The Room Behind the Door

The door opened without much noise.

Gavin stood in the doorway but did not go in immediately.

Beyond the door lay a spacious stone chamber, far larger than an ordinary classroom. Its ceiling was high, its walls bare, and only a few wall lamps glowed quietly. The floor was level. Several long tables, a row of wooden crates, and a few target stands that looked purpose-built for practice occupied one corner. There was even a blackboard against the wall, with chalk and an eraser beside it.

"Quite a thoughtful setup." Gavin was pleased.

He went in and glanced back. The door was still there, at least from where he stood inside.

I wonder if it's vanished on the outside. Gavin had no plans to investigate that just yet.

At least, that was how it worked in the original story. He could look into it next time. Right now, he needed to practice spells.

Gavin set the Dragon Hide Bag on a table and took out A Beginner's Guide to Transfiguration, Standard Book of Spells, Grade 1, a matchstick left over from the morning, and a feather.

Rather than begin at once, he walked around the room first.

The room seemed to adjust itself to the visitor's needs. An open area in the distance looked reserved for magic with a wider range; on the other side, a sturdy tabletop could clearly withstand a beginner repeatedly turning things into a mess.

He stopped by the table and tapped its surface.

"Better for experiments than the dormitory."

The word experiments was hardly out of place at Hogwarts. Most students probably would not have used it like that on their first day, though.

Gavin practiced the Levitation Charm first.

Succeeding a few times in class that morning did not mean he had mastered it.

He had barely learned the basics. True proficiency was still a long way off.

"Wingardium Leviosa."

The feather rose steadily.

About a foot high.

"A little higher."

He adjusted the sweep of his Wand and his intent. The feather climbed a little more, hanging in midair and slowly turning.

"So it really can be adjusted."

Gavin watched the feather, his thoughts beginning to wander.

If the Levitation Charm simply "made things fly," that would be far too crude. Clearly, there was more to it. He could adjust the height, the speed, and of course the stability. In other words, its effects were not all-or-nothing. They varied along a spectrum.

That made it worth studying.

He tried raising the feather, lowering it, holding it still, then moving it slowly sideways.

The first two times, it nearly flew straight into a nearby lamp.

On the third try, it finally traced a reasonably respectable, crooked line through the air.

"Looks drunk," Gavin observed.

At least it was moving.

He tried again with A Beginner's Guide to Transfiguration. One corner of the book merely lifted off the table, as if politely declining to cooperate.

Weight was indeed one of the variables.

Seen that way, first-year Ron levitating a Troll's club with a Wand that did not suit him was seriously overpowered.

The thought made Gavin want to see that famous scene up close and find out how Ron had done it.

He had a feeling Ron was fairly gifted at magic himself.

Gavin had no intention of trying the charm on a living creature yet.

The toad he meant to experiment on was still in the dormitory, leaving himself as the only live test subject at hand.

Getting himself stuck on the ceiling on his first day, then having to work out how to get down, would make him look rather foolish.

As for the Slowing Charm—

He did not know the incantation or the full wand movement, and Professor Flitwick had only mentioned it in passing. Gavin could not yet work backward from one spell to deduce the structure of another, so he could only make a note of the idea for now.

"If the Levitation Charm loosens gravity's grip, does slowing strengthen it?"

He wrote two lines on the blackboard.

[Levitation]

[Slowing]

After staring at them for a moment, he wrote a question beneath them:

[Does it affect gravity? Or mass?]

Once he had written it down, he did not pursue it further. The question was too big.

He would leave it there as a direction for future research.

What truly held his attention today was Transfiguration.

Professor McGonagall's brief remarks from that morning still circled in his mind.

Persistence.

Authenticity.

The change itself had to be sufficiently self-consistent.

The words were hardly straightforward, and he still did not quite understand what Professor McGonagall meant.

Gavin placed the matchstick on the table and raised his Wand.

"Vera Verto."

The matchstick changed rapidly into a silver needle.

It went even more smoothly than it had in class.

The needle was slender and bright, with straight edges. It looked no different from a real silver needle.

Gavin picked it up and rolled it between his fingertips.

Cool, hard, and so convincing in texture that it was almost beyond reproach.

"That's the problem."

He spoke under his breath.

If this really was a "fundamental change," a great many things made no sense.

According to Gamp's Law of Elemental Transfiguration, Transfiguration had Five Exceptions. You could not conjure food, create life, produce magical objects, change the number of objects, or bring matter or knowledge into existence from nothing—or, more strictly, create information from nothing.

"Matter or information can't come from nothing. That's very much in line with physics." Gavin leaned against the table, lost in thought.

Physics and Magical Theory briefly intersected.

In physics, there was a famous problem called the "Black Hole Information Paradox": if an object fell into a black hole, would the information it carried—the arrangement of its atoms, its quantum state—disappear? The current consensus was that information could not be destroyed, nor could it arise from nothing.

He looked again at the silver needle.

The first exception, the inability to conjure food, had always bothered him.

If Transfiguration could truly change a thing's fundamental nature, why could wood not become bread? In the end, both were combinations of carbohydrates, proteins, fats, and other organic substances. Wizards might not think about it that way, but from a material standpoint, the difference was hardly great enough to make it "absolutely impossible."

Unless—

Perhaps so-called permanent Transfiguration did not actually rewrite things at the most fundamental level.

Or perhaps there was a limit to how deep the rewriting went.

Gavin looked down at the silver needle in his hands and applied a little pressure with both hands.

Snap.

He broke the needle.

More precisely, he broke it in two.

At the instant it snapped, an almost imperceptible sensation brushed his fingertips, as though a layer clinging to the needle had suddenly dispersed.

The next second, the two pieces of "silver needle" in his hands revealed their true form.

They were not two broken pieces of needle.

They were two pieces of a snapped matchstick.

Gavin stared at his palm in silence for two seconds.

"That makes sense."

It explained at least part of the problem.

After the matchstick became a silver needle, its overall state was stable, and it did look as though the material itself had changed. But once it was damaged past a certain point, the magic clinging to it dispersed, exposing the original material underneath.

In other words, the changed form remained self-consistent as long as it was intact.

But once that consistency broke, it reverted to what it had been.

That could explain, for now, why you "couldn't conjure food."

After all, if you really turned wood into bread, took a bite, and the magic dispersed, leaving a piece of wood in your mouth, it would make a poor breakfast.

"The first exception makes sense for now."

Gavin put the two pieces of matchstick back on the table.

Then came the second: you could not create life, or transform an inanimate object into a living thing and vice versa.

"Too complicated. I'll leave it alone for now." He reached the sensible conclusion that life was an enormous subject.

The third exception: you could not Transfigure something into a magical object.

Gavin set that aside too. He had encountered very few magical objects so far.

The fourth: you could not change the number of objects. You could not turn one table into two deer, or three quills into one shovel, unless the objects were connected.

That was strange, but it also seemed reasonable. When the matchstick-turned-needle had broken in two, the magic had failed.

The fifth was the beginnings of the Information Conservation Principle, which Gavin understood easily.

Looking back over the Five Exceptions, Gavin could not shake the sense that something was off. Like so much else in the Wizarding World, the theory was abstract.

Someone had drawn up a set of conclusions in the eighteenth century, and everyone had happily used them ever since. As for the deeper question of why they held true—either no one asked, or no one followed up when they did.

"A law from the eighteenth century, and not a bit of progress since?"

Gavin looked at the textbook on the table, more than a little puzzled.

The Wizarding World's theoretical work had an almost lazy sense of stagnation about it.

That seemed something of a disservice to a phenomenon as unscientific as magic.

With that in mind, he decided to try it himself.

First, he would try making food. Something simple.

As for a food resembling a matchstick...

Some brand of shrimp snack sticks?

"It's not as though the United Kingdom's Wizarding World has a rule against thinking about snacks during magical research, is it?"

He picked up another matchstick and raised his Wand.

This time, he attempted a finer Transfiguration than he had that morning.

Gavin tried to picture the specific structure of a food as clearly as possible.

Seasoning powder on the surface, a crisp and airy texture inside, and the right color too.

This was clearly much harder than turning a matchstick into a silver needle.

On his first attempt, he made something that looked like a cotton swab.

The second looked more like a shrimp snack stick, except its surface gleamed as though someone had waxed it.

The third time, he succeeded.

At least, it looked like he had.

A tiny, slender shrimp snack stick lay on the table, golden in color, with a clear texture and an appealing crispness to its surface.

"That looks good enough for a convenience store," Gavin said.

Then he reached out and snapped it in two.

Snap.

It was almost exactly like before.

The faint sensation of magic dispersed, and the golden, crispy snack in his palm immediately gave itself away.

Inside was no puffed texture.

It was a broken piece of matchstick.

Gavin studied it in silence, then put both pieces back on the table.

"All right."

"At least I didn't eat it."

The result was not unexpected.

It was still a little disappointing.

Food Transfiguration in the truest sense was clearly far beyond him.

He sat down by the table and organized his thoughts on the blackboard.

[Transfigured objects remain self-consistent while intact]

[Once the structure is damaged, the magic cannot be sustained, exposing the original material underneath]

[The food exception may stem from an inability to create a stable, authentic transformation]

He paused, then added another line beneath them:

[Fifth exception: cannot create knowledge/information]

When he finished, he stared at the line for a long time.

The more he thought about it, the more he felt this might be the key.

Food, gold, life, and magical objects might simply be complex things on different levels. The fact that "knowledge" or "information" was singled out suggested that the most fundamental limit of Transfiguration might not be matter, but understanding.

Wizards could turn things into "what they understood those things to be."

But they could not get past the level they did not understand.

If a wizard knew nothing of bread's underlying structure, the "bread" he made could only be a shell of magic that looked like bread. If he did not know what truly made up a living thing, he could never create something genuinely alive. If he did not know what made gold gold, he could only produce a convincing-looking substitute that could not truly be gold.

"So maybe the world doesn't forbid the change."

Gavin spoke softly.

"Maybe wizards just don't know what they're changing things into."

Once the thought had taken hold, it was hard to suppress.

He stood and paced around the stone chamber twice.

"If that's true..."

Gavin stopped in front of the blackboard and stared at the words he had written.

"Then Gamp's Law isn't a universal truth. It's more like a summary of the limits of what wizards can understand."

The stone chamber was quiet.

Gavin felt as though he might have just opened a door.

And the world beyond it was far more fascinating than he had imagined.