This is a Harry Potter and the Methods of Rationality fan-fiction which contains spoilers. If you haven't, you should read or listen to Eliezer Yudkowsky's original work before reading this.

<< Chapter 1

White marble the floors, ochre the sculptured walls and grey the vaulted ceilings. Harry and Hermione walked together through the maze of ancient corridors that was Hogwarts School of Witchcraft and Wizardry.

“I must say Harry, I wasn’t expecting this. I thought you were all about logic and rational thinking – not emotions,” said Hermione. “I really don’t know how to feel about this. It’s either a really positive development or the start of something truly disastrous.” 

They rounded another corner passing a painting that showed a group of dogs sitting around a table playing exploding snap. Harry was sure they had walked past this one before but Hogwarts had a way of arranging its corridors so that you tended to reach your destination if you just walked with sufficient confidence towards the place where you felt a room should be. 

“The start of something truly disastrous?” asked Harry. 

“Well, aren’t you afraid this might, you know, turn out really really bad? Using magic to mess with your mind – don’t you see how that could go wrong?” 

“That is something that I’ve thought about. But I don’t see how magical research into psychology should be any more dangerous than research into physics which is what we’ve been doing so far – in fact there are good arguments that researching physics should be much more dangerous” 

Hermione was growing visibly more worried so he quickly changed tack. “But we’re getting ahead of ourselves. All I’m suggesting we do is work through this book.” 

Of all the magic they could learn it had been obvious that boosting their ability to think more effectively should be the first they focused on, if it indeed existed. But it wasn’t immediately obvious that it did. A cursory survey of the library hadn’t thrown up any spells like that.

And Harry’s Hufflepuff part did think Hermione had a point. Brute forcing a massive change to your neural architecture did sound like something that could go very wrong. Would disrupting the balance between the billions of interacting neurons in his brain immediately trigger some kind of mental breakdown?

Assuming it was possible to do safely, would he even want to do something that could modify his values, memories and personality in an instant? Sure, you changed slowly over months and years – hopefully in positive ways – but your sense of self had continuity through time. You were always only a slight modification of your previous self. A spell that changed your mind in an instant: how was that any different from dying and replacing yourself with somebody completely different?

So that had been one of the main principles in their new research programme. They were aiming for something like magical psychotherapy, not magical lobotomy. Magic that could help him understand his mind better, magic that could temporarily remedy the most obviously broken parts of human psychology and magic that could help him think more rationally more of the time. Psychomagic for Beginners had been Harry's best lead so far. A small foothold on that still dauntingly vast project.

He handed Hermione the book. “It’s kind of hard to describe. It’s not really like any of the other books in the library. Maybe that’s why Dumbledore keeps it in his private collection.”

“Dumbledore gave you this?” Hermione gasped.

“Yes… he didn’t really explain why. But then he couldn’t explain the rock either.”

Hermione raised an eyebrow.

“I’ll tell you about that some other time. Here we are.”

They opened the door onto the 7th floor study room. This had quickly become their favourite place to meet for magical research: far away enough that nobody would interrupt them or come running if something exploded, well furnished with low comfy seats and with a magnificent window covering one whole side of the room from which you could look out onto the spires, turrets and rolling forests below.

Bounding in, Harry took up station behind a heavy oak table at the front of the room where he reached into his mokeskin pouch and pulled out three envelopes. 

Harry began immediately “So a group of muggle scientists ran a neuroimaging study at University College London recently.” He removed a small card from the first envelope and placed it in front of Hermione. “This is my recreation of that experiment.”

“I’m going to tap the card like this,” Harry said as he touched his wand to the card, “and you’ll see a blur of changing shapes.” 

Harry had stayed up all night making these cards using a bottle of something Fred and George had called magical ink. It worked something like a flip book, each layer of ink you added forming the next frame in a hand drawn animation. On each layer he had drawn a different jumbled image of small overlapping triangles, squares and circles.

The jumbled shapes flickered from one random configuration to the next before abruptly coming to rest on the image of a large question mark.

“When they stop. You have to either touch the card with your wand or not touch the card. If you get it right you win a knut. If you get it wrong you lose a knut.”

“So I’ve got to work out some kind of pattern – when to touch and when to hold back?” asked Hermione.

“Something like that,” Harry smiled. “I don’t want to give away too much yet. Just focus on the card and try to win as many knuts as you can. I’ll loan you 5 knuts to start you off. Oh and one last thing, you have to answer as quickly as you can.”

Hermione nodded and then shifted her feet into position like a sprinter lining up at the starting blocks of a race, her gaze now fixed intently on the pile of cards.

Harry tapped the first card, the images running through their dance of random geometric shapes before abruptly dissolving into a static picture of a single large question mark once again. Hermione tapped the card and revealed an image of a smiling house elf who winked at her in congratulation.

“Great, that’s one to you,” Harry said as he added a knut to her side of the table.

Harry pulled a fresh card from his envelope and Hermione tapped again but this time revealed a frowning house elf and so lost a knut. They continued for several more rounds, Hermione sometimes tapping and sometimes not tapping – revealing smiling and frowning house elves in about equal quantities so never ending up significantly up or down on her initial 5 knut balance.

“I’ve tried all the obvious rules,” said Hermione. “Whether the previous run was a win or a loss. Where, when or how I tap doesn’t seem to matter.”

“Maybe for this one, just, you know… use your intuition?”

Hermione looked at him suspiciously. This wasn’t the kind of thing Harry normally said.

They continued for another 10 rounds, this time Hermione tapping more quickly and trying to be guided more by impulse than conscious deliberation. 8 knuts. She wasn’t getting it right every time but she did seem to have a slight edge now. This continued until she had 10 and then 15 knuts – past the point where a string of lucky guesses could explain what was happening.

“Beyond the images on the cards changing, is there any other magic involved here?” asked Hermione. “Are the cards responding to my thoughts or anything like that?”

“No, definitely not,” replied Harry.

Hermione stood in silence running through the different tests she had tried so far. Then it came to her.

“Okay, I think I’ve worked it out. My answer is: there is no pattern... At least, no pattern that I can see consciously.

“This is a subliminal messaging thing isn’t it? I don’t remember seeing any clues but my subconscious picked up on something? Like a hidden message that flashes somewhere at the start. If I go with my gut and pick the one that feels vaguely more familiar I’ll pick the correct one better than 50:50 odds.”

Harry smiled and asked “Would you like to try it with the images slowed right down then?”

“Yes, obviously,” replied Hermione impatiently.

Harry took a card from the second envelope this time, placing it on the table and tapping its front. The shapes on the surface now progressed much more slowly frame by frame.

“These are called masks. They sort of distract your mind so that if you flash it very quickly you can hide something immediately after the mask.”

Hidden among the clutter of overlapping shapes emerged a single frame, distinct from all the rest. A large solitary blue square.

They continued playing with these slower cards where the hidden signals were easy to spot. Within a few short minutes Hermione had figured out the pattern and was able to win on the majority of runs with ease.

“This one means tap to win a knut,” she said, pointing to the blue square. “The large circle means don’t tap. And finally the triangle... that’s about 50:50 odds I think. It doesn’t tell you anything?”

“Brilliant Hermione. Correct on every count!”

This wasn’t a difficult test, at least not compared to Harry’s usual standards, and Hermione knew that. But the warm glow of academic pride washed over her face all the same.

Hermione looked at the pile of coins on her side of the table “I was winning before we tried it with the slowed down cards though wasn’t I? I definitely couldn’t see those clues but I did far better than random guessing.”

“It’s even better than that Hermione. You managed to see the symbols and then learn what each symbol meant – all without being consciously aware any of that was going on in your mind.”

“And you remember how this was a neuroimaging study?” asked Harry. “In the real experiment they did all this inside an FMRI brain scanner. Obviously they showed the images on a computer screen instead of using pieces of card and magical ink. And it wasn’t simply about showing off all the weird party tricks that the subconscious mind can pull off. They were looking for something much more interesting.”

Harry opened the final envelope “These are the readings they got from the brain scanner when the test subjects saw the clues subconsciously, and then consciously.”

He took out two pieces of paper which showed grainy pictures of human brains in cross section with a series of small red arrows drawn on them. 

“When the clues were flashed quickly you did see them, in a sense. There’s a signal here, in your visual cortex, that spreads a little way and then dies out.” Harry pointed at the arrows in the first picture. “It does enough to do some very minimal processing. With enough repetitions you can learn a kind of vague aversion or attraction to the subconscious clues. That’s how you had an edge even before you were consciously aware of seeing any of the clues.

“When you saw the cards slowly it was completely different. You performed much better, and crucially you had the subjective experience of seeing the clues — I know because you could report seeing them to me. It’s no surprise that there’s way more going on in the brain when that happened. That was the trial with conscious awareness in the experimental setup.” 

He pointed to the second image which had far more arrows drawn on it, forming complex loops and tracks that connected many different parts of the brain. “Instead of dying out, if the stimulus is strong enough — if it’s above a certain level — it gets boosted until it’s much stronger. It’s like a snowball rolling down a mountain and turning into an avalanche versus petering out into nothing. If you see the clue for more than about 50 milliseconds that signal gets boosted into all these areas along a network called the Global Neuronal Workspace – and it’s sustained over time too, instead of immediately dying out.”

Hermione picked up the second picture, examining the complex swirl of arrows as Harry continued “So, the point is, there isn’t a consciousness lobe anywhere in the brain that generates conscious experience. What we mean when we say a thought is conscious is that a signal is being sustained and shared across distant parts of the brain along this Global Neuronal Workspace.

“That is if we’re talking about conscious access – being aware of the things that are happening in our mind and being able to report them to an experimenter. There are other definitions of the word consciousness… but that’s a rabbit hole we don’t need to go down right now.”

But Harry couldn’t resist adding “For what it’s worth, I think in twenty years’ time a lot of muggle philosophers are going to be rather embarrassed about how confused they managed to get themselves about those other definitions of the word consciousness.

“I think of the Global Neuronal Workspace like a shared radio channel that all these different parts of the brain can be tuned into. And of course they can broadcast things back on to the channel too. For instance, earlier, when you saw the clues consciously that information got broadcast onto the network and it was able to reach the hippocampus all the way over here where it could create a memory.” Harry pointed to a thin worm-like structure in the centre of the brain.

“Later when I asked you what you had seen you became consciously aware of that question and in response that stored memory broadcast the information back onto the Global Neuronal Workspace and so back into consciousness. The reason you don’t remember seeing the clue when it’s flashed subconsciously is because that information never got onto the Global Neuronal Workspace in the first place and could never reach the part of your brain that creates memories.”

“Okay Harry. This is all fascinating,” Hermione interrupted. “No, I’m serious. It is. But isn’t this where you tell me how this fits into our project? Does it have anything to do with the book that Dumbledore gave you?”

“Well that’s just it. All of this is in the book! Not in literally the same language but when wizards talk about legilimency they have a concept that’s just like the Global Neuronal Workspace. And they make predictions about the way the brain works that match these experimental findings.

“In most areas muggle scientists are light years ahead. Other than missing the magic part of the puzzle, muggle scientists’ view of the universe is just way more advanced than the wizarding world’s.”

Harry paused for dramatic effect.

“… everywhere except here. What I talked about today was the cutting edge of neuroscience. The technology needed to do these experiments was only developed in the last decade or two, but legilimens worked this out centuries ago.”

Harry remembered reading about Galileo and the history of telescopic astronomy. Early telescopes had been unreliable handheld devices and astronomers would often fail to replicate each other’s observations. With his rudimentary instruments even Galileo, a genuine scientific genius, had got a lot wrong – mistaking Saturn’s rings for moons, missing Neptune altogether and refusing to concede that the tides were caused by the moon. But this hadn’t mattered. Over the next 400 years telescopic astronomy followed a steady upward climb as observations were repeated, telescopes improved and the heavens slowly relinquished their secrets. 

This was not how psychology had progressed. Freud, like Galileo, possessed a similar mix of brilliant insights and embarrassing mistakes to his name. But his breakthroughs had not been built on in the same way and the steady accumulation of thousands upon thousands of verified and re-verified observations had not emerged. Consequently psychology became what is known as a soft science.

You could argue that something like the subconscious mind was fundamentally more perplexing than the orbits of planets but Harry suspected there was another explanation – psychologists had simply never found their equivalent of a telescope.

A century after Freud, psychology experiments were still notoriously slow, expensive and unreliable. If each of the thousand most important astronomical observations had required a room full of volunteers to fill out surveys, each of whom interpreted the questions slightly differently and whose aggregate answers only sometimes agreed when you ran the experiment again in a different laboratory – would astronomy have gotten anywhere? Would we still be arguing about whether Saturn had rings today?

Harry looked at Hermione expectantly “Don’t you see? With magic – with legilimency, with that memory extraction spell that Dumbledore uses, with this book of psychomagic spells, with everything else we can find – it’s a whole new set of scientific tools which were never available. We can use them to see inside the black box that is a human brain for the first time. We can start doing psychology as a hard science.”