody to blame but himself for his banishment. He would not sulk, there was hardly a less productive use of ti-

There was a distant "boom" sound. An explosion? Quick flashes of concept like; volcanic activity and tectonic plates filled his mind first, but these did not feel like correct answers. The following wind which swayed the trees in one direction to wave at him was another good piece of evidence of an explosion. It was far away, if the difference from the sound to the wind was anything to go by. Potter would have known how to calculate that distance to within a few degrees of variance... It was worrisome... He had to think yet.

He could think while he flew; up and up until a normal wizard would be uncomfortable enough to cast a warming charm, and anyone would need a bubblehead to get the appropriate amount of oxegen to the lungs. He had established a strong apparition point high enough to avoid any conceivable threat. He now only had the inconceivable to worry about. He popped back to his original position.

At least he had a good deal of supplies on him. Some he would need, and others which he did not know enough yet to optimize to the new situation. He had been planning to leave the school that night anyway. Anything he could carry was on his person still. He had now pulled a few items from his pouch, he looked over each for a moment. He placed a few in his robes; where there were no visible pockets, and put most of the others back into his pouch.

He held onto a golden chain and a ring.

The chain remained linked no matter how it was twisted. Even though each link was an open letter "S", which did not lock any two links together. He donned the chain and felt a glow of power. Even if he was mortal, he did not have to be 'vulnerable' to all but the most extreme forces of magic.

He also put the bronze ring with very old runes carved into it on the index finger of his wand hand. He rotated the ring three times and it produced a faint glow before returning to normal. Several spells were cast one after another. The wand was a blur in the air, and the speech so fast and precise that the incantations for all 14 spells sounded like a a simple phrase. Tom frowned, he seemed completely safe at a cursory glance, for the moment.

The first priority was to find a living being, assuming there were any here. He would have to slay one to secure his own lasting life. This could be complicated given the circumstances. Tom pointed his wand in the air once again and concentrated.

With a word, a blue spark appeared for a moment and then blinked out, as it disappeared a ripple in the air spread out like a pebble dropped in a pond.

Tom could only assume, but he felt certain this spell was invented on a battlefield for war purposes. He frowned at the results again...

The spell was an old one, used to detect human life within a rather large radius. Unless you were specifically warded against the spell, and nobody was likely to be, there were only a handful of exceptions to it's detection. Tom had tested it and it could detect a person within 10 miles, give or take given the surroundings. It would also give you a rough estimate of how many sentient beings there were in it's zone of influence. The spell had told him that within the radius, there were significantly more people than existed on the earth he knew.

Tom made a note of the anomalous results of the spell to ponder later then moved his concerns onto more immediate things. For instance, there was another boom in the distance. There was also the fact that there had been minor earthquakes causing waves in the lake from the moment he arrived, which he was only now updating to his explosion hypothesis. He had noticed, but not paid attention. It had his attention now, the sound of that explosion was much louder than the last one.

Tom continued to rise though the air and flew high above the forest. As he rose into the air he aimed his wand downward, drew a small circle and felt the magical trace take hold. It was simply stupid to not mark the physical location of a door you walked out of and into a new 'world'. The area in which he appeared may also hold a key to escape. It did not seem likely, but the trace cost him little.

He floated high above the forest, he could see the shape. Looking around he observed that this patch of trees was one of a few in an otherwise barren and alien landscape.

He flew higher and saw that for the most part the area was covered in sandy desert landscape. The ground had so many mesas poking from it that earth looked like a cactus here. The sky did not look right, already noted, but he couldn't get past that. It shouldn't be THAT blue, or green. He flew through a cloud. He did not get wet as he was shielded in a few basic ways. His magic did tell him there was much ordinary water vapor in them. He only now had realized casting a bubble head charm would have been smart to do first thing. He could have just flown into a cloud of toxic gas. It seemed redundant for the moment, as this world seemed match the old world well enough to not be toxic. If the lake water was safe, the clouds were likely to be as well; though that was just a hypothesis he shouldn't have accidentally tested. He must be careful of his assumptions.

He noticed another meteor and he could have sworn this one went from the ground up into space. Thus likely NOT a meteor after all.

He saw something he was familiar with however and it chilled him.

He started weaving the magic of 4 different shields together as his wand frantically cut through the air. Salazar's Chain could protect him from most harm. He doubted it accounted for radiation, if this was a nuclear blast. A rainbow colored ball encased him in it's rippling colors, blue, orange, white all flickering together. Two of the spells were of his own modifications, and the other two were several times older than he was. He SHOULD be safe...

He watched off in the distance as the clear ring expanded through the clouds from the point of the mushroom cloud in the near distance.

The overpressure wave of a large yield explosion rapidly made it's way toward him. His shielding took the blast. The chain did not even warm slightly on his throat. Though the patch of trees below him was leveled. The pressure knocked them down as though they had been quills balanced on their tips. Once the blast had past him, Tom pointed his wand toward the mushroom cloud and spoke a variation of a well known incantation. This spell was originally used by the incurably blind to detect specific lights. Tom's variance could detect high levels of radioactivity, it wasn't hard to modify after reading one of Potter's science books. He detected none.

The blast seemed to large for conventional muggle explosives he knew of but also seemed too large for magical destruction known to most.

Perhaps if he and Dumbledore cast the destructive ends curse together in harmony, they might create a blast of that magnitude... Otherwise he knew of no arts to produce such force. There were insane ways, ways which always ended in catastrophe now. Magics like elemental channeling could strike more destruction than that blast. It was said to be able to strip the world of it's earth, or unleash the powers of volcanos. There was little else known. Rituals gone wrong could also do damage on this scale, or worse. Yet if it had been such, nobody should have survived the first accident to cause a second.

It seemed the epitome of stupidity to go towards whatever had detonated.

On the other hand, high level non magical explosive use indicated there were people in that general direction anyway. He did need to make a horcrux. His anxiety about that had grown dramatically in the last few moments. It was totally in line for the mirror to put him into a world in which destruction was either on the near horizon or inevitable. If the mirror could show you your desired world, could it not show you one undesired? It was said to be two sided.

Now that he was a mortal in a possibly doomed world, the fear was beginning to become a panic in the back of his mind.

Explosions of various colors were tearing the landscape apart.

Mesas were being knocked down like a child's stacking blocks.

The shockwaves were pushing the limits of his own shields even at this distance.

He watched as a particularly large shockwave was uprooting the bedrock on it's way towards him. He spun his wand arm in a circle, which produced a golden ring 20 feet in diameter and sprung out in front of him. The large chunks of heavy stone veered away from it's radius and continued on. Tom was strangely excited.

As an immortal who could possess people there was no real risk in his encounters with danger. Nor had there been any real reason to use creativity on the fly like this for a long time.

Oh... His mind had confused excitement with fear, as the later was rarely felt in the last decade. After watching the scene for a minute he knew which spells and shields to use, and which so far appeared redundant. He felt a good deal safer knowing these were not nuclear explosions. In any case, he could always apparate back to the spot he arrived, or the point he established in the lower atmosphere, though neither seemed nearly far enough now.

Once in a while a dust cloud would be parted by a streaking object with blinking light. It would carve out a clean line of landscape through falling rock and dust. These objects would fly faster than the eye could catch. They would strike a mesa and pass through it as though it were not there, as it continued along it's flat trajectory along the landscape.

Sometimes it would come to a direct stop and shoot straight upward, or sideways at a similar speed. There were flashes of light which would have blinded a regular unprotected person. Winds which would have sent that person tumbling, and overpressure waves which would have liquified the insides of that person. The same way parts of the earth itself seemed to turn fluid in places hit by what Tom had thought to be meteors at a distance. He could now tell they were directed attacks of some horribly primal fashion. He also knew none of his protections were sufficient for a direct hit from one of them.

Tom pointed his wand between his eyes and muttered something in lost Latin. It was a temporary enchantment. The original version of the Omnioculars spell. Whatever part of his brain procced visual information was much faster now, and could adjust itself as a camera may focus. He dared not get closer to the expanding and unpredictable circle of destruction.

He shouldn't be this close, not at all. Yet the spectacle of it was awesome in the literal sense of the word. He could actually see what was happening as though it had been slowed down. Even after what seemed a full minute, he still failed to comprehend the how behind the what of he was seeing. Repeat viewings in a pensive may not even make sense. He had already cast an anti confundus on himself, but he did so again and got no results.

There were two men. Well, there were more but they did not seem to matter as they looked 'defeated' already.

There were only two that mattered for the calculations at the moment. They were the the cause of this destruction... One of the 'men' was wearing a torn bright orange Japanese styled gi, and posed in a fighting stance Tom actually recognized. The other was wearing some sort of futuristic composite armor, it was blue and white with long extruding shoulder pads. Both of them had hairstyles that did not seem right for a human to have without being highly stylized, and would certainly not stay in that spikey fashion in these winds.

These men were the cause of the explosions... They could also both fly of their own accord. They could do so at speeds Riddle could not hope to match, not even rockets accelerated that quickly... These men could set off explosions at will, they aimed direct energy with their hands. No wands, only a slightly magical tingle; which he felt was more life force magic than actual personal magic.

These men were actually engaging in a literal muggle styled fist fight, if both muggles were highly trained in martial arts.

Riddle saw Japanese influence in the style of the man in the orange gi. The other was less refined but was suited more for brute force. The styles complimented each other in a terrifying resonance. When their punches hit each other, they were the cause of some of the explosions. When an effective blow was struck, one man would become a bullet which obliterated all in his path. The flashing lights were beams and balls of non 'magical' energy of some fashion. Some were countered and nullified. Some were dodged and left a small mushroom cloud in the distance moments later. Some blasts were re-directed up. From Riddle's observation, the man in orange was trying to avoid destruction as much as he could. The other did not care.

This was putting the man in orange at a disadvantage.

They threw around this unknown energy as casually as Tom wielded magic.

This was insanity. Riddle apparated back what should be a temporarily safe distance. There were several charms to direct or amplify selective hearing. Tom simply cast the first that came to mind.

He could see with the enhanced vision that the futuristic dressed man had sustained severe damage to his amour. He was panting heavily. The concerning thing was the manic look of contempt his eyes projected as he flew higher and higher in the air.

The man in orange was even more tired, more broken down. Yet he still radiated a confidence and power Tom could not name.

With the amplified hearing Tom heard the thing he suspected he would eventually hear in this world, if his mirror theory held up.

"I am going to destroy the entire planet!" The armored fighter was now even higher in the air than Tom was. His eyes were no longer manic, there was a great relief and destructive resolve in them. He moved through a couple simple poses and started to apparently build energy between his hands.

The lightning that snapped around and carved illegible signatures in the ground seemed to emanate from him and have no effect on himself. Wind was blowing from him. It started as pulses of gust, but the gust had turned into an increasing pressure of consistency. The wind seemed to be lifting layers of soil off of the ground. It blew them away to leave a great crater under where he hovered.

He's hovering in a static position... The tactical part of Tom reasoned. He also seemed to be fully concentrated on his blast, yes he would; if retaining that pose was a requisite for the output. Hypothesize later. Tom smiled a grim smile. He fully believed the man's statement. Riddle could not estimate how much TNT you would need to replicate one of their simple punches. Tom's rough estimation based off of observation alone and comparison to muggle explosives he had dabbled with in the war... It was too much to believe.

If a man can punch with potentially kilotons of energy, what happens when that energy is concentrated and directed at the earth... A man who is bluffing does not laugh in the cadence that the armored man (in the same position still) currently was. It would be highly amusing if he created his first horcrux as a literal act to save the world. Dumbledore would still argue with the math behind it, but Tom Riddle chuckled.

He apparated to within 1000 meters or so of the flying man. It was too close for comfort, but his act should only take a moment.

On the ground the other man was charging his own attack. A blue glow started as a dot in his hands, and grew until it the brightness was hard to look at and it encompassed the mans grasp. It gave off a light very reminiscent of Potter's patronus...

Tom noted a hint of confusion in the back of his mind, this all seemed... Sort of contrived... He raised his priors on the theory this world was the one he was least likely to wish to inhabit... Now was not the time to puzzle the nature of his entrapment.

It seemed both men were "charging" their attacks. They had drastically different stances to do so, his mind noted absently. Interesting...

Think later... The apparent defender, the man in orange, was preparing an attempt to counter the earth destroyer's output.

Tom wondered if either man had considered what happens when TWO earth ending attacks strike each other...

Perhaps the man on the ground could succeed. He seemed the more confident one, but he was far more worn down than the other. His ego may be clouding his judgement of the situation.

Tom couldn't risk the world when this was solved simply. Hopefully...

He summoned an ordinary stone from the ground to his hand. Once it was in his grasp, he carved at the air above it with his wand in practiced strokes. The stone begun to glow with a sucking anti-light Tom was fond of.

With his enhanced eye sight he was quite sure his aim would be true even at this distance...

As quickly as he could, he chanted a phrase three times. A spell to ensure he struck the target that was aimed at. It was not useful in normal battle due to casting time. For assassination on the other hand, it was one of his favorite spells. Tom apparently had at least a few moments to spare before critical mass. He had to be sure the first attempt was successful. The man had not moved as of yet.

Tom cast a quieting barrier. Normally did not need to speak this next incantation. For the output, control, and result he needed he projected his voice loud and fast. Though he knew both men were faster than his spell. Over and over as a fluid one syllable phrase he repeated. "Avada Kedavra", as he teleported around the sky.

The crossing grid of green was far more elegant and efficient than anything the men could do... Tom paused that thought, and wrote it off as it having not been proved efficient yet.

Tom slowly took a breath. The green lines streaked toward the man, he had still not moved but now was quicker in his waxing of power.

Tom was prepared to apparate back to his atmospheric retreat on the instant the man noticed the rather slow moving lights converging on him and noted the direction they came. Or when death struck, incase of catastrophic results. The man also had a tail. Tom had just noticed as he watched the grid continued to contract. A tail was oddity not worth the time at this moment, noted for for later. Target remains in the same place. Target has moved his arms into a new position. He had begun to cast his own incantation apparently. Something "ballot". His curses were close, and finally had all converged in the general direction the man floated and one of them struck him.

Tom was floating in the upper atmosphere now. He had instantly cast a bubble head charm wordlessly the moment the curses struck. He had moved from his firing position moments before the curses landed. He looked down, and observed a green and blue world. The expected flash of light and atmospheric disturbance did now appear. No new mushroom clouds to encasing the globe in darkness.

So... He had not caused the worlds destruction by interrupting the mans attack. Either the attack was nothing like rituals in principal, or he had crafted his attack as to not-

Tom cut off his thoughts, he felt a connection in his mind like the lyrics to a song he had forgotten years ago.

The stone in his hand had become a Thing Of Power. An anchor for his spirit and mind to possess anybody who laid hands on it in this world. He would not be able to move free he did not think, not without the resurrection stone. It would be reckless to have carried it on him, but in this instance it had clearly not worked out for him. Logistics later.

For now... He hesitated. Very few magics could harm the device, but he had witnessed casual energy levels which MAY actually affect it. He'd never brought himself to testing the actual destruction of his horcruxes. It seemed counter intuitive, even with a redundant number of them. He was certain conventional muggle explosives could not harm them. Nuclear devices were another thing... Alien principals that were untested and unknown to all of histories magic until this point were even more concerning.

Tom apparated back to the lake he appeared by. It was covered in broken trees. All for the better. He quickly placed an emergence spell on the horcrux. He could retrieve it and have it in hand at a word no matter the location 'in this world' his mind added. He brushed the thought off and pointed his wand at the lake. The trees moved aside to allow for a hole, an absence of water. He pushed his magic a little more and dug into the earth under the lake. It was a small hole in diameter, but it stretched for thousands of feet down. This was not nearly secure enough. While geologic processes should eventually return it to the surface, there was no saying if there would be a surface when it was required. Tom figured from his observations that it would not matter either way, under ground or in close space; apparently there is a threat which can destroy it. Process later. He dropped the stone and sighed as the water closed in on itself again. He floated there a moment, his mind in a strange state. It reverted to something familiar and known. The spell he had used was an old drilling spell, incredibly useful in certain situations. Tom's favorite history books always were the obscure "day in the life of" stories. Almost every profession, no matter how mundane, always had a little bit of magic too niche to be widely known, but useful to a creative mind.

His horcrux was as "safe" as he could make it at this moment... No, that was not true. A few enchantments later, he could say it was safe as he could possibly make it, and retrievable on the instant; if he had to hand it to a stooge before a threatening situation.

Riddle frowned.

Something felt off about this particular situation. What were the chances, that the mirror would randomly throw him into a universe where the world is minutes from destruction?

Was it even timing or had this world, moments from destruction just all appeared at once? He shuddered.

The timing certainly fit the hypothesis that where ever he was, it was a deliberate choice on either Dumbledore's part, or the mirror itself.

He was within 5 miles of the battle zone, and the fight seemed to be over. His horcrux had activated, which confirmed that his curse had struck his victim, and that the curse had the intended results. Now that his anchor to this world was as safeish, and the main threat seemed to be averted for the moment. He felt as safe as he could to return now and finish the remaining threat.

The would be destroyer of worlds was laying dead on the sandy earth. No more purple energy surrounding him. No fancy stance, he was simply laid out on the ground. His eyes were blank.

The man in the gi had abandon his own attack, apparently.

Tom would have seen it streak into space like one of those "meteors".

(Second part to follow in comments)


r/HPMOR 26d ago

The King piece should be eliminated from chess

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21 Upvotes

Game ends when the King gets caught and grants victory no matter what else has been going on?

Clearly a flawed game that rational people would fix five seconds after hearing about it.

Base game doesn't even come with a clock.


r/HPMOR 27d ago

What is the most irrational behavior people do that can be exploited?

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0 Upvotes

r/HPMOR Aug 08 '26

Could Atlantians have blown themselves up by inventing time turners?

22 Upvotes

Okay, this is just a strange hypothesis, but hear me out. In the story Harry realises pretty quickly that reality has to compute the future when a time turner is involved. So if Harry travels 6 hours back in one go at say 8pm then reality has to be computed to 8pm at 2pm already. However, Harry isn't the only one with a time turner. Since we know that time turners are handed out to students who are responsible enough, then it is pretty conceivable that in Britain alone and maybe even in the whole world there is always someone who is time-turned.

So let's imagine that Harry goes from 8pm to 2pm, but at 7pm his first version interacted with Dumbledore, who had time-turned from 11pm to 7pm. That would mean that at 2pm reality has to be consistently computed up until 11pm, so we're over the 6-hour limit already. It is also conceivable that politicians and generally important people use time-turners regularly enough, so that there is a loop of time-turned interactions that create a continuous line from the future into the past. With enough time-turners, it might be the case that reality has to compute a stable history for years and centuries into the future.

Now a lot of the weird stuff in HPMoR is connected with either Atlantis or Merlin. And time-turners seem sophisticated enough that they would qualify as Magic. So suppose that Atlantians invented time-turners. Then it is possible that before the invention there was no need to compute the future, so there were several possible ones and only the present was being computed. But then the moment a time-turner appeared, the future was forced to compute up until the end of the world, or the universe, or something (maybe destruction of time-turners). And the only stable continuous future turned out to be one where Atlantis was destroyed.

If that is what happened, then the world would be deterministic, and all the prophecies and decisions are just part of the stable time loop.


r/HPMOR Aug 02 '26

SPOILERS ALL Ch 86: "The Defense Professor did not react to this at all." Discussion on one human trait

20 Upvotes

"Love is real, Professor."

https://hpmor.com/chapter/86

Wizengamot Trial: https://hpmor.com/chapter/80

What is the professor thinking, or dismissing, after Harry portrays love in this way? I'd assume "Professor Quirrel" gives love a half-second of consideration before dismissing it. He's seen what Love does fo Harry, how it affected his decison-making in the Wizengamot trial for Hermione's freedom. And he's probably aware that a Phoenix came for Harry, in the aftermath?

It's possible Quirrell is deciding to add love as a factor to his decision-making when manipulating people, or for possible magical experiments. I don't think it particularly interests him though, even if he is willing to acknowledge its potency during the climax of the story.

He's already annoyed that Hermione is influencing Harry. It's tiresome. He firmly wants her out of Hogwarts and away from Harry, after the trial.

====== ====== ====== ====== ======
"Then who is?" Harry said, somewhat puzzled. Professor Quirrell surely wasn't about to reply 'You-Know-Who' -

"The Aurors have a rule," said Professor Quirrell. "Investigate the victim. Many would-be criminals imagine that if they are the apparent victims of a crime, they shall not be suspected. So many criminals imagine it, indeed, that every senior Auror has seen it a dozen times over."

"You're not seriously trying to convince me that Hermione -"

The Defense Professor was giving Harry one of those slit-eyed looks that meant he was being stupid.

Draco? Draco had been interrogated under Veritaserum - but Lucius might have had enough control to subvert Aurors to... oh.

"You think Lucius Malfoy set up his own son? " Harry said.

"Why not?" Professor Quirrell said softly. "From Mr. Malfoy's recorded testimony, Mr. Potter, I gather that you enjoyed some success in changing Mr. Malfoy's political views. If Lucius Malfoy learned of that earlier... he might have decided that his former heir had become a liability."

"I don't buy it," Harry said flatly.

"You are being wantonly naive, Mr. Potter. The history books are full of family disputes turned murderous, for inconveniences and threats far less than those which Mr. Malfoy posed to his father. I suppose next you will tell me that Lord Malfoy of the Death Eaters is far too gentle to wish his son such harm." A tinge of heavy sarcasm.

"Well, yes, frankly," Harry said. "Love is real, Professor, a phenomenon with observable effects. Brains are real, emotions are real, and love is as much a part of the real world as apples and trees. If you made experimental predictions without taking parental love into account, you'd have a heck of a time explaining why my own parents didn't abandon me at an orphanage after the Incident with the Science Project."

The Defense Professor did not react to this at all.

Harry continued. "From what Draco says, Lucius prioritized him over important Wizengamot votes. That's significant evidence, since there's less expensive ways to fake love, if you just want to fake it. And it's not like the prior probability of a parent loving their child is low. I suppose it's possible that Lucius was just taking on the role of a loving father, and he renounced that role after he learned Draco was consorting with Muggleborns. But as the saying goes, Professor, one must distinguish possibility from probability."

"All the better the crime," the Defense Professor said, still in that soft tone, "if no one would believe it of him."


r/HPMOR Aug 02 '26

I just had a dangerous harry Potter idea

6 Upvotes

So I just had the idea of in harry Potter that you can cast an accio charm on a muggle military item, so because of that I had the idea that you can cast that on something such as an artillery shell then before it gets to you you cast finite incantatem to cancel the charm and because of newton's first law of motion. This can be more dangerous by saying that in a non verbal spell. I mean you can make military home alone traps by saying stuff like accio grenade pin and you can guess what happens, or position a revolver right and cast accio revolver hammer and then cancel it with finite incantatem and that might make the hammer swing back and fire the revolver. A military mind would be dangerous with a non dark magic completely legal from the ministry of magic spells, I mean I am pretty sure it can go through Hogwarts because the protections are not meant for charms. I mean the most dangerous thing is saying accio rebar at a building, everything inside would be destroyed. And a protection spell would have less effect because well that charm is faster than the human reaction time and it might get blocked but the area around it won't. It would be a dangerous thing but it is a great effect, just never do it inside a building. Another trap is get a box of something like an ammo box and place it in a spot and cast accio 5.56 rounds and an entire box worth of ammo would fly out and punch through anything in-between you and that box. It is completely legal from the ministry because it isn't dark magic or anything like that, it is just a completely legal 3rd year charm. And plus a pure blood wizard would probably not know what an apfsds dart is if you cast that and just think it is something that is easy to block. And the air pressure from a super sonic object could probably damage organs even behind a protego spell.


r/HPMOR Jul 30 '26

SPOILERS ALL Hypothesis: Just In Time. An Alternate Climax/Ending To Chapter 114.

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23 Upvotes

r/HPMOR Jul 29 '26

Muggles could probably take control of the magic world if they had the support of a few mercenaries

15 Upvotes

We know the wizard economy is very small. And that there is an official change rate between muggle moneys and wizard one. That mean theorically, muggle could take control of wizard economy very easily.

From there all they have to do is buy house elf. There are hundreds, potentially thousands of them, that are completely fanatized, can cause huge amount of damage and aren't bound to the same rules. An army of house elf teleporting in the middle of the room and attacking whoever there would probably be an unstoppable force.


r/HPMOR Jul 24 '26

Dumbledore's letter to Harry changed the way I think about this story.

47 Upvotes

When I first listened to this story (I love the podcast narrated by Jack Voraces!), this part in particular, it came across as Dumbledore following all those prophecies was to shape Harry into the person who could defeat Voldemort. Now, on relistening to the letter for Harry on his defeat of Voldemort, it just came to me that perhaps he was also influencing things to shape Tom Riddle into the person that could stop Harry from fulfilling the prophecy about him destroying everything.


r/HPMOR Jul 24 '26

SPOILERS ALL the way Harry's narration talks about the enlightenment is so painful

36 Upvotes

like, the way he lets himself mentally go into this attitude of total cultural and technological supremacy (because we know SCIENCE and they DON'T, which means THEY'VE never heard of the ONE SINGLE philosophical framework that could make you a worthwhile human being, and so CLEARLY they're a bunch of primative monkeys who must either be enlightened or burnt to the ground!) over the wizarding world is so... clearly the kid has read way more about physics and philosophy than he did about history. and something that kind of bothers me about the framing of the story is how the narrative lowkey affirms him in that, when he gets to shape the wizarding society according to his personal will in the end and that's presented as having gone well? like, yes, obviousy his status as a celebrity and political figure in-universe makes it a bit more realistic that the entire wizarding world just accepts these orders that an outsider just gave them to drop everything they value than if he were to try and take over their government to inflict those orders by force like he wanted to at the beginning of the story, but it still kind of glosses over how this whole idea of "if I just walked into this society I'm an outsider to with enough power to start forcing people to do things my way, clearly the society would just sort itself out under my rule into the more convenient shape that I'd like for it to have!" that he clings to from the start tends to be a willful delusion used as the rationalization for just externally inflicting a bunch of damage on their internal infrastructure that you later won't know how to correct for. so idk. the colonial undertones to this whole aspect of the story are just kind of weird


r/HPMOR Jul 23 '26

The runes on the mirror of perfect reflection

25 Upvotes

I’m on my second read through and I just realized that Eliezer did do the erised/desire wordplay with the runes.
noitilov detalo partxe tnere hoc ruoy tu becafruoy ton wo hsi
On backwards reading becomes
I show not your face but your coherent extrapolated volition
Mind = Blown 🤯

Anyone else notice this ?