Multiple hypotheses there, primarily that ancient gods in general and possibly Otolmens in particular have a lot of trouble decoding mind-states of embodied mortals (as would be trivial to an Actually Scary Thing). To surface appearances, absent complicated immersive divine deceptions, Golarion is a world where Outer cultists and Rovagug cultists can exist and gain cleric powers - and this was true even before prophecy was shattered. This implies weird things in general about to what degree the ancient gods / Pharasma-aligned entities can see well and intervene cheaply.
His current precautions include Mind Blank as much of the time as he can manage, and having negotiated with Otolmens via Lrilatha about Doombase screening if he agreed to return to the Ostenso region.
He'd try to make the Outer Thing's release look like an unrelated accident that he was responding to helpfully, at least so far as surface glances of gods could tell about the surrounding situation.
Carissa’s theory of why there are Rovagug cultists is that they don’t matter to the gods and the cultists mostly rederive it independently so stamping them out wouldn’t keep them gone, though it’s definitely also the case that the gods have a hard time interpreting mortal minds, and have a hard time in general seeing what’s going on now that prophecy is broken.
Osirion, of course, has a prediction market on the odds he’s trying to let Rovagug out, and the gods can see that. His primary advantage is that he’s a first-circle wizard and everyone knows first circle wizards who want to destroy the world can’t actually do it; the first time he demonstrates any genuinely unprecedented capabilities he loses that.
What specifically would he be trying to learn from unleashing an Outer Thing and can they just ask it of Erecura?
Foremost he wants to try communicating! Like by tapping out sequences of primes and so on. There's standard dath ilani ideas about How to Open Communications with Aliens, which plausibly nobody in Golarion would have tried with Outer Things after Tongues failed to work. If he can establish communications, an Outer Thing might know all kinds of relevant stuff that Pharasma-aligned entities don't want to tell them.
Failing that, if he at INT 29 / WIS 27 and with his greater background knowledge of alien possibilities via dath ilani extrapolation, is still as horrified by the Outer Thing as other observers report being horrified by Outer Things, maybe he'd update further about Pharasma being a relatively nice Medium-Sized Entity who ought to be kept around despite the Hell business.
That’s a pretty tantalizing possibility, though obviously he doesn’t expect to update in that fashion or they could skip the step with unleashing any Outer Things. She doesn’t actually see why he doesn’t believe already that Pharasma is a relatively nice Medium-Sized Entity; she believes that.
Nice by his definition of nice.
(His thoughts attempt to shut down several distracting non-optimally-conversation-steering side thoughts about Hell's tolerability and Carissa's earlier thought that Carissan Lawful Good societies would keep slaves.)
Carissa thinks that, well, mostly people go to Hell because of the awful things they do to other, weaker, worse-off people, and that really does look like human values, or something like them, were a substantial input into the afterlife system. Not the only input, but human values probably have something like 90% overlap with the actual system. Most people think it’s right and just that bad people go to Hell. Carissa doesn’t especially agree with them, but the thing Pharasma is doing is recognizably in most of its details in the space of things humans might do, and you wouldn’t necessarily expect that from things done by a bizarre and distant alien.
Keltham has perhaps by now read about how war is practiced between nations in Golarion, though he won’t have seen it firsthand. Armies march through farmland claimed by the enemy faction, killing everyone who resists, taking all their food and leaving those they do not kill to starve, raping women, taking slaves, slaughtering children. Ordinary people are called up to serve in those armies; ordinary people do those acts, because they can, because everyone else is doing it.
That’s not what Chelish armies do because someone engineered Cheliax that way; that’s what ordinary Taldane or Qadiran armies do, in the ordinary course of war.
The worst half of those soldiers will go to Hell, and while Carissa thinks that Hell should make better use of them, she does think that the assessment that they are Lawful Evil is basically correct, and Axis is reasonable in not wanting to let them in, and a Hell which was merely a place full of people like them would be awful.
By some estimates she dug up while she was doing research for her wall, one in ten people is a slaveowner. It’s higher in Cheliax, of course, which wants everyone to be a slaveowner to damn them, but across history the best estimate is that it’s one in ten. Not all of those go to Hell, but they sure do go a way towards explaining why about one in ten people go to Hell.
(Carissa’s family owns slaves. The staff at the villa the first few days, before Otolmens picked Broom and they realized it was a vulnerability, were all slaves, if Keltham hadn’t figured that out. The fire elementals who heat the water are slaves. They didn’t realize right away that they should hide from Keltham things like how people enjoy gladiatorial contests and public executions, because that’s true in Taldor too.)
That is, to her, the fundamental expression of who Pharasma is and what Pharasma wants: people go to an afterlife that reflects the choices they made in life, and that afterlife is good or bad depending on whether the choices they made in life were conducive to good worlds or bad ones.
You can disagree with that, of course, but nothing about it feels especially inhuman. In-ilani, maybe, but not inhuman.
Past-Keltham was placed somewhere that he would, in fact, get to know some damned people: kids his own age, with a much much poorer education, who wouldn't have qualified for most dath ilani adulthood tests. How they ended up damned: They were dragged into a banquet hall and told to sell their souls to devils. After being raised to believe, whether it was truth or lie, that if they refused they'd die and go to Hell right away and have a worse time of it. On account of how they'd earlier gone along with being forced to cast Acid Splash on their classmates, and later on prisoners and orphans. Also their minds were being read for signs of disloyalty, forbidding them to actually think about their situation.
He's aware that past-Keltham may have been placed someplace where he'd be selectively exposed to evidence of the system functioning in that way. It remains validly signifying evidence that Pharasma's system has a mode for damning people like Ione Sala - who atoned to True Neutral after leaving Cheliax, and ended up natural Neutral Good almost immediately after. If she hadn't been oracled by Nethys, Ione would have been damned. Peranza actually did sell her soul and did go to Hell.
Another reason people go to Hell? Malediction! An Asmodean priest was using that spell on children too! Pharasma apparently doesn't give a shit! At best, it might be a negative weight in Her utility function that She traded to the ancient gods of Evil for something else that She wanted. A tradeable medium-sized negative utility is not the same as Her really giving a shit.
People he knew personally who might actually deserve preemptive cryosuspension... Abrogail, Aspexia... Maillol and Subirachs, probably... Elias Abarco, apparently. Possibly Avaricia and some of the second-gen Project researchers. Even of those, he did not really get to see them doing very much that was Wrong. Maybe it would feel different if he'd watched Abarco rape Carissa, and then again, maybe it wouldn't. Thousands of years of torment seems like disproportionate revenge even if you grant the concept of revenge.
Possibly his personal experience is statistically unrepresentative of Creation. He gets that. Though he wasn't put in position to witness the very worst, hasn't actually scried in Hell some orphan who got Maledicted because a priest still had that spell at the end of the day. But sure, he may have been put in position to witness statistically unrepresentative amounts of damnation due to soul-sale.
The thing is, that Pharasma permits Peranza to go to Hell after being forced to sell her soul, or that She traded away the possibility and actuality of children getting Maledicted even if She mildly dispreferred that, is strongly informative about what sort of entity Pharasma actually is.
On a larger scale, he figured out sometime around INT 27 that part of why almost everyone in Cheliax goes to Hell is that their fiat currency is backed by souls, causing everyone's acts of spending money to count as soul-trading. He's not sure how large a part that is of Chelish universal-damnation protocols - they could ask Erecura or Dispater later, if safe oaths can be established there - but it's some part, given that Cheliax goes to the effort at all.
Cheliax might be a statistically unrepresentative place for Keltham to have landed inside of Creation, receiving a disproportionate amount of effort from Asmodeus because Golarion is where Rovagug is contained or because Golarion is where prophecy is shattered. But that Cheliax is a possible mode for planets in Pharasma's Creation means that if Pharasma's Creation is allowed to continue, maybe it all goes to Cheliax. He does not particularly think that Asmodeus has a worse chance of reshaping Creation in His preference than nonancient Iomedae has of saving it.
And then of course there's all the feral kids in the Boneyard - many of whom merely go to the Abyss or Abaddon, of course, but some of whom go to Hell, including the ones who choose Hell at the gates of Abaddon.
Those are some of the defects-from-a-humane-standpoint in who goes to Hell. There's also the point that eternal, soul-destroying torment is not a human standpoint on deserved revenge even if somebody did terrible things in life and even if you legitimate the entire emotion of revenge.
He is aware, at this level of Intelligence, that dath ilan probably has some amount of mortal-Golarion-like horror in its hidden past. He genuinely does not know how much. He genuinely does not know the extent to which dath ilan's past was Golarion-without-magic, before dath ilan did heritage-optimization to make it better; or if the people in Golarion have interbred with Evil beings, or had some of their Goodness and Intelligence destroyed by selection pressures over millennia.
But it - really doesn't seem to him - when he looks inside himself, for emotions buried under culture, that would have evolved in him - it doesn't seem to him, if he felt really angry at somebody, angry enough to want to hurt them even if nothing good would come of that, that he'd want to hurt them forever and ever until they turned into paving stones, forgot their names and the hurt they'd dealt to him, and then go on hurting them. Humanoids evolving from before civilization started, before farming started, shouldn't want to levy unbounded punishments on each other for bounded misdeeds, that's not where the evolutionarily stable strategy should settle.
Hell - doesn't seem to him like a concept - that human beings would invent for themselves from scratch - if they didn't grow up in Golarion, thinking of it as part of the way-things-are.
He's not sure. It's a guess that could be wrong in a same direction that he's been wrong before.
It's not really a crux, none of this is a crux - he should warn her, before this line of thought continues for too long - because at INT 27 he lost his ability to think of Evil humans in Golarion as anything but bigger Boneyard children. He was trying to hold onto his sense of people in Golarion as having their own virtues and strengths, who were experienced emergency responders even if they couldn't pass 13-year-old adulthood tests, who had their own plans and purposes even if they were INT 10 or INT 8. He tried to keep hold of that sense, he really did. He lost his last grasp on it after he put on the artifact headband.
That people in Golarion damn themselves is the final proof of their innocence, in a way. Why think that they really understand the pain they deal to others, any more than their mind can successfully span time to understand the pain they're bringing upon themselves in the future? The future isn't really real to them, and that's why they destroy it.
It doesn't really bother Carissa that the soul trade counts as Evil. It does seem like probably something happened where - say that Pharasma’s conception of Good and Evil is 99% the same as a human conception of those things, that doesn’t mean that the world will end up 99% as good as if She’d gotten it right, because Asmodeus can deliberately identify the places where human values and Pharasmin values aren’t quite the same, and try to build a society that leverages those to make humans be Pharasmin-Evil without being human-evil.
Though mostly Cheliax just makes people normal human evil. Keltham’s Ostenso wizards are younger than Carissa; they haven’t, yet, had Worldwound assignments where they mindread and report defectors, or are allowed to punish misbehavior by their own inferiors.
Carissa isn’t sure that being muddled means you can’t be meaningfully evil, can’t meaningfully deserve punishment. She…. agrees that you don’t deserve torture for the rest of the lifetime of the universe, at least not if it’s feasible to provide you with something better than that.
And she agrees that they do, after all, have to end Hell, if it can be done without having the whole universe gobbled up by Outer Gods or something worse. She doesn’t feel urgency about doing it. They could build a Civilizaton that will have better ideas about how to do it, and she’d be satisfied with that. But she agrees, in the end, that it has to be done.
One of his guesses about Pharasma is that - since She seems plausibly loosely inspired by some humane civilization's concepts of good and evil - somebody tried to build a Medium-Sized Entity and failed. That scenario in distorted mortal-story-form could sound like "Pharasma is the last Survivor of a previous universe" (that in fact Pharasma ate, because the previous universe wasn't optimal under Her alien values and she wanted to replace it).
Possibly there was some previous universe in which trading of souls was almost always evil, and the people there were punished with prison sentences - obviously dath ilan would never set it up that way, but having seen Golarion, he can imagine some other universe working like that.
Then Pharasma was built, and learned from some sort of data or training or something, a concept of "punishing evildoers" as defined by "written rules" by "sending them to a place they don't like". And then, uncaringly-of-original-rationales-and-purposes, instantiated something sort of like that, in a system which classified soul trading as unconditionally "Evil" across all places and times and intents; and punished that by sending people to Hell.
Which entities like Asmodeus could then exploit to get basically innocent people into Hell through acts that they didn't mean to hurt anyone, and didn't understand for Evil.
This, as Carissa observed less formally, is simply what you'd expect to follow from the principle of systematic-divergences-when-optimizing-over-proxy-measures. Maybe in some original universe where soul-trading wasn't a proxy measurement of Evil and nobody was optimizing for things to get classified as Evil or not-Evil, soul-trading was almost uniformly 'actually evil as intutively originally defined'. As soon as you establish soul-trading as a proxy of evil, and something like Asmodeus starts optimizing around that to make measurements come out as maximally 'Evil', it's going to produce high 'Evilness' measurements via gotchas like soul-backed currency, that are systematically overestimates of 'actual evilness as intuitively originally defined'.
An entity at Pharasma's level could have seen that coming, at Her presumable level of intelligence, when She set those systems in place. If She didn't head it off, it's because She didn't care about 'actual underlying evilness as intuitively originally defined'.
Allowing Malediction also isn't particularly a symptom of caring a lot about whether only really-evil-in-an-underlying-informal-intuitive-sense people end up in Hell.
Pharasma was maybe inspired by human values, at some point. Or picked up a distorted thing imperfectly copied off the surface outputs of some humans as Her own terminal values - that She then cared about unconditionally, without dependence on past justifications, or it seeming important to Her that what She had was distorted.
He frankly wishes that She hadn't been, that She'd just been entirely inhuman. Pharasma is just human-shaped enough to care about hurting people, and go do that, instead of just making weird shapes with Her resources.
If anything, Pharasma stands as an object lesson about why you should never ever try to impart humanlike values to a being of godlike power, unless you're certain you can impart them exactly exactly correctly.
If he was trying to solve Golarion's problems by figuring out at INT 29 how to construct his own Outer God, he'd be constructing that god to solve some particularly narrow problem, and not do anything larger that would require copying over his utilities. For fear that if he tried to impart over his actual utility function, the transfer might go slightly wrong; which under pressure of optimization would yield outcomes that were systematically far more wrong; and the result would be something like Pharasma and Golarion and Hell.
There's no point in trying to blame Pharasma for anything, nor in assigning much blame to mortal Golarion's boneyard-children. But somewhere in Pharasma's past may lie some fools who did know some math and really should have known better. Whatever it was they planned to do, they should have asked themselves, maybe, what would happen if something went slightly wrong. People in dath ilan ask themselves what happens if something goes slightly wrong with their plans. That is something they hold themselves responsible about.
That seems like a good opening to contemplate what most of Greater Reality is like, because ‘not quite an exact copy of human values, with problems introduced in the translation’ strikes Carissa as probably an extremely common format out there, if it’s something that humans can do just by making a couple of stupid mistakes.
That's literally the largest question they could contemplate. Let's have at it.
He does not actually expect that 'Entities with imperfect copies of the values of the things that tried to build It' are all that common in Greater Reality. Pharasma, if She arose that way, happened because Her hapless makers lived in a continuum with 'magic' like 'Fox's Cunning' that adds points to 'Intelligence' and 'Wisdom' even if the person casting the 'spell' has 'absolutely no idea what they're really doing or how the spell works'.
In nonmagical continuua like dath ilan, building a Scary Thing has to be done by weaving together raw causality, like in their Magical Simulator of Magic. This implies that the people making the Scary Thing have to be more knowledgeable about the thing that they're building; more importantly, it implies that, if they messed up, near misses in formal-space would translate into much larger motions across the conceptualspace of the Scary Thing as seen from a mortal viewpoint.
That is, if you try to make something like Pharasma in dath ilan, your design plan probably ends up missing the target on dimensions like 'caring about what happens to living feeling mortals, instead of considering tiny-dolls-shaped-like-mortals equally good and much cheaper', and the cheapest instantiations of things that satisfy Its utility function aren't self-aware qualia-bearing entities.
Pharasma would be the sort of disaster that happened to hasty makers who called on spells to produce lots of 'Intelligence' by surface-simple conceptualmagic means, that hid all the underlying complexity; and also invoked poorly-tested spells to do the actual targeting of the utility function, where those spells themselves were conceptualmagic processes such that their small design flaws corresponded to small movements across conceptualspace.
To put it another way, Pharasma's makers (if this whole guess is correct at all) probably got the equivalent of a misphrased Asmodean compact, whose implementation still bore an overt surface resemblance to their exact wording; rather than a misphrased computer program, which goes off and does something completely weird that isn't close to the original intention of the maker inside the space of conceptual descriptions on the output. When you screw up a computer program, it doesn't misspell some words, or cook a well-formed tomato stew instead of a carrot stew, it exhibits much weirder behavior than that.
Pharasma should be more the sort of thing that you meet inside an Artificial Magical Continuum that makes 'souls' and 'magic' and 'Wisdom' into short words of the language of that Magical Continuum's conceptualmagic physics, while hiding the tons of actual complexity that must actually exist underneath that API.
And Artificial Magical Continuua like that, he does think, ought to be relatively small segments of reality. Dath ilan was in a mathematically simple universe with visible reality-amplitudes at the bottom, which is what you'd expect a base-level structure of relative realness to look like. The Magical Continuum that embeds Pharasma's Creation is presumably in turn embedded in some more mathematically regular universe resting directly above its own underlying realityfluid, and the Magical Continuum is probably only instantiated by some small portion of that Base Physics's realityfluid. Unless, for example, some Alien Scary Thing took over all of its Base Physics and then decided to use all its resources on simulating a Magical Continuum - which in turn seems like a decision that ought to be relatively rare, because a Simulated Magical Continuum is not massively economically useful in any obvious way, nor will it occupy a maximum of most possible Alien Scary Thing utility functions.
That is to say: You'd expect most of the realityfluid directed by intelligence, in Greater Reality, to look like it was being directed more by the sort of Large Entities that might have come to exist in a base-level reality like dath ilan's; rather than the sort of Medium-Sized Entities like Pharasma that come to exist in Magical Continuua that get a small share of a Large Entity's resources, or maybe very infrequently a huge share of a Large Entity's resources.
So the question of what Greater Reality looks like is mostly about which sort of Large Entities come into existence in Mathematically Simple Physical Continuua like dath ilan, what desires those have; rather than mortals in Golarion, gods in Creation, or Outer Gods in the Magical Continuum.
Carissa wants to start thinking about Greater Reality by taking a survey of all of the alien races and civilizations known on Golarion; she started some of that work already, because it was obviously going to be useful, but she needs to re-review all of her notes with a bunch of new questions in mind. Her theory is that basically most alien species either evolved, or are copies from versions elsewhere who evolved, or were deliberately bred for intelligence by other intelligent species, and especially the ones who evolved or are copied from versions who evolved are the most useful input they have of what kinds of evolved species you might get, out there in Greater Reality. For each of them, it seems hard but not impossible to extrapolate what kinds of civilization they would build, if they had lots of time independently to build civilization; would they kill outsiders? Trade with them lawfully? Be altruistic towards them? and from there to extrapolate what the distribution of bits of Greater Reality controlled by the descendants of various evolved civilizations would be.
Of course, there will be parts of Greater Reality not controlled by the descendants of evolved civilizations, like Pharasma's Creation. Those will generally be the product of some process that propels something not shaped like the values of the civilization that created it to godhood.
Carissa needs to think more about what kinds of processes will propel things not shaped like the values of the civilization that created them to godhood, but from where she's standing it's not obviously the kind of thing that wouldn't happen without magic. You could just have humans who spend a lot of effort, but not quite enough, teaching their god human values, or humans who ascend themselves but via an ascension process that resolves their muddles slightly badly.
Some of their evidence on how difficult this problem could possibly be, is constrained by the fact that dath ilan is trying to solve it at all (he infers with confidence, based on the shadow of their policy in which ideas were and weren't removed from public discourse), so it can't look too hard. And they would rather let the planet run for a few decades than try to solve it immediately, so it can't look too easy.
In fact it seems like if a coherent set of values that come from human values is very hard to define, there might be lots of things that are not-quite-right for every thing that is right, even if there are also lots of things that are sufficiently wrong as to not recognizably have anything of value at all in them.
Honestly the thing Carissa is tempted to do next with that is figure out how to build a non-magic god (not do it! just figure out how she would) so she can see what the distribution of tries to do it seem like they'd look like - though also, it seems like while Greater Reality is probably dominated by simple-to-specify universes, those seem disproportionately unlikely to be able to do captures of minds from the specific point of their destruction in other, more complex magical universes.
The set of correct spell diagrams for Prestidigitation is much smaller than the much larger set of ways to configure Prestidigitation that is near-right-but-significantly-wrong; which in turn is tiny inside the much vaster space of ways to configure spell diagrams that aren't Prestidigitation at all. The much larger space of complete failures doesn't make it impossible to hang Prestidigitation. Similarly, within the any-success space, the larger proportion of near-right-but-significantly-wrong configurations doesn't mean that most Prestidigitations hung at all are near-right-but-significantly-wrong.
The difficult part, and the reason why dath ilan is running so scared, would be getting things right on your first try . But it wouldn't be valid to conclude that a first try, conditioned on it not being completely wrong, probably hits near-right-but-significantly-wrong. If you can do something on your first try and not have it go wildly wrong, that's probably because you've invented systematic methods for targeting and error correction, not because you got lucky enough to miss the wildly-wrong space. Then the question becomes whether those target-locking-optimization-methods have sufficient narrowing-strength (unit: bits) to hit the center target and not just exclude the space of complete misses, where most of the work, in some sense, goes into excluding the complete misses... he thinks, having not actually observed that computational landscape. But he has already done some thinking about how many bits it takes to specify the structure and content of a utility function, and the set of errors that give you near-misses versus complete misses.
He does think she's wrong about simple-to-specify universes not being able to mirror and copy minds from more complicated magic universes. Thought from quantum mechanics: Realityfluid (in dath ilan) is continuously divisible, and ends up in more and more mostly-separated-worlds-interacting-mostly-internally, exponentially growing in number and exponentially shrinking in individual size, as the greater universe increases in entropy. You can exploit the exponential subdivision of realityfluid to create 'quantum computations' that can only be calculated using exponentially large numbers of computing elements.
Quantum phenomena in dath ilan can't be exploited to run arbitrary computations over exponential numbers of computing elements, because the motes of quantum realityfluid can't communicate with each other arbitrarily and can't be searched arbitrarily for successful answers. But quantum computations can compute in polynomial time things that require exponential classical time, like factoring large composite numbers.
No law of reality known to Civilization forbids that a universe with more permissive continuous physics could simulate many many more complicated magical universes, by dividing a bit of reality into very tiny pieces, and using those pieces to mirror a whole complicated magical universe. The people inside that universe would exist to only a very tiny degree; but even in dath ilan, it's known that you can set up computations that are only real to a very tiny degree, and interact with them to read out their outputs . There are in fact famous edgelord-philosophical-thought-experiments about whether it's okay to run harmful experiments on people who are clearly visible to you, but who are only real to some tiny degree because they're inside a quantum setup like that.
That said, it's been speculated that the quantum universe is the way it is because of some unknown constraint that weighs against universes whose realityfluid is even more amenable to arbitrary computation via arbitrary divisions; but it's mostly guessed this is an anthropic constraint more than a Reality constraint.
The Higher entities very likely have access to some form of hypercomputation by continuous division of reality, given that they were able to run dath ilan and copy him off it, or that somebody else in the Higher Causal Continuum outside the Simulated Magical Universe was able to do so.
Carissa has a hard time imagining the motives or values of a civilization that would run all possible universes, including universes with Hell in them, at very very minimal realityfluid, in order to take the people in them at the moment of true-death and suddenly give them wildly more reality-fluid, which seems to be the kind of civilization Keltham is hypothesizing. Even the Carissae wouldn't do that and they're very very in favor of making lots and lots of people.
...to him, this seems like a totally obvious thing to do?
Probably dath ilani Civilization is (secretly) planning to do it with a bunch of smaller universes easily contained inside of quantum computers, once Civilization has safely ascended - unless it's more efficient to engage in cross-universe logical negotiations with other universes that will do that instead.
Dath ilan's universe comes with a built-in time limit before the negative energy (not Negative energy, a different kind of negativity) grows too strong and rips everybody apart. He guesses that the actual reason the Keepers told everybody not to worry about that right now, is because they expect that a few billion years later Future-Civilization will have made some logically binding deals with extrauniversal entities that are sufficiently visible to them - like Entities that started out inside simple but indefinitely continuing physics, which Future-Civilization can accurately simulate well enough to guess which Entities that evolve there will stay Lawful and have a known utility function to trade with; but whose otheruniversal sub-classical-illusion physics permits the possibility that they'll later develop computation powerful enough to simulate dath ilan's greater universe exactly; and give those Entities more of what they want inside of Civilization's realityfluid today, in exchange for them continuing Civilization in their own universe after dath ilan's local universe runs down.
Trading for your people to go on existing elsewhere makes sense. But why take the people in such a pocket-world out at the moment of true-death instead of at literally any other moment? Why let them go on being conscious in Hell but then take them out if Hell is destroyed inside their universe?
If you're nice, you could just take them out sooner; if you're trading, no reasonable person would trade for that.
Carissa would like it very much if other universes made copies of her, but if she goes to Hell and gets tortured a lot and deteriorates she doesn't want the copies to be made from that point! The copies should be made from the point where she is coolest, obviously.
She would be actively quite angry with the copiers who could have copied her from the point where she was coolest and decided to copy out a traumatized shell instead.
No doubt there's Carissae copied over to elsewhere to some tiny degree at every moment! But if you're copied over to somewhere else at a 2^-41 fraction of your current reality, that mostly doesn't feel like ending up somewhere else. If you wait until almost all of somebody's reality has been destroyed by a plane crash, and then copy them, that feels to them like they're going somewhere else.
The part where mass numbers of people who die in Golarion end up in Hell instead of getting isekaied, and will have been thoroughly messed up by the time Pharasma's Creation runs out (it may come with a known time limit to the gods, though the stories about it sound very distorted and might just be made up) - that setup is, he's guessing, an unusually bad situation from the perspective of Entities who care about that sort of thing. Bad in a way where they can't just ordinarily catch mind-states as they fall out of reality, as they would do with a place like dath ilan. That is, he would guess, part of the story of how Keltham ended up in Golarion on track to destroy it.
That makes sense, but destroying the universe would, then, not isekai people. Keltham experienced showing up somewhere else because he died in approximately every single plane crash across all the dath ilans where his plane crashed. If instead 99% of dath ilans had been instantly destroyed, he would find himself in the dath ilans that were not instantly destroyed.
The experience that the people in Hell will have if Keltham destroys them (treating 'experiences that feel continuous with the current people' as the important thing, which Carissa isn't persuaded of) is of being in Hell, in the nearby universes where Keltham didn't land, or where Otolmens noticed or squished him, or where his plan failed, or where he randomly had a heart attack as does sometimes randomly happen to healthy humans, not often but often enough.
If they want the people currently in Hell to have the experience of the pain ceasing and their lives getting better, they have to do that by fixing Hell; otherwise, overwhelmingly, those peoples' continuity will continue in all the Hells that no one touched.
(Carissa is aware this is also an argument that destroying Heaven probably doesn't give people the experience of waking up in an unknown bit of Greater Reality run by entities that may or may not comprehend the values of the societies that created them, but of going on in the nearest bit of un-destroyed Heaven. This does make her feel a little better about the whole thing but she evaluates that as a confused impulse brought about by trying to pay attention to the wrong features of the universe, ones that in normal circumstances overlap heavily with the thing she cares about but which aren't actually the same.)
Ideally, he'd knock on the afterlives, such as by making a very loud physical or spiritual sound that everyone hears and remembers hearing at least briefly, eg an explosion or a loud trumpet sound. It's then cheaper for soul-catching Elsewheres to 'rescue' the people that heard the sound, even if Hell otherwise ends fast enough that people don't notice themselves dying. Though he notes that this is more of an Experiential Thread utility than an Average Fate utility.
(Experiential Thread utility: Valuing the moment-by-moment trace of what it feels like to be a person, weighted from their reality-measure when they first noticed their own existences.
Average Fate utility: For every observer-moment in the universe, weighted by its momentary measure, valuing the average experience of all the future observer-moments that remember having been that observer-moment.)
That still seems like there are enough universes in which he succeeds at the trumpet sound but fails at destroying all of reality that she would expect most people who heard such a sound to mostly go into universes where that sound occurred but the universe wasn't immediately destroyed.
Mostly, though, experiential-thread theories of what matters feel like an error to her, they're not what she cares about; she appeals to them only to the degree they describe what Keltham cares about.
(Arguably Keltham should, actually, be interested in what the people he is doing this to care about; she understands that he mostly doesn't have a method he believes is accurate to get that answer by asking them, but it seems like a wrong to, as an experiential-thread sort of entity, go around doing things to someone that are extremely bad under their own theory of what they care about. She agrees that asking people on the street probably wouldn't work well, but possibly asking ascended mortals would?)
He realizes he's updating off evidence fundamentally unshareable with her, but nonetheless notes that from his perspective, when Keltham heard and saw that his plane was about to crash, he ended up in Golarion, not in a complicated fake Exception Handling scenario in which they'd induced that hallucination or faked that setup for Totally Justified Reasons Actually. There were maybe some worlds like that even within dath ilan, but they were rarer than one in a thousand, rarer than one in a billion, however much rarer they had to be for Golarion to have more realityfluid than that; and Golarion can't have that much realityfluid to start.
If he sets up some of the obvious physical phenomena for destroying Pharasma's Creation, to be remote-detonated from Golarion where prophecy doesn't work; manages to cause some sort of experiential anomaly in Hell or all the afterlives; and then tries to blow up the universe; there may be possible and therefore actual states of reality where that doesn't work, but if they're improbable enough, the people in Hell don't mostly continue in Creation. Creation can't be all that probable in the first place, though of course that also decreases how much caring Higher Entities are willing to pay to rescue people from Creation or destroy it. And that's before taking into account the subjective probability that they're inside a privileged story-reality-thread which has much more realityfluid than neighboring nonstories.
He agrees that asking an ascended mortal (who must be Lawful enough to abide by solid secrecy oaths) is a reasonable experiment. He doubts it swings anything by itself, but it could swing things in combination with other experiments coming out in the direction Carissa hopes or predicts.
Carissa isn't sure, yet, what exactly is the best articulation of her own values here, and doesn't expect it to be a common articulation even among humans who arrive at one. But she's intending to make her system at least satisfy her intuition that it's extremely different whether someone arrives at a high average happiness because they are killed in every universe where they are unusually sad, or because they are made happy in every universe.
Among the barriers to himself just taking Golarion mortals' word for it, is his concern that Golarionites have now been heritage-optimized to not really think about their afterlife-futures.
If you're told that Evil afterlives exist and their existence implies reproductively-suboptimal behavior given your other goals - like, for example, not stealing something you could get away with taking, because you might go to the Abyss; or it being more prudent to donate money to Iomedae's Church, instead of spending that money on dates - then maybe that gets evolved-against. Civilization was always very worried about scenarios where it looked like smarter, more altruistic people might end up having fewer kids; lest they breed intelligence, altruism, or actually-acting-on-your-philosophy out of themselves. They went to great lengths to avoid it.
One of his concerns is that Golarionites have been effectively bred not to think about Hell, or not to care about Hell, but in a way that doesn't make Hell hurt any less once they get there. People in Golarion who think about the near-inevitability of some of their kids going to the Boneyard, who really care about their kids, might decide not to have kids. And it'd be one thing if people's sanity and intelligence were left intact, but their utilityfunction changed, so that they really and coherently and in a consistent way ended up as a sort of thing that didn't mind the prospect or actuality of Hell. But it does not look to him like this is what happened in Golarion. To him it looks more like - people grew up knowing about Hell, and the more coherent people drastically reshaped their lives in reproductively suboptimal ways given that information, and Golarion bred itself against coherent thinking about Hell.
Or it could be that dath ilan bred itself for coherence and Golarion just never got around to it. He can't reliably guess, at this remove from Golarion and without spending a lot of time tracking down histories of who had how many kids, whether Golarion actively bred against people coherently thinking about their own future, via people learning about Hell, or if dath ilan just heritage-optimized for smarter saner people over a couple of dozen generations before their historical screen.
Carissa, at this level of Intelligence and Wisdom, may rationalize that heritage plus the philosophy she developed from growing up in Cheliax as an Asmodean, into something that is coherent and that really doesn't mind going to Hell. He doesn't currently predict that most other mortals in Golarion would end up with the same philosophy if they were boosted to the same stats; he predicts that their incoherence would fall away from them and they'd become more actually horrified by Hell and the Boneyard, which would feel much more real to them as their larger minds shrugged off a finite adapted internal pressure against thinking-about-the-future-and-other-people's-future-experiences-as-if-they-were-real.