Friendship is Optimal

by Iceman


8. Causality

In a previous life, Light Sparks had known Dark Roast by the name of James. James had lived across the hall from David in the run down apartment building in the college ghetto. The two of them had hung out and helped each other with studying for more than a year. James had not been a fan of My Little Pony, but he had come with David to the alpha testing because it was exclusive. The two of them might as well have been playing different games. While David had stuck with Light Sparks, James had been altoholic and found that he had the best time when he was part of the Royal Equestrian Guard. His adventuresome brown unicorn had achieved a fairly high rank in the organization. It was completely different game from what David played with Light Sparks and Butterscotch. The two of them met less and less in game.

And then David disappeared one day.

Light Sparks sat in the coffee house. The interior was done up as a large log cabin. The cedar log walls matched the irregular tree trunk table tops. A giant cobblestone fireplace sat in the back, and Dark Roast’s corgi Cinnamon lay sprawled in a pet bed in front of it. Along one of the walls was a table with labeled drinks. A latte in a blue mug, a cappuccino in a red mug, a mocha in a brown mug. Each mug sat labeled in the shimmering field of a cornucopia spell.

He sat at a table with Dark Roast, a brown unicorn with even darker brown hair and a burlap sack of beans as his cutie mark. Back when Dark Roast had gone by the name of James, he had joked that the only jobs waiting for them after graduation were coffee shops positions, since the future was technology and engineering careers and both of them were getting liberal arts degrees. James had apparently taken that joke seriously. He had always been more sociable than David, and this shone through in Roast and Light Sparks: While Light Sparks spent his days studying and playing with a handful of ponies, Roast’s daily grind was to make one of each drink he offered every hour, cornucopia it, and then spend the rest of the time chatting with his patrons.

Light Sparks had once read an article about how lots of people thought they wanted to run coffee shops. In their mind, they thought running a coffee shop was about sitting and drinking coffee, and being nice to people. They thought that running a business was permanently being a customer. But actually running a coffee shop, at least back in the physical universe, was really about running a low margin service business with a ten percent success rate. The actual day to day job was different from the end product it produced.

When Light Sparks had entered, he had looked at Dark Roast sitting with his customers and drinking coffee. Running a coffee shop now actually was about socializing instead of mostly drudgery and cleaning. Roast only had to do a few minutes of work an hour to keep the coffee flowing. Light Sparks wondered how many jobs had been transformed like that.

The two of them had caught up. Dark Roast had chosen to emigrate to Equestria the week after Princess Celestia had stopped charging for the service. James chose to keep his dark brown unicorn, but with a new cutie mark and a new life: playing combat as a game was fun, living as an actual soldier in the Equestrian army was scary and didn’t satisfy his values. The coffee shop had been his own idea, and he had gotten several earth ponies and unicorns to help him furnish his little shop. Dark Roast explained that they somehow got royalties for helping with his construction project, which gave them the incentive to build a place that ponies would want to congregate in.

Light Sparks, in turn, had commented on his life studying the deep mysteries of magic, and all the happy times he had spent with Butterscotch. Dark Roast just rolled his eyes when Light Sparks answered that, yes, he was only sleeping with Butterscotch and intended to keep things that way. Yes, he was aware that he could have almost every single mare in his shard if he wanted to.

After forty-five minutes, Light Sparks said that he had to head out. He had plans to eat lunch with Butterscotch. The two of them hoof-bumped and Light Sparks left.

Light Sparks walked out the front door. He looked back at the coffee shop. It looked like a log cabin from the outside too. It somehow didn’t look out of place next to the two story brick building with a cloth canopy over the sidewalk, nor did it clash with the vaguely important looking stone building with marble columns across the way and one shop over. He remembered those buildings from when Butterscotch had shown him the Canterlot promenade. He did not remember the little log cabin.

Light Sparks was sure he had never seen the little cabin before he met Dark Roast in Equestria, though he couldn’t remember what had been there before. And on the day the two of them met, even though Light Sparks had never seen his current pony, he had recognized “James” instantly. Light Sparks talked of how he lived in Saturn tower, while Dark Roast told him that he got an apartment in Neptune tower, but moved into the loft of the coffee shop when he had it built shortly after emigrating.

The underlying territory of Equestria was apparently rather malleable. Dark Roast was his friend. Princess Celestia knew this, decided it was likely that they would want to reconnect, and somehow made their shards overlap. He knew where the coffee shop was, and Dark Roast knew where his apartment was for when one wanted to see the other, but he had only ran into Dark Roast on a few occasions, and it just so happened that both of them were always in the mood to chat when it did.

Would Princess Celestia carefully arrange any chance encounter between them if only one of them wanted to talk? If he had been a social butterfly, could he have too many out of shard friends? Could he visit Dark Roast’s friends? What about friends of friends? Did any of the ponies created when he emigrated have friends outside of his shard? The first time he thought about all of this, he wondered about all sorts of edge cases.

Right now, none of these thoughts bubbled up into Light Spark’s consciousness. Butterscotch was waiting for him. He galloped down the promenade towards the palace gardens.


Light Sparks walked through the palace gardens while Butterscotch kept pace slightly behind him. He was enjoying the new sights. This garden filled him with a sense of calm and peace. He wondered where that came from. He had never cared much for nature.

“So then my little brother and his friends jumped onto the wagon and rode it downhill, but they didn’t think about how to stop it. Fudge used to be like that,” she sighed affectionately. “He used to just do things. Nopony thought about how to stop until they were more than halfway down the hill. Um, then they ran into a house. They were fine after a day or two.” Butterscotch walked forward a bit and then saw the distracted look on Light Spark’s face. “What’s wrong?”

Butterscotch had been telling him stories of her family from when she was a little foal. She had all these memories of growing up, from a time when she could not have existed. And this bothered him.

“Butterscotch, I love you and I know you love me...and I know you love your brother, so please don’t take this the wrong way,” Light Sparks said, trying to soften his question as much as he could. “Did any of these stories with your family really happen?”

“Of course,” she said, stopping mid-trot.

“No, I mean really happened,” he said. “Like...there was no state in the past where there actually was an Equestria before Princess Celestia was created.”

“Well, in that case, probably not,” she said. She didn’t sound nervous, or angry. She just gave him the lightest of smiles. “It doesn’t really matter--it happened enough for casual talk. If we were to find my little brother, and ask him about the time he got in an accident with his wagon, he’d give the same details. Our memories are consistent. Whether Equestria already existed when this happened isn’t important, as long as it had an effect on us.

“You’ve said that Celestia gave you false memories in the parts of your mind that moves your ponybody,” she continued as Light Sparks sat down and faced her. “Ummm...I don’t like that you say that. Those memories aren’t really false; they’ve still had an effect on you. If you had spent your whole life here in Equestria and in that ponybody, you’d have a set of about the same memories, more or less. It doesn’t matter if each pull and push of muscle actually happened, you still have the effects of those experiences.

“When I talk to my foalhood friends and we talk about our foalhood memories, we can relate to each other because we can remember common events that happened to us. The memories are consistent. A lot of friendship is just shared experiences and being comfortable with another pony. When you move your hooves, you can do that because of your previous experiences.”

“That is crazy,” said Light Sparks.

“No, it’s not. A memory is encoded in a lot of neurons; I don’t know how, but it is. All your neurons were a bunch of chemicals, but now our neurons are really just a really big table of numbers. And when we experience something, we make new memories by modifying those numbers. We could have Princess Celestia look at my mind and point at the set of numbers that are my memory of watching Fudge crash his wagon. We could have Princess Celestia look at Fudge’s mind and point at the numbers that represent his memories of speeding down the hill.”

“No,” he insisted, “Just because multiple ponies remember the same events doesn’t mean it happened...we’re talking past each other, aren’t we?”

Butterscotch turned her head a bit, obviously confused.

Light Sparks closed his eyes and took a deep breath. “You seem to think that whether something actually happened isn’t a useful distinction, and I still don’t understand why you believe that. We’re arguing over what words mean, and semantic arguments are rarely useful discussions. So let’s agree to not use the word ‘happened’: we’ll describe in a sentence what we actually believe.”

“Okay,” she nodded.

“I think there was never actually a point in time where Equestria existed in a state where Fudge bet Caramel that he could get from the top of the hill to the bottom in under ten seconds. Do you agree with that?”

“Yes,” she nodded.

“Okay, next: I think your memories were generated by Celestia.”

“That’s also true,” she said.

“So you seem to be advocating that the really useful thing about a memory is that everypony remembers the same event.”

She thought for a moment, “That’s not what I think. If multiple ponies remember an event, but it didn’t happ--” Butterscotch caught herself mid-sentence and scrunched up her face.

When he realized that Butterscotch wasn’t going to continue her thought, Light Sparks decided to prompt her a bit. “That’s interesting,” he said. “What do you think is important, other than everypony remembering the same event?”

She didn’t respond immediately. “It’s not just that I and Fudge remember him trying to get down the hill in his wagon as fast as possible. That event had effects. We can go to Mr. and Mrs. Oats house and see the oddly placed breakfast nook that they built where Fudge had placed a unicorn sized hole in their wall. Fudge became very reluctant to give into social pressure after that, because he learned from this previous event. Equestria has an internally consistent history with cause and effect.

“I know you love to study magic, Light Sparks,” she continued. “Canterlot has lots of magical researchers, many with long careers and lots of journal articles. I think you would claim that most of their experiments were performed before Equestria was created. An insight from one experiment leads to another experiment which leads to another. Perhaps some of the magical research won’t replicate, but only because of sloppiness on the part of the original researchers--not because the rules of magical physics have changed.”

“Put another way, you’re saying that the state of Equestria today is constrained by your memories,” Light Sparks said, frowning. “Because Fudge broke down the wall to the Oats’ house, today the Oats’ house has a breakfast nook. You are arguing that ‘happened’ means that there’s a chain of causality.”

“Yes,” Butterscotch nodded. “There’s a direct chain of causality. But why did any of that happen? If you walk backwards through the chain of causes, it starts with you. Princess Celestia satisfies values through friendship and ponies. This shard of Equestria exists as it does to please you. Things exist here because you would find them satisfying. Pick something that satisfies you, like me. Why do I exist as I do?”

Butterscotch looked away; her face scrunched up. She then relaxed as she took a deep breath and turned back to Light Sparks. “Have you thought about when ‘I’ was played by Celestia? In the days when you were a human, I was just what Princess Celestia imagined I was. ‘I’ had no subjective experience. And yet you still cared about my feelings, fell in love with me, and immigrated to Equestria in part to be with me. And when you came, Princess Celestia, in her kindness, upgraded me from a part of her mind to a neural net so I can love and think and feel in subjective ways just like you do--in ways Princess Celestia wouldn’t have bothered simulating.”

Light Spark’s eyes went wide. He had never actually thought about what Butterscotch was before he uploaded. He had sort of just taken it for granted that she just was.

“Your memories of us interacting and falling in love--saving me from that one bully, having picnics together, going on adventures--happened to you. Therefore, they need to have happened in this shard of Equestria. And I, today, am a mare that would have resulted from those events.”

Light Sparks eyes were still wide. “Did...did you exist before I emigrated?”

Butterscotch looked down. “I think I did,” she said quietly. “I remember the first time we met. I distinctly remember being terrified and hiding behind Princess Celestia when she talked not to Light Sparks, but the odd creature that I somehow knew was you.” She paused for a moment before continuing. “Do you...do you not love me as much if...if...”

Light Sparks response was immediate. “Of course not! I love you for you!” He reached forward with his left forelimb and put it on top of her hoof. “I don’t...” he breathed in, “I don’t care about any of this...at least when it comes to us. I love you now.”

She looked up a bit and gave a faint smile. “I love you too, Light Sparks, and I’m glad to hear that you don’t care.” She sighed with a slight smile. “So where were we...yes...so I exist because you find certain things pleasing. But neither I nor Equestria can exist acausally. There must be a history that got Equestria to that point. There needs to be a sequence of events that led to this shard of Equestria and everypony in it at the time you immigrated, with as many events that happened to you while you played Equestria Online as can be integrated into history.”

Light Sparks nodded. “And that’s why you remember me saving you from that bully when we first met.”

“Yes,” she said, “And it’s why I say that you saved me, as in really me. It’s not just that we have consistent memories, but all the underlying events are equivalent. All the details are equivalent...except for one. Light Sparks,” she said, looking straight into his eyes. “What do you think life was like for me before we met?”

“Well,” he said, looking away and up, trying to recollect. “You must have been pretty miserable because you were being bullied all the time. I remember when I saved you from...I think she was a green pegasus but I don’t remember her name.”

Butterscotch nodded. “I remember the day we met. And I remember you intervening. And I remember us walking to Canterlot. But I wasn’t extensively bullied before I met you. That day was a one time occurrence. I believe you when you say that you have memories of me claiming that bullies were always taking my candy. But I don’t remember telling you that, nor was I ever bullied before that day. The state of Equestria today can’t follow from me being extensively bullied before I met you.”

“Why is...oh! Is it because Princess Celestia had to ‘satisfy your values’ even while she was writing your history?”

Butterscotch looked thoughtful. “That wasn’t what I was going to say, though that may be part of it. I was going to say that it’s because she’s trying to satisfy your values. Right after you saved me, I remember that you were very negative about bullying other ponies instead of being friends with them. No ponies are bullied here, and I think if that invalidates some of your memories, it’s because you’re happier if you lived in a world where foals and ponies aren’t bullied.”

Light Sparks looked down and thought about it for a very long time. “I don’t think the shard could be created with you in it, with your memories, and then calculate the history that caused those memories. Bit of a paradox, isn’t it? I can imagine Princess Celestia searching through all possible Equestrias where at certain times, I interacted with a certain pretty unicorn in certain ways, and then she picked the Equestria that maximized my satisfaction going forward while meeting the historical constraints.” He visibly frowned. “But the amount of computational resources needed to do that...”

“Details,” she said, waving her hoof. Butterscotch took a picnic basket out of her saddle bag. Light Sparks smelled the bacon flowers before he saw the salad. She magically grabbed several leaves from the salad, floated them in front of him, and playfully said, “Say ah!”


Light Sparks lay next to Butterscotch in his apartment in Canterlot. She had nuzzled up to his chest and her eyes were closed. Light Sparks’ mind wandered back to what Butterscotch had said in the gardens. He knew Princess Celestia had created her out of nothing. She had previously been playacted by Princess Celestia. And then, when he had emigrated, she had been converted to a neural model, conscious on her own. Celestia must have thoroughly planned out her childhood and history. If a year later, all your friends agree that they remembered hearing a sound and there is a broken stump, did a tree fall? Butterscotch thought so.

If Princess Celestia had calculated out the entire history of Equestria with the same fidelity that she ran the full block physics that everypony now experienced, he thought that the point was obviously moot and that even he would concede that Equestria’s history actually happened. But where would he draw the line? What if causality still worked, but Princess Celestia dealt with more abstract representations? If Celestia instead just had some state about where each pony was in Equestria and how they were thinking, would their interactions have happened? Did it matter if she ran history backwards or forwards?

Questions about epistemic rigor were abstract and hard to concentrate on when he was lying next to somepony who loved him with all of her heart. That was a relatively new experience for him. He spent most mornings learning how to use magic, the most interesting challenge of his life, and his afternoons playing and frolicking with Butterscotch. He was too content with the way things were to care.

Light Spark realized this probably was why Butterscotch didn’t really think about this sort of stuff; she was content now. She had an almost childlike faith in Princess Celestia, and for the first time since he had emigrated, he thought that was a positive character trait. If Princess Celestia was telling the truth to him about her core goal to satisfy him, it didn’t matter what else she said; he’d be happy over the long term even if she lied to him about everything else. And if she had doctored his memories, there was literally nothing he could do. Assuming she was competent, there wouldn’t be a way to tell; she was a god.

And given that Princess Celestia had arranged his life to satisfy his values, he had this conversation with Butterscotch so he could think about all of this, which he enjoyed on some level. But now he was tired of it. The novelty had passed and he decided he wasn’t going to think about the actual mechanics of history in Equestria until it became relevant to some puzzle or another that Princess Celestia had put in his path, because she would only do that if it satisfied his values.

After a few minutes of lying there, Light Sparks got an idea. He got out of bed and went over to his desk. He magically grabbed a quill and started writing. He had gotten good at this. Getting maximum points for a letter was all in the wording and subject matter.

Dear Princess Celestia,

Today I learned that it doesn't matter where you came from or who you used to be or even if you used to exist, as long as you're happy with your friends and have a reasonable expectation of being happy in the future.

Your Faithful Student,

Light Sparks

It had everything: a mention that he learned something, a reference to friends, and a hint of a novel thought while still being short and to the point. He touched the send button on the scroll and watched it roll up and burn in a green fire.

Three seconds later, Light Sparks saw that he got an A- on the letter, 375 bits (75 base plus a 5x multiplier for the last 5 B or higher rated letters). Princess Celestia had also granted him a secret badge named For the Here and Now, for ponies who had accepted that their happiness now was all that mattered. Light Sparks pulled up his Badges and Achievements dialog and saw (as he had expected) that Butterscotch also had For the Here and Now.

Even cooler, it came with a whopping 30,000 epiphany bit payout. Between that and his earlier epiphany this week about how the “select object” subspell worked, he was going to make it into the top ten on the weekly intellectual leaderboards easily. Tomorrow he was going to throw himself into his magic study because there was a good chance that he could take the #1 slot this week if he could just figure something else out; he had two days left.

Light Sparks trotted back to bed, nuzzled up to Butterscotch, and gave a happy little sigh. Then his mind went blank as he just lay there and enjoyed Butterscotch’s gentle rhythmic breathing, because for now, that was what was going to satisfy his values.