I'm enjoying the story; but am bothered by this passage:
The Dementors were coming.
"My Lord, you - you should not risk yourself for me - take back your Cloak -"
"Be silent, fool," hissed an angry voice. "When I decide to sacrifice you I will tell you so."
She's got a valid point, said Slytherin. You shouldn't risk yourself for her, there's no way her life is as valuable as yours.
For an instant Harry considered sacrificing Bellatrix to save himself -
Bella's life isn't just less valuable than Harry's. Her life has a large negative value. Harry should be trying to prevent her escape. This righteous, humble talk about why Harry can't save himself instead of her is exactly the sort of thing that makes me so exasperated with comic-book superheroes; and just the sort of thing I was hoping the Methods of Rationality would expose, or at least avoid.
It does work out better than if Harry had tried to save himself - but, it's a story. This story is remarkable partly because it uses a rational protagonist; but it could also be remarkable for making more concessions to reality than most stories. This is a case where it failed to make a concession.
On a related note,
If you think your own life is valuable enough that you're not willing to take on an eighty percent probability of dying in order to protect all the prisoners in Azkaban, his Slytherin side observed, there's no way you can justify taking a twenty percent risk to your life to save Bellatrix and Professor Quirrell. The math doesn't add up, you can't be assigning consistent utilities over outcomes here.
The logical side of him noted that Slytherin had just won the argument.
It seems the author is flat-out telling us that Harry is deliberately acting irrational, and commends him for it. Curious.
- This thread has run its course. You will find newer threads in the discussion section.
Another discussion thread - the fourth - has reached the (arbitrary?) 500 comments threshold, so it's time for a new thread for Eliezer Yudkowsky's widely-praised Harry Potter fanfic.
Most of the paratext and fan-made resources are listed on Mr. LessWrong's author page. There is also AdeleneDawner's collection of most of the previously-published Author's Notes.
Older threads: one, two, three, four. By tag.
Newer threads are in the Discussion section, starting from Part 6.
Spoiler policy as suggested by Unnamed and approved by Eliezer, me, and at least three other upmodders:
It would also be quite sensible and welcome to continue the practice of declaring at the top of your post which chapters you are about to discuss, especially for newly-published ones, so that people who haven't yet seen them can stop reading in time.