Harry Potter and the Methods of Rationality discussion thread, part 4

[Up­date: and now there’s a fifth dis­cus­sion thread, which you should prob­a­bly use in prefer­ence to this one. Later up­date: and a sixth—in the dis­cus­sion sec­tion, which is where these threads are liv­ing for now on. Also: tag for HP threads in the main sec­tion, and tag for HP threads in the dis­cus­sion sec­tion.]

The third dis­cus­sion thread is above 500 com­ments now, just like the oth­ers, so it’s time for a new one. Pre­de­ces­sors: one, two, three. For any­one who’s been on Mars and doesn’t know what this is about: it’s Eliezer’s re­mark­able Harry Pot­ter fan­fic.

Spoiler warn­ing and helpful sug­ges­tion (copied from those in the ear­lier threads):

Spoiler Warn­ing: this thread con­tains un­rot13′d spoilers for Harry Pot­ter and the Meth­ods of Ra­tion­al­ity up to the cur­rent chap­ter and for the origi­nal Harry Pot­ter se­ries. Please con­tinue to use rot13 for spoilers to other works of fic­tion, or if you have in­sider knowl­edge of fu­ture chap­ters of Harry Pot­ter and the Meth­ods of Ra­tion­al­ity.

A sug­ges­tion: men­tion at the top of your com­ment which chap­ter you’re com­ment­ing on, or what chap­ter you’re up to, so that peo­ple can un­der­stand the con­text of your com­ment even af­ter more chap­ters have been posted. This can also help peo­ple avoid read­ing spoilers for a new chap­ter be­fore they re­al­ize that there is a new chap­ter.