doesn't that suggest that Magic can detect not only whether what Elspeth is saying (or considering saying) is honest, but also whether it is true?
Magic only cares whether Elspeth believes it is true. If she said "Alice and Jasper are still loyal to the Volturi" it would probably not sound true, because Elspeth wasn't sure of that at the moment.
What Magic helps Elspeth do is tell the truth, and to tell it in a particular way that the other person will understand. So the indirect trick she is using here was spelled out back in chapter 5:
Here is how I use my power to learn things about other people.
It takes a very, very long time. It's completely indirect. There is some guesswork. There are always gaps. I can't just call up my power and point it at someone and learn who they are.
First, I make a guess about the thing I am trying to learn. Then, I think of something about myself that is like my guess. And then I figure out how I would explain that part of myself to the person, and see if the explanation refers to things about my guess. If it is, then my guess was close to right.
It's confusing, and it took me a long time to figure out. Here's how it might work. Suppose I go back to Kora's town and find her, and she seems sad. I figure out as much as I can without any magic and I decide that my best guess is that she misses her best friend who is out of town. The closest thing I have to that is when I miss people who I have had to leave behind - people like Kora.
So I think about how I would tell her the way I feel about that. If I wanted to say to Kora, "I miss my old friend Raine as much as you miss your best friend", then that would mean saying that will make Kora understand something true, because that is how my power works. Then I would know that my feelings about Raine and Kora's about her friend are the same.
But it would not make sense to tell Kora that. I'm never going to see Raine again, and Kora's friend will come home, for one thing. I knew Raine for a much shorter time and we were not as close. And that is the biggest problem with using my power to do this. It only works if I make a correct guess, and I can only make a correct guess if I have something that's sort of like what's going on for the other person.
Sure, that was the limitation she was operating under back in Chapter 5, when (among other things) she wasn't able to interact with Magic as a separate subagent.
She communicates with her ability radically differently, now; there's no particular reason to believe the same limitation applies.
But, sure, maybe she experimented with this off-camera and concluded that it still does, for whatever reason, and we just haven't read about that. So, OK, maybe she can't attempt to say "Alice is still loyal to the Volturi" and see whether Magic objects.
Inst...
This is a thread for discussing my luminous!Twilight fic, Luminosity (inferior mirror here), its sequel Radiance (inferior mirror), and related topics.
PDFs, to be updated as the fic updates, are available of Luminosity (other version) and Radiance. (PDFs courtesy of anyareine). Zack M Davis has created a mobi file of Radiance.
Initial discussion of the fic under a Harry Potter and the Methods of Rationality thread is here. The first dedicated threads: Part 1, Part 2. See also the luminosity sequence which contains some of the concepts that the Luminosity fic is intended to illustrate. (Disclaimer: in the fic, the needs of the story take precedence over the needs for didactic value where the two are in tension.)
Spoilers are OK to post without ROT-13 for canon, all of Book 1, and Radiance up to the current chapter. Note which chapter (let's all use the numbering on my own webspace, rather than fanfiction.net, for consistency) you're about to spoil in your comment if it's big. People who know extra stuff (my betas and people who have requested specific spoilers) should keep mum about unpublished information they have. If you wish to join the ranks of the betas or the spoiled, contact me individually.
Miscellaneous links: TV Tropes page (I really really like it when new stuff appears there) and thread. Automatic Livejournal feed.