Healing the body was easy. But even Little Strongheart’s magic couldn’t heal the mind’s scars.

But, Spike was quick to point out, they didn’t need magic. They had Science. Specifically, they had the Science of Friendship.

Spike oversaw everything, having picked up a thing or two from Twilight, who mostly paid no attention. Applejack got to work drafting up a contract while Twilight rested and thought about dragons. Rarity surreptitiously sent her parasprite about gathering data about the preferences of ponies and buffaloes while Twilight read Gamma’s letter. Pinkie Pie was a boon in bringing ponies and buffaloes together with games like pin-the-tail-on-the-donkey[1] and catch-the-potted-plant, which Spike soon put a stop to, while Twilight planned the ascent of Hark Mountain. Rainbow Dash did her part in convincing everypony, pony and buffalo alike, that loyalty was totally awesome (she also might have promised everypony a substantial payout, but only if the agreement could be kept). Twilight, lost in a book about magical algebra, signed the agreement on autopilot. She was also sometimes busy outside the town with a few Breezies for protection, with Spike absolutely forbidden to follow.

[1] Nothing brought two divided species together like a common enemy.

And as for Fluttershy….

“Twilight,” she said. “I need to talk to you.”

It was the seventh day of their recuperation. Little Strongheart had said that she would do no healing on this day, and the Appleloosans refused to listen to any talk of contracts or game theory. Twilight was glad the ambient noise had died down a lot. It made it easier to read.

“I’m busy,” Twilight said, carefully studying a spell sequence. “Can it wait until after we’ve slain the dragon?”

“No. Um, I mean, it’s about that. The dragon, that is. Maybe we shouldn’t slay him.”

Twilight set the book down and frowned at Fluttershy. “You know Princess Celestia told us to. Besides, the dragon killed your cow.”

“He wasn’t my cow. Mr. Cow was free.”

“Uh, yeah.”

“But, um, I’ve been thinking.”

Don’t do that. “You can tell me.” Don’t tell me.

“What if, um, what if, um…it’s silly.”

Yes it is go away. “Of course it’s not silly. Fluttershy, don’t be, um, shy.” Shutupshutupshutup.

“What if the dragon’s not the problem? What if, um, we are?”

Poot. “Fluttershy, that’s just silly. He killed Mr. Cow! And the smoke will wipe out life on Equestria eventually if we don’t stop him.”

“Well, but, um, that’s the thing. I’ve been thinking about what you said about externalities. Um. Well, it just seemed to me that the externality isn’t just the smoke in the sky, exactly. The externality isn’t the smoke. It’s the harm the smoke causes.”

“Yes, exactly! And it is very harmful!”

“But it doesn’t have to be.  I realized this when I saw Bloomberg eating the smoke. The harm isn’t inherently a part of the smoke. The harm is the conjunction of smoke and critters who can’t breathe it.”

Oh, no. “So what?”

“So, um, you could see that by taking the dragon out of the picture, the harm goes away. So you could say the dragon causes the externality. But also—“

“Shut up.”

“—if you took the ponies and buffaloes and other critters out of the picture—“

“Shut up.”

“—the harm would also go away just the same. So critters like us are causing the externality just as much as Niddhog is.”

“So what? Removing the dragon is a lot better than removing all the critters on earth, Fluttershy.”

Fluttershy took a deep breath. “Well, we would think that way, wouldn’t we? That’s our privilege.”

“Fluttershy, what in the nine hells of economics is privilege?”

“Privilege is when ponies can talk and listen to each other, but they can’t understand each other anyway because they’re different. Because there are things that can’t be said but can only be lived.”

“Like the experience of all life on earth being wiped out by a dragon because we didn’t want to offend anypony.”

“Yes, that would be one example,” Fluttershy said seriously. “What do you do when there are no words? When something just can’t be put into a price?”

“Price it anyway.”

“The dragon won’t wipe out all life on earth,” Fluttershy said. “Life will just change. There will be smoke-trees and smoke-birds and smoke-ponies.”

“No, there won’t be. There’s going to be a dead dragon and a lot of happy ponies.”

“No,” Fluttershy said. “I won’t allow it. I won’t not check my privilege.”

Twilight groaned. She needed Fluttershy for this plan to work. “Fluttershy, self-preservation is the most basic instinct. The dragon has it too. This isn’t privilege, it’s survival.”

“No, no! We’re doing something wrong. I know it, I can feel it, I’m the Element of Rationality, and I am telling you something is wrong.”

“What am I missing?”

“I don’t know! That’s exactly it! There is something we understand that we can’t understand, and I don’t know what to do about that! It’s like a tree that doesn’t fall in the forest and doesn’t not make a thing that isn’t a sound!”

Twilight licked her lips. “Well, that’s not very helpful, is it?”

“And another thing. I don’t like the deal between the buffaloes and Appleloosans that Applejack drafted.”

“I don’t even care about that—“

“Everyp—everyone thinks it’s fine because it shares the land and the apple orchard, and many ponies and buffaloes are content with it. But even though it seems like the bargaining position are equal now, it ignores the years of history that led up to this point. The question shouldn't be how much buffaloes are willing to pay for the land but why they have to bargain over it in the first place. Who is listening to messages from the past? That’s called social justice, by the way.”

“Well, we can’t send messages to the past, so I don’t see why it matters. Also, bargaining position is not a thing. Also, seriously, Fluttershy, what do you want? What do you want me to do, rip up Applejack’s contract and leave everypony fighting again?”

“I want to go back in time and fix everything.”

“Good luck with that. What do you want me to do?”

Fluttershy walked over and sat down. “You’re the CEE of the Daughter of Ponyville. Protect the critters.”

“I am.”

“Not the ones who won’t even get to be ignored if we slay the dragon.”

“So you want me to let a dragon wipe out life on earth for the sake of the life that might come to be in millions of years. What about the intervening time? I’m sure there’s some argument to be made about…oh, no, that’s utilitarianism.”

“See the awful things that happen when you try to ignore things you won’t have to ignore?”

Twilight shuddered. “Okay, point taken, but seriously, I just don’t know what to say. I can’t let everypony die. Yet I can’t satisfy your concern for the never-born.”

“Then think about it for a few minutes. I don’t mind waiting.”

Twilight sighed. “If I think about it and can’t come up with anything, will you be satisfied?”

“No, but I’ll stop bothering you.”

“Fine.” Twilight thought for a few minutes. “Okay, I’ve got an answer.”

“I’m listening.”

“So, first of all, I’m pretty sure this whole privilege thing is just a basic economic fallacy. Social justice or whatever you called it is too.”

Fluttershy set one foreleg on top of the other and smiled politely. “Please explain.”

Twilight looked at Fluttershy sideways. She didn’t trust that smile, or rather, it was too trustworthy. Fluttershy was being kind.

“Let me give you an example of a privilege,” Twilight said. “When you’re a little filly, you’re only allowed to check two books out of the library a week for some ridiculous reason. But when you get a little bit older, they raise it to five. That’s a privilege, when a pony treats you differently and gives you something she doesn’t give to others because of some question of your status rather than objective merit.”

“Well, two books is a lot to carry for a small filly, and they can lose or damage them—“

“It’s a stupid rule! A stupid, stupid rule!”

“Um, okay. Sorry.”

“It’s fine.” Twilight took a deep breath. “It’s fine. Okay. Sunk cost fallacy. Moving on. So what about another situation? Say that a small filly is too short to reach the books on the high shelves, but a bigger pony is. Is that privilege to be able to reach the high shelves?”

“That doesn’t…feel right. And yet…it’s almost the same, isn’t it?”

“It sure is from the perspective of the fillies. Why should anypony care why they are constrained so long as it is a fact that they are constrained? Anyway, it seems to me we could do one of two things: we could call both situations and all situations like them examples of privilege, or we could call only the first situation and situations like it an example of privilege.”

“Like the Prisoner’s Dilemma.”

“More like the Grand Galloping Gala, in my experience. Anyway, if we call all those situations privilege, then the problem is that in practice privilege seems to amount to advantage. What’s a single advantage anypony can have over another pony that isn’t exactly like privilege?”

Fluttershy tapped her chin in thought. And kept tapping. Twilight surreptitiously began to read again.

“What if….” Fluttershy began.

“Yes?”

“Hm.” Fluttershy frowned. “No matter what, any advantage comes out to something one pony has or can do that another pony can’t. And that inevitably creates disparities in the experiences the two ponies know and therefore what they can communicate to each other about themselves.”

“And therefore of how much they can understand each other,” Twilight supplied. “So this is all silly, see?”

“Gosh,” Fluttershy said. “Privilege is an even bigger problem than I thought.”

Twilight sighed. “I suppose that’s a reasonable response. Um…okay, listen, if you want to call all that stuff privilege, that’s fine, really. I mean, ‘privilege’ is just a sound, a label, and what you apply it to doesn’t really matter so long as we all understand what it is and is not being used to represent. But then all you’re saying is that ponies have different advantages and disadvantages. Everypony knows that. And this idea of privilege has nothing to do with dragons.”

“But ponies really do treat ponies differently from other critters,” Fluttershy said.

“Yeah, but…it’s not something decided by anypony in particular, is it? Do you know what spontaneous order is?” Fluttershy shook her head. “So when ponies see order, they tend to think it implies a designer. Like you see a very geometric rock, for example, you might think somepony made it that way. These, uh, these weird monkeys called ‘humans’ thought the world itself and life on it were made by some kind of designer. Zebras believe that too, those [bad word].”

Fluttershy gasped. "Twilight! You really shouldn't say [bad word]."

"Why not? They say it all the time in their poems. Besides, it's just a word for a certain kind of critter. I don't mind when somepony calls me a Unicorn."

If steam wasn't rising out of Fluttershy's ears, it was because there wasn't actually any water in them to boil. "Twilight, you can't say that!"

Twilight frowned. "Yes, I can. Now think about the idea of a Life Creator. The world kind of looks like She made it, right?"

Fluttershy looked uncertain. “Then why did She make fillybirth so uncomfortable?”

“Kind of looks that way. Anyway, the point is, a lot of order is actually spontaneous, meaning it wasn’t created by anypony’s hoof. A pencil is made by many ponies, but it isn’t planned out or controlled by any pony in particular. Yet it happens nevertheless. Rocks really do take orderly forms and reach a balance, an equilibrium, without pony intervention. The planets orbit each other with a predictable regularity as if they can talk to each other. And pony society itself is a spontaneous order. No pony decided that ponies would be treated one way and critters another way—“

“Ponies are critters.“

“—so it isn’t a privilege, just another advantage.”

“But ponies are treating critters differently based on what kind of critter they are, so it is.”

“Then being tall enough to reach the high shelves is a privilege because ponies know some fillies are too small to reach up there, and they still build the shelves that high anyway. Which boils down to advantages and disadvantages again.”

“You said it doesn’t matter what it’s called. It’s a problem, and you know it.”

“Privilege is a real problem, and economists have a long history of fighting it. Who do you think told everypony that, no, the East Marwari Company doesn’t need the privileged right to control half the world’s resources in order to keep the entire economy from collapsing? Economists are the natural enemies of monopolies and the privileges that sustain them.”

“I hate that game.”

“Everypony does.”

“And yet you seem pretty happy with the contract Applejack made.”

“I seem totally indifferent to the contract she made, which is also how I happen to feel about it. I’m here to kill a dragon, not babysit a bunch of whiners. ‘Oh, no, my traditions!’ ‘Oh, no, my town!’”

“Why are you in charge of anything?”

“Because I have skills that matter. Which brings me to the next point, social justice or whatever you called it. Let’s work with two examples again. Suppose you’re walking along when a pony pours a bucket of water on you.”

“You mean Rainbow Dash?”

“It doesn’t matter who. Just say that some pony does it, and now you’re soaking wet. That’s an injustice, isn’t it?”

“It sure is! Darn it, Rainbow Dash! Um, don’t tell her I said that.”

“I won’t. Now suppose one day you’re walking along and it starts to rain.”

“Darn it, Rainbow Dash!”

“Um…no, I mean a natural rain. To you it’s the same, right? Either way you’re wet. But is rain unjust?”

“That doesn’t…feel right. I see. It’s the same, isn’t it? In one case someone chooses to make me wet, and in the other case I just get wet.”

“Yup. Just like privilege is either inapplicable to most of the stuff it is applied to or else it simply means ‘any kind of difference between two ponies that yields an advantage for one,’ social justice is either largely inapplicable or simply means ‘bad things that happen to somepony but maybe not to everypony.’”

“Gosh.”

“Economics has all kinds of applications you’d never expect. You just have to look.”

“I see.

“So are we done?”

“Just starting. You said before that self-interest is when ponies only pay attention to themselves. They only know themselves.”

“Yup.”

“Well, that’s privilege.”

“It’s the total opposite of privilege. You think that because ponies can never understand each other that they’re, I don’t know, stuck. Truth is, ponies don’t need to understand each other or have anything in common. They can still meet at the point of commonality that is just where their diversities happen to interact and trade. An isomorphism that can only be performed when you fold the two maps on top of each other. A system of mirrors that can only show you the image because the mirrors are there. Ever try giving yourself a haircut?”

“No. Is, um, is that why your mane—I could show you how to comb it—“

“And, what’s so incredible about this world where no pony has anything in common with anypony else is that it works. It works brilliantly. It’s just the best thing, perfect, immaculate, a garden of Econ. As long as there are no externalities.”

“Snakes in the garden telling lies.”

Twilight winced, thinking of what she had set up outside Appleloosa. “Something worse than lies. Maybe Nopony ever told Eve not to eat that apple.”

“I thought a snake lied to Adam.”

Twilight grimaced. “That doesn’t…feel right.”

“I agree.” Fluttershy covered her mouth with her hooves. “Snakes are suck honest creatures. Even rattlesnakes warn you before you’re about to step on them.”

“Yeah, well, Somepony should have stuck a Do Not Eat sign up in front of that tree.”

“No, She should have checked her privilege and not punished anyone for eating from a tree! It’s not like they had their own trees from before and outside time to eat from.”

“Mu.”

“What?”

“Something Pinkie Pie was telling me about. It’s like nothing at all, but philosophically. What do ponies have in common? Mu.”

“Mu-privilege.”

“Moo-oo,” Twilight laughed, and then gasped. “Fluttershy, no, I didn’t mean—“

Fluttershy got up and walked out.

Twilight followed her, mentally berating herself. “Fluttershy, I’m sorry, I wasn’t thinking.”

Fluttershy was stopped, looking at the smog where the sky should have been. “You have all of Rainbow Dash’s insensitivity but ten times her wit. It makes you intolerable sometimes. Should I have demanded five bits before you spoke?”

“I…I could pay you, but I don’t think that’s what you want. Um, I want to say sorry—“

“What you want. What you think.”

“…Yes, well, I don’t have anything else, do I?”

“Shut up! This isn’t about you!”

Twilight tried to remember if she had ever heard Fluttershy tell anypony to shut up before.

“I can’t save them,” Fluttershy said in a small voice. “I can’t even choose not to.”

Oh…ohhhhh.

“Fluttershy, come inside,” Twilight said. “We need to talk.”

“I’m going to kick one of your books. Hard.”

Twilight had seen Fluttershy’s idea of force before and wasn’t too worried. “Okay. I’m sorry. Please come inside.”

Fluttershy followed her in. She took Twilight’s book on algebra and threw it on the floor in front of her. Then, visibly struggling, she managed to push it a bit with her hoof.

“I mean it,” she said.

“I felt it,” Twilight said. “Really.” The thing was, she had.

“Say what you have to say.”

“Fluttershy…suppose that the buffaloes all started complaining about Sheriff Silverstar and all the things he’s done they disagree with. It wouldn’t hurt him much. He doesn’t interact often with buffaloes and doesn’t need their friendship. It could even make him better off because he does spend a lot of time interacting with the Appleloosans. He could say, ‘Look how the buffaloes hate me. I must be doing something right.’”

“Then he’s a fool.”

“The Appleloosans are, for buying it.”

“I didn’t think you could disapprove of anything that involved buying.”

Twilight shrugged that one off. Fluttershy wasn’t good at being nasty. “The point is, any buffalo in particular doesn’t gain much by trying to influence and control other ponies. It’s much easier for buffaloes to affect each other. They spend a lot of time around and depend on each other. If a random buffalo said to another buffalo, “We won’t be friends if you don’t stop doing this and start doing that,” it would have a lot more effect than if a random buffalo said the same to a random pony. So buffaloes aren’t going to fight with ponies over how ponies ought to think and act. They’re going to fight with other buffaloes.”

Fluttershy scowled. “And the same is true of ponies, I’m sure.”

“Yeah, obviously, what do you think this conversation is? Are you having fun? I’m not!”

“I’m not going to stop hurting you because we’re friends!”

“I wasn’t asking you too! I would never!”

“So…fine!”

“Now are you going to help me fight this dragon or not?”

“Oh, I was always going to do that.”

“The point is, Fluttershy, the ponies you’re going to hurt the most are the ones closest to you. And the pony closest to you is yourself.”

Fluttershy frowned. “I suppose there’s also a sense in which I’m infinitely far from myself. After all, there’s no distance I can travel to reach myself.”

“Very philosophical and doubtless representative of your current struggle. But more pragmatically speaking…do you know what the sunk cost fallacy is?” Fluttershy shook her head. “Basically it means there’s no use crying over spilt mi—no! It means that, um, losses that occur in the past shouldn’t affect you going forward. I mean, there’s no difference between losing five bits and just not having those five bits to begin with.”

“I could go back and find my bits.”

“Which is the same as just finding some bits somewhere. Ponies will say things like, oh, I already bought these movie tickets, I have to use them. But you don’t. If there’s something you want to do more than go see the movie, then you’re not losing the money you already spent on the tickets. You already spent that money! So it’s a choice between seeing a free movie, essentially, and doing whatever else. The past is not a problem that can be solved. All you can do is confront the given hypothetical.”

“The…the given hypothetical? But this is all real.”

“Of course this is all real, Fluttershy, but why on earth should that mean this isn’t happening inside your head?”

Fluttershy didn’t answer. Minutes passed.

“Do you—“

“I thought of my response, and then I thought of what you would say, and then I thought of my response to that,” Fluttershy said. “So I’ve just been having this conversation in my head.”

Twilight gave a sigh of relief. “That’s why I need you to come up Hark Mountain with me.”

“When we get up there, let’s do the most effective thing.”

“We will, at that place at that point in time.”

“Here and now.”

“Not yet. A little longer.”

Fluttershy didn’t answer. After a while, Twilight went back to reading her book. Markov chains, which had only been a tool before, were taking on meaning….

Twilight lay in the straw bed in one of the rooms the Appleloosan ponies had provided them. Pinkie Pie snored in the bed next to her. With the blanket drawn around her head, Twilight reread by horn-light Gamma’s letter, thinking about externalities.

It was unfortunate, she realized, that externalities were usually taught after markets, as if externalities were the exception to the rule. Twilight knew the reality was very much the opposite. If markets were streams of information, a catallaxy of stars in the night sky, then externalities were the vast emptiness in between and all around. It was necessary to teach markets first because it was only by starlight that the blackness could be seen.[2]

[2] She could hear Pinkie Pie’s voice giggling in her head. “Otherwise it would be too dark to see nothing!”

And then there was her brother—

A hoofstep. Twilight killed her horn-light and peeked out from under the covers, blinking away the purple blotches.

There was a figure standing in the room.

The tip of Twilight’s horn had only just begun to glow when the straw wrapped all around her, pinning her to the bed. It covered her mouth and wrapped around her horn, and a low voice warned, “No magic.”

Twilight obeyed. If Little Strongheart wanted to kill her, a rock through the skull would have done it. Still her breath came quick, and her eyes were wide, because she couldn’t imagine that Little Strongheart’s intentions were exactly friendly, either.

Little Strongheart approached her slowly. Twilight’s blurry vision gradually adjusted to the darkness. She saw Little Strongheart standing over her, the red crystal deep gray in the nighttime. Twilight exhaled, and Little Strongheart’s head darted forward, as if in desperation, like a tiny four-legged mammal might spring away from the hunting king snake. Her teeth closed around the skin on Twilight’s chest and bit. Twilight struggled to keep quiet, then struggled to keep still as Little Strongheart tore at the wound. Somehow tightening her neck helped keep the pain happening to some other Twilight, because sometimes there were things you didn’t want to hear other ponies say, and it was only after Twilight came back to herself that she realized Little Strongheart had laid herself across Twilight, the red crystal smeared in blood.

“Help me,” Little Strongheart gasped. “I can’t take it off—it won’t listen to me—I can’t not listen to it—“

Twilight couldn’t answer, and she wasn’t sure she wanted to. Nightmare Moon had not been so frightening. The terror, yes, the dread, but everything had been understood, foreseen. But Twilight did not understand Little Strongheart; she did not know what this meant.

“Please help me,” she said. “If you don’t, I’ll kill him.”

Twilight’s mind flashed through possibilities—landed on Spike—her horn glowed; the straw tightened, the blanket flew over her face, and only in the pure clarity of panic did Twilight remember what she had known from the moment she had met Little Strongheart.

Twilight awoke to an oat cake from Pinkie Pie and no sign of any wound on her chest. She wasn’t even sure if Little Strongheart had choked her to sleep or just snipped her consciousness from her body. Then—scrabbling—she found the note from Gamma, and exhaled.

Twilight wasn’t surprised to find Spike outside packing supplies for them to bring up the mountain. He smiled proudly at her.

“Good morning, Twilight!” Twilight winced at his enthusiasm. Braeburn was a bad influence.

“Morning,” she said. “Sure you don’t want to come with us?”

“I don’t think I’d be very helpful. Do you?”

“You’ll be very helpful here. Be on the lookout for Braeburn.”

“Because he said he was going to play a prank on Chief Thunderhooves? That was how cider talks in the company of mares; he’s not that dumb. Do you think Little Strongheart is going to attack him?”

“No, I just think he’s incredibly annoying, and I don’t want you around him. Keep the Cerberus company. The girls and I will be heading off soon.”

Applejack, Rainbow Dash, Pinkie Pie, and Rarity said goodbye to their pets, Bloomberg carefully kept close by the Cerberus. Then, with a dozen Breezies to ward the smoke, Twilight and her friends began the ascent of Hark Mountain. Next Chapter: Input-Output Estimated time remaining: 26 Minutes