This doesn't seem all that conclusive to me.
In fact, I'm pretty sure that events did not happen as Harry deduced them. In canon, Snape overheard the prophecy being given. This seems to match up with what Snape says in the chapter formerly known as 77:
I thought I had merely happened to overhear it, when in truth it was I who was overheard.
Therefore I suggest that Dumbledore did not tell Snape about the prophecy. I'm not sure why or how McGonagall knows: possibly, in a departure from canon, she was conducting Trelawney's interview instead of Dumbledore himself.
The beginning of Harry's line of reasoning is that Voldemort was not terribly eager to kill Lily Potter. This seems likely to be true, but is also not indicative of anything. It's a mildly strange thing to imagine, but we imagine strange things all the time.
Quirrell suggests that Harry can see Thestrals due to his memory of that night, which would suggest that it's a true memory. But Harry seems to think that he saw the Thestrals because he has realized that Dementors are death, so that he has "seen death and comprehended it" in a more literal sense.
I'm not sure why or how McGonagall knows: possibly, in a departure from canon, she was conducting Trelawneys' interview instead of Dumbledore himself.
Yep:
...The old wizard's face turned grave. "The same reason it must be kept secret, Minerva. The same reason I told you to come to me, if Harry made any such claim. Because it is a power that Voldemort knows not."
The words took a few seconds to sink in.
And then the cold shiver went down her spine, as it always did when she remembered.
It had started out as an ordinary job interview, Sybill Trelawne
The new discussion thread (part 15) is here.
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 82. The previous thread passed 1000 comments as of the time of this writing, and so has long passed 500. Comment in the 13th thread until you read chapter 82.
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.)
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