Tom Riddle: "And how exactly does one split his soul?"
Slughorn: "Well, you must understand that the soul is supposed to remain intact and whole. Splitting it is an act of violation, it is against nature."
Tom Riddle: "But how do you do it?"
Slughorn: "By an act of evil -- the supreme act of evil. By committing murder. Killing rips the soul apart. The wizard intent upon creating a Horcrux would use the damage to his advantage: he would encase the torn portion --"

MoR!Horcrux might be different, but it seems likely that killing a willing victim isn't good enough, it has to be murder most foul. If a MoR!Horcrux is different, and only requires a death, then why assume a human death is required?

By Word of God, we know that horcruxes exist in the HPMoR universe. It seems like by now we ought to be able to start figuring out what a horcrux is.

In Canon, a horcrux is a fragment of a soul. But it stands to reason that this will not be the full answer in MoR, as it's a fairly serious violation of the author's beliefs. So if we're to disregard supernatural and religious concepts, the obvious first idea is that horcruxes are storage media for some portion of a brain's data.

The problem is that most of what makes up a brain has been strongly hinted to not be the answer, either. It certainly looks like Harry is a horcrux in this universe, and Harry already thought of that possibility in different terms, yet the Sorting Hat says with 100% confidence that there is no extra "mind, intelligence, memory, personality, or feelings" in Harry's head. And I'm disregarding out of hand any clever-schoolboy loopholes like "The horcrux is Harry's foot!"

What is left of a brain, if mind and intelligence and memory and personality and feelings (and a soul) are eliminated? It would be fitting, though a bit precious, if the answer were somehow "rationality", if you could come up with a sensible reason to say that a person's decision-making algorithms don't fall under any of those five categories. But I certainly can't; "mind" by itself seems pretty all-encompassing to me.

But I'm new to Less Wrong and not yet very well read about the art of rationality, so it could be that this will be an easy question for some of you. What explanation remains that would describe what a horcrux is? Are there accepted theories out there that I haven't seen? Or is it maybe time to start questioning my premise that Harry is a horcrux in the first place?

It's an interesting idea, especially since Harry is entirely on board with dying wizards using their magic to fuel Unbreakable Vows. I forget, do Horcruxes require a murder of an unwilling subject specifically, or can they be created if the subject willingly sacrifices himself to fuel the ritual ?

"Even though I think you're wrong, I'd like to hear more" strikes me as better expressed as a comment rather than a vote.

That way, you can explain what you want to hear more about.

Conversely, we could establish the convention of downvoting stuff we consider valueless and upvoting stuff we consider valuable, and leave right and wrong out of it except insofar as voters value right things and antivalue wrong things. If we did that, we'd understand that highly upvoted comments were considered valuable, but not necessarily agreed with.

Oh, wait.

Sure, we could also create a mechanism whereby people could indicate whether they agreed with it (also whether they thought it was well-worded, clear, logical, funny, properly spelled, whether it rhymed, and various other attributes), but before doing that it's worth asking what the benefit of that would be.

I understand wanting to facilitate finding valuable comments and hiding valueless ones, but for the other stuff I'd like to see the benefits articulated, not just labelled "better".

I think the kind of people you're looking for are rare in general, so it shouldn't be a surprise that they are rare on LW.

That said, there's room for improvement. The karma system only allows for one kind of vote. It could be more like Slashdot and allow for tagging of the vote, or better yet allow for up/down voting in several different categories. If a comment is IMO well worded, clear, logical, and dead wrong, then it's probably worth reading, but not worth believing. Right now all I can do is vote it up or down. I'd like to be able to vote for clarity and against content at the same time. And as long as I'm wishing, I'd also like to be able to vote just to vote, so we can have user generated polls without needing a karma dump. And humor - that deserves it's own category. Better feedback, better results. Or at least, so I believe, never having had better feedback.

Additionally, it seems (at least in cannon) that making a Horcrux mutilates the person, damaging (or completely destroying) his ability to love, use empathy, ... so from an utilitarian point of view, it's not "a lot of life years" again "a few life years" but "a lot of years living a mutilated life" against "a few years living a complete life", which is not the same.

And if horcruxing really gets rid of empathy, love and related emotions, it's likely that if it were generalized, the whole society would collapse - leading to lots of negative utility.

Tom Riddle: "And how exactly does one split his soul?"
Slughorn: "Well, you must understand that the soul is supposed to remain intact and whole. Splitting it is an act of violation, it is against nature."
Tom Riddle: "But how do you do it?"
Slughorn: "By an act of evil -- the supreme act of evil. By committing murder. Killing rips the soul apart. The wizard intent upon creating a Horcrux would use the damage to his advantage: he would encase the torn portion --"

MoR!Horcrux might be different, but it seems likely that killing a willing victim isn't good enough, it has to be murder most foul. If a MoR!Horcrux is different, and only requires a death, then why assume a human death is required?

I thought Dumbeldore said that he found a way to imprison Grindelwald without dementors but I can't find were he says that. edit fixed major spelling error can->can't

Only a Hogwarts professor, Dumbledore, and maybe Lupin could do that.

What is special about Lupin that he could pull it off? The professors would probably have security clearance. Dumbledore has security clearance and is incidentally freaking Dumbledore but Lupin is just some wizard. He's fairly competent but not so much as, say, Mad-Eye. I suppose he has better than average Hogwarts-security knowledge due to his misspent youth...