Massive warning flag there: Claiming to have "scientific consensus" is routine for people who are arguing for things that have no actual scientific support. As it turns out, the rest of your post wasn't too horribly unreasonable, but it would still be best from a communications/linguistic standpoint to avoid phrasing that just screams "Don't take me seriously, I'm a quack".
Had humans remained isolated in groups there might be an argument for race stronger than there is now. However, the fact is that we have shuffled our genetic decks so much since humans began exploring, conquering and mixing with the rest of world that the idea is beyond any redemption
That wildly overstates the effect that transportation technology has had on genetic mixing so far. In most places, mixing has not progressed very far yet, so the local population's composition is still pretty close to what it was before Columbus (or a nearly total replacement of natives with immigrants), and by far most individuals' ancestry is pretty easy to identify. I don't deny that mixing has happened, more in some places than in others, but to claim that this has eradicated the races yet is just simply not being honest. If that were true, those differences you dismiss as "superficial" would not be merely superficial; they'd be
gone. For that to happen will, at current rates, take millennia (at least).
But I will leave it at that for the moment and invite arguments to rebut the idea that race is anything more than human based classifications...
We're humans, so any classification we come up with, including all of the ones you accept as perfectly real, will be human-based, in exactly the same way that this one is. But what does that have to do with any such classification's accuracy or inaccuracy at describing reality?
...for the purpose of anthropological understanding of genetics/health/populations
What else do you say anybody has ever claimed it is? Race denials that I've seen before always hinge on an assertion that there's some other meaning for the word "race" in this context other than a few large regional groups of people with internally shared ancestry (and thus biologically inherited traits) distinct from other such groups. But they can never explain exactly what else beyond that is allegedly part of the word's meaning, nevermind providing any support for the claim that it is what the word somehow really means or a single dictionary defining it that way or anybody actually using the word that way in real life.
If you disagree with me... you are going to have to make some compelling arguments in favor of race that isn't simply... bias or prejudice.
You're the one claiming that common knowledge and everyday casual observation is a delusion or a lie, equivalent to claiming the sky isn't blue and what goes up doesn't come down; that's taking the burden of proof upon yourself. But I'll play along anyway...
Your challenge is based, as race denial demands always are, on a straw man. You ask for evidence of something
beyond the observable sets of inherited traits in the bodies of humans born to populations that evolved in different regions of the world. But nobody I know of has ever claimed any such thing. We only claim the mundane part that you're insisting on looking
beyond: that human populations that have been established in different regions of the world have evolved different observable sets of physical (including chemical) traits. You seem to have have already stipulated that these are real, so it seems that I don't need to prove it to you; I'm only asserting the existence of what you've already said exist. You've dismissed them as unimportant or superficial or such, but those are not the same thing as non-existent, and address things that are not part of my claim or that of anybody else I know of.
However, since it's been said in this thread that there are just a few phenotypic traits such as hair texture, this seems like a good place to point out how much more there is to it than that. Here's a map showing distinct
sets of hundreds of mutually highly correlated genes apiece. (These are just the ones that were known several years ago. A lot more have been discovered since then, but maps like these haven't been made each time more are discovered and the list of genes in these groups gets longer, partly because it's happened too frequently lately, and partly because it isn't even newsworthy anymore; anybody who's been paying any attention to genetics already knows about these large genetic clusters, so there's no sense in another merely showing that they exist and where in the world they're found.) Identifying genes only by their correlations with each other found these groups which just happen to fall into the same geographic areas that were already known to be the homes of the different human races based on gross anatomy before genetics existed. There are no other such genetic groups in any other geographic distribution.
Purely linguistic note: Some of these genes control the classic "superficial" traits; skin color, for example, is controlled by about a half-dozen genes. However, some others affect the immune system and digestive enzymes and so on, which are real, actual differences between people who are members of different races but are pretty thoroughly internal and not visibly obvious, so they can't all accurately be called "superficial." Also, the functions of many of these genes aren't even known yet; all we know about them is their correlations with each other. If one wants to be dismissive about them, one could honestly call them unimportant or insignificant or minute or a small fraction of all human variation, but not superficial because they're not all visible from the outside.
So, your mission, race realists, if you are going to rebut the proposition...
I don't rebut the proposition. I rebut the idea that asking for a rebuttal of the proposition even makes any sense, since it asks us to support an idea that isn't what we think and isn't even defined in any detail other than as something we don't think (because it asks for something
beyond that which is the entirety of our position on this subject).
I was under the impression that genetic testing could determine a person's ancestry, particularly whether they have Asiatic, African, Caucasian, Hispanic, and multiple lineages. Is this true? If so, isn't this equivalent to saying race is a genetic trait or traits?
Yes. Race deniers spend lots of words trying to get away from that, but that's all there is to it.
We have fewer dissimilarities than many species in which only one variety is recognized.
Such as what? (I don't dispute their existence; in fact I presume they must exist. But I'd like to know the examples. The specific individual examples I'm familiar with actually all have significantly LESS difference between races/varieties/breeds/subspecies/whatever than we do, which makes it particularly ironic that the race deniers claim we don't have enough but don't object to classification within species with even less.)
All that separates people from different parts of the world are groups of particular genes that have higher distributions in some places than others
Bingo. There's no more to it than that.
No, at best it can follow a single maternal (mother's mother's mother's....) and paternal line.
That is simply false... spectacularly, flamboyantly so. The limit you're talking about applies exclusively to DNA that is passed on only by males or only by females, but most DNA, including all nuclear chromosomes except Y, gets passed on by both, and it's all the rest of that other DNA that's most useful in studying populations overall rather than just individuals.
For example, 10 generations back, you're descended from up to 1024 people. You got your Y chromosome from one of them and your mitochondria from another. You got everything else from the other 1022 people. Paying attention to only those two people, which add up to a whole 512th of your ancestry, ignores the other 511 512ths! The longer the time scale is, the worse this gets. Over dozens of millennia, there are hundreds of generations and the numbers get ridiculously huge/tiny. At that point, focusing on Y chromosomes and mitochondria alone is essentially considering an amount that's indistinguishable from zero--
none--of your ancestry, and deliberately choosing to disregard practically all of it.
Races are a matter of group/population, and the non-Y nuclear DNA is where you find out about those, precisely because the genes there can be mixed and passed on in various combinations by anybody.
