Hmm. My guess, based on the kind of logic that seems to govern most magic, would have been that the amount of magical energy required has something to do with how different the two things you're transfiguring between are. But again, who knows how the energy requirements of transfiguration really work.
I was also under the impression that Harry had to keep the rock with him at all times to keep it transfigured. Would he also have to keep Hermione with him at all times? Also, the transfiguration stops if Harry exhausts his magic for whatever other reason, and I don't think he'd want to risk that happening to Hermione.
He now has a ring on his hand without a jewel. He could put Hermione there.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 88-89. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: