Harry Potter and the Methods of Rationality
Based on Wikipedia: Harry Potter and the Methods of Rationality
What If Harry Potter Had Been Raised by Scientists?
Imagine you're eleven years old and you've just discovered that magic is real. Wizards exist. You can wave a wand and make objects fly. How would you react?
If you're the Harry Potter of the original novels, you're delighted. You escape your miserable cupboard under the stairs and embrace this wonderful new world with open arms.
But what if you'd spent your childhood being homeschooled by an Oxford professor? What if you'd grown up reading about the scientific method, cognitive biases, and the philosophy of knowledge? What if your instinct, upon learning that magic exists, wasn't wonder but rather a burning question: "How does this actually work?"
That's the premise of Harry Potter and the Methods of Rationality, a sprawling work of fan fiction that became something of a phenomenon in certain intellectual circles. Written by Eliezer Yudkowsky and published chapter by chapter between 2010 and 2015, it runs to over 660,000 words—roughly the length of the first five Harry Potter novels combined. And it uses the wizarding world as a vehicle for teaching readers about science, logic, and how to think more clearly.
A Different Boy Who Lived
The story hinges on a single change to the original timeline. In this version, Lily Potter used magic to make her sister Petunia beautiful. This seemingly small act cascades into enormous consequences. Attractive Petunia catches the eye of Michael Verres, an Oxford professor of biochemistry. They marry, adopt the orphaned Harry, and raise him in an environment saturated with scientific thinking.
So when Professor McGonagall arrives to inform young Harry that he's a wizard, she doesn't encounter a neglected boy desperate to escape. She meets a precocious child who immediately wants to know: If magic can violate the conservation of energy, does that mean you could power a perpetual motion machine? Why don't wizards rule the world if they can do impossible things? And most importantly—has anyone actually run controlled experiments on how spells work?
This Harry is irritated by the wizarding world. He finds it maddening that these people possess what might be the most powerful force in the universe and they use it to... play sports on broomsticks. The magical community, he discovers, is backwards, superstitious, and incurious about its own abilities. They've had thousands of years to figure out how magic works at a fundamental level, and they've accomplished almost nothing.
Teaching Rationality Through Fiction
Yudkowsky wrote the story with an explicit educational purpose. He wanted to introduce readers to concepts from cognitive science and rational thinking—the same ideas he'd been developing on his community blog called LessWrong. But instead of writing another blog post about Bayesian reasoning or the planning fallacy, he decided to embed these lessons in a story people might actually enjoy reading.
The approach works because the concepts emerge naturally from the plot rather than being delivered as lectures. When Harry encounters magical phenomena, he approaches them the way a scientist would. He forms hypotheses. He designs experiments. He considers what results would prove him wrong.
Consider the Patronus Charm. In the original Harry Potter books, it's a spell that produces a guardian made of light to ward off Dementors—terrifying creatures that feed on human happiness. Wizards in that world understand the spell as requiring the caster to focus on a happy memory.
In Methods of Rationality, Harry looks at Dementors and asks a different question. What are they, really? Not what do wizards believe about them, but what's actually happening? He eventually concludes that Dementors are essentially manifestations of death itself—the universe's way of representing the cold, empty reality that awaits all living things. With this insight, he invents a new version of the Patronus Charm that doesn't just repel Dementors but can destroy them entirely. He does this by channeling not a happy memory, but a fundamental rejection of death as acceptable.
It's a powerful narrative moment. It's also a lesson in how reframing a problem—looking at it from first principles rather than accepting conventional wisdom—can lead to solutions nobody else imagined.
The Rationalist Community's Origin Story
To understand why Methods of Rationality matters, you need to know something about the community it emerged from. Yudkowsky is a researcher focused on artificial intelligence safety—the question of how to ensure that advanced AI systems remain beneficial to humanity rather than becoming catastrophically dangerous. He's a central figure in what's sometimes called the "rationalist" community, a loose network of people interested in improving human reasoning and decision-making.
This community overlaps significantly with effective altruism, a movement dedicated to using evidence and careful analysis to do the most good possible with one's resources. Both groups tend to attract people with backgrounds in science, technology, mathematics, and philosophy. Both emphasize updating beliefs based on evidence rather than clinging to comfortable assumptions.
Methods of Rationality served as a kind of gateway drug to these ideas. Someone might stumble across the fan fiction because they loved Harry Potter, get hooked on the story, and find themselves learning about cognitive biases, the scientific method, and how to think more clearly. Many people in the rationalist community credit the story with introducing them to these concepts.
The story also became a fundraising tool. Yudkowsky has used it to solicit donations for the Center for Applied Rationality, an organization that runs workshops teaching the thinking skills the story promotes.
A Different Kind of Hero
The Harry of Methods of Rationality isn't the humble, somewhat ordinary boy of the original series. He's brilliant, arrogant, and often insufferable. He corrects his teachers. He condescends to his classmates. He's convinced he's the smartest person in any room he enters.
This isn't a bug—it's a feature. Part of what makes the story interesting is watching Harry learn that intelligence alone isn't enough. He makes catastrophic mistakes because he's overconfident. He underestimates other people. He assumes that being right about facts means he's right about strategy.
The story's version of Professor Quirrell—who in the original books concealed Voldemort's spirit beneath a turban—is reimagined as a far more complex antagonist. He becomes Harry's mentor in Defense Against the Dark Arts, teaching him not just spells but the ruthless logic of conflict. Their relationship is fascinating precisely because Quirrell often seems more rational than Harry, forcing readers to grapple with uncomfortable questions about whether evil can be more clear-headed than good.
This tension reflects a genuine debate within communities focused on rational thinking. Can someone be brilliantly logical and still morally monstrous? History suggests yes—some of history's greatest villains were quite clever. Methods of Rationality doesn't shy away from this uncomfortable truth.
Friendships Rewritten
The original Harry Potter series draws clear lines between good and evil. Harry befriends Ron Weasley, a member of a kind-hearted magical family. He's rivals with Draco Malfoy, son of a former servant of Voldemort. Hermione Granger becomes his other best friend, her bookishness complementing Ron's loyalty.
Methods of Rationality scrambles these relationships in illuminating ways. This Harry sees potential in Draco and decides to befriend him rather than dismiss him. He sets out to convince Draco, through patient explanation and evidence, that the Malfoy family's bigotry against non-magical-born wizards is simply factually wrong.
The scenes where Harry teaches Draco basic biology—explaining that the genetic differences between "pure-blood" and "muggle-born" wizards are trivial, that concepts like blood purity make no scientific sense—are some of the story's most compelling. Watching Draco's worldview slowly crumble as he confronts evidence he can't dismiss is both satisfying and instructive.
Hermione remains important but takes on a different role. She's Harry's scientific collaborator rather than his homework helper. Together they run experiments on how magic actually functions, treating spells as phenomena to be investigated rather than incantations to be memorized.
The Question of Adaptation
Methods of Rationality exists in a peculiar legal and cultural space. It's fan fiction, which means it uses characters and settings created by J.K. Rowling without her permission. Fan fiction occupies a gray area in copyright law—it's technically infringement, but most authors tolerate it as long as nobody's making money.
Some successful novels began as fan fiction before being rewritten to remove the original intellectual property. Fifty Shades of Grey, for instance, started as Twilight fan fiction. Someone suggested Yudkowsky could do the same thing—strip out the Harry Potter elements and sell the story as original fiction.
He declined, explaining that the story can only be understood against the background of the original novels. Many scenes derive their power from how they contrast with or comment on the source material. Remove that context and you lose much of what makes the story work.
Reception and Controversy
Within the fan fiction community, Methods of Rationality generated strong reactions in both directions. Some readers found it brilliant—a deeper, more intellectually satisfying exploration of the wizarding world. Others found it pretentious, with a protagonist who's more annoying than admirable.
The story attracted attention beyond typical fan fiction circles. Science fiction author David Brin praised it in The Atlantic as "terrific" and "stimulating," wishing more Potter fans would discover it. Legal scholar William Baude, writing in The Washington Post, called it "the best Harry Potter book ever written" and "one of my favorite books written this millennium."
Critics noted that the story sometimes functions as propaganda for Yudkowsky's specific worldview. James D. Miller, an economics professor, described it in his book Singularity Rising as an "excellent marketing strategy" for Yudkowsky's ideas about artificial intelligence and human rationality. He found something uncomfortable in the notion that teaching people to think rationally would make them more likely to agree with Yudkowsky's conclusions—a somewhat circular assumption.
But perhaps the most remarkable testament to the story's impact came from Russia. In 2018, a former leader of the Russian Pastafarian Church launched a crowdfunding campaign to print a three-volume Russian translation. The campaign reached its goal of just over a million rubles—roughly seventeen thousand American dollars—within thirty hours. By the time it ended, supporters had contributed over eleven million rubles, making it briefly the largest crowdfunding project in Russian history.
Over twenty thousand copies were printed, some donated to libraries and schools. The publishers even approached J.K. Rowling's representatives about commercial publication, but were refused.
Why It Matters
At its core, Methods of Rationality asks a question that extends far beyond the wizarding world: What would it look like to take our capabilities seriously?
The wizards in the story have access to what might be unlimited power. They can transform matter, travel instantly across vast distances, and even manipulate time. Yet their society is stagnant. They use these godlike abilities for trivial purposes while major problems go unsolved. Sound familiar?
The real world isn't so different. We have technologies our ancestors would have considered miraculous. We understand physics, chemistry, and biology well enough to reshape the planet. And yet we tolerate enormous amounts of preventable suffering because addressing it seems too hard or too expensive or too politically complicated.
Methods of Rationality uses its fictional setting to make this gap visceral. When Harry rages at wizards for failing to cure diseases they have the power to cure, readers might find themselves asking uncomfortable questions about their own world. When he insists that death itself is a problem to be solved rather than an inevitability to be accepted, he's channeling arguments that some people make quite seriously about real-world research priorities.
Whether or not you find these arguments convincing, the story succeeds in making them emotionally compelling. That's the power of fiction—it can make abstract philosophical positions feel urgent and personal in ways that essays rarely achieve.
A Community's Touchstone
When Methods of Rationality concluded in 2015, readers around the world held wrap parties to celebrate. The story had become more than entertainment—it was a shared reference point, a common vocabulary, something that identified you as part of a particular intellectual community.
Fan-created audiobooks brought the story to new audiences. Translations appeared in over a dozen languages including Czech, Chinese, French, German, Hebrew, Indonesian, Italian, Japanese, Norwegian, Spanish, Swedish, and Ukrainian. The ideas spread far beyond their English-language origins.
For better or worse, Methods of Rationality helped define a generation of people interested in clear thinking, effective giving, and the long-term future of humanity. It's a strange legacy for a work of fan fiction—but then again, the whole point of the story is that strange origins shouldn't prevent us from taking ideas seriously on their merits.