Okay, this thread it to discuss what counts are Pureblood, and what doesn't.

The definition that I follow is that no Muggle (including Squib) blood can be in the line, whatsoever. A single Muggle is enough to make you non-Pureblood. Many people take offense at this definition. So I am going to explain it fully for you, with use of a JKR quote:

The important parts of this quote are the following:

These are the important concepts. So, to summarise:

1. In Blood Purity terms, Muggleborn = Muggle.

2. Muggle parent makes you non-pureblood.

3. A single non-pureblood grandparent is enough to make a wizard non-pureblood.

At first, this looks like it goes against my idea - all you need is purebloods back to your grandparents and you're a Pureblood yourself.

But a closer look is needed.

Let's say we have a situation in which a person has magical people back to his grandparents, but his great-grandparents are Muggles/Muggleborns. You'd think that he'd be a Pureblood, since he has 2 generations of magical people behind him (parents and grandparents).

But he isn't.

To see why, we have to look at the grandparents. The grandparents themselves do not have Pureblood parents, and so they are not pureblood. Therefore, they are enough to pollute the line. The whole thing collapses.

So in other words, even though you count as Pureblood so long as you're parents and grandparents are Pureblood, those parents and grandparents themselves have to have Pureblood parents and grandparents to count as Pureblood in the first place, and so on to infinity. Therefore, you have to have NO Muggle blood connected to you whatsoever in order to be a Pureblood.

Obviously, this is not possible. This leads us to the natural conclusion - and the point that JKR was trying to make about blood superiority - that Blood Purity is a false position, whose adherents aren't even Pureblood themselves, by their own definition. It's a political movement, not a biological one.

Furthermore, this quote:

 

The criteria is not having all pureblood grandparents, is having all wizard grandparents.

 

Yes, but from a pureblood's point of view the only people that are actually wizards are Purebloods. Everyone else are either half-wizards or Muggles.

 

Well, it looks like your going to get rid of all confusing notions in Harry Potter.

I guess I agree with most of what you have there, but wouldn't wizards have to come from somewhere?

 

Which is why there are no Purebloods and it's an imaginary concept with no actual examples.

But yes, presumably wizards came from somewhere. My best guess is that somewhere in history a mutation occurred, creating the magic gene, which then spread through the human race by the rules of evolution (accidental magic is a selective advantage).

 

I just assumed that purebloods were those who couldn't trace/hid all evidence of muggle blood in their genealogy. As it's a purely subjective view and as there were clear benefits to being a "pureblood" people would obviously do everything to erase evidence. And if that means moving to a country where nobody has heard of you (Malfoy -> England) then so be it.

 

I've always thought that a pureblood was someone who had had seven generations of ancestors who were magical.

 

Sophistry!!
The whole concept of 'half-wizard' is incoherent, and obivously makes no sense, even to pureblood fanatics. You're just defining things the way you like for your intended result to obtain--I think you know that that's completely ad hoc too...

 

No, it comes straight from the quote...

 

Well, yea I know, but isn't that from the HP Lexicon?

 

No, it's from JKR's website.

Link:

http://www.jkrowling.com/textonly/en/faq_view.cfm?id=58

 

It has, admittedly, been a long time since I read the entire series. Is the idea of 'full' blood a entirely fanon concept?

And she said that a single 'muggle' grandparent pollutes the line. Therefore, if both grandparents are half-blood at the least, and one of their children bears child with a pureblood then the grandchild is, by her definition, a pure-blood.

She gives us a definition of pureblood and never once says that polluting even once makes ALL members a mud-blood. Therefore is would be how far back your ancestry stretched that would matter.

I.E Are you a fifth generation Pure Blood, meaning it has been eight or so generations since a mudblood or muggle has sullied your line? Or are you a second generation halfblood, meaning the next generation will be pureblood?

 

This is the bit where we disagree I think.

I would say that the grandparents themselves have to be Pureblood. And for them to be Pureblood, their grandparents need to be so. And so on.

Why do I say that the grandparents need to be Pureblood? Because the Purebloods, who created this ideology, consider only Purebloods to be wizards, so to say you need Wizarding grandparents is the same as saying you need Pureblood grandparents.

 

But, as you said, half-bloods are half a wizard. After a few generations, their kids are no longer halfs but wholes.

I do see what you mean about there never truly being a pureblood in the very beginning, but the very beginning is only a legend, and you can make up whatever you want in legends.

 

But would it really work like that? It seems to me, from the fact that Muggleborns are considered the same as Muggles, that the issues of having magic and purity of blood are completely unrelated.

So it may be that Half-Bloods will only ever produce Half-Bloods, no matter how many generations of magical people, because they come from a Muggleborn, and a Muggleborn is the same as a Muggle.

 

But there seem to be a good number of pureblood families that we see in the books.

The Weasleys are considered pureblood, and there is no way that they were so obsessed with keeping their marriages completely within the pureblood folds. I think they are more of the accidental kind of purebloods.

I think there must be a way to get your family into the pureblood lines without being an original pureblood. By JKR's definition, the way to do this is to have halfbloods at the least all the way up to your grandparents.

 

I suppose that's the only way to reconcile JKR's quote with what we're presented in the books.

I concede this one to Half-Blood Prince.

 

If that were the case, why go to grandparents? Wouldn't it be enough to say both parents must be wizards?

 

To stress the Nazi parallel?

 

Well presumably there are issues with both the genetics (how far back their /pure/ line goes) and there are issues with manner. Have they been in the wizarding world long enough to learn the proper cultural customs. A family that doesn't practice these customs probably wouldn't be considered pure of blood. Conversely, the stigmatism attached to muggleborns itself seems born out of a feeling of contempt for any persont that doesn't use all their power to their own advantage, hence the Malfoy Weasley Feud.

While having magical grandparents might be enough to be considered a pureblood, it would be technicality unless the family in question was 'their kind of people' to the Most Ancient Houses.


Genetically, all one should really need is two magical parents to be considered Pure of Blood, though I would never say Harry is 'half' a wizard, because magical or not, that's not the way babies are made. Muggleborns are still wizards, though obviously they haven't had the centuries for their wizarding talent to stabilize and become dominant, rather they're the first of their so called 'line'. This would actually favour wizard/muggleborn marriages, because it would ensure the passing on of the pureblood line family traits, though occasionally a stronger trait from the muggleborn 'line' might override those. The reason why muggleborns aree shunned by and large by the magical society might actually be out of fear. They fear the potential that muggleborns might bring a new, unknown trait to the currently stable (but weakening through inbreeding) magical gene pool. A trait that has the potential, being unknown, to completely destabilize the gene such that any resulting progeny might be little better the squibs. While the occasional squib comes from pureblood pureblood mariages, they are written off the family lines because of both the disgrace, but also because their genetics are the result of a failed union. Thus they are either killed or exiled to prevent their known failure of magical talent from contaminating the rest of the gene pool.