Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Behind him, he heard Harry exhale a breath, as though in relief.

Draco gazed into the white light. It seemed he wasn't lost completely, after all.

"That reminds me," said Harry after a while. "Can we test my hypothesis about how to use a Patronus to send messages?"

"Is it going to surprise me?" said Draco. "I don't want any more surprises today."

Harry had claimed that the idea wasn't all that strange and he didn't see how it could possibly shock Draco in any way, which made Draco feel even more nervous, somehow; but Draco could see how important it was to have a way of sending messages in emergencies.

The trick - or so Harry hypothesized - was wanting to spread the good news, wanting the recipient to know the truth of whatever happy thought you'd used to cast the Patronus Charm. Only instead of telling the recipient in words, the Patronus itself was the message. By wanting them to see that, the Patronus would go to them.

"Tell Harry," said Draco to the luminous snake, even though Harry was standing only a few paces away on the other side of the room, "to, um, beware the green monkey," this being a sign from a play Draco had once seen.

And then, just like at King's Cross station, Draco wanted Harry to know that Father had always cared for him; only this time he didn't try to say it in words, but wanted to say it with the happy thought itself.

The bright snake slithered across the room, looking more like it was slithering through the air rather than the stone itself; it got to Harry after traveling that short distance -

- and said to Harry, in a strange voice that Draco recognized as how he himself probably sounded to other people, "Beware the green monkey."

" Hsssss ssss sshsshssss, " said Harry.

The snake slithered back across the floor to Draco.

"Harry says the message is received and acknowledged," said the shining Blue Krait in Draco's voice.

"Huh," Harry said. "Talking to Patronuses feels odd."

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"Why are you looking at me like that?" said the Heir of Slytherin.

Aftermath:

Harry stared at Draco.

"You mean just magical snakes, right?"

"N-no," said Draco. He was looking rather pale, and was still stammering, but had at least stopped the incoherent noises he'd been making earlier. "You're a Parselmouth, you can speak Parseltongue, it's the language of all snakes everywhere. You can understand any snake when it talks, and they can understand when you talk to them... Harry, you can't possibly believe you were Sorted into Ravenclaw! You're the Heir of Slytherin! "

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"SNAKES ARE SENTIENT?"

It was Saturday, the first morning of February, and at the Ravenclaw table, a boy bearing a breakfast plate heaped high with vegetables was nervously inspecting his servings for the slightest trace of meat.

It might have been an overreaction. After he'd gotten over the raw shock, Harry's common sense had woken up and hypothesized that "Parseltongue" was probably just a linguistic user interface for controlling snakes...

...after all, snakes couldn't really be human-level intelligent, someone would have noticed by now. The smallest-brained creatures Harry had ever heard of with anything like linguistic ability were the African grey parrots taught by Irene Pepperberg. And that was unstructured protolanguage, in a species that played complex games of adultery and needed to model other parrots. While according to what Draco had been able to remember, snakes spoke to Parselmouths in what sounded like normal human language - i.e., full-blown recursive syntactical grammar. That had taken time for hominids to evolve, with huge brains and strong social selection pressures. Snakes didn't have much society at all that Harry had ever heard. And with thousands upon thousands of different species of snakes all over the world, how could they all use the same version of their supposed language, "Parseltongue"?

Of course that was all merely common sense, in which Harry was starting to lose faith entirely.

But Harry was sure he'd heard snakes hissing on the TV at some point - after all, he knew what that sounded like from somewhere - and that hadn't sounded to him like language, which had seemed a good deal more reassuring...

...at first. The problem was that Draco had also asserted that Parselmouths could send snakes on extended complex missions. And if that was true, then Parselmouths had to make snakes persistently intelligent by talking to them. In the worst-case scenario that would make the snake self-aware, like what Harry had accidentally done to the Sorting Hat.

And when Harry had offered that hypothesis, Draco had claimed that he could remember a story - Harry hoped to Cthulhu that this one story was just a fairy tale, it had that ring to it, but there was a story - about Salazar Slytherin sending a brave young viper on a mission to gather information from other snakes.

If any snake a Parselmouth had talked to, could make other snakes self-aware by talking to them, then...

Then...

Harry didn't even know why his mind was going all "then... then..." when he knew perfectly well how the exponential progression would work, it was just the sheer moral horror of it that was blowing his mind.

And what if someone had invented a spell like that to talk to cows?

What if there were Poultrymouths?

Or for that matter...

Harry froze in sudden realization just as the forkful of carrots was about to enter his mouth.

That couldn't, couldn't possibly be true, surely no wizard would be stupid enough to do THAT...

And Harry knew, with a dreadful sinking feeling, that of course they would be that stupid. Salazar Slytherin had probably never considered the moral implications of snake intelligence for even one second, just like it hadn't ever occurred to Salazar that Muggleborns were intelligent enough to deserve personhood rights. Most people just didn't see moral issues at all unless someone else was pointing them out...

"Harry?" said Terry from beside him, sounding like he was afraid he would regret asking. "Why are you staring at your fork like that?"

"I'm starting to think magic should be illegal," said Harry. "By the way, have you ever heard any stories about wizards who could speak with plants?"

Terry hadn't heard of anything like that.

Neither had any seventh-year Ravenclaws that Harry had asked.

And now Harry had returned to his place, but not yet sat down again, staring at his plate of vegetables with a forlorn expression. He was getting hungrier, and later in the day he would be visiting Mary's Place for one of their incredibly tasty dishes... Harry was finding himself sorely tempted to just revert back to yesterday's eating habits and be done with it.

You've got to eat something, said his inner Slytherin. And it's not all that much more likely that anyone sneezed self-awareness onto poultry than onto plants, so as long as you're eating food of questionable sentience either way, why not eat the delicious deep-fried Diracawl slices?

I'm not quite sure that's valid utilitarian logic, there -

Oh, you want utilitarian logic? One serving of utilitarian logic coming up: Even in the unlikely chance that some moron did manage to confer sentience on chickens, it's your research that stands the best chance of discovering the fact and doing something about it. If you can complete your work even slightly faster by not messing around with your diet, then, counterintuitive as it may seem, the best thing you can do to save the greatest number of possibly-sentient who-knows-whats is not wasting time on wild guesses about what might be intelligent. It's not like the house elves haven't prepared the food already, regardless of what you take onto your plate.