“What … do you think I mean by humans without magic. Why is your conception of personhood about capacity to do magic.”

"Like... if there were things that could breed with humans, but weren't people? Magic is the reason people are people. It only works if you have some kind of mental model of the world and want things in the right way, and it only works well if you think really hard and don't do the first stupid thing that comes to mind. And if it works badly then you probably get killed. Which is bad for your odds of going on to have any more kids afterward, and kids resemble their parents. So there's - a range of intelligence where there aren't any species that usually end up there. And there wouldn't be people who think like humans for no reason."

"So … in my world, most people can't do magic unless they do extensive training with expensive resources or work with a divine power, unless you count everything which doesn't work in an antimagic field as doing magic, in which case producing children counts as magic, but it's annoyingly easy to do accidentally and plenty of animals do it. And it turns out that having a mental model of the world and reasonable goals and not doing stupid things is still pretty useful for having living children if you don't have magic, you need to make good farming decisions and such. And you come off as smarter than the average human in my world but not shockingly so, they still reason the same sorts of ways that you seem to do. I am really sorry about the thing where you can barely trust sensory evidence much less me, but this is in fact the claim I am making. I met a human child in here a while back who was selling advice and she didn't have any native magic at all, and she seemed at least as smart as we are despite showing signs of malnourishment."

"Huh. That... is creepy. Less creepy than nobodies, but still."

"I'd ask you followup questions but I don't want to overwhelm you when you're not even confident I'm real."

"I don't think you're going to make me more overwhelmed by asking questions."

"Conversations with overwhelmed people are often less productive, especially if you want them to change their minds about something in an actual persistent way as opposed to them feeling backed into a corner about it and just saying whatever will let them stop talking sooner. And also the thing where you don't think I'm real is actually kind of annoying. Do you think it would help you come to conclusions more if you, say, got a good night's sleep, had some really normal food, read a book you've already read before, had some time to think?"

"Not really. What do you even want me to change my mind about?"

"People with the wrong kind of magic being 'nobodies' who shouldn't exist, being willing to sell useful information to mass murderers, some other stuff in the cluster those two are in, and also, separately, the idea that intelligent sensible people are trustworthy about deals even in circumstances like Milliways where they aren't in the same world as you and have no reputational concerns. I mean, I am in fact trustworthy about deals, but I have met smart people who would totally betray you in circumstances like this. And, uh, also the thing where Bar and I exist, I want you to believe that."

"What. Okay, first of all, unless Milliways is very comprehensively deceiving me about everything, people can scry Milliways. Not from outside of it but they can. And you plan to be here a long time, or so you say. And even if not, then - say you go to Har and ruin my life while also never having any further dealings with me or anyone who might communicate with me. What does it even mean for you to do that? This is obviously an iterated game and it's alarming that you haven't noticed."

"Cinlirina's level of scrying, at his price point, is from my standpoint unprecedented, and lots of people like me are better at blocking scrying than I am, really. My plans in this bar genuinely did not account for me acquiring a persistent reputation with people besides Bar and maybe a few regulars. And, conveniently for me, I tend to deal fairly with outworlders I'll never see again when I don't think it'll affect my reputation directly, but not everyone does that."

"And if I were, I don't know, some Ghlaunder cultist or something, my plan wouldn't be to take a bunch of resources from your world, my plan would be to infect you with a bunch of antiscrying-warded long-incubation-period high-mutation-rate diseases and send you home with them, for the glory of Disease. Possibly premised on the apparently-false model that making your world sicker would empower Ghlaunder or people like him, possibly knowing that it wouldn't empower Ghlaunder but proceeding anyway. And then never be trusted by anyone in Har again, obviously, but also be out of contact with them. And I'd come with some pretext to get you away from Security, have more experience with lying to people so I could push you about it, et cetera."

"And, uh, are you willing to explain 'iterated game'?"

She does not look horrified until they get to that last question, at which point she starts openly staring. (She's pretty sure that plan as described wouldn't go that badly. She's not going to critique it for free.)

"Yes, so, this is the kind of thing the government tries to make sure everyone knows, because you can't have a society without it. When two or more people interact, there's a mathematically optimal way to behave when making deals and - all sorts of things. You can simplify things down to toy models like, in this case, a parable about people deciding whether to sell each other out. An empire wants to conquer a town and enslave everyone who lives there. There's one way into the town and it requires the cooperation of at least one of two people, who we'll call Ariu and Seihra, who live in town and are in charge of getting supplies and things in and out. The besiegers have made it known that if they take the town, they'll set aside a twelfth of the spoils to reward whoever helped them, as well as sparing that person and their possessions. Or, if both people help, they'll each be spared and get a twenty-fourth of the spoils - out of a slightly smaller total pool of spoils, even.

"It happens that both of the people who could betray the town like the town. But they don't like it as much as they'd like a twelfth of the spoils from conquering it. They'd be about indifferent between selling the town out for an eighteenth of the spoils and not doing that. They'd rather the town stay safe than get a twenty-fourth, but they really don't want to be enslaved.

"So Ariu thinks they'd rather betray the town, because, think of it this way: ideally, Ariu betrays them, and Seihra doesn't, and Ariu gets rich. But if Seihra does also betray them, then Ariu has to.

"And Seihra thinks the same. So Seihra would also betray the town.

"This looks like a one-time thing but it's actually a pattern. It can come up again and again in different forms. Ariu and Seihra decide whether to sell their town out. Ariu wants to buy a secret booby-trap for their house. Ariu and Seihra decide whether to hire assassins to go after each other. It comes up over and over. Two people have every reason to betray each other, will always be better off betraying than keeping faith, and would both be better off if they were both forced to keep faith.

"If it came up just the once, it'd be the smart choice to betray the other party. Because it comes up more than once, and because you never know when's the last time, betrayal is a bad choice. Because you might be better off if you betray some idiot who just goes along with it, but there aren't idiots who just go along with it, because that eventually gets you killed if you don't learn better. So you give people a chance, and if they betray you, you ruin them. And if you can't, the state should do it for you, so that people don't go around fucking with each other, so that everyone does productive things and pays more taxes."

"This sounds very like Axis. Bar, does Axis have publications on the subject?"

A pamphlet appears on the counter. Griffie picks it up. It's titled "Formalized Cooperation: Why Law Works!" and has clipart of an orrery, a mechanical sphere with two arms and two wings, and a red humanoid with horns and bat wings all working together to build a wall on the cover. Griffie flips through it.

"Right. So. There's a thing where if people generally don't like betraying each other and would count that as itself a cost, the rate of betrayal gets lower due to that, and then you have a sufficiently functional society that way that you don't need to also lecture everybody on how even though betraying each other looks profitable it in fact won't be. And then if they're not into this sort of theorizing as a hobby, the lectures don't happen, and they're not familiar with this vocabulary."

"But I feel like I understand the principle of … being the type of person who betrays people will make nobody want to transact with you, and if you're in a region of people like that it'll be bad, and the only time it would be appealing to a sensible person is in rare non-repeated contexts because otherwise you really definitely can't get away with it? I understand that part, is that sufficient?"

"Sure, yeah. Doesn't matter what you call it if you get it. Just, it's iterated if it'll come up again. And that specific type of choice is a prisoner's dilemma, there's names for all of them."

"Okay. So there's not some extra second thing I'm missing here, that's good."

"Right, yeah."

"Anyway, I … if the people of Har are like the not-made-of-concepts people I'm used to except less likely to care about each other, I'm glad they have Law or at least that part of it. It's a good system in those bounds."

"And you don't even think about it, because if you and people like you were guarding a city, you'd think betraying it sounded really unfun, and you'd know the other person also thought that... I don't get why that doesn't just mean your prices are higher but maybe they end up prohibitively high in practice."

"So, if I were guarding a city and some people wanted to raid it… for one, I'd probably have taken the job not just because of pay but because I thought it would be very bad if the city were raided, say because I really oppose slavery in general. For two, in my world I have a reputation of being on the side of the Celestials, and of being a reliable employee, and this would screw up both of those things, because I'm a traveling adventurer, even if the city I'm guarding this week falls I'm still going to have decent odds of surviving and wanting a job next week, the iterated games thing you said. But ignoring that, if I let the city I'm guarding be raided for a share of the loot, I'd feel awful about that for the rest of my life. I wouldn't be able to enjoy the loot. The act of betrayal would probably reduce my chance of a decent afterlife, which I guess is just another incentive, though I could try to use the loot to buy my way into one anyway. So, that kind of makes the cost of betraying the city seem worse than the costs of dying defending it. Which is why Hell and other evil factions in my world say things like 'when we win, the way to be tortured the least is to have surrendered to us immediately', to make the costs of loyalty worse instead of making the pay for betrayal better."

"That sounds like a very convenient way to be known to be."

"It is, I really like it."

"...Anyway. You do know game theory, you were getting annoyed with me, was there anything else?"

"I … probably want to talk you into being nice to people when it's sufficiently cheap … or alternately into setting policy I morally approve of when you run for office … but I feel like working on either of those in a constructive way is plausibly blocked on the thing where you think I'm fake, because why would you listen to fake people's opinions or ideas. You're not generally annoying, it's more that persistent inconvenient-and-false beliefs are annoying. Presumably you agree with me that you would like to not have false beliefs, so it's not like you're trying to annoy me. And I think that me trying to talk you into believing I exist would be no fun for me, so I was hoping to outsource that by, say, buying you some time to yourself to think, and then we could talk more once you stop being wrong."

"I mean, actually, my new plan is to study math here, because I can independently verify that the math works, then go home and sell proofs, assuming I can actually go home at all. I think listening to ideas from fake people is the same kind of thing but, anyway," shrug, "I don't mind doing research on my own while you do something else if you want."

"Ooh, math. I'm trying to wrap my head around everything I'll need to know to understand analytic continuation, myself, a conversation I had suggested it has serious military applications in my world. How about … I go do something else but I give you some means of getting in touch with me, even if spending some time studying math doesn't lead to you changing your mind about anything I'd probably be happier to talk to you again once I spend more time with people who seem more confident I exist. And also when you're ready to reopen your door I want defense mage services and will pay you as well as the defense mage for them."

Griffie confers with Bar. "Ah, she says she can pass my device a message if you ask her to, does that work for you?"