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p.reference extractsStudy materialsInteresting relevant topics
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SubjectQuoteRelevant LW sequencesBooks and articlesRelevant LW concepts & articlesSubjectURLs & titles
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3Experimental method“If it’s true, we can just get a Hogwarts professor here and see the magic for ourselves, and Dad will admit that it’s true. And if not, then Mum will admit that it’s false. That’s what the experimental method is for, so that we don’t have to resolve things just by arguing.”
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11Conservation of Energy; Quantum Hamiltonian; FTL signaling“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 signalling! And cats are COMPLICATED! A human mind can’t just vi- sualise 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?”
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18Bystander effect (Latane and Darley)The Dark Lord had raged upon wizarding Britain like a wilding wolf, tearing and rending at the fabric of their everyday lives. Other countries had wrung their hands but hesitated to intervene, whether out of apathetic selfishness or simple fear, for whichever was first among them to oppose the Dark Lord, their peace would be the next target of his terror.
(The bystander effect, thought Harry, thinking of Latane and Darley's experiment which had shown that you were more likely to get help if you had an epileptic fit in front of one person than in front of three. Diffusion of responsibility, everyone hoping that someone else would go first.)
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21Seigniorage"And can anyone coin them, or are they issued by a monopoly that thereby collects seigniorage?"
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22HedgeOn the other hand, one competent hedge fundie could probably own the whole wizarding world within a week. Harry filed away this notion in case he ever ran out of money, or had a week free
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23Fermi calculation "Hm?" Harry said, his mind elsewhere. "Hold on, I'm doing a Fermi calculation.”
“A what?” said Professor McGonagall, sounding somewhat alarmed.
“It’s a mathematical thing. Named after Enrico Fermi. A way of get- ting rough numbers quickly in your head...”
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29Fundamental attribution error"You saved them from You Know Who," said Professor McGonagall. "How should they not care?"
Harry looked up at the witch lady's strict expression beneath her pointed hat, and sighed. "I suppose there's no chance that if I said fundamental attribution error you'd have any idea what that meant."
"No," said the Professor in her precise Scottish accent, "but please explain, Mr. Potter, if you would be so kind."
"Well..." Harry said, trying to figure out how to describe that particular bit of Muggle science. "Suppose you come into work and see your colleague kicking his desk. You think, 'what an angry person he must be'. Your colleague is thinking about how someone bumped him into a wall on the way to work and then shouted at him. Anyone would be angry at that, he thinks. When we look at others we see personality traits that explain their behaviour, but when we look at ourselves we see circumstances that explain our behaviour. People's stories make internal sense to them, from the inside, but we don't see people's histories trailing behind them in the air. We only see them in one situation, and we don't see what they would be like in a different situation. So the fundamental attribution error is that we explain by permanent, enduring traits what would be better explained by circumstance and context." There were some elegant experiments which confirmed this, but Harry wasn't about to go into them.
The witch's eyebrows drew up beneath her hat's brim. "I think I understand..." Professor McGonagall said slowly. "But what does that have to do with you?"
Harry kicked the brick wall of the alley hard enough to make his foot hurt. "People think that I saved them from You Know Who because I'm some kind of great warrior of the Light."
"The one with the power to vanquish the Dark Lord..." murmured the witch, a strange irony leavening her voice.
"Yes," Harry said, annoyance and frustration warring in him, "like I destroyed the Dark Lord because I have some kind of permanent, enduring destroy the Dark Lord trait. I was fifteen months old at the time! I don't know what happened, but I would suppose it had something to do with, as the saying goes, contingent environmental circumstances. And certainly nothing to do with my personality. People don't care about me, they aren't even paying attention to me, they want to shake hands with a bad explanation ."
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16Situational context"He was in a situational context where those actions made internal sense "
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20Planning fallacyMuggle researchers have found that people are always very optimistic, compared to reality. Like they say something will take two days and it takes ten days, or they say it'll take two months and it takes over thirty five years. For example, in one experiment, they asked students for times by which they were 50% sure, 75% sure, and 99% sure they'd complete their homework, and only 13%, 19%, and 45% of the students finished by those times. And they found that the reason was that when they asked one group for their best case estimates if everything went as well as possible, and another group for their average case estimates if everything went as usual, they got back answers that were statistically indistinguishable. See, if you ask someone what they expect in the normal case, they visualise what looks like the line of maximum probability at each step along the way everything going according to plan, with no surprises. But actually, since more than half the students didn't finish by the time they were 99% sure they'd be done, reality usually delivers results a little worse than the 'worst case scenario'. It's called the planning fallacy, and the best way to fix it is to ask how long things took the last time you tried them. That's called using the outside view instead of the inside view. But when you're doing something new and can't do that, you just have to be really, really, really pessimistic. Like, so pessimistic that reality actually comes out better than you expected around as often and as much as it comes out worse.
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20Outside viewOutside view (LW Wiki)
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21Effect sizeWhat happened to me personally is only anecdotal evidence," Harry explained. "It doesn't carry the same weight as a replicated, peer reviewed journal article about a controlled study with random assignment, many subjects, large effect sizes and strong statistical significance
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24Bayes's TheoremBayes's Theorem said that any reasonable hypothesis which made it more likely than a thousand to one that he'd end up with the brother to the Dark Lord's wand, was going to have an advantage.
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31Resonant doubtIt was at times like this that Harry hated his mind for actually working fast enough to realise that this was a case where "resonant doubt" applied, that is, if he'd started out thinking that he would go through the barrier he'd have been fine, only now he was worried about whether he sufficiently believed he'd go through the barrier, which meant that he actually was worried about crashing into it
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34Influence: Science and Practice by Robert Cialdini"Wow," Harry said. Reading Robert Cialdini's Influence: Science and Practice probably didn't stack up very high compared to that (though it was still one heck of a book). "Your dad is almost as awesome as my dad."
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34Fundamental question of rationality"I ask the fundamental question of rationality: Why do you believe what you believe? What do you think you know and how do you think you know it? What makes you think Lucius wouldn't sacrifice you the same way he'd sacrifice anything else for power?"
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×××
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35Reciprocation"Draco," Harry said, "just so you know, I recognise exactly what you're doing right now. My own books called it reciprocation and they talk about how giving someone a straight gift of two Sickles was found to be twice as effective as offering them twenty Sickles in getting them to do what you want..."The Norm of Reciprocity (psychwiki.com)
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36Carbon dioxideMaybe I should just chug the whole thing as fast as possible... and hope my stomach doesn't explode from all the carbon dioxide, or that I don't burp while drinking it... The health effects of carbonated drinks Sugar: The Bitter Truth (90min lecture)
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38Age of EnlightenmentHarry stared down at the can in his hand, the coldness settling into his blood. Charming, happy, generous with his favors to his friends, Draco wasn't a psychopath. That was the sad and awful part, knowing human psychology well enough to know that Draco wasn't a monster. There had been ten thousand societies over the history of the world where this conversation could have happened. No, the world would have been a very different place indeed, if it took an evil mutant to say what Draco had said. It was very simple, very human, it was the default if nothing else intervened. To Draco, his enemies weren't people.
And in the slowed time of this slowed country, here and now as in the darkness before dawn prior to the Age of Reason, the son of a sufficiently powerful noble would simply take for granted that he was above the law, at least when it came to some peasant girl. There were places in Muggle land where it was still the same way, countries where that sort of nobility still existed and still thought like that, or even grimmer lands where it wasn't just the nobility. It was like that in every place and time that didn't descend directly from the Enlightenment. A line of descent, it seemed, which didn't quite include magical Britain, for all that there had been cross cultural contamination of things like ring pull drinks cans.
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44Eidetic memory"Professor McGonagall and I believe I see why. Do you have an eidetic memory, Hermione?"
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44The Baconian Project"I want you to help me do the research, of course. With your encyclopedic memory added to my intelligence and rationality, we'll have the Baconian project finished in no time, where by 'no time' I mean probably at least thirty five years."
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46Null hypothesis"The sad thing is," said the boy, "you probably did everything the book told you to do. You made a prediction that would distinguish between the robe being charmed and not charmed, and you tested it, and rejected the null hypothesis that the robe was not charmed. But unless you read the very, very best sort of books, they won't quite teach you how to do science properly . Well enough to really get the right answer, I mean, and not just churn out another publication like Dad always complains about.
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462 4 6 taskThis is a game based on a famous experiment called the 2 4 6 task, and this is how it works.
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47Positive bias"What you've just discovered is called 'positive bias'," said the boy. "You had a rule in your mind, and you kept on thinking of triplets that should make the rule say 'Yes'. But you didn't try to test any triplets that should make the rule say 'No'.
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48Desensitisation therapyThat's called desensitisation therapy, by the way
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48ConsequentialismThat's called consequentialism, by the way, it means that whether an act is right or wrong isn't determined by whether it looks bad, or mean, or anything like that, the only question is how it will turn out in the end what are the consequences.
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×××
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49Bayesian probability theory"So," Harry Potter said, "how much science do you know exactly? I can do calculus and I know some Bayesian probability theory and decision theory and a lot of cognitive science, and I've read The Feynman Lectures (or volume 1 anyway) and Judgment Under Uncertainty: Heuristics and Biases and Language in Thought and Action and Influence: Science and Practice and Rational Choice in an Uncertain World and Godel, Escher, Bach and A Step Farther Out and—"
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49Decision theory
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49Cognitive science
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49The Feynman Lectures
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49Judgment Under Uncertainty: Heuristics and Biases
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49Language in Thought and Action
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49Influence: Science and Practice
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49Rational Choice in an Uncertain World
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49Gödel, Escher, Bach
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49A Step Farther Out
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56Evolutionary psychologyDo 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 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
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56Self delusion
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56Evolutionary psychology of self delusion
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58Baconian experimental method I thought at first it was because of Professor Snape, but I followed the Baconian experimental method which is to find the conditions for both the presence and the absence of the phenomenon, and I've determined that my scar hurts if and only if I'm facing the back of Professor Quirrell's head, whatever's under his turban.
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81The anthropic principleTHAT IS NOT REASSURING! HAVEN'T YOU PEOPLE EVER HEARD OF THE ANTHROPIC PRINCIPLE? AND WHAT IDIOT EVER BUILT ONE OF THESE THINGS FOR THE FIRST TIME?
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81Simulacron 3You know right up until this moment I had this awful suppressed thought somewhere in the back of my mind that the only remaining answer was that my whole universe was a computer simulation like in the book Simulacron 3 but now even that is ruled out because this little toy ISN'T TURING COMPUTABLE!
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81Turing computable function
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81Acyclic digraphsSO THAT'S HOW THE COMED TEA WORKS! Of course! The spell doesn't force funny events to happen, it just makes you feel an impulse to drink right before funny things are going to happen anyway! I'm such a fool, I should have realised when I felt the impulse to drink the Comed Tea before Dumbledore's second speech, didn't drink it, and then choked on my own saliva instead drinking the Comed Tea doesn't cause the comedy, the comedy causes you to drink the Comed Tea! I saw the two events were correlated and assumed the Comed Tea had to be the cause and the comedy had to be the effect because I thought temporal order restrained causation and causal graphs had to be acyclic BUT IT ALL MAKES SENSE ONCE YOU DRAW THE CAUSAL ARROWS GOING BACKWARDS IN TIME!Acyclic Digraph (wolfram.com)
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82Mind projection fallacy by E. T. JaynesUp until this point Harry had lived by the admonition of E. T. Jaynes that if you were ignorant about a phenomenon, that was a fact about your own state of mind, not a fact about the phenomenon itself; that your uncertainty was a fact about you, not a fact about whatever you were uncertain about; that ignorance existed in the mind, not in reality; that a blank map did not correspond to a blank territory. There were mysterious questions, but a mysterious answer was a contradiction in terms. A phenomenon could be mysterious to some particular person, but there could be no phenomena mysterious of themselves. To worship a sacred mystery was just to worship your own ignorance.
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82Acyclic causal networksNow, for the first time, he was up against the prospect of a mystery that was threatening to be permanent . If Time didn't work by acyclic causal networks then Harry didn't understand what was meant by cause and effect; and if Harry didn't understand causes and effects then he didn't understand what sort of stuff reality might be made of instead; and it was entirely possible that his human mind never could understand, because his brain was made of old fashioned linear time neurons, and this had turned out to be an impoverished subset of reality.◆Causal Network — http://mathworld.wolfram.com/CausalNetwork.html
◆The sequencing of Events in the Universe — http://www.wolframscience.com/nksonline/page-497
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137Representativeness heuristic "What on Earth do I have to do to convince you? "
[...] "I suppose you could just raise your right hand."
"What?" Harry said blankly. "But I can raise my right hand whether or not I " Harry stopped, feeling rather stupid.
"Indeed," said Professor Quirrell. "You can just as easily do it either way. There is nothing you can do to convince me because I would know that was exactly what you were trying to do. And if we are to be even more precise, then while I suppose it is barely possible that perfectly good people exist even though I have never met one, it is nonetheless improbable that someone would be beaten for fifteen minutes and then stand up and feel a great surge of kindly forgiveness for his attackers. On the other hand it is less improbable that a young child would imagine this as the role to play in order to convince his teacher and classmates that he is not the next Dark Lord. The import of an act lies not in what that act resembles on the surface, Mr. Potter, but in the states of mind which make that act more or less probable."
Harry blinked. He'd just had the dichotomy between the representativeness heuristic and the Bayesian definition of evidence explained to him by a wizard.

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137Bayesian evidence
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139Preference utilitarianism"Surely you've wanted to hurt people," said Professor Quirrell. "You wanted to hurt those bullies today. Being a Dark Lord means that people you want to hurt get hurt."
Harry floundered for words and then decided to simply go with the obvious. "First of all, just because I want to hurt someone doesn't mean it's right"
"What makes something right, if not your wanting it?"
"Ah," Harry said, "preference utilitarianism."
"Pardon me?" said Professor Quirrell.
"It's the ethical theory that the good is what satisfies the preferences of the most people "
"No," Professor Quirrell said. His fingers rubbed the bridge of his nose. "I don't think that's quite what I was trying to say. Mr. Potter, in the end
people all do what they want to do. Sometimes people give names like 'right' to things they want to do, but how could we possibly act on anything but our own desires?"

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139Atlas Shrugged"Not to mention," Harry said, "being a Dark Lord would mean that a lot of innocent bystanders got hurt too!"
"Why does that matter to you?" Professor Quirrell said. "What have they done for you?"
Harry laughed. "Oh, now that was around as subtle as Atlas Shrugged. "
"Pardon me?" Professor Quirrell said again.
"It's a book that my parents wouldn't let me read because they thought it would corrupt me, so of course I read it anyway and I was offended they thought I would fall for any traps that obvious. Blah blah blah, appeal to my sense of superiority, other people are trying to keep me down, blah blah blah."
"So you're saying I need to make my traps less obvious?" said Professor Quirrell. He tapped a finger on his cheek, looking thoughtful. "I can work on that."
They both laughed.
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146Escalation of commitment"You lost the bet," Hermione explained, "so you have to pay a forfeit."
"I don't remember agreeing to this!"
"Really?" said Hermione Granger. She put a thoughtful look on her face. Then, as if the idea had only just then occurred to her, "We'll take a vote, then. Everyone in Ravenclaw who thinks Harry Potter has to pay up, raise your hand!"
"What? " shrieked Harry Potter again.
He spun around and saw that he was surrounded by a sea of raised hands.
And if Harry Potter had looked more carefully , he would have noticed that an awful lot of the onlookers seemed to be girls and that practically every female in the room had their hand raised.
"Stop!" wailed Harry Potter. "You don't know what she's going to ask! Don't you realize what she's doing? She's getting you to make an advance commitment now, and then the pressure of consistency will make you agree with whatever she says afterward!"
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146Consistency (persuasion)The psychology of persuasion – consistency (takebackyourbrain.com)
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148The Bottom LineThe third option is that I teach you of genetics and evolution and inheritance, what you would call blood "
"That one," said Draco.
The figure nodded. "I thought you might say as much. But I think it will be the most painful path for you, Draco. What if your family and friends, the blood purists, say one thing, and you find that the experimental test says another?"
"Then I'll figure out how to make the experimental test say the right answer!"
There was a pause, as the shadowy figure stood there with its mouth open for a short while.
"Um," said the shadowy figure. "It doesn't really work like that. That's what I was trying to warn you about here, Draco. You can't make the answer come out to be anything you like."
"You can always make the answer come out your way," said Draco. That had been practically the first thing his tutors had taught him. "It's just a matter of finding the right arguments."
"No," said the shadowy figure, voice rising in frustration, "no, no, no! Then you get the wrong answer and you can't go to the Moon that way! Nature isn't a person, you can't trick them into believing something else, if you try to tell the Moon it's made of cheese you can argue for days and it won't change the Moon! What you're talking about is rationalization , like starting with a sheet of paper, moving straight down to the bottom line, using ink to write 'and therefore, the Moon is made of cheese', and then moving back up to write all sorts of clever arguments above. But either the Moon is made of cheese or it isn't. The moment you wrote the bottom line, it was already true or already false. Whether or not the whole sheet of paper ends up with the right conclusion or the wrong conclusion is fixed the instant you write down the bottom line. If you're trying to pick between two expensive trunks, and you like the shiny one, it doesn't matter what clever arguments you come up with for buying it, the real rule you used to choose which trunk to argue for was 'pick the shiny one', and however effective that rule is at picking good trunks, that's the kind of trunk you'll get. Rationality can't be used to argue for a fixed side, its only possible use is deciding which side to argue . Science isn't for convincing anyone that the blood purists are right. That's politics! The power of science comes from finding out the way Nature really is that can't be changed by arguing! What science can do is tell us how blood really works, how wizards really inherit their powers from their parents, and whether Muggleborns are really weaker or stronger "
The Bottom Line (LW)
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152Star lifting
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152David Criswell
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155Blind experimentNowadays it was called "blinding" and it was one of the things modern scientists took for granted. If you were doing a psychology experiment to see whether people got angrier when they were hit over the head with red truncheons than with green truncheons, you didn't get to look at the subjects yourself and decide how "angry" they were. You would snap photos of them after they'd been hit with the truncheon, and send the photos off to a panel of raters, who would rate on a scale of 1 to 10 how angry each person looked, obviously without knowing what color of truncheon they'd been hit with. Indeed there was no good reason to tell the raters what the experiment was about, at all. You certainly wouldn't tell the experimental subjects that you thought they ought to be angrier when hit by red truncheons. You'd just offer them 20 pounds, lure them into a test room, hit them with a truncheon, color randomly assigned of course, and snap the photo. In fact the truncheon hitting and photo snapping would be done by an assistant who hadn't been told about the hypothesis, so he couldn't look expectant, hit harder, or snap the photo at just the right time.
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156The Lake Wobegon effect"Okay! So you gave me this whole long lecture about how hard it was to do basic science and how we might need to stay on the problem for thirty five years, and then you went and expected us to make the greatest discovery in the history of magic in the first hour we were working together. You didn't just hope, you really expected it. You're silly."
"Thank you. Now-"
"I've read all the books you gave me and I still don't know what to call that. Overconfidence? Planning fallacy? Super duper Lake Wobegon effect? They'll have to name it after you. Harry Bias."

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159Socratic MethodDraco had heard of something called the Socratic Method, which was teaching by asking questions (named after an ancient philosopher who had been too smart to be a real Muggle and hence had been a disguised pureblood wizard). One of his tutors had used Socratic teaching a lot. It had been annoying but effective.
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162Litany of Tarski"Draco, let me introduce you to something I call the Litany of Tarski. It changes every time you use it. On this occasion it runs like so: If magic is fading out of the world, I want to believe that magic is fading out of the world. If magic is not fading out of the world, I want not to believe that magic is fading out of the world. Let me not become attached to beliefs I may not want. If we're living in a world where magic is fading, that's what we have to believe, we have to know what's coming, so we can stop it, or in the very worst case, be prepared to do what we can in the time we have left. Not believing it won't stop it from happening. So the only question we have to ask is whether magic is actually fading, and if that's the world we live in then that's what we want to believe. Litany of Gendlin: What's true is already so, owning up to it doesn't make it worse. Got that, Draco? I'm going to make you memorize it later. It's something you repeat to yourself any time you start wondering if it's a good idea to believe something that isn't actually true. In fact I want you to say it right now. What's true is already so, owning up to it doesn't make it worse. Say it."
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162Alfred Tarski
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162Litany of Gendlin
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162Eugene Gendlin
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165Deoxyribose nucleic acid"The secret of blood," said Harry Potter, an intense look on his face, "is something called deoxyribose nucleic acid. You don't say that name in front of anyone who's not a scientist. Deoxyribose nucleic acid is the recipe that tells your body how to grow, two legs, two arms, short or tall, whether you have brown eyes or green. It's a material thing, you can see it if you have microscopes, which are like telescopes only they look at things that are very small instead of very far away. And that recipe has two copies of everything, always, in case one copy is broken. Imagine two long rows of pieces of paper. At each place in the row, there are two pieces of paper, and when you have children, your body selects one piece of paper at random from each place in the row, and the mother's body will do the same, and so the child also gets two pieces of paper at each place in the row. Two copies of everything, one from your mother, one from your father, and when you have children they get one piece of paper from you at random in each place." [...]
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166Mendelian inheritance"And that brings me to the prediction," said Harry. "What happens when two Squibs marry. Flip a coin twice. It can come up heads and heads, heads and tails, tails and heads, or tails and tails. So one quarter of the time you'll get two heads, one quarter of the time you'll get two tails, and half the time you'll get one heads and one tail. Same thing if two Squibs marry. One quarter of the children would come up magic and magic, and be wizards. One quarter would come up not magic and not magic, and be Muggles. The other half would be Squibs. It's a very old and very classic pattern. It was discovered by Gregor Mendel who is not forgotten, and it was the first hint ever uncovered for how the recipe worked. Anyone who knows anything about blood science would recognize that pattern in an instant. It wouldn't be exact, any more than if you flip a coin twice forty times you'll always get exactly ten pairs of two heads. But if it's seven or thirteen wizards out of forty children that'll be a strong indicator. That's the test I had you do. Now let's see your data."
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180That was the other reason Harry had guessed the Mendelian pattern would be there. If magical genes weren't complicated, why would there be more than one?
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Gregor Mendel
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168Belief in beliefHarry Potter shook his head. His voice came in a whisper. "Draco... I'm sorry, Draco, you don't believe it, not anymore." Harry's voice rose again. "I'll prove it to you. Imagine that someone tells you they're keeping a dragon in their house. You tell them you want to see it. They say it's an invisible dragon. You say fine, you'll listen to it move. They say it's an inaudible dragon. You say you'll throw some cooking flour into the air and see the outline of the dragon. They say the dragon is permeable to flour. And the telling thing is that they know, in advance, exactly which experimental results they'll have to explain away. They know everything will come out the way it does if there's no dragon, they know in advance just which excuses they'll have to make. So maybe they say there's a dragon. Maybe they believe they believe there's a dragon, it's called belief in belief. But they don't actually believe it. You can be mistaken about what you believe, most people never realize there's a difference between believing something and thinking it's good to believe it." Harry Potter had risen from the desk now, and taken a few steps toward Draco. "And Draco, you don't believe any more in blood purism, I'll show you that you don't. If blood purism is true, then Hermione Granger doesn't make sense, so what could explain her? Maybe she's a wizarding orphan raised by Muggles, just like I was? I could go to Granger and ask to see pictures of her parents, to see if she looks like them. Would you expect her to look different? Should we go perform that test?"
"They would have put her with relatives," Draco said, his voice trembling. "They'll still look the same."
"You see. You already know what experimental result you'll have to excuse. If you still believed in blood purism you would say, sure, let's go take a look, I bet she won't look like her parents, she's too powerful to be a real Muggleborn "
Belief in Belief (LW)
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Belief in beliefBelief in belief (rationalwiki.org)
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176Rule of three (writing)That was when Father had told Draco about the Rule of Three, which was that any plot which required more than three different things to happen would never work in real life.
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178Depth of recursionJust pretend to be pretending to be a scientist, Harry had told him.
Draco didn't have words to describe exactly what was wrong with Harry's mind (since Draco had never heard the term depth of recursion) but he could guess what sort of plots it implied.
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178Chimpanzee PoliticsEnding up with that gigantic outsized brain must have taken some sort of runaway evolutionary
process, something that would push and push without limits.
And today's scientists had a pretty good guess at what that runaway evolutionary process had been.
Harry had once read a famous book called Chimpanzee Politics. The book had described how an
adult chimpanzee named Luit had confronted the aging alpha, Yeroen, with the help of a young, recently matured chimpanzee named Nikkie. Nikkie had not intervened directly in the fights between Luit and Yeroen, but had prevented Yeroen's other supporters in the tribe from coming to his aid, distracting them whenever a confrontation developed between Luit and Yeroen. And in time Luit had won, and become the new alpha, with Nikkie as the second most powerful...
...though it hadn't taken very long after that for Nikkie to form an alliance with the defeated Yeroen, overthrow Luit, and become the new new alpha.
It really made you appreciate what millions of years of hominids trying to outwit each other an evolutionary arms race
without limit had led to in the way of increased mental capacity.
'Cause, y'know, a human would have totally seen that one coming.

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184Norman Maier's problem-solving experimentHarry then launched into an explanation of a test done by someone named Norman Maier, who was something called an organizational psychologist, and who'd asked two different sets of problem solving groups to tackle a problem. The problem, Harry said, had involved three employees doing three jobs. The junior employee wanted to just do the easiest job. The senior employee wanted to rotate between jobs, to avoid boredom. An efficiency expert had recommended giving the junior person the easiest job and the senior person the hardest job, which would be 20% more productive. One set of problem solving groups had been given the instruction "Do not propose solutions until the problem has been discussed as thoroughly as possible without suggesting any." .??? The other set of problem solving groups had been given no instructions. And those people had done the natural thing, and reacted to the presence of a problem by proposing solutions. And people had gotten attached to those solutions, and started fighting about them, and arguing about the relative importance of freedom versus efficiency and so on. . The first set of problem solving groups, the ones given instructions to discuss the problem first and then solve it, had been far more likely to hit upon the solution of letting the junior employee keep the easiest job and rotating the other two people between the other two jobs, for what the expert's data said would be a 19% improvement.
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Norman Maier
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Organisational psychology
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184Robyn Dawes(Harry also quoted someone named Robyn Dawes as saying that the harder a problem was, the more likely people were to try to solve it immediately.)
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207Eric DrexlerEarlier, Harry had very secretly he hadn't even told Hermione tried to Transfigure nanotechnology a la Eric Drexler. (He'd tried to produce a desktop nanofactory, of course, not tiny self replicating assemblers, Harry wasn't insane.) It would have been godhood in a single shot if it'd worked.
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Molecular assembler
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208Carbon nanotube"They're called buckytubes, or carbon nanotubes. It's a kind of fullerene that was discovered just this year. It's about a hundred times stronger than steel and a sixth of the weight."
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213Timeless physicsQuantum mechanics wasn’t enough,” Harry said. “I had to go all the way down to timeless physics before it took. Timeless physics (lesswrong.com)
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226Robbers Cave experimentThere was a legendary episode in social psychology called the Robbers Cave experiment. It had been set up in the bewildered aftermath of World War II, with the intent of investigating the causes and remedies of conflicts between groups. The scientists had set up a summer camp for 22 boys from 22 different schools, selecting them to all be from stable middle class families. The first phase of the experiment had been intended to investigate what it took to start a conflict between groups. The 22 boys had been divided into two groups of 11 and this had been quite sufficient.
The hostility had started from the moment the two groups had become aware of each others' existences in the state park, insults being hurled on the first meeting. They'd named themselves the Eagles and the Rattlers (they hadn't needed names for themselves when they thought they were the only ones in the park) and had proceeded to develop contrasting group stereotypes, the Rattlers thinking of themselves as rough and tough and swearing heavily, the Eagles correspondingly deciding to think of themselves as upright and proper.
The other part of the experiment had been testing how to resolve group conflicts. Bringing the boys together to watch fireworks hadn't worked at all. They'd just shouted at each other and stayed apart. What had worked was warning them that there might be vandals in the park, and the two groups needing to work together to solve a failure of the park's water system. A common task, a common enemy.
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229Defeat in detailA large force concentrating fire on a small force could deplete that force rapidly without taking much damage in return. If twenty soldiers faced ten soldiers, twenty sleep spells would be aimed at the ten soldiers with only ten sleep spells going the other way, so unless every one of those first sleep spells hit its target, the smaller force would lose more people than they could manage to take down with them. Defeated in detail was the military term for what happened when you divided your forces like that. What could Hermione possibly be thinking...
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240Procopius CaesarensisDumbledore gazed out at the tables with a distant look. "In every city, " the old wizard quoted softly,"the population has been divided for a long time past into the Blue and the Green factions... And they fight against their opponents knowing not for what end they imperil themselves... So there grows up in them against their fellow men a hostility which has no cause, and at no time does it cease or disappear, for it gives place neither to the ties of marriage nor of relationship nor of friendship, and the case is the same even though those who differ with respect to these colours be brothers or any other kin. I, for my part, am unable to call this anything except a disease of the soul... "
"I'm sorry," said Minerva, "I don't "
"Procopius," said Dumbledore. "They took their chariot racing very seriously, in the Roman Empire. Yes, Minerva, I agree that something must be done."
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243Prisoner's Dilemma"Yesss," hissed Harry, like the boy thought he was a Parselmouth. "We must cooperate to destroy Sunshine, and only then fight it out between us. But if one of us betrays the other earlier on, that one could gain an advantage in the later fight. And the Sunshine General, who knows all this, will try to trick each of us into thinking the other has betrayed them. And you and I, who know that, will be tempted to betray the other and pretend that it is Granger's trickery. And Granger knows that , as well."
Draco nodded. That much was obvious. "And... both of us only want to win, and there's no one else who'll punish either of us if we defect..."
"Precisely," said Harry Potter, his face now turning serious. "We are faced with a true Prisoner's Dilemma."
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244Douglas HofstadterSuppose, Harry had said, you were playing the game against a magically produced identical copy of yourself. [...] suppose the copy had been of someone completely selfish (Pansy Parkinson had been the example they'd used) so each Pansy only cared what happened to her and not to the other Pansy.
Given that this was all Pansy cared about... and that there was no Dark Lord... and Pansy wasn't worried about her reputation... and Pansy either had no sense of honor or didn't consider herself obligated to the other prisoner... then would the rational thing be for Pansy to cooperate, or defect?
Some people, Harry said, claimed that the rational thing to do was for Pansy to defect against her copy, but Harry, plus someone named Douglas Hofstadter, thought these people were wrong. Because, Harry had said, if Pansy defected not at random, but for what seemed to her like rational reasons then the other Pansy would think exactly the same way. Two
identical copies wouldn't decide different things. So Pansy had to choose between a world in which both Pansies cooperated, or a world in which both Pansies defected, and she was better off if both copies cooperated.
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244Newcomb's problem"But I have to remind you, Draco, that I didn't say you should just automatically cooperate. Not on a true Prisoner's Dilemma like this one. What I said was that when you choose, you shouldn't think like you're choosing for just yourself, or like you're choosing for everyone. You should think like you're choosing for all the people who are similar enough to you that they'll probably do the same thing you do for the same reasons. And also choosing the predictions made by anyone who knows you well enough to predict you accurately, so that you never have to regret being rational because of the correct predictions that other people make about you remind me to explain about Newcomb's Problem at some point. So the question you and I have to ask, Draco, is this: are we similar enough that we'll probably do the same thing whatever it is, making our decisions in mostly the same way? Or do we know each other well enough to predict each other, so that I can predict whether you'll cooperate or defect, and you can predict that I've decided to do the same thing I predict you'll do, because I know that you can predict me deciding that?"
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258Reversed stupidity is not intelligenceIt was very hard for Harry to control his breathing. "Professor Quirrell, I said a good deal less than I wished to say, but I had to say something. Your proposals are extremely alarming to anyone who has the slightest familiarity with Muggle history over the last century. The Italian fascists, some very nasty people, got their name from the fasces, a bundle of rods bound together to symbolize the idea that unity is strength "
"So the nasty Italian fascists believed that unity is stronger than division," said Professor Quirrell. Sharpness was beginning to creep into his voice. "Perhaps they also believed that the sky is blue, and advocated a policy of not dropping rocks on your head."
Reversed stupidity is not intelligence; the world's stupidest person may say the sun is shining, but that doesn't make it dark out... "Fine, you're right, that was an ad hominem argument, it's not wrong because the fascists said it. But Professor Quirrell,