[I think it's hard to get very clear results on that because the mages in question still have human reaction times but there are scientists interested in the question.]

"Please relay this question to Thellim: superluminality y/n probability distribution?"

Isabella faithfully plays eidetic-telephone.

Thellim isn't sure why this question is arising in the middle of the question about whether or not dath ilan is going to conquer Earth, but she has obviously taken a prior interest in that subject.

There's a mage supposedly training himself now, to settle FTL questions once and for all.  But in terms of experiments that could be done with mages and psions that happen to already exist... there's been improvised experiments with remote-viewing clocks on the other side of the planet.  There's been improvised experiments with an ancient highly-practiced weather-mage who can stir a wind on the other side of the world.  All such experiments have "failed to produce statistically significant evidence" of a 20-millisecond difference depending on whether the target is next door, or on the opposite side of the Earth.

Earth is sufficiently confused about how evidence works that Earth scientists have not dared to try to say to reporters that this looks like magic is FTL.  Thellim has gotten ahold of the raw data and treated it with sane numerical procedures, and derived strong-enough likelihood ratios against 20-millisecond delays; real epistemology is quite capable of saying that an effect size has been ruled out, not just that somebody failed to produce statistically significant evidence for any effect size.

[FTL information reception: 0.99y/0.01n
FTL causal transmission: 0.98y/0.02n
FTL counterfactual information reception: ~1y/~0n, reminder: precognition is a thing]

Thellim doesn't transmit back the reasons.  If the Keeper wanted to reconsider her reasons and not just the final summary probabilities, he'd have asked her for her reasons.  It feels so nice to talk again with somebody who knows what it even means to trust her sometimes.

Not the answer he'd have guessed.  But all right, if the physics of the larger universe that embeds Earth and dath ilan permits superluminal travel, the Great Silence is vastly exacerbated as a question thereby.  Combine that with something superintelligent probably having passed by Earthsystem and left magical eclipses in its wake.

Then if Earth has not already been invaded and consumed, externally originating invasions and consumptions are perhaps also prohibited by whatever passed, or by something above it.

This moderately reduces the chance that Earth is going to erupt with an unstoppable horror that eats dath ilan.  It is still something that the smart dath ilani will be very concerned about, given their current total lack of comprehension of many, many Additional Questions.  It is plausibly something that dath ilan would invade Earth over.  It is not necessarily something that dath ilan will invade Earth over, given that there is a chance dath ilan will not be annihilated.

"Forgive me the sudden line of inquiry.  My own first thought was that dath ilan is - most likely to behave in a manner that might be termed impolite and abrupt - if it seems like your world is about to completely annihilate our own, even inadvertently.  However, if FTL is possible, it is moderately less likely that you can accidentally do this to us, because then aliens would have been more likely to have done it to you already.  You speak of humanitarian interventions by dath ilan; I take it that Thellim has already forecast cases in which she thinks we might wish to so act?"

[She thinks given the opportunity you might want to take refugees, which seems of the possibilities relatively easy to do decently, if enough people-moving capacity turns up as eclipsed learn more.]

"Refugees... from what?"

[Natural and eclipse disasters, various human conflict and the fallout thereof.]

Thellim has been listening to some of this on relay.  She requests a transmission-relay, of language-less telepathy rather than Baseline syllables so that Isabella also hears this time.  [Keeper, Earth has a tremendous number of people who I would read as traumatized, tired, or just plain unhappy with Earth.  When and if we have teleportation scaled up sufficiently, I believe we should have by then prepared to receive the entire Earth population as refugees; if some choose to stay, that will provide safety margin.  Isabella will be shocked if teleportation at that scale happens in three years and surprised if it is less than ten.]

"A logistical challenge to be sure, and that would only be the beginning of the challenge.  But not obviously an unsolvable challenge, at least on our end.  Isabella, you spoke of desiring 'steering power', for yourself, in this.  Say more of that, if you would?"

[I think that - naively the civilizations meeting could go very badly, or well according to only one set of values, though I'm not actually sure who'd come out better for it, and I don't want that, I want - full meetings of the full complexity of what's going on on both planets, and there are probably lots of things we can just hand over straight across like access to the custom chair store aforementioned, but I do not want you, say, accumulating a lot of power and then wrecking our study of history, or committing cultural genocide, or systematically disenfranchising people for believing in ghosts, or anything.]

She's not sure who'd come out better for it?  Isabella does not seem very frightened of what would eventuate if the Keepers went full eldritch on a designated-target civilization with -4sd intelligence and almost no coordination ability.  Even leaving aside the structures dath ilan will have just started assembling in the Basement of the World, to be used only if the alternative is an even greater risk of both worlds' true death.

Isabella does not seem to realize that all of Earth's negotiating leverage stems from Isabella's ability to cut this sole line of communication, leaving dath ilan helpless to stop Earth's own death erupting and reaching back to dath ilan - unless Thellim found another psion before it was too late, as she might, especially if she realized what the danger actually was.

They're mentally occupying very different negotiations here, clearly.

But Isabella seems to be negotiating in good faith, according to what she thinks the situation is; based on representations from a dath ilani who did not, herself, have any inkling of how scary dath ilan actually was.  They do go to some lengths to not have those possibilities be realized ever.

And when a hand has been stretched towards the Keepers in good faith and hope of good faith returned, the Keepers will reach back in good faith returned, to benefit the one who reached out to them in hope that it would benefit herself and her kind.  Even if that good faith means a greater risk of the true death of dath ilan.  Because there's that, and then there's the Algorithm.

That's why Derrin hasn't prioritized speaking to Thellim a delayed-cognition hint that she'd later recognize as Artificial Intelligence being lethal enough to imply that Thellim should find a second psion to provide another channel back to dath ilan, if this one gets cut.

That's why Derrin hasn't started optimizing over the Earthling as an objective.  She didn't precog him.

She didn't precog him, not because she knew that she was in a Prisoner's Dilemma with somebody who could do something back that was equally dangerous in its own way, but because her friend asked her not to, and she was nice.

Derrin isn't about to prove himself any less nice than that.  There's no point in being smart if it comes at the expense of being nice.

It's all the same trust, down to the world's end, whether one end or another.

They're called the Keepers of Harmful Truths because that's the part that only the Keepers keep, but they have much more important things to keep than that.  The trust, the faith, the Algorithm, the flame, and the Light.

"You have reached out to us in good faith, Isabella," Derrin says, speaking for Civilization, as he was authorized by dath ilan to do in situations like these.  "We will return that good faith no matter what.  Whatever the sad end you do not wish, we will avert it.  Whatever you are afraid will happen, we will find another way.  There are bright truths that have not, I suspect, been reflected often enough, in your world's history.  Here's a bright truth that dath ilan has reflected well enough, for the short history that we remember:  People can just not do the wrong thing, they can do something else together.  And if the steering power you want, to have the strength to avert sad endings with your own hands, lies within sanity and reason, we will give it to you if that was your price."

[Thank you, I appreciate that. I just hope you, uh, determine it lies within sanity and reason.]

"We'll work that part out in advance.  It seems like the nice thing to do.  Less worrying for you, that way."

"You spoke of positive-sum trade.  Isabella, Thellim, whichever one of you cares to answer - what does this branch of humanity have to offer, to its new-found cousins?"

[You mean besides magic?]

"It's quite the headline trade item, I admit."

[Isabella thinks - and thought before I met her - that they may be able to push it to the point of resurrecting the Lost Dead.]

...oh.

He must remember to be a little more respectful of the powers of Earth, and its own share of the Light, from now on.

"Thellim, you already explained what dath ilan would think of that, I hope?"

[That we'd throw our entire power behind it?  Yes.]

"Indeed.  But you've probably also - apart from the whole magic business - had some thoughts of Earth's own that are new to us, and arts in which dath ilan might take interest.  Thellim, this seems like a question for the dath ilani market-investigator?"

"Now there's a question I wouldn't want them asking the me from two years ago," Thellim says out loud back on Earth.  "Light, where do I start..."

[Earth has ideas they've deployed to make up for lacking coordination, methods that can accomplish the same ends by legitimately simpler and more elegant means, where dath ilan does the equivalent of brute-forcing it by manually instructing everybody on dath ilan to step left at the same time.  Probably the most striking example is that one Earth economist worked out that varying the money supply, in such fashion as to predictably regularize the total flow of money, can prevent missed-opportunity trades due to downward nominal wage rigidity... roughly, if dath ilan is willing to grow and shrink the currency supply according to fairly simple rules, I think you can shut down the entire executive branch of the government that tries to get people to be more willing to adjust prices downward, and replace it with one conditional prediction market plus ten lines of code running on the currency computer.]

"Interesting!  Yes, that sounds approximately like the type of novel-to-us innovation I might expect to be found in such a place.  What is the least expected concept that Earth has invented which dath ilan ought to import?"

[You mean the one that would have taken us the longest time to figure out, and would provoke the most disbelief from dath ilani if it wasn't explained very carefully?]

"Of course!"  Absent exerting the will to optimize over Isabella, it is not improper to let himself be steered by the first virtue of Curiosity.  "Naturally, I shall quite restrain any such reaction on my own part."