It's not like this is the only serious blind spot he has regarding Quirrell, though, is it?

My current theory seems almost obvious, after I coincidentally decided to reread HPMOR myself shortly after rereading Chamber of Secrets with my daughter:

Early in Chamber of Secrets, a Death Eater gives Tom Riddle's horcrux, a nearly-indestructable magical diary, to Ginny. One of the powers that diary has is to take partial control of her as she reads it intently over the coming year, and one of the ways that control manifests itself is to make it difficult for her t... (read more)

It's not really a blind spot against Quirrell. If what Quirrell says it's true and Quirrell dies soon, it's important information to acquire from him.

There no time pressure to read the diary. There's time pressure to get information from Quirrell. It requires an environment where Quirrell can cast the spells against eavesdropping.

Harry Potter and the Methods of Rationality discussion thread, January 2015, chapter 103

by b_sen 1 min read29th Jan 2015174 comments


New chapter, and the end is now in sight!

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 103.

There is a site dedicated to the story at, 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

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:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.