"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
Harry Potterand the Methods of Rationality is an on-going Harry Potterrational 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.Recaps of all chapters can be found here (currently under construction).SPOILER ALERT: Through this article you will find spoilers EVEN if you have read every chapter published by the author (by august 2014), continue at your own peril.
Harry Potter and the Methods of Rationality provides examples of the following tropes:
Harry: They, ah, I have to do dishes and wash problems and they don't let me read a lot of books and—-
Discussed when Harry tells Hermione how this trope could have made him more independent.
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: Played with. Harry generally respects adults and understands the value of experience, but that doesn't change the fact that many adults will not take anything a child says seriously. This arrogance seriously offends Harry and leads him to drop all respect for any adults who dismiss what he has to say outright. Making matters worse is that most magical adults have no concept of logic, rationality, or other critical thinking skills. In the end, adults have their uses, but most of them simply aren't as smart as Harry.
Subverted in chapters 12 and 14: After coming up with two bad plans for dealing with the mysterious message with the help of students, he comes up with plan C of being Genre Savvy enough to just ignore the thing and then plan D of bringing the matter to the teachers' attention and letting them look into it. He then chastises himself for not thinking of that first and goes on to do exactly that, further assuring McGonagall that if he finds even a hint of the Chamber of Secrets he will back off immediately and inform her so a team of professionals can be sent in.
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 (whch, if you're talking about regular pentagons, is mathematically impossible).
All There in the Manual: Arguably. The fact that Voldemort turned the Pioneer plaque into a Horcrux 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: Chapters 24-26. Chapters 24 and 25 proceed in numbered acts 3, 2, 1, 5, 6, and 4; act 6 takes place in the middle of chapter 26.
When Harry claims that he managed to create a plothole in reality in chapter 17 and gets called out by Dean Thomas, Harry points out that they're in the middle of a broomstick lesson and tells him to shut up.
Harry himself possesses rather arbitrary skepticism regarding souls and the afterlife. He does ask for evidence, but when it is not immediately available he keeps taking for granted that they do not exist. Explained later by him getting his hopes up when he first met a ghost, then emotionally crashing when he found out they were only reflections and not true life after death.
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.
When Bellatrix Black incredulously says "I'm... alive...?", Harry is tempted to say "no" just to see the reaction.
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.
Author Tract: invoked Most of Harry's extended conversations with Dumbledore. Especially notable is the scene where Harry is speaking to Draco about his Patronus and explaining how to cast one. The author himself declares the work to be an author tract unabashedly.
"As with self-inserts and harem fics, the reason Author Tracts have a bad reputation is just that most people don't even try to do them correctly, develop any skill at doing them, or try to compensate for the literarily obvious problems (e.g. skewing of power balance / loss of driving story conflict, in all three cases) that would otherwise develop. Self-inserts can be done well if you amp up the villains to where they can kick hell out of the SI (e.g. Hybrid Theory), harem fics can be done well if you preserve romantic conflicts throughout (hard to think of a strong example, maybe Negima, but the romantic conflicts don't present enough of a story challenge compared to e.g. the Mage of the Beginning) and Author Tracts can be done well if you strengthen the argumentative power of the side you disagree with as much as possible."
It gets better, but the first few chapters amounts to the author pointing to every single physical inconsistency in the Harry Potter universe and screaming "THAT SHOULD NOT WORK!"
The "Roles" arc is pretty heavy-handed about doing what's necessary, not just what's reasonable. McGonnagal's focus on authority and reasonableness stops students breaking rules even when it's the right thing to do, possibly costing a student their life and she has a breakdown as a result, recanting publicly.
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. note Justification: It's very practical for what it was intended to do — which is to let members of very rich, very powerful families have honor duels without being interfered with by outsiders or risking actual injury. It does, by implication, have a version that does lethal damage — Hermione says that the version that Neville and Daphne cast during the fight is "cast for stun", and it's used for duels, which in a pseudo-medieval society like MoR!Magical-Britain are likely to be Serious Business. It's certainly a one-on-one dueling spell, though, not a melee combat spell (the useful aspects of playing Tennis Boss are entirely subsumed by the shield spells that the Auror used in Azkaban).
Hermione in a desperate act had her army fly her into the air so she could try to use Stupefy to get through Harry's armor. 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 the unkillable soul-eating monster is scared of me. Now sit down and shut up."
The girls of SPHEW: "We'll come for the darkness, and make it face us, and teach it to be afraid."
The Auxiliary Protective Special Committee: "The enemy is attacking Hogwarts students, and Hogwarts is going to fight back."
Badass Fingersnap: Most of the students in Hogwarts think that Harry can do just about anything by snapping his fingers.
Bathroom Stall of Overheard Insults: Hermione overhears girls talking about her in the shower. They're not really insulting, but it causes Hermione to realize that she's becoming nothing but a side character for the extravagant life of Harry Potter.
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. Subverted in that he was only saying that to get her to be a hero. Quote:
"My dear," said the old wizard, "after you have dealt with your thirtieth hero or so, you will realize that they react quite predictably to certain things; such as being told that they are too young, or that they are not destined to be heroes, or that being a hero is unpleasant; and if you truly wish to be sure you should tell them all three. Although," with a brief sigh, "it does not do to be too blatant, or your Deputy Headmistress might catch you."
Really driven home with Harry's talk about heroic responsibility in chapter 75.
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.
Gryffindor's Autobiography: No rescuer hath the rescuer. No Lord hath the champion, no mother and no father, only nothingness above.
Dumbledore's hidden room, unlocked by the passphrases "phoenix's price" and "phoenix's fate": A room of broken wands and pictures, each of them belonging to someone who died as a result of Dumbledore's actions, directly or not. It is essentially his room of shame, despite Harry INSISTING those sacrifices were worth it.
Beyond the Impossible: Harry does things no one in the wizarding world believes can be done, such as partial transfiguration and destroying Dementors. In canon, the best one could hope for is driving them away.
Beware the Nice Ones: Chapter 30. Rationalist!Harry (with a secret dark side) and Draco (raised by a flawless instrument of death to be his successor) are fighting Hermione, whose army is named the Sunshine Army and whose badge is a smiley face. One guess who wins.
And again in Chapter 78:
[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.
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.
Big "NO!": Early in the story, based on the Quibbler headline about how Harry gets Malfoy pregnant, the author got several e-mails asking if Luna was a seer, and if the story was going to turn into an HPDM bottom!Malfoy mpreg fic. The author regretted that fanfiction.net did not allow a larger font with which to say NO.
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 Widow: Blaise Zabini mentions that his mother might be one. To be fair, that's practically canon.
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.
Bluff the Impostor: Chapter 79, in which Professor Quirrell appears to have fallen for it.
Subverted in chapter 69 with Quirrell, probably so people won't be 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).
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!
"Most wizards," Professor Quirrell said, "do not bother much with what a Muggle would term martial arts. Is not a wand stronger than a fist? This attitude is stupid."
Brainwashed and Crazy: In Chapter 51 and Chapter 52, Quirrell tells Harry that Bellatrix Black only served Voldemort because she ended up this way after being Mind Raped (and also raped in the normal sense, as Voldemort let the Lestrange brothers have their way with her).
Brass Balls: Harry's first interaction with Snape. Complete with increasing gasps and lapses in breathing from the other students, all the way up to Neville diving under a desk when Harry Crosses the Line Twice.
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 Harry Potter. Okay, probably not the sacrifice part.
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...
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?"
In reference to the page quote (when Professor McGonagall turns into a cat in Chapter 2):
Chapter 14: "You’re having another ‘you turned into a cat’ moment, aren’t you, Mr. Potter. You probably don’t want to hear this, but it’s quite endearingly cute." Chapter 81: Harry turned his head back to look at Lord Malfoy, who looked like he’d seen a cat turn into a person and start eating other cats.
Announcement at Dinnertime:
Chapter 15: "My, I wonder how long it will take before Miss Granger does something deserving of a dinnertime announcement? I look forward to seeing it, whatever it may be." Chapter 93: When Professor McGonagall makes an announcement about Hermione at dinnertime it is to announce Hermione's demise.
People will remind Harry about sharpening Hufflepuff bones into weapons.
In chapter 89, the Sword of Gryffindor is summoned, and the blade has been inscribed with "nihil supernum" ("nothingness above"), a portion of Godric Gryffindor's (very short) autobiography.
Harry decides against it after the traumatic events of Hermione's death, concluding it wouldn't help.
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 (it turns out there's no evidence they are).
Cast from Hit Points: Although most in-universe magic draws on a caster's magic reserve, so that people who exhaust their magic faint or are physically fatigued, and students magic grows year by year, Harry's Patronus charm draws on something besides that magic. In Chapter 54 it threatens to consume his life when he loses control over it. Other Patronuses are based on running from death not combating it, so presumably do not have this issue.
Cast from Lifespan: In Chapter 90, Quirrell reveals that casting Fiendfyre will make your body lighter by one drop of blood, each time you cast it. PERMANENTLY.
Cat Girl: In something of Continuity Nod to the Chamber of Secrets, it is revealed in chapter 78 that a Beauxbatons girl was accidentally was stuck as one permanently after getting cat hair in Polyjuice potion and then not getting help immediately.
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."
Chekhov's Gun: Harry's father's rock. Discussed outright in chapter 97.
Chekhov's Gag: A subtle one. The way Harry gets Hermione to avoid going to Askaban for allegedly attempting to murder Draco is inspired by the fake setup of the Weasley twins' prank on Rita Skeeter.
Harry: It would seem that one Mr. Arthur Weasley was placed under the Imperius Curse by a Death Eater whom my father killed, thus creating a debt to House Potter [...] Do people actually do that sort of thing around here?
Chess Motifs: Frequent references to someone's "game," "pieces," "pawns," and "sacrifice" (in the context of sacrificing a piece to further one's political game, not magic rituals that require sacrifice).
Child by Rape: Likely the case with Bellatrix Black's son Lesath Lestrange, as Voldemort "gave" her to the Lestrange brothers.
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.
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.
"And you, Mum, your theory says that the professor should be able to do this, and if that doesn't happen, you'll admit you're mistaken. Nothing about how magic doesn't work when people are sceptical of it, or anything like that."
Chapter 33, who will get the Christmas wish is up to Zabini. (Chapter 41 contains more of a Literal Cliffhanger.)
The author's note at the close of Chapter 80 is:
This story will next update on Tuesday, March 27. You have five days to think of something.
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.
Harry feels this way about the entire rest of the wizarding world after Malfoy tells him that 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.
When listening to the Weasley twins discussing the Chudley Cannons, Harry figures it is "some bizarre, mind-affecting substance".
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.
Complexity Addiction: Lucius is definitely against this. According to his "Rule of Three", any real-world diabolical scheme will only work if it depends on no more than three events happening, unlike in fiction (note that the lead-in to giving Draco this lecture was a play titled The Tragedy of Light). And since "only a fool would attempt a plot that was as complicated as possible, the real limit was two."
Dumbledore takes the opposite approach: set up *as many crazy plans as possible*, so that even if most of them are going to fail, at least one of them is likely to succeed anyway - or, at least, leave you in a position where you can take the credit for whatever it is that actually happened.
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.
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.
Couch Gag: The J.K. Rowling attribution at the beginning of the first 30 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 Hermione's trial. And then escalates his antics, and then escalates it a little more. And then once more at the end just to impress everyone.
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.
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.
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!. 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.
Amelia Bones, Head of Magical Law Enforcement. Who has come up with a procedure manual which includes possibilities such as a code RJ-L20 "Guard requires relief because prisoner is attempting psychological warfare against him/her and is succeeding". It also states that it is not up to the person receiving this code to determine whether or not it is valid. They are merely required to act on it immediately. Its validity will only be evaluated after the guard in question has been relieved.
Crouching Moron, Hidden Badass: Professor Quirrell seems to flip between narcoleptic weirdo and intensely-passionate professor regularly. And apparently, he's a sixth dan in at least one martial art, and he completely outclasses a trained Auror in combat. Though this is only natural, given that he's Voldemort.
One case of true curiosity had the same sort of redeeming power in rationality that one case of true love had in movies.
Curiosity Is a Crapshoot: A character is at one point "almost killed by his lack of curiosity."note Harry is so distracted by Neville's rememberall and getting admonished for improper time-turner usage that he doesn't realize broomsticks work by Aristotelian motion. In Chapter 59, he attaches a quite powerful Newtonian rocket to a broomstick with unexpected consequences.
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) Voldemort made the Pioneer plaque a Horcrux.
In 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 Voldemort, much of the cast (especially Harry, Quirrell, anyone Slytherin) use it to refer instead to methodologies involving force, trickery, threat of force, blackmail, etc.
Discussed in this quote from Hermione: "But the thing that people forget sometimes, is that even though appearances can be misleading, they're usually not."
Dark Is One Big Happy Family: Averted. 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. And now Bellatrix has escaped from Azkaban. From a Gryffindor perspective, it probably looks like Magical England has its own Big Bad Ensemble. And that's without mentioning Mr. Hat And Coat, "Santa Claus," and the fact that Lucius and Draco believe that Professor Dumbledore immolated Narcissa Malfoy.
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:
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.
Deliberate Values Dissonance: Discussed in chapter 47. Salazar Slytherin could cast a Patronus, but many modern Slytherins can't despite sharing most of his values. Harry hypothesizes that Salazar's hatred for Muggleborns was more "innocent" in that it was simply something he grew up believing; even while hating Muggleborns, he saw nothing wrong with it and as such was happy enough to cast a Patronus. On the other hand, modern Slytherins simply need Muggleborns as a scapegoat to hate because on some level they realize that they are pathetic and weak despite the proud Slytherin tradition.
Democracy Is Bad: Professor Quirrell strongly argues this to Harry in favor of a strong magical dictatorship which could fend off a Dark Lord and set things right.
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.
Having the enemy just bypass all the protagonists' work, as a result of planning and actions taken out of literary sight, would be a diabolus ex machina, and dramatically unsatisfying.
Difficult but Awesome: In the battle of the Self Actualization arc, Harry and Neville had to train very hard to be able to wear full suits of armor and cast Stupefy. Still, the spell takes a LOT out of Harry's magic reserves to use, but allows him and Neville to take out Sunshine Army by themselves.
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.
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.
Door Stopper: The story's word count so far exceeds that of the first four Harry Potter books put together, and when formatted like an actual Harry Potter book, the first 83 chapters exceed 1300 pages. 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 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 being knocked out by sleep hexes.
In Chapter 76, Rianne Felthorne thinks the description of stalking both applies and is okay when she thinks it is referring to her behavior towards Professor Snape, but not when it turns out to be about a boy in her class toward her.
Dramatic Irony: Many of the things that Quirrell 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.
The mutual reaction of Harry and his father when McGonagall uses Wingardium Leviosa on the latter. Harry himself is confused as to why his reaction was so low-key, being of the opinion that his entire world being turned on its head should merit at least a minor Freak Out!.
Harry looked at his father. "Huh," Harry said. His father looked back at him. "Huh," his father echoed. Then Professor Verres-Evans looked back at Professor McGonagall. "All right, you can put me down now."
McGonagall turning into a cat does get an extreme reaction, apparently because the associated violations of thermodynamics are much more fundamental violations of physical laws than a floating human.
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).
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.
Empty Shell: Harry becomes this for a few paragraphs due to prolonged exposure to a Dementor. He still acts and reacts, but his internal monologue is utterly mechanistic.
Enemy Mine: Draco and Hermione eventually are driven to make common cause. After Hermione is murdered, Lucius Malfoy realizes he's been played and allies with Harry against their common enemy, together bringing in enough allies to get the board of governors to act on Harry's plans for security.
Enemy Within: While Harry is a superb rationalist, he resorts to his dark side when he needs to bring out the big guns.
Entertainingly Wrong: When he sees a photo of Ginny "sighing longingly" over a photo of himself, Harry thinks this has probably been staged.
Epic Fail: Only mentioned after the fact, but Harry once had a pet rock. It died.
Even Evil Has Standards: In Chapter 20 it's shown that Professor Quirrell strongly resents Muggles for inventing nuclear weapons., though at the same time he's fond of space travel, since it would allow wizard kind to live settle beyond Earth. Also, in Chapter 42 it is shown that the wizarding world doesn't think highly of homophobia 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 mind-boggled by color-based racism.
Just as it had not occurred to Gandalf that the Enemy might learn to comprehend the good intentions of his enemies by looking...
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. He continues to try for several hours, memory-wiping her every time he reaches an impasse in the conversation, and eventually hits on disguising himself as something less dark. 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.
Quirrell's speech itself, for that matter. It's essentially about the "security vs. freedom" debate, except he doesn't recognize the "freedom" side as even existing. Either it didn't occur to him or he dismissed it as irrelevant.
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 Quirrell. 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 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 everyone immortal.
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.
In Chapter 25, Quirrell says to Rita Skeeter: "Yet I find that I cannot deny myself the pleasure of simply crushing you."
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.
Evidently common in Ravenclaw, as when Harry promises in chapter 14 that he doesn't intend to prank his fellow students, it takes Penelope Clearwater only a few moments to determine that he didn't leave any loopholes. Though she's not entirely correct on that count, as he was planning to use his newly-obtained Time Turner to prank his past self and complete the Stable Time Loop, which his promise does not preclude him from doing.
How Harry gets around the promises he had to make before meeting with the Malfoys in Gringotts.
Expo Speak Gag: While shopping in Diagon Alley for first aid supplies, Harry encounters a "Dementor Exposure Treatment" (chocolate).
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?"
In chapter 16, Harry desperately tries to come up with something to counter Quirrell's assertions that Harry has the killing intent—but the only thing he can come up with is "I'm not a psychopath, I'm just very creative", which is hardly any less ominous.
Inverted in chapter 30. "Dragon Army has never lost a single battle."
Feed the Mole: A lot of moles get fed in chapter 33 after traitors have turned the battles into a farce.
Felony Misdemeanor: Played for laughs in Chapter 29 when Hermione goes to Quirrell for advice.
Hermione: I have a lot of Quirrell points, don't I? Professor Quirrell: You do indeed. Though one less than you had before. Terrible, isn't it? Just think, if I don't like your reason for coming here, you could lose another fifty. Maybe I'd take them away one... by one... by one... Hermione: You're really evil, did anyone ever tell you that?
Figure It Out Yourself: Justified; once Harry figures out how to destroy a Dementor, 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.
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.
Harry doesn't help the case for Hermione being the Smart Guy by virtue of the fact that he has a high enough IQ to be able to understand the blueprints of a solid fuel rocket well enough to transfigure one from everyday household objects.
Flat Earth Atheist: Discussed 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.
After McGonagall awards Harry ten points for thinking of putting protective shells on Spimster wickets, thereby increasing Harry's House Point lead over Hermione, but still earned non-academically:
"PROFESSOR!" Harry shrieked. "This is our war! Stop meddling!" "Now you have until Thursday of next week, Mr. Potter. Unless, of course, you engage in some sort of mischief and lose House Points before then. Addressing a professor disrespectfully, for example." Professor McGonagall put a finger on her cheek and looked reflective. "I expect you'll hit negative numbers before the end of Friday."
Guess what happens on Friday. McGonagall continues, likely referring to the events in Self-Actualization.
"My, I wonder how long it will take before Miss Granger does something deserving of a dinnertime announcement? I look forward to seeing it, whatever it may be."
In chapter 20, Harry finds out that Quirrell loves the idea of space travel, and secretly cast some kind of spell on the Pioneer plaque. Harry then wonders aloud about the nature of the spell, one suggestion being binding someone's ghost to the plaque. Upon hearing this, Quirrell immediately tells Harry not to talk of such things, as any spell like that would be considered Dark. In case you haven't figured it out, the Pioneer plaque is one of Voldemort's Horcruxes.
In chapter 6, Harry's worst-case imagining of a classmate being bitten by a horrible monster cursing him with her dying breath for not being prepared prompts him to buy a magical medkit. In chapter 89, Harry's nightmares come to pass pretty much as imagined. But no amount of medical preparation is sufficient to save Hermione, and her last words are "not your fault".
Harry: I shall achieve my objectives through the power... of Science!
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?"
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 Transfiguration / science experiments with Hermione.
Gaining The Will To Kill: Harry Evens-Verres crosses this line during a battle with a mountain troll, and a close friend is mortally wounded,. And later cooly plans the murder of Lucius Malfoy if he refuses his offer to form an alliance, as he will otherwise remain an enemy.
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:
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.
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 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."
Getting Crap Past the Radar: Dumbledore has an instrument that counts the, ah, "sneezes" of left-handed witches within the borders of France. Pro Tip: sneeze is code for orgasm.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.
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.
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.
It's not just Quidditch that the Snitch horribly unbalances; as Quidditch points are directly added to House Points, Harry points out that Seekers earning 150 of them per game far, far outstrips any contributions any other students could make by doing well in their classes and makes the House Cup content more of a sporting trophy than anything academic.
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.
Chapter 89: After Hermione dies, Quirrell finally approves of the strength of Harry's determination… and then Trelawney makes a prophecy about the end of the world. In the next chapter Quirrell is grimly trying to get Professor McGonagall to divert Harry from his resolution and spell research.
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.
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.
Gossipy Hens: The girls of Slytherin. Especially Millicent Bulstrode.
Hell, almost all the schoolgirls.
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, Azkaban's guards send patrols to be safe. Another sign of Amelia Bones's genre-savvy-ness.
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.
However, the Weasley twins are fairly prominent and important characters, as is the head of house, far more so than the other heads of house (save Snape).
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.
Humans Are Bastards: Quirrell 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.
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.")
In particular, Harry agreeing to help rescue Bellatrix from Azkaban was really stupid, especially since Quirrell's argument that she was corrupted doesn't support his thesis that she's innocent now (and that's assuming he's telling the truth at all). It is in-character for Harry (given his extreme hatred of Dementors and cynicism about the Ministry) and he does call himself on it later when he has twenty-twenty hindsight, but still. (And conveniently, the actual moment of decision happened off-screen.)
Referenced among Madeye's list of precautions as "Bahl's Stupefaction", a highly addictive drug which hands you an Idiot Ball as a side effect.
I Gave My Word: Quirrell seems surprised when Harry tells him he would never break a promise.
I Know You Know I Know: Quirrell teaches Harry to pull off more subtle kinds of deception, leading to situations like this:
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.
"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'm a Humanitarian: Once Harry realizes that Parsletoungs are capable of speaking to snakes he starts to worry if this means snakes, and potentially any other thing he eats, my be sentient. While Harry hungrily wonders about the moral implications Hufflepuff suggests he fix the problem by eating his fellow students. After all there is no debate rather *they* are sentient.
After Draco has dropped Hermione 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".
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.
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:
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.
Chapter 67, about the rules how Hogwarts changes its geometry:
Even after eight centuries, Hogwarts was still a little shy about changing in front of people.
Hermione's cheeks were going even redder. "You're really evil, did anyone ever tell you that?" "Miss Granger," Professor Quirrell said gravely, "it can be dangerous to give people compliments like that when they have not been truly earned. The recipient might feel bashful and undeserving and want to do something worthy of your praise...."
Harry: You are about to invite me to join a secret organization full of interesting people like yourself, one of whose goals is to reform or overthrow the government of magical Britain, and yes, I'm in.
When Harry tells Hermione about his inner personalities, represented as inner voices discussing with each other inside his mind, she briefly considers trying this approach before her Common Sense warns her it might be a dangerous thing to try.
Harry's insistent reasoning on why to buy a medical kit.
I Shall Taunt You: Draco thinks Harry is trying to break up his alliance with Hermione by teasing him about it mercilessly.
Mere eyes could not have seen the invisible others: the eleven-year-old Boy-Who-Lived, and the living skeleton that was Bellatrix Black, and the Polyjuiced Defense Professor of Hogwarts, all traveling together through Azkaban. If that was the beginning of a joke, Harry didn't know the punchline.
It's All About Me: This is Hermione's motivation for becoming General Sunshine, mainly because she resents that Harry gets to be the centre of attention all the time.
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 setting up the Game, and it's implied in several other conversations.
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.
The Sorting 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:
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.
Deconstructed when Harry makes a series of less than optimal decisions in quick succession while rescuing Bellatrix Black (whom he saw as a Damsel in Distress) from Azkaban. 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.
Subverted in Chapter 85 when Harry decides to wait to get stronger before going to Azkaban because there are many people he wants to save and going now could result in his death, and in doing so misses out on ever having his own phoenix.
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.
Love Potion: Discussed by Professor Quirrell in regards to witches using them to enchant and rape Muggle men (some wizards also do the same thing to Muggle women). It also alludes to how Voldemort was conceived, something few know about. Quirrell has been possessed by him, however...
Lowest Common Denominator: In-universe. Harry suspects the Sorting Hat is being forced to fill up Slytherin with these people because its Death Eater reputation leads to anyone with a brain pleading with the hat not to be put into Slytherin.
The Magic Goes Away: This is what Harry and Draco suspect might be happening. It turns out to have been a mostly decoy theory Harry didn't have much faith in, but included to keep Draco interested in theories other than the Pureblood dilution one.
Magitek: It's coming, in a big way. Also, Voldemort turned the Pioneer plaque into a Horcrux, so one could argue that it's already there.
The broomstick mated to the solid-fuel rocket booster that Harry uses to break Bellatrix out of Azkaban definitely counts.
"Can I ask you never to repeat what I’m about to say?" said Harry. "Absolutely," said Professor Quirrell. "Consider me asked."
Bellatrix: My Lord, where are we? Harry:[posing as Voldemort] We are on a broomstick.
Meaningful Name: Hermione tries to use it to justify her desire to be a heroine.
"I'm quite certain," said Hermione. "Why, my name practically spells out 'heroine' except for the extra 'm', I never noticed that until today."
Mêlée à 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.)
Metaphorgotten: On one occasion, Hermione feels so embarassed that she thinks steam should be coming out of her ears. Which in turn should be melting them off along with her flesh.
Mexican Standoff: In chapter 17 during broomstick flight class, Goyle stealing Neville's dropped Remembrall and hopping on a broomstick leads to the Hufflepuffs pointing wands at Goyle, Slytherins pointing wands at Hufflepuffs, and Gryffindors pointing wands at Slytherins. The Ravenclaws take out their wands too; it's not stated who they're pointing at, but it's presumably Slytherin.
Morality Chain: Hermione Granger is this for Harry. Leads to High Octane Nightmare Fuel when she dies, as not only was he holding back almost entirely just because she thought he should, but he also seems willing do whatever it takes in order to get her back.
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.
Also inevitable given the story revolves around 3 of the most intelligent students in the year. Other students tend to act more normally.
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.
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.
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.
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).
Chapter 9: "Harry didn't see why Hermione had been so tense about it. In what weird alternative universe would that girl not be Sorted into Ravenclaw?"
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 "for enemies". Sound familiar?
Right after the incident between the 6th year Gryffindor and the 6th year Slytherin, Harry suggests to Quirrell that a safety lecture should be conducted for all Muggle-raised students, to tell them not to do certain things that wizard-raised children would not think of doing, including brewing high-level potions without supervision in a bathroom.
The Headline engineered by the Weasley twins stated that Harry was betrothed to Ginny.
"Molly Weasley against Bellatrix Black? Who does she even think she's kidding?"
Chapter 33 : "Yessss," hissed Harry, like the boy thought he was a parselmouth.
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.
On a darker note in Chapter 70 Quirrell mentions how some witches give love potions to handsome Muggle men and then have sex with them, which is how Voldemort was conceived who's possessing Quirrell at the time.
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.
Quirrell: Such a thing might be possible with forty thousand Galleons...
It's later strongly implied that someone Memory-Charmed the reporter to make her believe she had seen the evidence, and then left the twins with no memory so that they couldn't testify in court.
"You can't do that!" "I don't see why." "That's because you don't have the tiniest smidgin of romance in you."
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 exhaustion, and the shield breaks.
Harry speculates whether this works on the Dark Mark.
No Plans, No Prototype, No Backup: Enforced by the Interdict of Merlin, which prevents the passage of powerful spells through text. They can only be spread directly by one wizard to another, and any notes or written instructions will be magically rendered impossible to read by anyone else. Harry is pretty sure this is why modern wizards are weaker than their predecessors-instead of building on previous knowledge it is slowly being lost. Quirrell hypothesizes that averting this is the true reason for the Chamber of Secrets and the Basilisk—a centuries-old monster who could only speak with a Slytherin Parselmouth would be the best way to pass Salazar's magic on to an heir.
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.
Harry: "Snape and Dumbledore!?". Then Harry heard the words that had just come out of his mouth, and hastily added, "Not that there's anything wrong with that -"
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:
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.
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 Hermione'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 (correctly) that Harry is Not So Different from Voldemort, though he's not sure how since he was never able to understand Voldemort anyway.
Quirrell believes that the path being a hero and of being a dark wizard are essentially similar and followed by similar people. He'd know.
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:
"My goodness," said Penelope Clearwater. "I think that's the most overtly evil Defense Professor we've ever had."
Offscreen Moment of Awesome: The Weasley Twins fake for the benefit of Rita Skeeter a prophecy, 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.
Old Master: Quirell recounts how he learned from one in chapter 19. The character is also implied to fulfill the Magical Asian trope, which is ironic as he's noted to have been a Muggle in the literal sense.
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 himselfin 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).
Well, we don't actually know that Muggleborn students aren't told how to find it in canon. All we know is that Hagrid didn't tell Harry and it's easy to assume that he was supposed to, but forgot.
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.)
In chapter 39, Harry is surprised and disappointed to discover wizards (or at least Dumbledore) haven't done this. However, chapter 61 does indicate that the concept of God is unique to "Muggle religion", so apparently wizards have outgrown that much.
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, after one time when Fawkes gets especially upset at Dumbledore, the phoenix spends an entire evening riding on Harry Potter's shoulder. 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". Though this is also possibly an inversion, as absent the shout-outs, this is an example of a very strong password generation algorithm.
Peaceful in Death: During the underwater battle, Harry notes that Hermione looks rather peaceful after he shot her.
... 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.
Photographic Memory: While Hermione doesn't have true photographic memory, she can remember exactly anything she reads five times. This is arguably better, since she actually learns it instead of having to mentally read it to get what she wants.
The Power of Hate: As in canon, the power behind the Ava Kadava curse. You have to really want your target dead. The thing is, using it multiple times in a single fight against the same opponent is excessively difficult: You basically have to want to slit their throat, then strangle the corpse, etc etc. "Very few can hate enough to kill someone five times. They would get bored." This is one of the reasons Voldemort was so terrifying, in that he basically used the Killing Curse as much as he wanted. Quirrel mentions that a witch calledthe Dark Evangel once used the Killing Curse twelve times in a single fight, and asks Harry if he can figure out the secret to the true form of the curse, like he figured out the true form of the Patronus Charm. It's not hate, it's apathy. Hate implies a kind of respect; you care about someone enough to want them dead. To cast the true Killing Curse, you have to completely and utterly not care about the life of your opponent. You're not killing them. You're just not bothering to allow them to live any more.
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.
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.
Prophecy Twist: This trope apparently has the strength of a law of physics in the Wizarding world, but we don't know what they are yet. Several characters have plans laid against what they expect it will be for the one from canon (for instance Dumbeldore is arranging for Harry to be ready and surrounded by allies if it turns out the Dark Lord mentioned is Dumbeldore turned evil).
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). 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).
Actually, while rape is often not considered as serious a crime, raping a child is. Child molesters are generally considered the most evil of criminals. Even people who have committed murder aren't targeted the same way or put on offender lists.
It was also at this point that Hermione realised the other thing - well, one of the things - which was odd about [Harry]. Apparently people who were in books actually sounded like a book when they talked. This was quite the surprising discovery.
Reality Is Unrealistic: Harry's inner Ravenclaw wonders "if a real healer would seem more fake than an actor told to play one?"
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 the Ravenclaw girls expect her to be the 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, when the plan goes wrong, Professor Quirrell; 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.
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.
Of course, his various side activities include creating a Horcrux that has long left the Solar System, breaking Bellatrix Black out of Azkaban and possibly framing Hermione for attempted murder.
Retroactive Preparation: From the moment he gets the Time-Turner, Harry can't resist exploiting this trick. Which is why Professor McGonagall puts a lock on it shortly afterwards. 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.
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.
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.
Right for the Wrong Reasons: Quirrell guesses what memory Harry relived before the Dementor, but that's not why he can now see Thestrals.
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.
Rules Lawyer: This trope is why the first few Three Armies battles don't have an explicit win condition—it'd be way too easy for Harry to game the rules somehow. Later on, the school administration requests that Quirrell add a win condition, and of course, Harry games the rules.
If it is true, then this confession of Harry's qualifies:
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.
Similarly, Quirrell in chapter 79, when he reacts to being accused of keeping "the real Quirrell" captive for polyjuice ingredients, may or may not be telling the truth.
Science Destroys Magic: A theory raised as to why none of the modern wizards are as good as the ancient ones. Turns out to not be true.
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 Hermione's head at a Wizengamot meeting, Draco's probably right too.
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, "I'm not serious, I'm not serious, I'm not serious" 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.
Consider that even Lucius Malfoy thinks that Ravenclaw is an acceptable House for Draco to find a wife in. Then consider that at least in canon, girls can go into the boys' dorms but not vice versa.
See Water: Averted: "even with the potion you couldn't see very far in the darkness of the lake."
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-Made Orphan: This aspect of Voldemort's backstory is hinted to have been carried over from canon on a couple of occasions.
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 for the Lestrange brothers.
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."
Almost all of the wizarding world, which is canon, but also Harry at times:
Harry: What could possibly be more important than plants turning out to be sentient?
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.
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.
Slippery Skid: Transfigured bearing balls in the upper level battle. Ouch.
Slouch of Villainy: 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 was implied that Lucius is one of the best Masterminds of Magical Britain, an excellent manipulator and a "beautiful killing machine" then Professor Quirrell shot it to hell in one sentence in front of hundreds, stating that Lucius was incompetent enough to let the Death Eaters implode at the brink of victory and had to return with his tail between his legs. That had to hurt.
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.
Snowball Lie: Discussed in Chapter 65, 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.
The recurring Comed-Tea, which is advertised to cause somethingSpit 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. It's at least one part Divination, and gives the would-be drinker a sudden urge to drink Comed-Tea prior to ridiculous events — Harry resists the urge at one point and promptly chokes on his own spit a moment later. 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 the latter reveals that the Sorting Hat's secret message was likely in Parseltongue.
Split Personality: Harry thinks of his Dark side as something like a split personality, one that he can choose to allow to 'take over' temporarily but can't risk allowing to fully control him
Harry also has 'personalities' representing each of the other houses speak up to make suggestions to him, though these are treated as less 'crazy' and more just an active imagination assigning titles to the thoughts in his own head. Outside of Slitheren giving voice to the temptations he is trying to resist at times these 'personalities' mostly show up to add ammused comments about his current troubles. See I'm a Humanitarian above for an example
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 Stations of the Canon: The early chapters 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.
In the later chapters, the troll makes an appearance, although not at Halloween and with far worse consequences than the original. A little after that, the detention to find out who is attacking unicorns in the forbidden forest also takes place. Draco is the only one of the four involved in both versions but Harry still ends up alone with a centaur.
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 Harry destroys a Dementor, Professor Quirrel, asked what they should say to the Ministry, says: "Tell them I ate it." Since the Dementors represent death, he basically says that he is a Death Eater.
Strawman Political: Massively averted with Quirrell. While the author's notes stress that he is evil, he's allowed to make strong arguments in favor of dictatorship and against democracy.
He has been able to create partial transfigurations which he uses to kill a troll by transfiguring part of its brain into acid, and an improved form of the Patronus by applying various type of analysis to the issues.
Superpowered 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: Goes without saying. Special mention goes to Amelia Bones, who is not only afflicted with this trope, but is fully aware of it. As a result, she personally oversees her subordinates as a preventive measure.
Blaise Zabini at the end of the pre-Christmas battle, although it's technically a fourth option. He also gleefully refuses to take sides within his House after Bellatrix is freed. 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.
And, in an earlier chapter, Harry was commanded by Quirrell to either hex a fellow student (bad), or lose House Points (bad). He hexed himself.
Whereupon Quirrell deducted points anyways, for being clever instead of actually learning.
The story likes to poke fun at some absurdities of the original books (see Mythology Gag), and notably some of the most stupid moments of both Harry and Voldemort.
Almost all of ch. 64's Omake, but ones for The Lion, the Witch, and the Wardrobe and Twilight in particular. The one for MyLittlePonyFriendshipIsMagic has 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..."
In chapter 97, at journalists:
"I wouldn't think a newspaper would be able to report on a concept like 'Either X or Y must be true, but we don't know which.' I would only expect journalists to report stories consisting of series of atomic propositions, like 'X is true', 'Y is false', or 'X is true and Y is false'. Not more complex logical connectors like 'If X is true then Y is true, but we don't know whether X is true'."
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 Black and Pettigrew were at one point lovers. Seems like a take that at Yaoi Fangirls because Peter Pettigrew hardly gets shipped.
In chapter 91, the readers who shipped Harry/Hermione got one:
Harry: "I didn't like Hermione in that way. Why does everyone keep thinking it has to be about that? It's disrespectful to her, to think someone could only like her in that way."
Teacher's Pet: Harry to Quirrell, although nobody seems to actually hate him for it, though Hermione is afraid Quirrell will lead Harry astray.
Three-Point Landing: Neville Longbottom 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.
Quirrell: In your future career, Mr. Zabini, I do not suggest trying any plots that complicated. They have a tendency to fail. 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.
To Be Lawful or Good: Harry repeatedly presses McGonagall on whether she will simply act the responsible authority figure even if it's ineffective or do whatever it takes to do good even if it's risky or unconventional. She leans towards the former.
In Chapter 88 this comes back to bite her when her lawful reputation makes the other students too afraid to ignore her orders to stay put and help Harry save Hermione. Afterwards she decides her rule-biding attitude has crushed Griffindor's heroic spirit and attempts to resign as head of house.
The story in general seems to favour the latter position, emphasising doing whatever it takes and not just making a token effort and going through the standard motions. This is especially clear in the "Roles" arc.
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....)
Tranquil Fury: Harry's "dark side" is very controlled and cold, even if it doesn't think too much about consequences.
Trauma Conga Line: Things have been getting worse and worse for Harry. He retains his optimism after his harrowing visit to Azkaban but it's quickly followed by losing Draco and almost losing Hermione in the trial, losing his chance to ever have a phoenix immediately afterwards and then, worst of all, seeing Hermione die in front of his eyes.
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.
Harry tries to use this in chapter 17 to factor a product of two prime numbers. The result? "DO NOT MESS WITH TIME!"
Azkaban is subject to its own, immutable timeline. Dumbledore stumbles on a paradox and consults with Snape later. They find it impossible to work out the problem without drawing diagrams.
Later, when Hermione dies, Harry begs Dumbledore to simply travel back in time, save Hermione and fake everything, so that time never actually changes. Dumbledore explains that that doesn't tend to work out well.
Harry himself develops a reputation at Hogwarts for being able to do anything with his trademark finger snap, but that comes to bite him in the ass when Lesath Lestrange, certain that he can do anything, went on his knees and begged Harry to release his mother Bellatrix Black from Azkaban. He makes sure that The Daily Prophet releases absolutely ridiculous rumors about him, so that no one ever believes what the papers say about him anymore. He scares a Dementor in front of the Wizengamot, and they take it in stride, because he's The Boy-Who-Lived and it fits story logic. Well, most of them do.
Draco Malfoy cannot do a good deed without everyone thinking he is plotting something nefarious.
Dumbledore's Obfuscating Insanity confuses people as to whether he's sane pretending to be insane, or insane pretending to be sane pretending to be insane. He may or may not have used Obfuscating Evil on the Death Eater faction to stop them from taking people's families hostage, but now they think Dumbledore isn't above stooping to any low. But people still have trouble believing that he's set fire to a chicken.
Defense Professors have had such a terrible record over the last decades that any accusation against them is plausible... which is why the teachers don't want to hear them, because they don't want to have to fire the professors mid-year; this is for the sake of their students' education.
Überwald: 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". Probably not more than 40 galleons in any case.
The Unfettered: In chapter 86, Harry tries—and fails—to explain to the adults that if Voldemort was as smart as Harry but evil, they would have all died in the first seconds of the war. Harry tries to think of a reason why someone like that might choose not to fight at full capacity, but is interrupted before he can think of anything.
Harry himself after Hermione dies. Having previously considered the merits of trying to pursue a path where no-one dies and everyone is saved, Harry decides that from now on he will stop at nothing to create a resurrection spell, no matter what he has to do to achieve that.
Harry would learn whatever he had to learn, invent whatever he had to invent, rip the knowledge of Salazar Slytherin from the Dark Lord's mind, discover the secret of Atlantis, open any gates or break any seals necessary, find his way to the root of all magic and reprogram it. He would rip apart the foundations of reality itself to get Hermione Granger back.
Lucius Malfoy threatens to become this if anything happens to Draco.
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.
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.
Used again in the Taboo Tradeoffs battle in a virtual arms-race of this trope. Hermione's immediately revealed brute force strategy defeated by Harry's gambit which only emerges gradually over the course of the battle. Both are then defeated by Draco, whose unspoken plan to counter Harry's gambit succeeds.
Unwitting Pawn: Harry. Quirrell likes to bounce "hypothetical" ideas off of him, and Harry volunteers information to him that he doesn't understand the significance of, like how to recognize one of the Deathly Hallows.
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...
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.
Harry 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.
Britpicking is currently in progress to rewrite the story in British English.
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.
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.
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, "How did you know I meant Bellatrix?"
Also somewhat parodied earlier on.
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.
Chapter 78, to the surprise of pretty much everyone (including Harry himself):
"Hermione Granger," Auror Komodo said in a toneless voice, "you are under arrest for the attempted murder of Draco Malfoy."
Chapter 84, Quirrel and Hermione talking about heroics:
"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," said Professor Quirrell. "I stopped trying to be a hero, and went off to do something else I found more pleasant."
In Chapter 89, directly after Hermione dies and Harry vows to bring her back by any means necessary, we finally hear the full (and updated to fit the circumstances) version of Trelawney's cut-off prophecy:
Trelawney:HE IS HERE. THE ONE WHO WILL TEAR APART THE VERY STARS IN HEAVEN. HE IS HERE. HE IS THE END OF THE WORLD.
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.
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: Blaise Zabini. Given the nature of the War of Three Armies, the fact that he manages to distinguish himself as this is truly impressive.
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 beat both of them at magic paintball 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 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.
A Wizard Did It: Defied continually and with extreme prejudice, since one of Harry's goals is to completely eliminate this trope and discover the rules for all magic.
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.
Harry uses the simple "Magic" answer when speaking to his father... who uses Harry's same response of "That's not an answer!"
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.
World of Snark: Many of the student characters get this along with their intelligence upgrade, and many of the adults are similarly snarky. The whimsical magical world produces a large number of Only Sane Men and Women.
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.
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. His father takes some of the wind out of his sails in chapter 97.
Lucius: My son, truly, you have done well this day. However, this is not a play, we are not Aurors, and we do not put our trust in trials.
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.
One of the Lovegoods thinks it's a more... "exotic" romance novel.
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. Doesthatsound familiarto you?
The basic premise of the Xanatos Gambit was described earlier, in Chapter 22, though the wording was slightly altered as a joke.
Xanatos Speed Chess: During the Stanford Prison Experiment in particular, but predicted much earlier:
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.
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 And What Other Army: This is what Harry says to Hermione in chapter 67 when he and Neville confront her and the entire Sunshine Regiment while the rest of the Chaos Legion deals with the Dragon Army.
You Are Not Ready: Invoked on several occasions, most notably when Harry refuses to explain his Patronus 2.0.
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.
After learning Slytherin's secrets from the Basilisk, Voldemort didn't want to leave it around for anyone else to learn from. At least, that's what Quirrell assumes. But he's only pretending to guess. Either Quirrell is referring to his own actions or is lying to dissuade Harry from attempting to find it.
Also, Madam Bones assumes this is what happened to whoever helped Bellatrix escape.
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 Quirinus Quirrell. Who the HELL are you?"