Your reasoning makes sense, but I believe we're clearly supposed to understand that Harry's going over to his Dark Side was the premeditated purpose of Quirrell bringing the Dementor to Hogwarts in the first place. Quirrell's plan was defeated that day, more or less because of Harry's love (not romantic love, necessarily) for Hermione. That day Quirrell realized that to really turn Harry Dark, he had to neutralize those Harry holds dear.
Thank you. {EDIT} I reserve most of my nonsensical actions for comic relief in tense real life situations.
Well for me two obvious questions arise: Why are we supposed to believe so? Given that Quirrelmort is dark, wouldn't the Dementor just be the experimental method applied so as to test whether or not his brain-wave patterns interfered with Harry's ability to act as a champion of light? {added} Also any of the given actions that day might as well have been a test of Harry's current limits and willingness to follow a plan.
Even if not, shouldn't Quirrelmor...
EDIT: New discussion thread here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With two chapters recently the previous thread has very quickly reached 500 comments. The latest chapter as of 17th March 2012 is Ch. 79.
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.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight, nine, ten.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting 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: