"It's the Rovagug situation," says Gregoria, "which you solve with an oath, if you're a god or a king or it's very important."

- note to self which is coming too late to do any good figure out why Keltham shouldn't just ask them all for oaths because if he does that everything's going to fall apart or everyone be forsworn by the end of the day. 

"And which none of you have the training to do," she says, which is false, because they were just about to be deployed to the Worldwound, but she's pretty sure it is worth lying about. 

"I wouldn't have expected anyone here to know how oaths work, now that I think back on it using my current knowledge.  That takes Law well beyond the level of the stuff I was just teaching you, along that same pathway, and I would've expected it to be straight-up too Lawful for Golarion period - wait.  What does the Taldane word 'oath' mean to you?  I know what it translates into in Baseline but that may be deceptive."

No one else answers, probably because she's now established that they're lying and so they don't know how much lying they're doing. She isn't sure either. The Taldane books did mention people taking, and occasionally breaking, oaths of fealty but Taldor's not a Lawful country. - oh, there is an angle on making Keltham not want to insist -

"It is when you swear by your god to make a commitment in the way that gods make them, where you cannot be the sort of person who'd break them, and if you do break them you've betrayed Law enough you lose your afterlife and your soul goes to Abaddon and gets eaten. ...with some caveats."

...okay, in retrospect, the situation where he was doubting her intentions right after they met, where the alien with vital knowledge for her entire world expressed doubt about a statement she'd already made and knew to have been honest, might very well, for all she knew, have been that urgent, but FLAMING SHIT CARISSA.

What even is the POINT of doing THAT if the alien doesn't KNOW THAT'S HOW IT WORKS -

She didn't know he didn't know that was how it worked.  Though, the absence of gods and afterlives should've been a hint -

Maybe she just didn't think of that fast enough.  Time pressure.

"I see," Keltham says rather shakily.  "Well, no gods or afterlives in dath ilan, so we - try to understand enough Law that - we're governed by the same sort of Law that governs gods directly?  Which dath ilani short of high-ranked Keepers can't actually do, but even at levels short of that, there's a shadow of the Law whose connection to us shatters a little more each time it's betrayed, not just for us, but all across everywhere governed by math, which is understood by society to be a serious affair.  When people write novels about aliens attacking dath ilan and trying to kill all humans everywhere, the most common rationale for why they'd do that is that they want our resources and don't otherwise care who's using them, but, if you want the aliens to have a sympathetic reason, the most common reason is that they're worried a human might break an oath again at some point, or spawn the kind of society that betrays the alien hypercivilization in the future."

Humans on Golarion totally do break oaths but the Chelish students think that anyone who wants to murder them all about it is pretty justified, though Asmodeus would probably collaborate with that entity on instead making them all stop by enslaving them. 

"I - am guessing, theological education doesn't mostly get into the details of this if you're training to be a combat wizard, but I think that - the thing you just said - is also a shadow of why Asmodeus was angry, when humans were given free will."

"Not quite valid under my own utility function, but understandable for Asmodeus, yeah."

"Anyways.  The Ultimatum game is the shadow of a situation that isn't rare enough, in real life, that you could afford to deal with it using solutions that require gods, kings, and risking your literal actual existence.  What other solutions can you come up with?"

"I mean, you can just have a reputation for turning down trades where you don't get much," Meritxell says. "Or if you expect to be deciding the split about as often as vetoing it you can try to specifically play nice with people who play nice with you."

"Well, let's run a trial then and see who can end up with the most hypothetical jellychips after 5 rounds, everyone paired up at random in each round, all results of previous rounds public.  That's not the same instruction or incentive structure that dath ilani kids get, their instructions are to seek more jellychips not the most jellychips, but frankly I'm curious what you peculiar aliens do if you get that instruction instead."

The students offer and accept 50-50 splits all around.

Keltham pauses them after round 1.  "Nobody can end up with the most chips if you all do that," Keltham observes.  "Don't get me wrong, that's fine for the real life situation and it's what dath ilani kids do with the usual instructions, but you can't play to get the most chips that way.  If I already had money I'd offer an actual gold piece - or fraction of one, depending on how many I had - to the winner."

"I'm not sure there's a strategy for ending up with the most beyond hoping other people fireball each other," says Meritxell. "Or offering out of context rewards for cooperation but I assume we're not supposed to do that either."

"Well, I didn't tell you that you couldn't!  The less a game is winnable by ordinary means, the more it's implied that maybe you're expected to go outside it."

"Why didn't anyone try offering a 7:5 split?"

"If you accept that then you definitely lose the overall game, you're going to end up with a lower score than other people. And since you've lost anyway you might as well burn them to the ground so they know not to mess with you."

"I see.  I suppose the same would've applied to announcing that you wouldn't accept any splits less than 5:7?  Anyways, among the tactics I'd try in that situation is offering to generate a random number and split 11:1 or 1:11 based on that, in which case we'd each have a fifty percent chance of winning the whole game, if we did it on the last round and nobody else had caught on earlier."

"...no one would believe you that you really did that, though."

"Ah.  Clarification.  It's not assumed in these games that you're supposed to roleplay being not trustworthy.  Unless you've got a card from the older kids telling you to do that, but, at least at the age this game is usually played, they'd always tell you in advance if cards like that might be handed out.  I didn't tell Meritxell to cheat, with the card I gave her, just for her to try to end up with more jellychips."

"Though in this situation, if it's the last round, there's not much of a loss from carrying out your part?  If you both witness the randomness generation and it says you get the lower side of the split, failing to follow through at that point just causes nobody, including you, to be the winner.  The game instructions don't say that you do any worse by scoring lower than average - you either win or don't win.  It's a bargain where you don't actually lose anything from following through, even if you lost, which is part of the reason I'd expect it to work even in a lower-trust situation."

"Oh, you mean if you use something publicly observable to decide which of you gets the split?"

"Yeah, my - time-telling device that attaches to my wrist - would've done it, but that didn't follow me here.  Anything with a precise physical symmetry will do, though, like if it's got two identical sides you can toss it upwards while spinning it, and you can both see which side lands facing upward."

"Totally random question I keep forgetting to ask, how do you tell the time around here?"