"You have secrets of immortality?"

Plagueis's eyes light up. "Rather incomplete secrets of immortality. At the moment they only extend to an especially powerful Sith Lord being able to cure themself of diseases, and minor wounds. Why, for me to finish my research entirely, I would need access to resources that I simply don't have at the moment, resources that would require the support of, oh, a Senator from Naboo, or perhaps even a Galactic Chancellor. Who might, in the meantime, be busy pushing for charitable pursuits that would help the many peoples of the galaxy."

"I will do literally whatever you want as long as I get to live forever."

"Well, then we're in agreement!"

"Except for one little thing. You don't care about other people, do you? You want power for yourself, you want the resources they might have... how do I know that once you had everything you wanted from me and the galaxy, you wouldn't just turn around and betray us?"

"A shame, isn't it. We could have worked together, except that I know that once I've already helped you gain power, then you'll have no further reason to help me. I suppose there's no way to solve that problem, though; there's nothing I could do to stop you then. I'll just have to kill you."

This is clearly a test, but... what could Plagueis have in mind? He knows Palpatine would betray him, that's true, there's no changing it, and even if Plagueis does have some defense he can use against Palpatine later on, to stop him from betraying him, it still wouldn't be worth it, there would always be a chance that Palpatine would find a way around it. Which they both know he would.

"I'm not seeing it," he admits after a few minutes of thinking.

Plagueis shrugs, and a blowtorch from inside of the speeder flies into his hand. With a casual movement, he ignites it and presses it to Palpatine's skin.

He is not going to die he is not going to die this is a test of some sort he is an aspiring Sith Lord and he will not succumb to mere pain and holy shit that hurts and he's screaming.

The blowtorch turns off after a few seconds; Plagueis doesn't want to hurt him permanently. Even as it is, though, the burn's pretty bad.

"It's simple enough, really. Just swear that even once you can betray me, you won't. And mean it."

"I swear it," Palpatine says, "I won't betray you, I'll do what you want, we can both get what we want - "

"Lies," smiles Plagueis, and now there is another burn.

"I - I was lying, yes, but it's not - I want it to be true! But I can't just - I can't make it so that I want to help you!"

"You may not follow the ideals of improving the galaxy, Palpatine, but you are still some version of a Sith, or at least you think you are. What makes you a Sith?"

"I want power, I want to become stronger, I want to be the best possible - "

"The best possible version of yourself is quite clearly that which does not betray me," says Plagueis. "Why not just simply be the person who doesn't betray me, because that's the only one who won't die today, and then you'll have what you want?"

"Well, yes, right now I want to be that person, but when the time comes I'll want to betray you..."

"Such a shame," Plagueis says, accompanied by another burn.

"You know, there's a fascinating area of logic called decision theory, that I think is somewhat relevant to our own situation. It's about modelling people trying to achieve their goals, with math. Most of the applications people discuss seem to be about nothing more practical than playing games, and most of the people talking about it have no idea what they're saying."

"And there are common situations just like this one, that people debate. Imagine if you were left for dead in a broken vessel in space, and a traveller comes along. He's a professional at analyzing people's expressions, he's wonderful at predicting exactly what other people will do. He knows that at but a small inconvenience to himself, he can rescue you. While he doesn't actually want to save your life for its own sake, he would certainly do it if he knew that you would pay him afterwards. So he asks you, will you pay him a hundred thousand credits, as soon as he gets you to safety?"

"And the ridiculous thing is, for all that these decision theorists think they know, they insist that the right answer is that once you get to safety, you don't pay him. You see, if you simply analyze the, ah, expected utility, you'll find that once you've been saved, you have a simple choice between keeping money, or not keeping money, and obviously keeping money is better."

"And so the traveller realizes that you of course won't pay him the money - after all, it's not the logical thing to do - and then he abandons you, and you die."

"So you're saying that since I'm a Sith, I should be better than that, and I know that and I know it's ridiculous but in the future it won't be any more, what the choices mean will have changed."

"That's certainly what your typical decision theorist says!" Burn.

"So, if you want the answer... well, there have been a lot of clever tricks people have tried to come up with, like this one idea about doing whatever would have been, were you to have learned about it as an outsider, evidence that you would have done the best? Or something like that? But none of those really worked perfectly."

"The actual solution is quite elegant, and indeed has always been one of the core tenets of the Sith way."

"You see, everyone thought the way to formalize decisions as logic was about how an agent, at any individual moment in time, picks the action with the best expected outcome. Whereas what actually works isn't about choosing the optimal action at any given point, it's about implementing the optimal strategy over all time, about being the most effective possible person you could be."

"So what, you're saying that - that even in the future, once I can betray you, I should notice that that's not the strategy that would make the most sense overall, and choose not to do it? But by then, it'll have already happened! I would already know exactly what I was getting from you, I can't actually go back and change the past and so it wouldn't make sense to - "

Burn.

" - it's because - oh so it's because you can predict me - so it's almost like I can influence the past, because my decisions are going to be the same as the ones in the prediction you're making right now, so - so it is best - "

"Exactly." Plagueis finally tosses the torch back into the speeder, now.

"So, I ask you again."

"Will you, even then in the future, be the person that refuses to betray me? Or will you be the person that betrays me, and thus doom yourself to not even having the chance to keep existing and betray me in the first place?"

"I'll - I'll - "

"Wait."

"Wait a second. Hang on." Because he does understand this, it makes perfect sense, but when he thinks about it, there's also another obvious meaning, something Plagueis clearly didn't want him to notice.

"Okay, so right now I know that if I agree to do what you want, it'll make things better for me in the future."

"But - if we also think about the past and things that were influenced by your predictions of me, if we think about me as - as a person doing certain things across time - then me agreeing right now, is actually - it's bringing about predictions of me, that I wouldn't have wanted you to have in the first place, just like what you were saying."

"Because you just tortured me, right, because you predicted that torturing me would make me think about it more, would make me start agreeing with you. But you didn't have to do that, right? You could have just talked me through it the long way, been patient or whatever, but no, you had that prediction that torturing me would be a little better for your goals, and so you tortured me."

"So if I'm the kind of person that does what you want when he gets tortured, then across all time, that's worse for me, even if it seems like it's better right now."

"All right, that is brilliant and I am legitimately very impressed that you figured that out so quickly. Yes, correct decision theory implies that you shouldn't ever give into threats that come from someone who can predict you, in a situation like this, and you are entirely correct."

"I didn't actually mean it as much of a harm to you, to be honest. Suffering through intense pain, and becoming stronger because of it, is an essential part of the Sith experience, and you will have to go through it more. But yes, it could certainly be considered a threat in that sense... hmm. Well, I can correct that."

Plagueis waves his hand, and a large bag arrives in Palpatine's hands. "That should contain several million Republic credits, which I was going to use as a bribe for the soon-to-be king, although I can find more elsewhere. Millions of credits is worth, if we were to use the colloquial term lifetime that really just means a hundred years or so, several dozen lifetimes' worth of everything you could ever want to buy. It is clearly worth so, so much more than the pain you were inflicted. I have now unambiguously done you a favor, meaning that you no longer have any reason not to have wanted the sum of this interaction."

"Now, can you swear it to me?"