Harry Potter and the Methods of Rationality



""You turned into a cat! A SMALL cat! You violated Conservation of Energy! That's not just an arbitrary rule, it's implied by the form of the quantum Hamiltonian! Rejecting it destroys unitarity and then you get FTL signaling! And cats are COMPLICATED! A human mind can't just visualize a whole cat's anatomy and, and all the cat biochemistry, and what about the neurology? How can you go on thinking using a cat-sized brain?""

Harry Potter and the Methods of Rationality is an on-going Harry Potter fanfic by Eliezer Yudkowsky, AI researcher and decision theorist.

This is an Alternate Universe story, where Petunia married a scientist. Now rationalist!Harry enters the wizarding world armed with Enlightenment ideals and the experimental spirit.

It should also be noted that the author is aware of us and has links to this page on his author's notes for chapter 20. And that the piece of fanfiction is the single most reviewed one in the Potterverse on the entire internet.

And welcome to those of you from the fanfic's website!

A-E

 * Academy of Adventure: Insane headmaster, obviously evil Potions master, arguably evil Defense master, students fight mock battles, even bullying gets caught up in political machinations.
 * Action Girl: Hermione is one of the three generals of the student armies. She's also founded an organization, S.P.H.E.W, the Society for the Promotion of Heroic Equality for Witches, to help other girls become this.
 * Adaptive Ability: A rational combatant adapts to the changing situation. The ones who don't (tends to be Hermione), quickly get beaten.
 * Adults Are Useless
 * In general, Harry thinks adults are not responsible (i.e., rational in their actions, especially when he brings something to their attention) and therefore does not respect their authority. He acknowledges that adults have stronger magic.
 * Subverted in chapters 12 and 14:
 * Alien Geometries: Hogwarts has corridors which can change when you aren't looking. The number of stairs you climb has only a passing correlation to your actual elevation when you look out the window. At least one corridor is tiled in pentagons.
 * An Aesop: At least one in most chapters.
 * Ain't Too Proud to Beg: Quirrell feels this is an important quality to instill in Harry.
 * All There in the Manual: Arguably. (Note: Spoilers even if you've read every chapter) The fact that is heavily implied, but by no means confirmed, in the text. It is explicitly stated in the author notes.
 * Always Someone Better: Harry realizes Hermione's ability to rapidly assimilate information and do academic work better, as well as having unwavering morality is superior to him. Hermione, in contrast, recognizes that Harry is a Chessmaster that she frankly cannot outplot no matter what she tries, and that he's far less naive than her. Both of them are jealous of the other's better points.


 * Anachronic Order: Ch. 24 & 25.
 * Armor-Piercing Question: The Sorting Hat tries to deliver one to Harry: "What happens if you fail?" But even though it goes on to spell out the answer, Harry still refuses to hear it.
 * Ascended Extra: Some characters with only background roles in the original series have much more fleshed out parts, most notably Blaise Zabini.
 * (Almost) All members of S.P.H.E.W. have much more fleshed out motivations than in the original series.
 * Amelia Bones is probably the most significant adult example.
 * Ask a Stupid Question
 * "Seriously, who reads this stuff?" "You."
 * When told that a sixth-year Gryffindor had deliberately cast a Dark curse on a sixth-year Slytherin - a curse he knew nothing about except that it was "for enemies" - Harry is unable to stop himself from asking "Are you serious?" No, Quirrell is in a bad mood today for no reason.
 * When  incredulously says "I'm... alive...?", Harry is tempted to say "no" just to see how she reacts.
 * Atlantis: Draco makes what might just be a metaphoric reference to the "blood of Atlantis," but eventually Harry starts to think magic might actually have come from Atlantis or somewhere like it. Later it is mentioned that something wiped Atlantis from the time stream.
 * Attention Deficit Ooh Shiny: invoked nearly by name in chapter 6.
 * Awesome but Impractical: The prose and Hermione and Harry's reaction implies the Light Saber (Lucis Gladius!) spell is this. It allows the user to play Tennis Boss with magic spells but has an obscenely long and complicated cast sequence, takes a huge amount of energy to maintain, and requires distance closing—and there may not even be a version that can do "real" physical damage.
 * Hermione in a desperate act had her army fly her into the air so she could try to use . She is able to cast the spell. Harry steps out of the way and Hermione crashes into a wall. Quirrell later berates her for it.
 * Badass Army: The armies, but the Chaos Legion stands out the most. By Chapter 67, they devolve into evil laughter and are capable of curb-stomping the other armies.
 * Badass Boast: "I make you this one offer," said the Boy-Who-Lived. "I never learn that you've been interfering with me or any of mine. And you never find out why is scared of me. Now sit down and shut up."
 * Badass Finger-Snap: Most of the students in Hogwarts think that Harry can do just about anything by snapping his fingers.
 * Bag of Holding: Harry's trunk and mokeskin bag both qualify. (Harry even explicitly thinks of the latter as his Bag of Holding.)
 * Bathroom Stall of Overheard Insults: Hermione overhears girls talking about her in the shower.
 * Beat Them At Their Own Game:
 * Draco is getting better at using rationality during battles. During the Taboo Tradeoffs battle, his response to Harry's stratagem enabled Dragon Army to win.
 * Lucius Malfoy plays a game of political influence and psychological manipulation. Dumbledore plays the opposing side and keeps Malfoy in check. Harry tends to wreck the board by being far from subtle.
 * Behind the Mask:
 * Behind Obfuscating Insanity, Dumbledore is very aware of the consequences of his decisions to win the next war.
 * Harry's is worried about his dark side, even though it is very useful.
 * Maintaining the mask and hiding their agenda until too late is the mark of a Slytherin.
 * Being Good Sucks
 * Dumbledore understands that some people are destined to become heroes no matter what, but it's nonetheless a fate that he wouldn't wish on anyone due to the ordeals involved. Though he's resigned to Harry Potter's fate, he tries to discourage Hermione from becoming a heroine for this reason. Quoth:

"Harry: It means that whatever happens, no matter what, it's always your fault. [...] Following the school rules isn't an excuse, someone else being in charge isn't an excuse, even trying your best isn't an excuse. There just aren't any excuses, you've got to get the job done no matter what."
 * Really driven home with Harry's talk about heroic responsibility in chapter 75.

"Gryffindor's Autobiography: No rescuer hath the rescuer. No Lord hath the champion, no mother and no father, only nothingness above."
 * And later

"[A]lthough, Draco was beginning to realize, when he and Harry and Professor Quirrell had dismissed Miss Granger as having as much intent to kill as a bowl of wet grapes, they'd never seen her angry."
 * Dumbledore's hidden room, unlocked by the passphrases "phoenix's price" and "phoenix's fate":
 * Berserk Button: Don't imply Harry's adoptive parents are abusive.
 * Beware the Nice Ones: Chapter 30.
 * And again in Chapter 78:

"Quirrell: The Killing Curse is unblockable, unstoppable, and works every single time on anything with a brain. If, as an adult wizard, you find yourself incapable of using the Killing Curse, then you can simply Apparate away!"
 * Big Bad: Depending on their political orientation, people think either Lucius Malfoy or Dumbledore is this. However, Dumbledore plays the game as if Voldemort is still the Big Bad.
 * Black and Gray Morality: According to Draco, many Death Eaters knew Voldemort was evil but joined him anyway because they thought Dumbledore was worse.
 * Black and White Morality: Hermione is very definite about what Good and Bad is.
 * Black Widow: Blaise Zabini mentions that his mother might be one. To be fair, that's practically canon.
 * Blackmail
 * Harry uses this to get Snape taken down a peg, while the Slytherin students suspect it's how Snape keeps his job.
 * Also, Draco figures the details of Harry's first date will make good blackmail fodder someday.
 * Blood Knight: Neville takes to this readily. Originally it is because he wants to become the cool Neville that exists only in his head. Later, he views it as training for fighting Bellatrix Black. He wields the Charm of the Most Ancient Blade on multiple occasions and overcomes his fear of broomsticks, though he hesitates (fatally, within-game) after kicking fellow Hufflepuff Hannah in the stomach.
 * Blue Eyes: Quirrell has the icy kind. Dumbledore's reflect his emotional state.
 * Bluff the Impostor: Chapter 79, in which  appears to have fallen for it.
 * Or he intentionally pretended to fall for the trick and get beaten up so people aren't suspicious that he needs to take a few days off to recover.
 * Boring but Practical: The Killing Curse and Apparition according to Professor Quirrell (except against adult wizards).

"Chapter 17: Professor Blake was caught in a closet with no fewer than three fifth-year Slytherins last February... Chapter 75: Arty Grey, the seventh-year who was leading in their competition by three witches and a Defense Professor..."
 * Brainwashed and Crazy: In Chapter 51 and Chapter 52, Quirrell tells Harry that only served Voldemort because she ended up this way after being Mind Raped.
 * Brick Joke: Quidditch without the Golden Snitch.
 * Bully Hunter: SPHEW, Hermione's little Amazon Brigade. It spirals out of control very quickly, and ends with sacrificing the Outer God, Yog-Sothoth, in order to summon . Okay, probably not the sacrifice part.
 * Calling Your Attacks
 * Neville, in his Crazy Awesome Badass mode. Since his attacks require allies to buff him, it's justified.
 * And much of the rest of the series, too, since (as in the original) much of magic requires you to say the right magic words.
 * Call Back
 * Scandalous continuity.

"Chapter 73: "I think our Sunshine General has him pretty well sewn up by now -- you'd have better luck convincing Hermione that the three of you should have one of those, you know, arrangements..." Chapter 75: "Do the three of you have one of those, you know, arrangements?""
 * Also:

"Neville: Do you have to do literally anything anyone asks you? Harry: Do? No. Feel guilty about not doing? Yes. [...] Every time someone cries out in prayer and I can't answer, I feel guilty about not being God."
 * People will remind Harry about sharpening Hufflepuff bones into weapons.
 * Calvin Ball: The Aurors on duty at Azkaban are playing Dragon Poker, from the Myth Adventures universe—although they've added Dementor-related rules.
 * Canon Illustrations: Dinosaurusgede's Fan Art (Recursive Fan Art?) seems to have this status
 * Carnivore Confusion: When Harry discovers Parseltongue, he stops eating meat in case snakes and other animals really are sapient—and then wonders in horror if plants are too.
 * Cast From Hit Points: Although most in-universe magic draws on caster's magic reserve, so that people who exhaust their magic faint or are physically fatigued, and students magic grows year by year,
 * Celebrity Paradox: Chapter 30 mentions "John Williams's Imperial March". So about ten years after the time frame of this story, what film is John Williams going to be writing the musical score for if it's not the first Harry Potter movie?
 * Another instance is Lampshaded in an author's note: "The version of decision theory used in this chapter is not the academically dominant one. It's based on something called 'timeless decision theory' that's under development by (among others) Gary Drescher, Wei Dai, Vladimir Nesov, and, well... (coughs a few times) me."
 * The Chessmaster: Dumbledore, Lucius Malfoy, and Voldemort.
 * Chess Motifs: Frequent references to someone's "game," "pieces," and "pawns".
 * Chirping Crickets: The noises made by the various gizmos on Dumbledore's desk fill the awkward pauses in his conversations with Harry.
 * Chronic Hero Syndrome: Harry has a bad case of it—something that becomes particularly clear in Chapter 27.


 * Made even funnier when he concludes that the obvious solution is to hurry up and become God.

"This story will next update on Tuesday, March 27. You have five days to think of something."
 * Cliff Hanger: Chapter 33,  (Chapter 41 contains more of a Literal Cliff Hanger.)
 * The author's note at the close of Chapter 80 is:

"The only possible explanation for how this mode of humming came to exist is that it was deliberately designed by some unspeakably cruel genius who woke up one day, feeling bored with ordinary torture, who decided to handicap himself and find out whether he could break someone's sanity just by humming at them."
 * Colorful Theme Naming: Trying to remain incognito and failing during his first trip to Platform 9 3/4, Harry asks Ron to call him Mr. Black. Malfoy arrives and says it is a good name, but the Black family may object. He suggests Mr. Silver instead, Ron counters with Mr. Gold, but Harry decides to Take a Third Option with Mr. Bronze, foreshadowing Harry's sorting a few chapters later.
 * The Complainer Is Always Wrong: Harry argues against Quirrell's call for unity by pointing out that this trope is what you get when you have too much unity.
 * Comically Missing the Point
 * Harry feels this way about the entire rest of the wizarding world after Malfoy tells him that the as far as they're concerned, the most important implications of his Parselmouth abilities involve him possibly being the Heir of Slytherin. Harry, meanwhile, has more important things to think about: "SNAKES ARE SENTIENT!?"
 * The non-muggleborn members of S.P.H.E.W. don't exactly get what Hermione is trying to tell them about Feminism.
 * Composite Character: Hagrid and Dumbledore are still there, but Professor McGonagall takes most of their roles of concerned guardian and reasonable authority figure. This frees Dumbledore to play up his Chessmaster persona.
 * Confusion Fu: The tactic adopted by Harry's Chaos Legion, with appropriately varying effectiveness.
 * Cool and Unusual Punishment: Quirrel has turned annoying humming into an art. Note that no magic is involved.

"Mad-Eye Moody had once worked out how long it had taken him, in retrospect, to achieve what he now considered a decent level of caution -- weighed up how much experience it had taken him to get good instead of lucky -- and had begun to suspect that most people died before they got there. Moody had once expressed this thought to Lyall, who had done some ciphering and figuring, and told him that a typical Dark Wizard hunter would die, on average, eight and a half times along the way to becoming "paranoid". This explained a great deal, assuming Lyall wasn't lying."
 * Couch Gag: The J.K. Rowling attribution at the beginning of the early chapters.
 * Courtroom Antic: Despite Dumbledore's severe warning that doing anything fancy will just make things worse, Harry eventually succumbs to this trope when it becomes clear they're going to lose . And then escalates his antics, and then escalates it a little more. And then once more at the end just to impress everyone.
 * Courtroom Episode: Chapters 80 and 81 in Taboo Tradeoffs.
 * Crazy Prepared
 * Harry insists on filling up his Bag of Holding with anything he could end up needing if something goes horribly wrong, and explains the Planning Fallacy to anyone who tells him not to worry so much. He ends up using much of it, too.
 * And of course Moody himself.

"One case of true curiosity had the same sort of redeeming power in rationality that one case of true love had in movies."
 * Snape's preparations against the possible, eventual return of Voldemort, while reasonable for the level of threat the man presents, are nonetheless frightening in their thoroughness. For years Snape had been going around and spiking graves with different potions in the event Voldemort might try to use the contents of his father's grave for some resurrection ritual. Many different graves over a wide area were similarly booby-trapped in the event that Voldemort thought ahead and obscured the grave's true location beforehand. The "most likely" grave is laced with seventeen different draughts, refreshed yearly, including LSD, just on the off chance it'd have any actual effect on Voldie!
 * And conversely, Snape and Mad-Eye come to the conclusion that Voldemort probably out-Crazy Prepared them by simply making the actual grave into an unremarkable field.
 * Crouching Moron, Hidden Badass: Professor Quirrell seems to flip between narcoleptic weirdo and intensely-passionate professor regularly. And apparently, he is a sixth dan in at least one martial art, and he completely outclasses a trained Auror in combat. Translation for those who don't know what that means: Quirrell is Badass. Though this is only natural, given that.
 * Cryptic Conversation:
 * In Chapter 27, Harry talks to Snape about a bully and a love, the identity of whom he finds out too late.
 * Harry bluffs his way through one of these with Lucius Malfoy in Chapter 38, without ever figuring out what it was really about. It turns out that this may have been a bad idea.
 * Curb Stomp Battle: Quirrell vs. Auror Bahry in chapter 53.
 * Curiosity Causes Conversion: Part of Harry's plan for Draco.

Also, Dark Is Not One Big Happy Family. Most of the characters who were villains (or came off as villains) in canon do not have a mutual agenda here, to the point that Draco has somewhat different priorities than Lucius, neither of them trust Quirrell, Snape doesn't collaborate with any of them, and Harry's in some way or another getting what he wants from all of them. Blaise Zabini seems to be quite happy to do whatever the hell he wants, and then you have Slytherins like Daphne Greengrass who seem more motivated to enjoy childhood and get through school than participate in any sort of conspiracy. From a Gryffindor perspective, it probably looks like Magical England has its own Big Bad Ensemble. "Snape: Should I teach him to brew Polyjuice, Headmaster? I ask only for the sake of completeness, in case you are not satisfied with the magnitude of your pet disaster. Dumbledore: Maybe next year."
 * Curiosity Is a Crapshoot: A character is at one point "almost killed by his lack of curiosity."
 * Dangerously Genre Savvy
 * This version of Voldemort has apparently read (actually, written his own version of) the Evil Overlord List. This has made him smarter about how he manipulates people, but it also strengthened him to the extent that in chapter 20 we find that (same spoiler as All There in the Manual)
 * In chapter Chapter 49, Quirrell mentions two of the rules by number, except that his versions of the rules are nearly the opposite of the rules on the Evil Overlord List (e.g. "Never turn into a giant snake" vs. "Become an animagus"). So if Quirrell wrote the Evil Overlord List, then he intentionally introduced some errors in it to throw people off the scent! Sort of. Because he also pointed out to Harry in an earlier chapter that if you're going to follow all the rules all the time, there's no point in even being a Dark Wizard. So being an animagus may be a place his disagrees with the real Evil Overlord List, but then again it may be one of those exceptions he allowed himself. The fact that he calls it a rule implies the former, but it's hard to say.
 * Dark Is Not Evil: Thoroughly Deconstructed. Although most noteworthy evil wizards are referred to as Dark, including the Big Bad, much of the cast (especially Harry, Quirrell, anyone Slytherin) use it to refer instead to methodologies involving force, trickery, threat of force, blackmail, etc. Especially early on Harry finds that Dark tactics can be used to achieve good goals and to do things he couldn't accomplish without them; however, he eventually realizes that anything he achieves that way turns out to not be quite as good as it would if he'd done it without (for example, scaring a rumormonger straight ends Hermione's problem and may ultimately help the victim but angers Hermione and risks her reputation; going with an even darker plan of manipulation would have solved Hermione's problem but not helped the rumormonger at all. He realizes he should have just talked to her directly) and usually raises the stakes in ways that have unpleasant consequences. Too many Dark actions also affect people's perception of him. Even as he comes to understand this, though, he can't give up the sheer utility of his dark side entirely.
 * Also discussed in this brilliant quote from Hermione: "But the thing that people forget sometimes, is that even though appearances can be misleading, they're usually not."
 * Dark Mistress: Bellatrix.
 * Dead End Job: Emphasized more than in canon. Everyone knows they'll only have Quirrell for one year, and just hopes they'll at least have him for the whole year. Whatever it takes.
 * Deadpan Snarker
 * Snape seems to have elements of this. Professor McGonagall, in hysterics, points out that the remarkably disruptive Harry Potter has an invisibility cloak, is immune to mind-reading (and, due to the same discipline, is able to resist truth-potions), and is friends with the Weasley twins, to which Dumbledore helpfully adds mention of the Time Turner. Snape then contributes:

"Hermione: Can you tell me what's eight, times four, divided by zero? Harry: lim epsilon approaching zero plus of eight times four divided by epsilon... 10:47AM on Sunday."
 * Deconstruction Fic: Multiple tropes are Deconstructed.
 * Demoted to Extra
 * Hagrid is in the fic, but has no relevance to the plot or even any dialogue.
 * Ron appears every now and again but generally stays Out of Focus. Harry says after first meeting Ron that he sees no reason for him to exist. Ron's main personality trait is undying loyalty to his general, Hermione.
 * Design It Yourself Equipment: What happens when transfiguration is commonplace.
 * Devil's Advocate: As a rationalist, Harry has it as a defining character trait that he must assess all available sides of an argument, whether no true advocate of that argument is present, or even exists. This has led to him acting as the Devil's Advocate for himself, as well as using the trope for other people as a form of the Socratic Method of argument.
 * Diabolus Ex Machina: Comed-Tea is a comedy version.
 * Did Not Do the Research: "I haven't read Deathly Hallows, so my knowledge comes from either the Wikia or from other fanfiction". Fortunately, the story's premise allows for inconsistencies with the books, and the fic is at least partially a paean to Harry Potter fanfic (as opposed to canon). The only time it's really bitten him so far was when he came away with the impression that Lily and Snape were once dating.
 * Difficult but Awesome: In the battle of the Self Actualization arc, Harry and Neville had to train very hard to be able to wear . Still, the spell takes a LOT out of Harry's magic reserves to use, but allows him and Neville to.
 * Disguised Hostage Gambit: Amelia Bones warns her Aurors to make sure this isn't being pulled on them.
 * Ditzy Genius: Harry.
 * Divide and Conquer: A common strategy in the battle sequences.
 * Divide by Zero: Harry actually manages it, using real world math (and some slightly hubristic assumptions).

"Harry: I'm wondering if there's a spell to make lightning flash in the background whenever I make an ominous resolution."
 * Originally, he just said "divided by zero". But then some readers didn't get the joke and complained, so Yudkowsky fixed it by making the math sound more complicated. Though not actually correct.
 * Don't Call Me "Sir"!: "Please, Harry! Headmaster sounds so formal. Just call me Heh for short."
 * Doomy Dooms of Doom
 * The Chaos Legion's marching song. To the tune of the imperial march no less.
 * Also, McGonagall briefly fears that the Sorting Hat will create a new House of Doom just for Harry.
 * Not to mention the inexplicable feelings of doom Harry gets when he stands too close to Quirrell.
 * Also Susan Bones' thoughts about SPHEW's latest mission. It's doomed.
 * You can't see Neville being a badass and not think it requires musical accompaniment.
 * Doorstopper: The story's word count so far exceeds that of the first four Harry Potter books put together, and it appears to be nowhere near finished, considering that its apparent ambition is to resolve the plot of all seven books before Harry's first year is out.
 * Double Reverse Quadruple Agent: Blaise Zabini.
 * Double Standard: Hermione suspects McGonagall is more protective of her than she would be if Hermione were a boy. Also, Harry is especially bothered by the sight of girls knocked out by sleep hexes.
 * Dramatic Irony: To someone who has read the original series and author's notes, many of the things that Quirrellmort and Dumbledore say, largely concerning horcruxes, the prophesy, and Deathly Hallows, have hidden meanings that Harry misses because he lacks backstory to make alternative hypotheses plausible.
 * Dramatic Reading: There is now a nice podiobook available.
 * Dramatic Thunder: Lampshaded, like so many others.

"Just as it had not occurred to Gandalf that the Enemy might learn to comprehend the good intentions of his enemies by looking..."
 * Dying Alone: Hermione's greatest fear.
 * Dying Like Animals: Quirrell delivers a lecture about how this happened in the first war.
 * Eccentric Mentor: Dumbledore, even more so than his canon counterpart.
 * Empathic Environment: Mary's Room.
 * The chair in McGonagall's office has been transfigured so many times it seems to reflect her moods. At one point, it is so big and soft it seems to be giving Harry a hug.
 * Quirrell's room in the infirmary has no natural light. It may be that the infirmary has a variety of rooms for different tastes, or Hogwarts alters rooms to suit patients.
 * Enemy Mine: Draco and Hermione eventually are driven to make common cause.
 * Enemy Within: While Harry is a superb rationalist, he resorts to his dark side when he needs to bring out the big guns.
 * Ethical Hedonist: May not be Harry's exact ethical calculus, but is most likely close. At least when he's thinking things through...
 * Even Evil Has Loved Ones: Whatever else you can say about Lucius Malfoy, he appears to genuinely love his son.
 * Even Evil Has Standards: In Chapter 20 it's shown that Professor Quirrell strongly resents Muggles for inventing nuclear weapons. Also, in Chapter 42 it is shown that the wizarding world doesn't think highly of prejudice against homosexuality in the Muggle world, with one Slytherin girl even believing stories of violence carried out against homosexuals are just a rumor spread by Death Eaters to make Muggles look bad. They are also boggled by color-based racism.
 * Everything's Better with Sparkles: Averted for Daphne, who is cursed to sparkle by upperclassmen.
 * Evil Cannot Comprehend Good
 * Or at least Dumbledore believes this, though that may just be his idealism showing.
 * In an Omake about if it was a The Lord of the Rings fanfic, this was implied to be defied by Awesomeness By Analysis.


 * In Chapter 76, Mr. Hat and Cloak attempts to convince Hermione to flee Hogwarts. He fails utterly because he doesn't understand that Hermione just won't trust someone cloaked in an all-covering black mist.  Given Mr. Hat and Cloak's previous competence at running conspiracies, it seems his ability to form mental models of people has serious flaws when it attempts to analyze Hermione.
 * For a truly epic example, in chapter 38, Lucius tells Harry "When I read your response to Professor Quirrell's little speech... I was puzzled, at first, for it seemed not in your own interest." Which mistakenly assumes that Harry is self-interested. It's never explicitly said what conclusion Lucius reached as a result of this mistake, but it's implied that Lucius ended up concluding that Harry is Voldemort.
 * Evil Counterpart: Grindelwald was Dumbledore's "dark mirror," and Dumbledore thinks Voldemort must be Harry's. Harry is dubious.
 * But he doesn't know about . If he did, he'd realize that Dumbledore is actually spot-on. Both are rationalists who are exasperated by irrationality in others; both reject/fear death and seek immortality; and both have a strong interest in space travel.
 * Bellatrix is the evil counterpart of Hermione. Both were the most promising witch of Hogwarts and considered nice if quiet by friends. Bellatrix had to suffer dementors for ten years, and Hermione is terribly afraid of them. And both are bound to Voldemort and Harry, respectively, by something deeper than an Imperius curse.
 * Evil Is Stylish: Generally averted. Quirrell won't let anything get in the way of his plans, but even he occasionally deviates from his Evil Overlord List because to always live by them would not be worth it. Harry does like to things with his own flair, like gluing bullies to the ceiling, but is resisting evil.
 * Evil Laugh: Harry often uses one, usually when role-playing as an Evil Genius, or just to sarcastically point out how non-evil his plans are, such as his plot to make Draco friends with Hermione, or desire to find a way to make immortal.
 * Evil Mentor: Professor Quirrell
 * Evil Me Scares Me: Harry's "mysterious dark side"
 * Evil Overlooker: The commissioned poster.
 * Evil Sounds Deep: This makes it harder for eleven-year-old Harry to sound truly fearsome, even when he tries.
 * Evil vs. Evil: Draco believes (along most Slytherins, apparently) Dumbledore was the Greater Evil and that Voldemort and his Death Eaters, though bad, were the only people with a chance to stand up to him.
 * Exact Words
 * In Chapter 25, Quirrell says to Rita Skeeter: ""
 * Later, "I promise not to help General Granger in any way that the two of you don't know about."
 * Quirrell figures that the portkey given to Harry would take him to someplace in London, instead of the wizarding school in America as promised. He then notes that the attached letter did not explicitly say the portkey would take Harry there; merely that the Salem Witch's Institute would accept him, and that Harry now had a portkey.
 * Expy: Rationalist!Harry shares quite a few similarities with Ender, such as his intent to kill, the mock battles, and his ingenuity. He explicitly embraces the comparison: "Why are you all upside down?"

F-J
"Then a boy's voice said, calmly and quietly, "What.""
 * Face Palm: The usual response to Harry's antics.
 * False Reassurance: Inverted in chapter 30. "Dragon Army has never lost a single battle."
 * Family Feud: Harry really doesn't want one with Draco.
 * Fandom Nod: As a paean to Harry Potter fanfic, there are several.
 * Mention of the idea of breaking a time-turner leading to being trapped in an eternally looping Thursday. ("Getting the Hang of Thursdays")
 * The mockery of Peggy Sue plots in Chapter 29.
 * A briefly-mentioned discussion of the infamous "Marriage Law"... in the Quibbler, naturally.
 * The infamous "Most Ancient House of Sparklypoo" later gets mentioned in Chapter 69.
 * Fantastic Time Management: Harry gets a Time Turner to cure his sleep disorder.
 * Feed the Mole: A lot of moles get fed in chapter 33 after traitors have turned the battles into a farce.
 * Figure It Out Yourself: Justified; once Harry figures out how to, he realizes that just telling someone the secret won't make it work for them, but will render their ability to use the Patronus Charm useless without the proper mindset. Making any explanation a potential Brown Note.
 * The Film of the Book: A Sims version
 * Fingore: A bully threatens quite seriously to "accidentally" break Harry's fingers.
 * First Girl Wins: Harry's and Hermione's parents are already hearing wedding bells, just because Harry is the first boy Hermione's ever seemed to notice in "that way" and Hermione is the first child Harry's ever seemed to notice even exists.
 * Though Harry's parents don't know about Draco, whom Harry did befriend even before Hermione....
 * First-Name Basis: Harry often doesn't bother to call his professors by title or even last name.
 * Five-Man Band: It looks like Harry's making one.
 * The Hero: Harry
 * The Lancer: Draco
 * The Smart Guy: Hermione
 * The Big Guy: Neville
 * The Chick: Quirrell/Dumbledore
 * Flat Earth Atheist: Discussed Trope in the author's notes—Yudkowsky stated that he wished to demonstrate that even though there is an afterlife in the canon Harry Potter series, the dearth of available evidence (without, you know, dying) meant that disbelieving in its existence was still a thoroughly reasonable standpoint. This arguably required Dumbledore to do a fairly poor job of presenting said evidence—see The War On Straw, below.
 * Flat What
 * Happens in the very first chapter:

"Harry Potter: ... and in any case you're asking the wrong question. The question is, did it do more good than harm, or more harm than good?"
 * In chapter 24, Harry mentions stealing gold from his own Gringotts vault. This is reaction.
 * Forbidden Friendship:
 * Hermione and Draco. One's a mudblood, one's the son of the top Death Eater. Everyone in Slytherin expects Draco to destroy her.
 * Harry and Draco. Dumbledore and Lucius Malfoy only allow it to continue to turn the other.
 * Forbidden Fruit: Harry muses on how susceptible people are to this after he himself discovers that he desperately wants to be able to  as soon as he's not allowed to.
 * Forced to Watch: The martial arts instructor who wouldn't teach Voldemort had to watch his students tortured and killed.
 * For Happiness

"Harry: I shall achieve my objectives through the power... of Science!"
 * For Science!:

"I think I just had to get it out of my system by writing, at least once in my life, something more complicated than Death Note."
 * For the Evulz: Harry and Dumbledore ponder why Voldemort has become so inhumanly evil. The best answer they can come up is that a dark wizard might look at the injustice of the world and ask, "Why not?"
 * Fridge Horror: A few, In-universe.
 * After Harry finds out about Parseltongue he starts to wonder if any other animals are intelligent enough to communicate. Then he starts to wonder about plants. Then he starts to skip meals. Confounded by the fact that the next meal he has is Tenorman's family chili. Harry makes sure that it contains no meat of snakes or squirrels, since those are the only (potentially) talking animals...
 * More subtle is the fear Harry learns when he sees what kind of proper protections he should have had in place when doing Transmutation / science experiments with Hermione.
 * Gambit Pileup:
 * The War of Three Armies. One of the few cases where "thirty" is an understatement. The author actually apologizes for the pileup in the author's notes, but explains that:

"To understand everything important there is to know about the universe, apply that knowledge to become omnipotent, and use that power to rewrite reality because I have some objections to the way it works now."
 * In the main plot, Harry, Draco, Dumbledore, and Quirrell all trying to be The Chessmaster, with varying degrees of success.
 * A recent chapter has Snape commenting, "If I have learned anything in my tenure as Head of Slytherin, I have learned what ridiculous messes arise when there is more than one plotter and more than one plan."
 * Gambit Roulette: Lucius also seems to have summed this one up perfectly: he's told Draco that "any plot which required more than three different things to happen would never work in real life". However, "only an idiot would try a plan that is as complicated as possible, so the real limit is two."
 * Genre Savvy / Wrong Genre Savvy: Harry. Also Dumbledore, who is a big fan of The Lord of the Rings and consciously casts himself into the role of Obi Wan / Manipulative Bastard while pretending to be a Cloudcuckoolander.
 * Getting Crap Past the Radar: Dumbledore has an instrument that counts the, ah, "sneezes" of left-handed witches within the borders of France. .Though the radar was for the sake of Harry himself.
 * Girls Have Cooties: Harry doesn't mind being around girls per se, but objects strongly to notions of romance or kissing.
 * A Glass in the Hand: Snape's reaction to the Ghostbusters song. Instead of glass, though, it was a silver goblet.
 * A Glass of Chianti: Quirrell's usual drink in Mary's Room. No, not evil at all...
 * A God Am I: Harry's ultimate goal is:

"Harry: Of course whatever Dark wizard who created them in the first place was evil beyond compare, but that was no reason to deny the poor creatures the servitude they were bred to enjoy."
 * Golden Snitch: Upon having Quidditch explained to him, Harry immediately points out that the Trope Namer makes the entire rest of the game meaningless, and resolves to remove it. Not right away, he has other stuff to do... but, you know, eventually.
 * Gone Horribly Right: Dumbledore's pushing of Hermione towards trying harder to be a hero in her own right works all right. It works so well that the entire next eight chapters are about just how much trouble she stirs up as a result. Long before the end he is fearing for her life should things escalate further.
 * Good Angel, Bad Angel: In more than one scene, Harry debates with his inner Gryffindor, Ravenclaw, Slytherin, and Hufflepuff, as represented in this piece of fanart. Amusingly, or perhaps bizarrely, all but Ravenclaw start making fun of him when he gets worried about the implications of parseltongue, in ways that have nothing to do with moral arguments (for instance Hufflepuff starts insisting he resort to cannibalism). Chapter 63 contains what may be a justification for all the voices in Harry's head sounding so much like distinct individuals, but nothing but the Rule of Funny can save them in chapter 48.
 * Gossipy Hens: The girls of Slytherin.
 * Gossip Evolution: Rumors in Hogwarts have a tendency to mutate. Some had few witnesses to the original event (e.g., Harry using the Ghost of Slytherin to stop Padma from spreading rumors about Hermione; what exactly happened in Hermione's Wizengamot trial) and some had many witnesses (e.g., Harry returning from dementation). Harry allows them to spread because uncertainty makes more likely that the truth will remain hidden.
 * Hermione wonders what older Ravenclaw girls are reading that makes them ship Harry-Hermione.
 * Gravity Master: Feather Falling potion works much like the similarly-named D&D spell.
 * The Grovel: Harry's lack of experience dealing with friends combined with following the advice of Quirrell has lead to multiple instances with Hermione.
 * The Guards Must Be Crazy: Averted, even for a small thing like patronuses acting strangely,  guards send patrols to be safe. Another sign of  's genre-savvy-ness.
 * it was probably nothing, but procedure was procedure.
 * Guest Fighter: In chapter 77, from the Sburb Patch Notes thread.
 * Happily Adopted: One of the main differences from canon; Petunia and her husband think of Harry as their son, and are kind and loving parents.
 * Happiness in Slavery: The House Elves, of course. However, in this version Hermione's issues with it are downplayed.

"So either Severus was in fact modeling Harry as a one-level player, which made Severus himself two-level, and Harry's three-level move had been successful; or Severus was a four-level player and wanted Harry to think the deception had been successful."
 * Head Desk: McGonagall, in chapter 61.
 * Heel Realization: Harry seems to be on the verge of this around chapter 55, at the worst possible place and time for it to happen:
 * And in chapter 82.
 * Hellhole Prison: Azkaban, described even more vividly than in canon.
 * Heroic Resolve
 * Harry, in  when he realizes that giving up would doom.
 * Villainous example (maybe): Tracey Davis in Chapter 70, after Quirrell chastises her.
 * Hesitation Equals Dishonesty: Chapter 63, Harry and Draco both use this as a litmus test.
 * Hitler Ate Sugar: Harry falls into this fallacy briefly in chapter 35, but even after he's called on it his point still stands.
 * Hobbes Was Right: Professor Quirrell's viewpoint, which he hopes to bring Harry to.
 * Homeschooled Kids: Harry was one before attending Hogwarts.
 * Hopeless Boss Fight: The Hogwarts battle in Chapter 67 is basically a non-video game example of this.
 * Hot for Teacher: Rianne Felthorne is hopelessly infatuated with Snape, and when he demands her presence in his dungeons she immediately assumes he's propositioning her. For a threesome with Hermione Granger, no less!!
 * Hufflepuff House: Oddly enough, Gryffindor, which is mainly filled with none too bright troublemakers, impulsive hotheads, and most of the non-Slytherin bullies. Hufflepuff itself is Rescued From the Scrappy Heap by dint of hard work and loyalty being strong, positive traits in this universe.
 * Humans Are the Real Monsters: Quirrel believes this. Harry thinks while many may be people also have the potential to be good and that some (like Hermione) are able to act on it.
 * Humans Are Morons: The premise of the fic is that most humans do not bother to think deep enough.
 * Humans Are Special: And our Hat is that of the Manipulative Bastard. Yay.
 * Harry believing this gives him the power to destroy Dementors. So, yeah, definitely.
 * Human Sacrifice: It's strongly implied that Grindelwald was using the Holocaust to fuel some Dark ritual. Dumbledore mentioned that he was literally invincible while his Muggle allies were still making blood sacrifices for him, and they had to be stopped before he could be defeated. So yes, in those months where the wizarding world claimed Dumbledore was "waiting for the most dramatic moment," he was actually stopping the Holocaust.
 * Hurl It Into the Sun: Harry asks if this would destroy a dementor. Quirrell, not content with giving a simple response, deliberately misinterprets the question as asking if the sun would be destroyed. (The answer is "probably not, but I still wouldn't recommend trying it.")
 * I Always Wanted to Say That
 * "Red 5 standing by."
 * Also, "Why are you upside down?"
 * I Can Still Fight
 * Quirrell has to order Harry to rest after the events of the infamous Chapter 19.
 * Hannah Abbott literally says this during Quirrell's battle in Chapter 78.
 * Ice Cream Koan: When Dumbledore desperately asks him for some wisdom, Harry resorts to spouting fake profundity—and then is rather appalled at how easily Dumbledore buys it.
 * Idiot Ball
 * Discussed Trope in the Ch. 33-34 Author's Note: "It is a general law of MoR that no one is ever holding the Idiot Ball." However, Quirrell does explicitly break his own Evil Overlord rules when telling Harry about the Pioneer plaque, and Harry in turn seems to be trusting Quirrell to an unreasonable extent even given their burgeoning friendship.
 * Referenced among Madeye's list of precautions as "Bahl's Stupefaction".
 * I Gave My Word: Quirrell seems surprised when Harry tells him he would never break a promise.
 * I Have This Friend: With a touch of And That Little Girl Was Me. Harry learns it's dangerous to give advice unless he knows who his interlocutor is really talking about.
 * I Know You Know I Know: Quirrell teaches Harry to pull off more subtle kinds of deception, leading to situations like this:

""I do hope those five Galleons will be enough to last, since you counted them so carefully," said Professor Quirrell. "I doubt the Headmaster shall be so eager to entrust me with your vault key a second time, once he discovers I've been tricked.""
 * I Know Your True Name: Neville pretends to summon Harry "by the power of [his] true name."
 * I'll Pretend I Didn't Hear That: On Harry's second trip to Diagon Alley:

"Which was far too good a line for anyone to keep to themselves, so by nightfall it was all over Hogwarts, and the next morning it was the Quibbler's headline."
 * I'm a Doctor, Not a Placeholder: "I'm a hat, not a god."
 * Immortality Immorality: According to Dumbledore, simply fearing death, let alone trying to avoid it, is enough to warp one's soul.
 * Immortality Seeker: Harry wants everyone to be immortal.
 * Improbable Age: ... Kinda goes without saying.
 * Incredibly Lame Pun
 * After Draco has dropped off the roof of Hogwarts (It Makes Sense in Context and the victim Got Better), it is speculated that his goal is to drop all the Muggleborns. That's right: he's the Heir of "Slipperin" and the next "Drop Lord".

"His inner Slytherin's mental voice was grim. You too will someday embrace the doctrine... that the end justifies the meats. This was followed by some mental snickering."
 * When Harry is trying to decide whether it is moral or not to eat meat, his inner Ravenclaw, Slytherin, Hufflepuff, and Gryffindor try to help:

"Even after eight centuries, Hogwarts was still a little shy about changing in front of people."
 * Chapter 67, about the rules how Hogwarts changes its geometry:

"Mere eyes could not have seen the invisible others: the eleven-year-old Boy-Who-Lived, and the living skeleton that was, and the Polyjuiced Defense Professor of Hogwarts, all traveling together through . If that was the beginning of a joke, Harry didn't know the punchline."
 * Insufferable Genius: All of Ravenclaw house, of course, but especially Harry, natch.
 * I Need a Freaking Drink: McGonagall needs one desperately after shopping with Harry.
 * Intelligence Equals Isolation: Harry spells this out to McGonagall.
 * Intrinsic Vow: Harry, even under will not kill.
 * Invisible to Normals: Harry's trunk is weird enough that his very unmagical dad has trouble looking directly at it.
 * I Owe You My Life: Life debts in the wizarding world appear to be Serious Business, as the Wizengamot (at least sometimes) makes official rulings about them.
 * Ironic Echo
 * Harry turns Dumbledore's "This is not a request. This is your punishment" back on him.
 * Dumbledore notes on separate occasions that "Common sense is often mistaken for Legilimency," and that "Legilimency is sometimes mistaken for common sense."
 * I Shall Taunt You: Draco thinks Harry is trying to break up his alliance with Hermione by teasing him about it mercilessly.
 * Is This a Joke?:

"Harry should have been more frightened, more reluctant, but instead he felt only that it was time and past time to start becoming the people he had read about in his books; to begin his journey toward what he had always known he was meant to be, a hero."
 * It's Quiet... Too Quiet: Spoofed in Chapter 13, when Harry wakes up thinking his dorm room is suspiciously quiet and then remembers there's a silencing charm on the bed.
 * I Was Never Here: Harry says this to Professor Sprout when the Game, and it's implied in several other conversations.
 * Jack Bauer Interrogation Technique: Harry suspects that Quirrell gained a certain piece of information through the use of "lead-pipe Legilimency"... which is itself a "Hold Your Hippogriffs" version of "rubber-hose cryptanalysis"—that is, whipping somebody until they tell you the password.
 * Jerkass: Harry can get a little bit... abrasive with people who do not meet his personal standards. Example: telling a friend's parents at their first meeting that history will only remember them as her parents.
 * Or when, immediately following that, he says that the only reason history will know what their job was would be because they were her parents.
 * Jumped At the Call
 * The Hat tells Harry: "You're just guessing, or to put it more exactly, wishing that you have some ready-made heroic role that is your personal property." And Harry certainly acts the part later:


 * Deconstructed when Harry makes a series of less than optimal decisions in quick succession while . He recognizes that this is a flaw in his own psychology and it remains to be seen how badly this will come back and bite him in the end.
 * Played Straight again in Chapter 69 for Tracey Davis, who is making up for the opportunity she realized she missed in Chapter 46.

K-O
"My Lord, where are we? Harry: We are on a broomstick."
 * Kangaroo Court: Although the entire court is not on the prosecution's side and its highest-ranking member is leading the defense, was hardly what one would consider "fair".
 * Kick the Dog: Draco Malfoy, in chapter 7.
 * Killed Mid-Sentence: Neville gets a little cocky in his first mock battle.
 * Lampshade Hanging: All over the place. Gloriously so.
 * Late Arrival Spoiler: For the many readers who never got into the original Harry Potter books. Quirrell is whom? He did what to the ?
 * Like an Old Married Couple: Harry and Hermione, according to Harry's dad.
 * Little Professor Dialogue: Harry. Lampshaded frequently, and likely to be justified/deconstructed—by now, most of the cast (including Harry himself) are aware that there is something very, very wrong with him. Draco's lapses into this, on the other hand, are a bit less excusable.
 * Living Forever Is Awesome: Harry believes this. Dumbledore doesn't.
 * Loophole Abuse: At Hogwarts, "invisibility cloaks aren't against the rules -- I suppose they're rare enough that no one ever got around to putting them on the list."
 * Loser Son of Loser Dad: Lesath Lestrange
 * Lowest Common Denominator: In-universe. Harry suspects the Sorting Hat is being forced to fill up Slytherin with these people because Death Eater reputation leads to anyone with a brain pleading with the hat not to be put into Slytherin.
 * Magic A Is Magic A: As with the books, magic has consistent, if unknown, limitations. However, Harry wants to take it a step further (see Sufficiently Analyzed Magic below).
 * The Magic Goes Away: This is what Harry and Draco suspect might be happening..
 * Mathematician's Answer:

""I'm quite certain," said Hermione. "Why, my name practically spells out 'heroine' except for the extra 'm', I never noticed that until today.""
 * Meaningful Name: Hermione tries to use it to justify her desire to be a heroine.

"Harry knew pi out to 3.141592 because accuracy to one part in a million was enough for most practical purposes. Hermione knew one hundred digits of pi because that was how many digits had been printed in the back of her math textbook."
 * Melee a Trois: The intra-school army competition. An all-out war for a prize of a Quirrell wish. Although each year has its own set of three armies, you would be forgiven to forget this small tidbit, since the First year had evolved far beyond what anybody (except Quirrell) could dream of. The three sides are: Dragon army, led by Draco Malfoy; Sunshine Regiment, led by Hermione Granger; and the Chaos Legion, led by Harry James Potter-Evans-Verres.
 * Mentor Occupational Hazard: Lampshaded: Dumbledore warns Harry that if he accepts Quirrell as a mentor, he'll surely end up losing him in some tragic fashion. (He becomes slightly more resigned to the idea when he remembers that Harry's going to lose him anyway.)
 * A Million Is a Statistic: Harry explains this to Hermione in chapter 48.
 * The Mind Is a Plaything of the Body: After being in Animagus form, it takes a while to become interested in human food again.
 * Missed the Call: Tracey Davis fears she was "supposed" to have kissed Harry.
 * Missing Mom: Narcissa Malfoy, for rather unpleasant reasons. Also, Hermione's maternal grandmother was a witch who may have been killed by Grindelwald.
 * Mister Seahorse: Draco, according to the Quibbler.
 * Mister X and Mister Y: Mr. Crabbe and Mr. Goyle.
 * Moral Myopia: Quirrell claims everyone suffers from this.
 * Most Writers Are Adults: One of the most persistent criticisms of the story is that a lot of the characters really don't feel like the prepubescent children they are. Given the story's premise of a rationalist Harry, and the fact that Yudkowsky deliberately boosted the intelligence, knowledge-base, and reasoning skills of most of the rest of the cast in order to avoid the Mary Sue effect, this was probably inevitable.
 * Mundane Utility: Harry's always on the lookout for possibilities. Even he is aghast at the wizarding world's trivial uses of time machines... at first.
 * Mouthful of Pi: More true of Hermione than Harry.

"Moody had once seen an addicted Dark Wizard go to ridiculous lengths to get a victim to lay hands on a certain exact portkey, instead of just having someone toss the target a trapped Knut on their next visit to town; and after going to all that work, the addict had gone to the further effort to lay a second Portus, on the same portkey, which had, on a second touch, transported the victim back to safety. To this day, even taking the drug into account, Moody could not imagine what could have possibly been going through the man's mind at the time he had cast the second Portus."
 * Muggles Do It Better: A large part of the premise; Muggle technology isn't necessarily better than magic, but the wizarding world clearly could use a hearty dose of the scientific method.
 * Mysterious Past: Dumbledore hires Quirrell without looking too deep into his history. Madam Bones thinks she has identified Quirrell as a hero figure from the previous war (not Tom Riddle; the author has changed his birth year to make this clear).
 * Mythology Gag
 * In Chapter 26, Quirrell is absolutely livid about a 6th year Gryffindor who hit one of his 6th year Slytherins with a Dark curse, of which the former knew only how to cast it and that it was to be "directed at an enemy". Sound familiar?
 * While Moody was working with a particular potion called Bahl's Stupefaction in Chapter 63, he recalls an anecdote that should sound very familiar to those who read Harry Potter and The Goblet of Fire:

""Casst Killing Cursse?" Harry hissed in incredulity. "At me? Again? Ssecond time? Nobody will believe Dark Lord could posssibly be that sstupid -""
 * "Molly Weasley against Bellatrix Black? Who does she even think she's kidding?"
 * Before the start of Harry Potter and The Philosopher's Stone, Voldemort used the Killing Curse on Harry, which rebounded and destroyed Voldemort's body. In Harry Potter and The Goblet of Fire, he tried it again, and it failed again. In Harry Potter and The Deathly Hallows, he tries a third and fourth time, with the fourth time rebounding and permanently killing him. In Chapter 65:

""You think Lord Slytherin would've put the entrance to the Chamber of Secrets in a bathroom?""
 * Chapter 71 pokes fun at Harry Potter and The Chamber of Secrets:

"She nodded, frightened and with a strange hope dawning in her heart (well, not exactly her heart)."
 * "So where's, eh? Under an Imperius in the bottom of a trunk somewhere, while you take a hair now and then for your illegal Polyjuice?"
 * Narrative Profanity Filter: Rianne Felthorne gets a small one in chapter 71:

"Harry: You bite one math teacher and they never let you forget it, do they?"
 * Never Live It Down: In-universe.

""You can't do that!" "I don't see why." "That's because you don't have the tiniest smidgin of romance in you.""
 * News Travels Fast: In chapter 46, for example, the Hogwarts grapevine is shown to be remarkably efficient. It helps that some people have time turners (see Mundane Utility).
 * No Except Yes: "World domination is such an ugly phrase. I prefer to call it world optimization."
 * No One Gets Left Behind: Subverted in a thoroughly justified fashion in chapter 41, which incident is later discussed with some fascination:

"Harry: Just what kind of statistical summary do your "feelings" come from, anyway! Do they take into account that I come from an Enlightenment culture, or were these other potential Dark Lords the children of spoiled Dark Age nobility, who didn't know doodly-squat about the historical lessons of how Lenin and Hitler actually turned out, or about the evolutionary psychology of self-delusion, or the value of self-awareness and rationality, or-- Hat: No, of course they were not in this new reference class which you have just now constructed in such a way as to contain only yourself."
 * No Ontological Inertia: Harry's first Transfiguration class asserts that transfigurations are not permanent and need periodic maintenance to keep them from reversing themselves. McGonagall gives the example of someone drinking a block of wood transfigured into a glass of water and asks the class to consider the consequences given the above.
 * Most other forms of magic work on this principle as well. The best way shown to break shield charms is to keeping hitting the shield till the user collapses from exhastion, and the shield breaks.
 * No True Scotsman: In-universe. Harry tries to convince the Sorting Hat that he's not like the other potential Dark Lords the hat has met:

"Quirrell: Such a thing might be possible with forty thousand Galleons..."
 * Noodle Incident: Several.
 * The "Incident at the Potions Shop".
 * The "Incident with the Science Fair Project".
 * Others include Harry's pet rock.
 * The prank involving Kevin Entwhistle's cat.
 * Somehow, the Weasley twins were able to falsify a betrothal contract between Harry and Ginny and get it published in the Daily Prophet. They did this by somehow faking a lot of evidence that most would believe near-impossible to fake (and then changing it back to normal after the fact). The only thing we know about how they did it was that it was on a budget of forty Galleons. Even the Weasley twins don't know how they did it because they also got themselves obliviated after the deed was done.

""My goodness," said Penelope Clearwater. "I think that's the most overtly evil Defense Professor we've ever had.""
 * It's later revealed that they.
 * The Not-Secret: A number of students at Hogwarts have time turners, and pretty much everyone knows who they are, since its hard to hide the whole "going to multiple classes at once" thing. Then there's one girl who tends to spread rumors before the event in question actually happens.
 * Not So Different: Harry and Snape, surprisingly. Although Snape doesn't have Harry's scientific background, his muggle uprising gives him a perspective on the wizarding world similar to Harry's own. Most obvious when they are trying to prevent 's trial, and Harry keeps getting dumbstruck at the ridiculously lax and corrupt legal procedures. Snape cynically notes that they're not in Muggle Britain anymore.
 * Dumbledore knows that he was Not So Different from Grindelwald and believes that Harry is Not So Different from Voldemort, though he's not sure how since he was never able to understand Voldemort anyway.
 * Quirrel believes that the path being a hero and of being a dark wizard are essentially similar and followed by similar people.
 * Note to Self:
 * Harry bites his lip hard whenever he thinks someone might be about to wipe his memory, so that a minute later when his lip hurts inexplicably, he'll know that he's been made to forget something, even if he doesn't know what.
 * See also "Recognition Code 927, I am a potato" and various uses of the Time Turner.
 * Obfuscating Insanity
 * Dumbledore is widely believed to be using this. It's effective nevertheless, as it not only gives him an excuse to do whatever he wants, it's also impossible to tell the difference between when he's just keeping up the act and when he's executing some brilliant, secret plan right under your nose.
 * Notably, Quirrell at least believes that Dumbledore used to be using this, but proved so good at affecting false insanity that no one but Quirrell (and possibly McGonagall) noticed when it became senility pretending to be cunning pretending to be insanity.
 * Recently, Harry has begun to suspect that Dumbledore really is sane (albeit extremely depressed and basically just waiting to die), pretending to be senile pretending to be cunning pretending to be insane.
 * Also, Harry can't decide whether Luna is using this or not. Though he still hasn't actually met her, he just can't imagine anyone actually believes the kind of things she writes.
 * Obviously Evil: Penelope Clearwater seems to think Professor Quirrell is this:

""Brilliant!" Harry whispered. "If everyone knows, no one will suspect it's a secret!""
 * Offscreen Moment of Awesome: The Weasley Twins fake for the benefit of Rita Skeeter a prophesy, a betrothal contract, a Gringotts seal, and a session of the Wizengamot for a grand total of 40 galleons. How they do it isn't explained until 50+ chapters later.
 * Oh Crap: Harry often ends up inducing this in himself and others.
 * Omniscient Morality License: Dumbledore apologizes in advance for this.
 * One Steve Limit: In chapter 69, Michael Hopkins says, "there aren't any other Mikes in all of Hufflepuff this year, would you believe it?" The irony being that he's a subversion for this fanfic, as it already contains Professor Michael Verres-Evans and Michael Corner.
 * Only Sane Man: Basically the entire premise. (It's worth pointing out that the author views himself in that way.) As the story progresses, though, it's increasingly difficult to tell who's the sane one...
 * Only Smart People May Pass: Harry guesses that the challenge of finding Platform Nine and Three-Quarters might be meant as an I.Q. test (and when you think about it, it's kind of ridiculous that in canon there doesn't seem to be any good reason why Muggleborn students aren't actually told how to find it).
 * OOC Is Serious Business: When Dumbledore asks Harry what Quirrell could be plotting that requires him to bring a Dementor into the castle, Harry argues that this is completely in-character for him, and naturally, in-character is business as usual. But he realizes that something is wrong anyway, because even coming out of his own mouth it's a Suspiciously Specific Denial.
 * Open Secret: Just about everyone in Ravenclaw House claims to have "heard" that Dumbledore is a secret mastermind whose apparent insanity is just a cover.


 * Opposing Combat Philosophies: Draco, at least in the beginning, uses the command philosophy of command push (all orders come from the top, and subordinates are trained to carry out orders efficiently without questioning them, but this structure tends to be inflexible if the commander is out of touch with the situation). In contrast, Harry uses some elements of recon pull (subordinates are allowed to use initiative to do what they think is right for their situation, and the commander acts as coordinator who concentrates on the big picture).
 * Orwellian Retcon: Several of the chapters were revised after they were posted. (The changes are generally minor, though.)
 * Overshadowed by Awesome: Hermione has this problem with regards to Harry.

P-T
"... they dragged poor Bill Weasley off to St. Mungo's and it turned out to be a pretty standard schizophrenic break... Guy was convinced he was ninety-seven years old and had died and gone back in time."
 * Papa Wolf: Lucius Malfoy
 * Parody Episode: Omake files.
 * Parrot Pet Position: Dumbledore frequently carries Fawkes The Phoenix on his shoulder. Once, he has both Fawkes and his Phoenix Patronus on his shoulders. Then, . It is later discussed whether having a phoenix on your shoulder is a sign you're a "good" person or not.
 * The Password Is Always Swordfish: In chapter 51, Harry uses the password "Sword fish melon friend".
 * Peggy Sue: Mocked in chapter 29:

"Dumbledore: And here I was expecting you might try to redeem the heir of Malfoy by, say, showing him true friendship and kindness. Harry: Ha! Yeah, like that would have worked."
 * The Perfect Crime:  in chapter 53.
 * Pie in the Face: Wielded by an invisible hand, no less.
 * Playing Possum: Sunshine's tactic for the first battle.
 * Portmanteau: Draco's Dragon Army + Hermione's Sunshine Regiment = "Dramione's Sungon Argiment."
 * The Power of Friendship
 * Roundly mocked:

"Dumbledore: You are not to attempt the forbidden door on the third-floor corridor. There's no possible way you could get through all the traps, and I wouldn't want to hear that you'd been hurt trying. Why, I doubt that you could so much as open the first door, since it's locked and you don't know the spell Alohomora."
 * Harry's plan to redeem Draco involves overcoming his prejudices using logic and manipulating Draco into situations where he will see the ridiculousness of his preconceptions, but the friendship thing actually seems to be pretty effective (and the part that seems to impress—and frighten—Lucius the most).
 * Simultaneously, Fred and George are trying to redeem Harry the same way, although they're not sure what side he's actually on.
 * Proud to Be a Geek: Harry sprinkles science fiction and fantasy references liberally. None of his muggleborn peers seem embarrassed to admit they understand them as well, in particular lightsabers and "Red Five, standing by."
 * Rage Against the Mentor: Harry to both Dumbledore and Quirrell.
 * Rape Is a Special Kind of Evil: Possibly averted in the wizarding world; Draco is puzzled when Harry tells him that "in Muggle Britain there's a hell of a political difference between getting away with murder and getting away with raping a little girl." May just be skewed perception of Draco, as it's easier for him to get away with rape than murder (Obliviate the rape victim, not much you can do about the murder victim), so to his young mind it seems like murder is a bigger deal (though still something the "cool kids" do). Also, the fact that magic can remove the victim's memory of the rape, but can't bring a murder victim back to life. It's actually entirely possible that a society with such easy removal of terrible memories, and magic psychological healing would actually see rape as a much lesser crime, as it may leave the victim much less harmed in a much shorter time than it does in real life where magic cannot heal the damage.
 * Murder is considered a worse crime than rape in the muggle world, it's just that there are a hundred and one good reasons to murder someone and very few good reasons to rape someone, so rape tends to be much more of a Moral Event Horizon. Also, for a child who barely knows anything about sex or trauma, rape does seem to be a much less severe crime than murder on first hearing about it (think of Scout's reaction in To Kill a Mockingbird).
 * Reality Is Unrealistic: Harry's inner Ravenclaw wonders "if a real healer would seem more fake than an actor told to play one?"
 * Reality Subtext: The case of Amanda Knox, who is allegedly a reader of the fanfic. May also qualify as a Tear Jerker.
 * Reasonable Authority Figure: Professor McGonagall. Also becoming something of a surrogate mother-figure to Harry.
 * "The Reason You Suck" Speech: Harry's Sorting basically consists of the Sorting Hat directing one of these at him.
 * Reckless Wand Usage: Harry points a wand at someone accidentally-on-purpose when asked to hand it over.
 * Reference Overdosed: Plenty of shout-outs in the pre-chapter disclaimers...and a few more subtle ones in the story as well. They have their own subpage.
 * Recursive Fanfiction: The story has already inspired some.
 * Reformed Rakes: After seeing him demented, people believe Harry has been hiding his urge to kill pointless people (i.e., just about everyone). Hermione brings him back, and so all Ravenclaw girls expect her to be one who saves him.
 * Required Secondary Powers: In order to survive things like falling on their head when dueling, flying, levitating, playing Quidditch, etc., wizards and witches are said to be more durable than Muggles.
 * Rescue Arc: Two so far: one for Bellatrix Black and; another for Hermione. However, Harry is too much of a Lone Wolf to gather True Companions for these quests, though he does accept help from teachers.
 * Reset Button
 * Snape takes a huge number of points from Harry; Quirrell finds an excuse to give them right back. Notable in that Harry isn't happy with this; he feels he really did screw up in Snape's class and shouldn't be allowed to just dodge the consequences.
 * Quirrell does it again in Chapter 75, this time for Hermione, and in front of Snape no less.
 * Retired Monster: Quirrell shows a startling commitment to actually teaching (as opposed to the canon version who simply wanted the Stone so he could get back in the game). Though it would follow with the pattern of the book that this is just another Plan, there also seems to be a distinct possibility that he has given up on his ambitions, and has instead resigned himself to teaching his philosophy to the youth (especially Harry Potter, who he is overtly offering to help become the next Dark Lord). The upshot is that the motivation to make others think the same way you do is far more realistic than wanting to take over the world, and this fic is intent on adding as much realism as possible.
 * Retirony:, with a Fatal Family Photo mentioned as well.
 * Retroactive Precognition: Used to spread gossip and knowledge of some upcoming S.P.H.E.W. fights.
 * Retroactive Preparation: From the moment he gets the Time-Turner, Harry can't resist exploiting this trick. Which is why . And while it's against all the rules to use it for general purposes, McGonagall does tell him that this is a better way to get out of a locked room than traveling back in time to before it was locked.
 * Reverse Psychology
 * Dumbledore tries this on Harry:

"Lucius Malfoy: What was your purpose in maneuvering your good friend, my son, into a public alliance with that girl? Harry: Oh, that's obvious, right? Draco's working with Granger will make him realize that Muggleborns are human after all. Bwa. Ha. Ha."
 * He also succeeds in using it on Hermione in "Self Actualization". While at first it seemed as if things would have gone the same way whether or not he had meddled, because of it Hermione gets a small group of fellow witches who also want to be heroes. Which wasn't actually part of Dumbledore's plan.
 * Roof Hopping: Briefly in chapter 41.
 * Romanticism Versus Enlightenment: Dumbledore's conversations with Harry often seem to invoke this conflict. Essentially, the whole premise of the story is putting an Enlightenment hero in Rowling's Romanticist Potter Verse.
 * Rousing Speech: Parodied in Chapter 30, in which Harry gives a particularly silly one.
 * Ruined FOREVER
 * Numerous persons, reacting to Ch. 19, when . Some other readers liked it though, and overall it was a very Love It or Hate It chapter. Apparently people thought the author was advocating child abuse but it turns out that Quirrell is in fact !
 * Also, the reactions of a thankfully small number of readers at the later revelation that yes, homosexuality exists in this fanfic's universe.
 * Running Gag
 * Callbacks to the turning-into-a-cat incident.
 * Dumbledore once set fire to a chicken.
 * Always more Hufflepuff bones to sharpen.
 * Sadistic Choice: Chapter 12 mentions offhand that Harry sees ordering in a restaurant as one of these. "Find out about only one of the mysteries on this list, ha ha ha!"
 * Sarcastic Confession: If it is true, then this confession of Harry's qualifies:

"If you got too close to the Boy-Who-Lived, you became part of his story. You didn't get your own."
 * Similarly, Quirrell in chapter 79, when he, may or may not be telling the truth.
 * Satellite Character: Hermione eventually sees that's she's becoming this in-universe, and struggles against it.

"Snake!Quirrell: Thirty-sseven ruless, number thirty-four: Become Animaguss. All ssensible people do, if can. Thuss, very rare."
 * Scaled Up: Quirrell is an unregistered snake Animagus.

"Was Dumbledore's forbidden corridor meant to lure people so stupid that they didn't notice the security was worse than what Draco Malfoy could put on it?"
 * Scare'Em Straight: The whole point of McGonagall's first class
 * Schmuck Bait
 * The third-floor corridor.

""They've even got a picture of the two of them together, so we know who it is that's secretly the same person.""
 * Later it's mentioned that all the Gryffindors have tried it.
 * Science Destroys Magic: A theory raised as to why none of the modern wizards are as good as the ancient ones.
 * Screw the Rules, I Have Connections: Draco is confident not only that anyone from his family could legally get away with rape, but that the victim would have to pay them reparations for having dared to accuse them.
 * Judging by how lopsided the vote is when Lucius Malfoy calls for head at a Wizengamot meeting, Draco's probably right too.
 * Screw the Rules, I'm Doing What's Right: Harry has no qualms at all about breaking the law if he thinks it would serve the greater good.
 * Second Verse Curse: Harry only knows the first and last couple of lines of Tom Lehrer's "Be Prepared"; his parents rather wisely didn't teach him the rest.
 * Secret Identity
 * Sirius Black is really Peter Pettigrew, according to the Quibbler.

"Harry: And I. Am. Not. Her. Boyfriend!"
 * In canon, the Quibbler was correct about Sirius being innocent. They were completely bonkers in their "proof", but their premise was correct. Could be the same thing here.
 * One of the prisoners in Azkaban can be heard repeating, over and over. Just try to guess what he IS, instead.
 * Secret Passages: Hogwarts seems to be full of them, though a slight subversion in that everyone knows about all of them.
 * Of particular note: the not-so-secret staircase from Ravenclaw Tower to the Slytherin Dungeons, which only witches can use. Hermione wonders why witches in particular would need a fast route between the two.
 * Selective Obliviousness: Dumbledore and McGonagall will not hear any "niggling complaints" against Quirrell... at least not until he's seen the students through their end-of-year exams.
 * Self-Fulfilling Prophecy: Part of the reason Slytherin House has gone downhill: once your house develops a reputation for being full of bigots, only bigots and people who don't mind bigotry are willing to be sorted there if they have any other options.
 * Self-Plagiarism: The story repackages some of the content of Eliezer's essays and blog posts in a more light-hearted format. (Links to said essays/blog posts can be found in the "LessWrong" author profile.) A lot of the quotable things said by Harry James Potter-Evans-Verres in the story were said by Eliezer Yudkowsky as Eliezer Yudkowsky first.
 * Sequence Breaking: The way Rational!Harry handles things prevents a lot of canonical trip-ups, but also give him some weird looks when he's being particularly Genre Savvy.
 * Sex Slave: Voldemort seems to have made Bellatrix into one.
 * Shaped Like Itself: "First years should note that the forest on the grounds is forbidden to all pupils. That is why it is called the Forbidden Forest. If it were permitted it would be called the Permitted Forest."
 * She Is Not My Girlfriend: Harry about Hermione in chapter 75.

"Harry: What could possibly be more important than plants turning out to be sentient?"
 * Hermione followed suit a few lines later.
 * Shipper on Deck
 * Daphne Greengrass ships Harry×Hermione.
 * And either Luna or Xeno seems to ship Harry×Draco.
 * Shown Their Work: Author is a professional researcher. What did you expect? Though oddly, he Did Not Do the Research for the books themselves, or at least the last one.
 * Sibling Yin-Yang: Padma Patil tries a little too hard to be different than her twin.
 * Single Line of Descent: As in the original work, Harry's ownership of the invisibility cloak. Debatable whether there can be more than one Heir of Slytherin at a time.
 * Skewed Priorities: Almost all of the wizarding world, which is canon, but also Harry at times:

"Hermione: I'm getting tired of hearing people talk about the Boy-Who-Lived like you're -- like you're some kind of god or something. Harry: Same here, I must say. It's sad how people keep underestimating me."
 * In the long term, plants being sentient should be extremely high on any priority list. In the immediate term, and in the scope of an 11 year old boy learning magic and getting involved in lots of things 11 year old boys shouldn't get involved in? Not so much.
 * If snakes are sentient, other animals might be as well. That makes every non-vegetarian a serial killer. It's pretty important.
 * Sliding Scale of Idealism Versus Cynicism: The story features characters with extremely different views on life, Professor Quirrell being probably the most cynical, Hermione and Dumbledore being idealistic. Harry falls somewhere in between and at the moment seems to be on his way to becoming a Knight in Sour Armor. As a whole, the fanfic is more cynical than the original books, but still manages to be rather idealistic.
 * Sliding Scale of Unavoidable Versus Unforgivable: Dumbledore has accepted that I Did What I Had to Do. Harry is still trying to figure out where to draw the Moral Event Horizon.
 * Slouch Of Villany: Averted. All the evil characters have carefully maintained images. Most Slytherin aim for a noble, dignified composure that would crush their enemies if necessary, with minions as part of that costume. When Quirrell goes into zombie mode, he doesn't do it to look cool, and most people write it off as something to do with the curse on the Defense position.
 * Small Name, Big Ego: During the first 34 chapters it had implied that Lucius is one of the best Masterminds of Magical Britannia, an excellent manipulator and a "beautiful killing machine" then . That had to hurt.
 * Smug Super: Harry has the attitude down pat.

""It is very curious indeed that you should be destined for this wand when its brother why, its brother gave you that scar."
 * Snowball Lie: Discussed in the chapter appropriately titled "Contagious Lies". Of particular note is that Harry thinks this is the primary reason having a phoenix is not considered a sign of being Good—it benefits those without phoenixes, so they say whatever it takes to keep people from believing a phoenix's decision is made with sound reasoning.
 * Spin-Off: Another writer on the "Less Wrong" community blog has done something similar to the Twilight series with her story Luminosity.
 * Spit Take
 * The recurring Comed-Tea, which is advertised to cause something Spit Take-worthy to happen within moments of drinking it. Harry spends a brief but consequential period of time trying to game the rules of the drink to achieve omnipotence before realizing how it actually works. He doesn't know for sure that this is how it works, as he's been too busy to test it, but it seems likely.
 * Harry also gets a coughing fit while trying to drink water when Prof. Quirrell guess he's a Parselmouth. And then again when.
 * Split Personality Merge: Harry does this with his dark side.
 * Stable Time Loop: Time-Turners are only capable of producing these, in up-to-six hour increments every twenty-four hours. When Harry tries to test his in a way that would cause a Temporal Paradox (see Tricked-Out Time below), he receives a resounding "DO NOT MESS WITH TIME" from his future self for his troubles. Dumbledore later encounters a similar situation under different circumstances (with a simpler but no less poignant "NO"), but he knows through experience not to fiddle with paradoxes.
 * The Starscream: Draco, to Harry, in a Russian Nesting Doll of plann-ing.
 * Start of Darkness: Quirell answers Dumbledore's manipulation of Hermione by doing the same to Tracey Davis, and just might have turned her into Daphne Greengrass' Slytherin complement in Chapter 70.
 * The Stations of the Canon: The early chapter contain the requisite steps of Hogwarts Letter, Diagon Alley, Hogwarts Express, and Sorting Ceremory. The parts which would be little to no different from the canon are simply skipped over. For example, the story goes straight from the Hogwarts Express to the Sorting Ceremory, skipping over the first years getting off the train and riding the boats up to the castle.
 * Stay in the Kitchen: The founding members of S.P.H.E.W. take offense that women are being dissuaded or prevented, either by Dumbledore or gender roles within the wizarding world, from becoming heroines, seeing as heroes and Dark Lords are overwhelmingly male. Dumbledore sets the record straight that he neither encourages or discourages any student, male or female, from the call.
 * Stealth Hi Bye: Harry does this to the Gryffindor bullies in chapter 27.
 * Stealth Pun: After, Professor Quirrel, asked what they should say to the Ministry, says: "Tell them I ate it." Since , he basically says that he is
 * Strawman Political: Massively averted with . While the author's notes stress that he is evil, he's allowed to make strong arguments in favor of dictatorship and against democracy.
 * Sufficiently Analyzed Magic: Harry Potter is hoping to achieve this. So far, he hasn't had much success.
 * Summoning Ritual:
 * Super-Powered Evil Side: Harry suspects he has one; this is where his Genre Savviness fails him however, because it turns out to be just evil (or, at least, dark), but not even remotely superpowered. It is, however, more skilled than him at certain kinds of problem solving, and he repeatedly invokes it to give him the courage to go through with a plan that involves doing something distasteful (like blackmail).
 * Surrounded by Idiots
 * Take a Third Option
 * at the end of the pre-Christmas battle, although it's technically a . He also gleefully refuses to take sides within his house after He has a reputation to keep, after all.
 * In general, Harry also doesn't agree with the Order of the Phoenix, the Ministry of Magic, or the Death Eater party lines either.
 * Take My Hand: In chapter 41, shortly followed by an I Will Only Slow You Down.
 * Take That
 * In Chapter 26, Harry's conversation with Quirrell in his office hours loudly points out how completely stupid many of Canon!Harry's actions are, if described without the knowledge that the perpetrator is the protagonist.
 * And in chapter 63, Moody relates the story of a Dark Wizard who went to obscene amounts of trouble in order to get a target to touch a particular hard-to-reach Portkey, rather than just passing him a trapped object, then enchants it again in a way that allows the victim to escape back to where he started just by touching the Portkey again. He attributes it to being under the influence of Bahl's Stupefaction.
 * Almost all of ch. 64's Omake, but ones for The Lion, the Witch and the Wardrobe and Twilight in particular.
 * From another Omake in Ch. 64, a jab at mainstream academia: "Everyone knew that no matter how honest, investigating, skeptical, creative, analytic, or curious you were, what really made your work Science was when you published your results in a prestigious journal. Everyone knew that..."
 * Chapter six:

That could not possibly be coincidence. There had been thousands of wands in that shop. Well, okay, actually it could be coincidence, there were six billion people in the world and thousand-to-one coincidences happened every day. But Bayes's Theorem 101: any reasonable hypothesis which said it was more likely than a thousand-to-one that he'd end up with the brother to the Dark Lord's wand, was going to have an advantage.

McGonagall had simply said how peculiar and left it at that, which had put Harry into a state of shock at the sheer, overwhelming obliviousness of wizards and witches. In no imaginable world would Harry have just went "Hm" and walked out of the shop without even trying to come up with a hypothesis for what was going on."

""He can get away with it," Isabel whispered back to her, "he's Dumbledore, not even Fate takes him seriously anymore.""
 * Take That, Audience!: Many of his fans had suggested or asked if the story would be Harry×Draco because of the Quibbler headline, so Harry apologizing to Hermione by being dangled off the roof by Draco just as Hermione had done the previous day seems like this.
 * Also, in that same chapter, Harry figures out that Black probably killed Pettigrew because . Seems like a take that at   because
 * Teacher's Pet: Harry to Quirrell, although nobody seems to actually hate him for it, though Hermione is afraid Quirrell will lead Harry astray.
 * Tell Me About My Father: Harry asks Lupin about his birth parents the very first time he meets him.
 * Tempting Fate: Happens a fair amount.
 * For example, toward the end of chapter 47 when Draco says, "I don't want any more surprises today."
 * Discussed in chapter 57, after Dumbledore declares himself to be invincible:

""Yes, I'm very angry!" said Harry. "Grrr!" Harry's Internal Critic promptly awarded him the All-Time Award for the Worst Acting in the History of Ever."
 * That Makes Me Feel Angry: Harry is able to get away with this when Dumbledore is expecting him to be angry and doesn't seem likely to question it:

"Quirrell: In your future career, Mr. Zabini, I do not suggest trying any plots that complicated. They have a tendency to fail.
 * The Five Elements In chapter 46, when Professor Quirrell asks Harry how to hide something permanently, Harry responds using the Western five elements of Earth, Fire, Water, Air, and Aether (outer space).
 * They Called Me Mad: One of the official mottos of the Chaos Legion is revealed in chapter 70 to be "We'll show them! We'll show them all! Evil Laughter".
 * Think Nothing of It: Harry references this trope when asking not to be rewarded for reporting the extra spell on the Sorting Hat.
 * This Means War!: In chapter 15, Harry says the Bugs Bunny line to Hermione after she does better than he does during class.
 * Those Two Bad Guys: Crabbe & Goyle
 * Three-Point Landing:  does a dramatic drop from a broomstick into the middle of the Taboo Tradeoffs battle. It's such a Dynamic Entry that all the other fighters momentarily pause, stunned.
 * Tickle Torture: Harry threatens Quirrell with this in chapter 19.
 * Time for Plan B:

Blaise: Um, I said that to the Headmaster, actually, and he said that was why it was important to have more than one plot going at a time."


 * Title Drop: In chapter 24.
 * Thinks Like a Romance Novel: A lot of the Hogwart girls are very guilty of this. Even Hermione, a bit, at the beginning, though she gets over it.
 * Too Spicy for Yog-Sothoth: McGonagall conjectures that Harry "triumphed over the Dark Lord by being more awful than he was, and survived the Killing Curse by being more terrible than Death."
 * A recent chapter has revealed that it is entirely possible that Yog Sothoth was sacrificed to summon Harry. Consider that carefully...
 * To the Pain: McGonagall threatens to "string [Harry] up by the gates of Hogwarts with [his] own intestines and pour fire beetles into [his] nose." (She probably doesn't really mean it....)
 * Totalitarian Utilitarian: Harry as a "Dark Lord" would assuredly fall under this.
 * Tranquil Fury: Harry's "dark side" is very controlled and cold, even if it doesn't think too much about consequences.
 * Treacherous Advisor: Quirrell is the only one Harry looks up to as a rationalist, and this plays into Quirrell's hands. Hermione seems to be the only one who realizes how bad Quirrell is.
 * Tricked-Out Time
 * Harry tries to use this in chapter 17 to factor a product of two prime numbers.
 * Azkaban is subject to its own, immutable timeline. Dumbledore and consults with Snape later. They find it impossible to work out the problem without drawing diagrams.
 * Trickster Mentor: Dumbledore, although who can tell for sure?
 * True Love's Kiss: Mildly subverted.
 * Try and Follow: In chapter 41, with the actual words "Follow if you dare."
 * Turncoat: Chapter 33 is full of these.
 * Turn Out Like His Father: Harry himself is afraid he'll turn into a bully like James.
 * Twin Switch:
 * The battle.
 * Susan Bones and

U-Z
""Honestly, I expected my body to be hitting the ground with a thud about now." There was a distinct body-hitting-the-ground-with-a-thuddish sort of sound."
 * Uberwald: It is hinted that places like this exist in the magical world. Mad Eye Moody, in pursuit of the Eye of Vance, hunted down one Dark Lord who ruled a small fiefdom. That left a power vacuum until another Dark Lord moved in a couple weeks later.
 * Undisclosed Funds: In chapter 24, Harry asks Draco for a loan described only as "almost all the spending money Father had given Draco to last out the whole year".
 * Unnecessarily Large Interior: The generals' offices seem this way to Draco and Harry, with Draco unable to think of any reason for their size other than to show off the generals' status, and Harry not even thinking of that. It doesn't occur to either of them that they might be meant to use that space to meet with their advisors, because it doesn't occur to them that they might want to have advisors. Hermione, understanding their psychology, had her officers' chairs removed for her meeting with Draco.
 * Unsound Effect:

"Harry: If it's money that's the problem, I have some ideas for making large amounts of money quickly-- Dumbledore: Thank you Quirinus, your wisdom is now quite evident and I am sorry for disputing it."
 * Unspoken Plan Guarantee: In the first wargame (ch. 30), we see Draco and Harry explaining their strategies to their armies, while we know nothing about what Hermione has planned. Guess who wins. It was a valiant try at a Double Subversion, but nobody was fooled.
 * Unsportsmanlike Gloating: Hermione does this to Harry despite feeling that it's very naughty of her.
 * Unwitting Pawn: Harry.
 * Up, Up, and Away: Neville uses it for his Chaotic Leap in the first battle. Hermione uses it as Super-Hermione during the battle inside Hogwarts.
 * Verbal Backspace: When Quirrell insists that Harry's Occlumency tutor be Obliviated after each session, Dumbledore wonders why such expensive services are necessary, but...

"It said something, Hermione Granger thought, and it was something rather sad -- as the eight of them strolled back through the maze of twisty little passages that was Hogwarts, their time before the next class having run out without finding any bullies -- that she genuinely didn't know whether Harry Potter had been led around by the ghost of Salazar Slytherin or a phoenix or what. And whatever Harry had done, she hoped it didn't work for them. And most of all she hoped that the others didn't vote for Tracey's idea of stunning Harry Potter and carting his unconscious body around with them to attract Adventures. That couldn't possibly work in real life, or, if it did, she was giving up."
 * Walking Wasteland: Quirrell displays a touch of this while Christmas shopping.
 * Wall Bang
 * Harry somehow gets an impression of the Sorting Hat doing this.
 * McGonagall does it later.
 * The War On Straw: For some, the debate on life extension. Actually averted: Yudowsky argues in the author's notes that these are the points that Dumbledore and Harry would make and are not intended to be the best possible arguments on either side (some arguments even being left out), and that Yudkowsky's (opposing) view isn't represented at all in canon so he's still being fairer than Rowling.
 * We All Live in America: An amazingly comprehensive selection of American idioms to come from the mouth of a child brought up in Oxford by academics; minor Americanisms have been corrected, however - originally Lupin spoke of "diapers"...
 * It is still evident that the author is American even from the very first chapter, "math" replacing "maths" and the term "college" used where a Brit would say "university" or "uni".
 * Although the story is set a decade before the 2005 revival, for Harry to NOT think of Doctor Who when learning of Time Turners seems a conspicuous omission.
 * Weirdness Magnet: Tracey seems to think Harry Potter is literally this, to the point where she suggests stunning him, tying him up and dragging him around with them to attract Adventure.

"Draco sat down, as he was having trouble standing. You got this feeling about once a month around Harry Potter, and it hadn't happened yet in January, so this was due."
 * McGonagall calls Harry a "weirdness magnet" in Chapter 17.
 * Wham! Line: In Chapter 51, when Quirrell tells Harry that there is an innocent person in Azkaban, Harry correctly deduces that it is "a person named Black." Quirrell is surprised and tells Harry he is correct, then asks,
 * Also somewhat parodied earlier on.


 * Chapter 78, to the surprise of pretty much everyone (including :

""So -" Hermione's voice sounded strange in the night. "You left your friends behind where they'd be safe, and tried to attack the Dark Wizard all by yourself?" "Why, no," "I stopped trying to be a hero, and went off to do something else I found more pleasant.""
 * Chapter 84, and Hermione talking about heroics:

"I have a truly marvelous story for this crossover which this margin is too narrow to contain."
 * What Could Have Been: An Omake chapter explores the possibility of applying the "rationalist" concept to other works of fiction, including The Lord of the Rings, Twilight (which Yudkowsky explicitly states is the premise of Alicorn's Luminosity), and The Lion, the Witch and the Wardrobe. A brief margin is dedicated to a Gurren Lagann/Warhammer 40000 crossover, but leaves it simply as:

"Tracey Davis: We'll show him! We'll show them all! Daphne Greengrass: Okay, now that was definitely Evil. Padma Patil: No, that's one of the Chaos mottoes, though she didn't do the laugh."
 * What Do You Mean It's Not Heinous?: Played for laughs in Chapter 29 when Hermione goes to Quirrell for advice.
 * What Measure Is a Non-Human?: "Snakes are sentient!?"
 * What the Hell, Hero?: Frequent, though the Sorting Hat's was probably the most memorable, borrowing Harry's own intelligence and using it to refute the boy's own plans and arguments.
 * Who's Laughing Now?:

"If you were Harry's enemy, his plots might be hard to see through at first, they might even be stupid, but his reasoning would make sense once you understood it, you would comprehend that he was trying to hurt you. The way Harry was acting toward Draco right now did not make sense. Because if you were Harry's friend, then he tried to be friends with you in the alien, incomprehensible way he'd been raised by Muggles to do, even if it meant destroying your entire life."
 * Who Names Their Kid "Dud(l)e(y)"?: The reason Petunia didn't marry Vernon Dursley in this version of the story: she had this reaction when he told her what he was planning to name his firstborn.
 * Wicked Stepmother: Dumbledore appears to have thought Harry ought to have wicked stepparents, and seems disappointed to hear that they aren't even a little bit wicked. Though they don't take him seriously, and that frustrates Harry to no end.
 * Wild Card: . Given the nature of the War of Three Armies, the fact that he manages to distinguish himself as this is truly impressive.
 * Will Not Tell a Lie: When Harry is asked to lie outright rather than use his usual techniques of misdirection and half-truth, he has to be told that the need is desperate before agreeing.
 * Dumbledore as well, to the point that when the Weasley twins tell him the only way to activate the Marauder's Map is by saying "I solemnly swear I am up to no good," he refuses to say it, but then makes the map work for him anyway.
 * Wise Beyond Their Years: Harry, the eleven-year-old boy currently working on a reliable means of mass-producing carbon nanotubes, Draco, the twelve-year-old Evil Chancellor, and Hermione, the girl who by the end of Chapter 30.
 * With Friends Like These...: Draco realizes (a little too late) that having Harry for a friend is at least as dangerous as having him for an enemy:

""If there is any character in Methods who is a Self Insert, it is Godric Gryffindor.""
 * A Wizard Did It: Defied continually and with extreme prejudice. Once Harry gets his mokeskin bag, he's frustrated at its inconsistency with object's names when summoning; when he asks McGonagall why it works that way, her reply of "Magic" does not satisfy him.
 * Words Can Break My Bones: If Dumbledore is to be believed, there do exist Words of Power and Madness that are dangerous to utter—it's just that no one these days knows what those words are.
 * The World Is Not Ready: Harry decides that he and other wizarding scientists—unlike Muggle scientists—should keep their discoveries secret until they're sure humanity won't misuse them.
 * Word of God: The author posts on this work's discussion page.


 * Wouldn't Hit a Girl: The bullies are cast in a negative light through continual reminder that their opponents are first-year girls.
 * Generally averted during battles, as students target girls as much as boys. One exception is when Neville kicks Hannah in the stomach and immediately feels remorse.
 * Wrong Genre Savvy
 * As of chapter 21, it's pretty clear that Dumbledore believes they are in an epic fantasy (unless that's just part of his Obfuscating Insanity), Harry is seeing it as science fiction or a computer RPG, and Hermione apparently thinks it's a romantic comedy. Somebody is mistaken about the genre they're in, but it's not quite clear who at this point.
 * Draco seems to be convinced that he is Light from Death Note, which is definitely wrong.
 * It seems the girls of Slytherin House are enjoying a trashy romance novel, starring Harry Potter, Hermione Granger and Draco Malfoy as the competing love interests.
 * And one of the Lovegood's think it is more... "exotic" romance novel. We dearly hope they are wrong...
 * Xanatos Gambit: Described in Chapter 24 with Draco thinking about Harry's plans and those of stories he was told by his father. Not just a story - a story about a clever hero who always tricks a band of gargoyles into furthering his plans. Does that sound familiar to you?
 * The basic premise of the Xanatos Gambit was described earlier, in Chapter 22, though the wording was slightly altered as a joke.

"And it was also clear that Potter was brilliant, and a whole lot more than just slightly mad, and playing a vast game that Potter himself mostly didn't understand, improvised at top speed with the subtlety of a rampaging nundu."
 * Xanatos Speed Chess: During the Stanford Prison Experiment in particular, but predicted much earlier:


 * X Meets Y: Harry Potter meets rationalism.
 * Yaoi Fangirl: Apparently, most girls in the wizarding world.
 * You All Meet in An Inn: Harry meets Hermione, Neville, and Ron on the Hogwarts Express / Platform 9 3/4. In particular, McGonagall tells Harry to be on the look out for Hermione on the train, and Harry wonders whether she is a PC or NPC. Harry also has his first real conversation with Draco on the platform. Justified because on the train will be the first time most Hogwarts students meet each other.
 * You Are Not Ready
 * Harry doles out information about science to Draco very carefully, and uses this exact explanation. Draco is surprisingly okay with this, because his father taught him to take those words seriously. In fact, he becomes quite upset when Harry assumes Draco is rather more ready than he actually was.
 * Harry wants to access his Gringotts vault in order to go Christmas shopping, diversify his assets, and buy items he thinks he might have a use for later. Dumbledore says that he isn't ready, and Harry is less than cooperative. See "I'll Pretend I Didn't Hear That".
 * You Don't Want to Know: During the jailbreak scene: "You don't want to see who's behind me. Trust me, you don't."
 * You Fool!: Specifically, Quirrell calls Harry "fool boy" twice in Chapter 58 when the plan goes pear shaped.
 * You Go, Girl!: Hermione leads an army and the S.P.H.E.W. girls fight bullies to show they can keep up with Harry Potter. However, people still view Hermione as being Harry's rival rather than a protagonist in her own right.
 * You Have Outlived Your Usefulness
 * After learning Slytherin's secrets from, Voldemort didn't want to leave it around for anyone else to learn from. At least, that's what Quirrell assumes.
 * Also, Madam Bones assumes this is what happened to whoever helped  escape.
 * You Just Told Me:
 * McGonagall uses this on Hermione and then smilingly warns her not to fall for it again: "Miss Granger, you aren't supposed to admit anything just because I say I know."
 * Discussed in Chapter 18, when Harry says that he should have tried this on Dumbledore, McGonagall, or Snape to try to get more details about Voldemort out of them. There's also a more subtle example earlier in that same chapter: Harry gives Dumbledore the excuse for keeping Snape around that Dumbledore then repeats back to him - that Hogwarts needs an evil Potions Master in order to be a proper magical school.
 * Invoked in chapter 79. "You're not Who the HELL are you?"
 * You Killed My Father
 * Draco is determined that will pay for his mother's death.
 * And Neville wants revenge on Bellatrix.
 * You Remind Me of X: Snape thinks this, although not quite in the way that Harry imagines.