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gwern comments on Luminosity (Twilight Fanfic) Discussion Thread 3 - Less Wrong

10 Post author: Alicorn 30 December 2010 02:37PM

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Comment author: gwern 04 February 2011 12:22:04AM 3 points [-]

I'm troubled by Elspeth's new power in ch36, where Magic seems to have suddenly jumped from being solely about Elspeth's own personal subjective error-filled beliefs to being a royal road to objective Truth.

At least, I can't put any subjective spin on things like

"Well," I said to Magic, while everyone watched me to see if I was done thinking, "would it make sense to use that story as an analogy to what Alice and Jasper are doing? If I compared those things, would it make them understand something true?"

(What, Elspeth has to ask what she thinks about such a comparison?)

This turns Elspeth into an oracle who can answer any computable question. Memories are heavily fictional (at multiple levels, from not including all perceptions, including inferences and assumptions built into 'mentalese', to wishful thinking and biases, to simply what one pays attention to and doesn't, when the memories aren't outright false as in experimentally demonstrated induced memories by suggestion). Elpseth can compare memories against a question. That's all that's needed. Now Elspeth can have any question, and either already has a relevant memory from millions of years of memories or can just think of a fiction (a story), which lets her answer it.

Nor is there any obvious mechanism to defeat this. She can only compare memories? Fine, she compares against a memory of the story she just wrote to answer her question. Memories have to be vampirically good? Now she can't compare against her own memories, all the humans from Aro, werewolf memories, and this is an ad hoc & unmentioned limitation - which can probably be gotten around anyway. (All you need is some telepathic communication and editing ability, of one's own or another person's abilities. For example, hire CGI artists to render a needed fiction, watch it, and send Elspeth the memory - shorn of the memories of entering and exiting the theater. Or edit Elspeth directly. Or maybe memories of lucid dreaming would work, or maybe memories of hallucinogens.) And so on.

Comment author: Alicorn 04 February 2011 12:51:44AM 0 points [-]

I really should have thought about how annoying and complicated it would be to explain this power over and over before I gave it to Elspeth. Suffice it to say that she's not an oracle and does not have the capacity to turn into one.

Comment author: gwern 04 February 2011 01:23:16AM 2 points [-]

Well, I hope there will be an explanation and/or rewrite. The last few chapters have been annoying - 'Elspeth is an oracle, why do they keep on speculating and discussing when they could just ask Elspeth their questions? It didn't take all that long the first time they asked the oracle a question. Arrgh, stop saying words!'

Comment author: Sheaman3773 04 February 2011 01:51:57AM 1 point [-]

I think she would have to have a comparable situation in her memory--I don't think memory of a story would fit, but that's speculation--and she has to be communicating with someone who already knows.

It's stated very early on that her power sometimes changes what she says when she's telling the truth to phrase it so that the listener would understand. That's already admitting that her power can reveal facts about the people she's communicating with, more specifically what they find to be true.

They have to speculate because they don't have anyone there who knows. Now, if they kidnapped someone who was in the know, and had Elspeth try to run through scenarios to see which analogies fit, then they could get information out of that person. Really, she's more of a sort of mind reader, in an incredibly roundabout manner, than any kind of oracle.

Assuming that my understanding is sound, did that clarify anything with you?

Comment author: gwern 04 February 2011 02:41:33AM 0 points [-]

I don't think memory of a story would fit, but that's speculation

Already gave a number of possible workarounds to demonstrate that any ad hoc rule will leak. This reminds me of computer security - someone puts forward an ad hoc system, someone else immediately breaks it, the first patches the exploit, and so on ad infinitum until eventually the patches start introducing as many security flaws as they fix and they just give up.

Really, she's more of a sort of mind reader, in an incredibly roundabout manner, than any kind of oracle.

I went back and re-read the scene. That could be the right explanation.

But that's not much better. Nothing in the scene forces Alice & Jasper to be there. For all we know, Elspeth could have run through the exact same mental steps with them on the other side of the planet (assuming A&J had telephoned with news of their defection or something): 'Magic, would comparing A&J to Del convince someone of the comparison?' 'Nope!' 'Oh good.' In fact, since truth or falsity do not change, Elspeth could as easily have worded her analogy as 'would comparing A&J at the instant they called to Del convince someone?' and gotten the same answer.

So your reading brings Elspeth down from logical omniscience to 'merely' being able to find out anything anyone has ever known (and maybe will know). Which is still so impressive a power that Alicorn couldn't've intended it.

Comment author: Sheaman3773 04 February 2011 04:02:23AM 0 points [-]

Her magic changes what she says when she's communicating with people. I agree, nothing in the scene forces A&J to be there, but Elspeth's power--as I understand it--requires her to be communicating to the people she's testing for it to work.

Now, the fact that her magic now has an avatar might change the rules, but as Alicorn obviously didn't intend for it to work like how you are describing, you can assume that her magic is still limited to needing to be in communication with the person in question for it to determine whether the analogies fit.

Comment author: TheOtherDave 04 February 2011 05:30:46AM 2 points [-]

Even with those constraints, there are experiments that seem worth performing.

Experiment one: select some known object X. A confederate either puts X in their pocket, or doesn't. Elspeth attempts to say "You have X in your pocket" to the confederate. Does Magic object to Elspeth saying that when it isn't true?

If that doesn't work, set up an indirect version of the same thing where, instead of saying "You have X in your pocket," Elspeth calls up a memory of the person having X in their pocket and says "You're in a situation like that time when you had X in your pocket." That, at least, ought to work... it's essentially what Elspeth did to Alice.

Either way, there's a whole series of experiments to be performed in the same vein to establish whether this depends on someone having the knowledge, or whether it merely depends on the state of the world. E.g., experiment 1b: there are three people in the room, two of whom have a sealed box in their pocket. One of the boxes contains X. The third person in the room knows which box it is, but nobody else does. Elspeth attempts to say "You have X in your pocket" (or equivalent memory) to both people. 1c: get rid of the third person. Nobody knows which box it is. 1d: get rid of all the people; there are two boxes, left and right. Elspeth attempts to say to herself "The {left, right} box contains X".

Another direction of experimentation... set up the same experiment, but Elspeth is in another room far away, communicating by telephone. If that works, hang up, and have Elspeth simply intend to communicate by phone. (This should work if the first one does, since we've seen Magic answer questions about intended communications.) If that works, throw the phone away and have Elspeth intend to communicate in some unspecified fashion... or, if that fails, have her write the answers on a piece of paper with the intention of handing the paper to the appropriate person at the first convenient opportunity. If any of this works, how far away is too far? What if she doesn't know exactly where the people are?

Yet another variation: set up a probabilistic test case. That is, instead of "You have X in your pocket," try it with "This coin is about to come up heads." If it fails, try it again with Alice, after she has determined how the coin will come up.

Completely different: Every thirty seconds, Elspeth looks around the room and says "There are N people in this room." Allirea is in the room, fading in and out. Can Magic tell when what Elspeth wants to say is false? Does it matter if Bella is in the room?

It seems like these would be useful things to know about Elspeth's talent, not to mention useful directions to train it in if the potential exists. Some of them I expect to fail, because Word of God says she's not an oracle, but I'm not clear on which ones as I'm not exactly clear what an "oracle" is. In any case, Elspeth doesn't have access to Word of God, all she has is experiment.

But maybe Addy's the only one who has an experimental mindset about this stuff.

Comment author: Alicorn 05 February 2011 05:32:44PM 0 points [-]

Completely different: Every thirty seconds, Elspeth looks around the room and says "There are N people in this room." Allirea is in the room, fading in and out. Can Magic tell when what Elspeth wants to say is false? Does it matter if Bella is in the room?

This one fails trivially. Elspeth has, in the past, without so much as a twinge from Magic, neglected Allirea's existence verbally and explicitly:

Siobhan pursed her lips and closed her eyes. "Elspeth, how many children does Joham have?" she asked, slowly and carefully.

"Three," I said.

"And their names are, from oldest to youngest...?"

"Noemi, Nahuel, and Iseul. Don't you already know -"

Comment author: TheOtherDave 05 February 2011 06:55:26PM 0 points [-]

True. Cool, they can scratch that one off the list.