Chapter 21
Draco's choice of subject. Expected, but unfortunate. It would be fun to know the physics of the magical universe. The biology is not completely exempt from the physics, of course. Also, there can be many fun incidents introduced when they are trying to sample people. Imagine trying to get a skin sample from albus dumbledore, the most powerful wizard around or trying to figure out why Aberforth wasn't that great.
The Dark Mark - They would have thought about it. My guess is the dark mark came around only after a certain power threshold was already crossed and the death eaters were able to ahem... signal freely.
Speculations on Santa Claus
Sirius - Most probable. Sounds like him, sounds like Pettigrew is dead from information in the train station chapter. Sirius is out of azkaban or is remote controlling someone (kreacher?) really well.
Nicholas Flamel - Well, his name is Nicholas :-) and he is knowledgeable enough to create a philosopher's stone and is brave enough to cross over to the threshold of death without worrying much. (In the HP universe, death is not final. It is kind of a change of state, like uploading. ) So, he could have been curious enough to examine the cloak, while having a reputation strong enough that james would give it to him. He also knows Dumbledore's weakness as a holy grail seeker, sorry, seeker of the deathly hallows.
Albus Dumbledore - Also very probable. And giving away partial information is also a good tactic to give the impression that it is someone else.
Lupin - For all the reasons similar to sirius, but not rich enough to give away money.
In the HP universe, death is not final.
What? Doesn't that flatly contradict what some character in Goblet of Fire said once?
Update: Please post new comments in the latest HPMOR discussion thread, now in the discussion section, since this thread and its first few successors have grown unwieldy (direct links: two, three, four, five, six, seven).
As many of you already know, Eliezer Yudkowsky is writing a Harry Potter fanfic, Harry Potter and the Methods of Rationality, starring a rationalist Harry Potter with ambitions to transform the world by bringing the rationalist/scientific method to magic. But of course a more powerful Potter requires a more challenging wizarding world, and ... well, you can see for yourself how that plays out.
This thread is for discussion of anything related to the story, including insights, confusions, questions, speculation, jokes, discussion of rationality issues raised in the story, attempts at fanfic spinoffs, comments about related fanfictions, and meta-discussion about the fact that Eliezer Yudkowsky is writing Harry Potter fan-fiction (presumably as a means of raising the sanity waterline).
I'm making this a top-level post to create a centralized location for that discussion, since I'm guessing people have things to say (I know I do) and there isn't a great place to put them. fanfiction.net has a different set of users (plus no threading or karma), the main discussion here has been in an old open thread which has petered out and is already near the unwieldy size that would call for a top-level post, and we've had discussions come up in a few other places. So let's have that discussion here.
Comments here will obviously be full of spoilers, and I don't think it makes sense to rot13 the whole thread, so consider this a 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.