Harry Potter and the Methods of Rationality

Harry Potter and the Methods of Rationality is a book by Eliezer Yudkowsky based on the series of "Harry Potter" books. The book was published in sequels in the years 2010-2015.

Harry James Potter-Evans-Verres

• When you walk past a bookshop you haven't visited before, you have to go in and look around. That's the family rule.
• World domination is such an ugly phrase. I prefer to call it world optimisation.
• The Dark Lord is alive. Of course he's alive. It was an act of utter optimism for me to have even dreamed otherwise. I must have taken leave of my senses, I can't imagine what I was thinking. Just because someone said that his body was found burned to a crisp, I can't imagine why I would have thought he was dead. Clearly I have much left to learn about the art of proper pessimism
• I am not going to be in Gryffindor

Professor McGonagall

• I would be doing a great service to wizarding Britain, Mr. Potter, if I locked you in this vault and left you here.
• "So here we part ways, for a time. This has been the strangest day of my life for... many a year. Since the day I learned that a child had defeated You-Know-Who. I wonder now, looking back, if that was the last reasonable day of the world."

hermione granger

"I..." Hermione's mind went blank for a moment. She loved tests but she'd never had a test like this before. Frantically, she tried to cast back for anything she'd read about what scientists were supposed to do. Her mind skipped gears, ground against itself, and spat back the instructions for doing a science investigation project:

Step 1: Form a hypothesis. Step 2: Do an experiment to test your hypothesis. Step 3: Measure the results. Step 4: Make a cardboard poster.

Harry explains

fundamental attribution error

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.

planning fallacy

Muggle 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'

dialogue

Slowly, Draco nodded. "You think you can master both arts, add the powers together, and..." Draco stared at Harry. "Make yourself Lord of the two worlds?"

Harry gave an evil laugh, it just seemed to come naturally at that point. "You have to realise, Draco, that the whole world you know, all of magical Britain, is just one square on a much larger gameboard. The gameboard that includes places like the Moon, and the stars in the night sky, which are lights just like the Sun only unimaginably far away, and things like galaxies that are vastly huger than the Earth and Sun, things so large that only scientists can see them and you don't even know they exist. But I really am Ravenclaw, you know, not Slytherin. I don't want to rule the universe. I just think it could be more sensibly organised."