Well, for my own part I don't find the two arguments comparable, because they talk about different things.
Harry's situation, like real-world situations, is about expected utility calculations. He's asking the question: "given my best estimates of the probabilities of various outcomes to my actions, and of the utility of those outcomes, including my best estimates of my estimates being wrong, what actions provide the most expected utility?"
But DSvT isn't like that at all. If I Introduce imperfect information and human cognitive limitations to the dust-specks argument and the whole thing collapses... how do I know there's actually a choice between torture and lots of dust specks? How do I know how many dust specks there are? How likely is it that whoever gave me this information is lying? And so forth.
This isn't unique to the dust-specks argument. Any thought experiment that depends for its force on a really really big disutility, but which doesn't take into account the magnitude of the probability of that disutility or the associated expected disutility, is hard to translate into a world of imperfect information and human cognitive limitations, where probability and expected utility are all we have to work with.
To say that more concretely: if we put Harry in the position of absolutely believing that he must choose between 50 years of torture or 3^^^3 dust specks, should Harry shut up and torture? Well, it probably doesn't matter: the most likely conclusion from that premise is that Harry is insane.
This, in my mind, puts the entire premise of the DSvT post in a very dark light. Given what we know about the real world and the real limitations of practice (vs theory) then the only effect of the DSvT post is to make people more likely to torture (or to excuse torture) in the real world - which is exactly where the hypothetical is completely inapplicable. It makes the world a slightly worse place for no benefit.
Or at least none that I can see. Is there a benefit I'm missing?
And if not, does this make it a mini-basilisk? Something that's true but that everyone's better off having never read?
Update: Discussion has moved on to a new thread.
After 61 chapters of Harry Potter and the Methods of Rationality and 5 discussion threads with over 500 comments each, HPMOR discussion has graduated from the main page and moved into the Less Wrong discussion section (which seems like a more appropriate location). You can post all of your insights, speculation, and, well, discussion about Eliezer Yudkowsky's Harry Potter fanfic here.
Previous threads are available under the harry_potter tag on the main page (or: one, two, three, four, five); this and future threads will be found under the discussion section tag (since there is a separate tag system for the discussion section). See also the author page for (almost) all things HPMOR, and AdeleneDawner's Author's Notes archive for one thing that the author page is missing.
As a reminder, it's useful to indicate at the start of your comment which chapter you are commenting on. Time passes but your comment stays the same.
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: