Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Harry's knuckles had gone white on his wand by the time he stopped trying to Transfigure the air in front of his wand into a paperclip. It wouldn't have been safe to Transfigure the paperclip into gas, of course, but Harry didn't see any reason why it would be unsafe the other way around. It just wasn't supposed to be possible . But why not? Air was as real a substance as anything else...

Well, maybe that limitation did make sense. Air was disorganized, all the molecules constantly changing their relation to each other. Maybe you couldn't impose a new form on substance unless the substance was staying still long enough for you to master it, even though the atoms in solids were also constantly vibrating all the time...

The more Harry failed, the colder he felt, the clearer everything seemed to become.

All right. Next on the list.

You could only Transfigure whole objects as wholes. You couldn't Transfigure half a match into a needle, you had to Transfigure the whole thing. Back when Harry had been trapped in that classroom by Draco, it had been the reason he couldn't just Transfigure a thin cylindrical cross-section of the walls into sponge, and punch out a chunk of stone large enough for him to fit through the hole. He would have needed to impose a new form on the whole wall, and maybe a whole section of Hogwarts, just in order to change that little cross-section.

And that was ridiculous .

Things were made of atoms. Lots of little tiny dots. There was no contiguity, there was no solidity, just electromagnetic forces holding the little dots related to each other...

Mandy Brocklehurst paused with her fork on her way to her mouth. "Huh," she said to Su Li, sitting across from the now-empty space beside her, "what got into Hermione?"

Harry wanted to kill his eraser.

He'd been trying to change a single spot on the pink rectangle into steel, apart from the rest of the rubber, and the eraser wasn't cooperating.

It had to be a conceptual limitation, not a real one. Had to be.

Things were made of atoms, and every atom was a tiny separate thing. Atoms were held together by a quantum mist of shared electrons, for covalent bonds, or sometimes just magnetism at close ranges, for ionic bonds or van der Waals forces.

If it came down to that, the protons and neutrons inside the nuclei were tiny separate things. The quarks inside the protons and neutrons were tiny separate things! There simply wasn't anything in reality, the world-out-there, that corresponded to people's conceit of solid objects. It was all just little dots.

And free Transfiguration was all in the mind to begin with, wasn't it? No words, no gestures. Only the pure concept of form, kept strictly separate from substance, imposed on the substance, conceived of apart from its form. That and the wand and whatever made you a wizard.

The wizards couldn't transform parts of things, could only transform what their minds perceived as wholes, because they didn't know in their bones that it was all just atoms deep down.

Harry had focused on that knowledge as hard as he could, the true fact that the eraser was just a collection of atoms, everything was just collections of atoms, and the atoms of the little patch he was trying to Transfigure formed just as valid a collection as any other collection he cared to think about.

And Harry still hadn't been able to change that single part of the eraser, the Transfiguration wasn't going anywhere.

This. Was. Ridiculous.

Harry's knuckles were whitening on his wand again. He was sick of getting experimental results that didn't make sense.

Maybe the fact that some part of his mind was still thinking in terms of objects was stopping the Transfiguration from going through. He had thought of a collection of atoms that was an eraser. He had thought of a collection that was a little patch.

Time to kick it up a notch.

Harry pressed his wand harder against that tiny section of eraser, and tried to see through the illusion that nonscientists thought was reality, the world of desks and chairs, air and erasers and people.

When you walked through a park, the immersive world that surrounded you was something that existed inside your own brain as a pattern of neurons firing. The sensation of a bright blue sky wasn't something high above you, it was something in your visual cortex, and your visual cortex was in the back of your brain. All the sensations of that bright world were really happening in that quiet cave of bone you called your skull, the place where you lived and never, ever left. If you really wanted to say hello to someone, to the actual person, you wouldn't shake their hand, you'd knock gently on their skull and say "How are you doing in there?" That was what people were, that was where they really lived. And the picture of the park that you thought you were walking through was something that was visualized inside your brain as it processed the signals sent down from your eyes and retina.

It wasn't a lie like the Buddhists thought, there wasn't something terribly mystical and unexpected behind the veil of Maya, what lay beyond the illusion of the park was just the actual park , but it was all still illusion .

Harry wasn't sitting inside the classroom.

He wasn't looking at the eraser.

Harry was inside Harry's skull.

He was experiencing a processed picture his brain had decoded from the signals sent down by his retina.

The real eraser was somewhere else, somewhere that wasn't the picture.

And the real eraser wasn't like the picture Harry's brain had of it. The idea of the eraser as a solid object was something that existed only inside his own brain, inside the parietal cortex that processed his sense of shape and space. The real eraser was a collection of atoms held together by electromagnetic forces and shared covalent electrons, while nearby, air molecules bounced off each other and bounced off the eraser-molecules.

The real eraser was far away, and Harry, inside his skull, could never quite touch it, could only imagine ideas about it. But his wand had the power, it could change things out there in reality , it was only Harry's own preconceptions that were limiting it. Somewhere beyond the veil of Maya, the truth behind Harry's concept of "my wand" was touching the collection of atoms that Harry's mind thought of as "a patch on the eraser", and if that wand could change the collection of atoms that Harry considered "the whole eraser", there was absolutely no reason why it couldn't change the other collection too...

The Transfiguration still wasn't going through.

Harry's teeth clenched together, and he kicked it up another notch.

The concept Harry's mind had of the eraser as a single object was obvious nonsense.

It was a map that didn't and couldn't match the territory.

Human beings modeled the world using stratified levels of organization, they had separate thoughts about how countries worked, how people worked, how organs worked, how cells worked, how molecules worked, how quarks worked.

When Harry's brain needed to think about the eraser, it would think about the rules that governed erasers, like "erasers can get rid of pencil-marks". Only if Harry's brain needed to predict what would happen on the lower chemical level, only then would Harry's brain start thinking - as though it were a separate fact - about rubber molecules.

But that was all in the mind.

Harry's mind might have separate beliefs about rules that governed erasers, but there was no separate law of physics that governed erasers.