I am very interested in what the effect of magics to nullify "opposite reaction science" will be. Biochemistry cannot work in such a regime, and unless the witch actively puts in something to account for this, you're going to get a lot of dead Aurors and prisoners; although I suppose they'll learn this as they experiment with the jinx. Even if it does work in the sense of not instantly killing everyone in the area of effect, there will be much weirdness; whatever humans expect when they start to consciously think about physics, our reflexes have to be tuned for Newtonian mechanics. I will look forward to seeing how plausibly weird this can get.
On another note, I wonder if we can create a repository of links to other Internet discussion of the fic? I'll start with this thread on Orson Scott Card's discussion site.
My take on this is that it's just an illustration that wizards really don't understand science, and they'll be unsuccessful at implementing their anti-physics charm.
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: