I'd love to see aliens get given the most basic historical and environmental facts about the various races of all world
Any rational objective outside observer would conclude that there are (still) multiple races of humans on the planet. I realize that's super, super offensive ...if you're not rational and objective, but it's absolutely true and very easy to prove.
If these are distinct species:
Then surely there are distinct human species.
It is here that a Leftist (having never debated this topic but smugly believing their worldview to be obviously correct) will hit me with the Lewontin Fallacy: "there is more variation within a race (any race) than between any two of them"
Then they'll get upset when I easily rebut that by pointing out: yes, that's always true, and not just of race. There's more variation
in height within the group called "men" than between that group and the group called "women" (i.e. men range in height from perhaps 4'6" to 6'6" a difference of 24" but the difference
between gender groups is only 5'9" for men and 5'3" or just 6"). If you'd like to see a that done with PCA, here you go:
Next the Leftist will assert, "we clearly aren't different species, since we're able to breed" - and I'll ask them what percentage of DNA in modern humans comes from Neanderthals (mostly European humans, btw) and they'll pause, because they have heard of that before, but never thought about what it means. It means that humans bred with neanderthals ...even though you recognize those as different species.
In desperation, the Angry Leftist will assert that humans are a young species, and that no population has diverged enough, or been isolated long enough to be as different from each other as any two recognized species are.
Here again, I will be ready to go with sources-a-plenty. The way to measure the difference between two species is with a "fixation index" or FST. 0 means the two populations are identical. 1 means they share nothing in common. The FST of the American Gray Wolf and Coyote is 0.153 (source:
https://redwolves.com/newsite/wp-content/uploads/2017/02/vonHoldt.pdf)
The FST of Europeans and Sub-Saharan Africans is also 0.153 (source:
https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0005472&type=printable)
Next (or often first) the Leftist will wave their arms angrily and proclaim, "race has no scientific basis" (or sometimes they'll say "no biological basis" or they might pull out the old "it's a social construct"). All of these are linguistic arguments - they're saying that because there's a coloquial definition that may lack precision, that means all the other facts (like PCA and FST) that I can point to are moot.
My response is, "nuh uh." Basically, if we use the word "species" to classify and distinguish other species, then that word can also be applied to humans. And the only thing stopping us from doing that is lack of objectivity, lack of rationality, and fear of being called racist. And the only reason the Angry Leftist is able to avoid this conversation is that he bullies people with censorship.
But an extraterrestrial would tell us that we're full of shit. There are several species of human.
Thanks for listening to my TED talk. Here's trans-racial pioneer Rachel Dolezal tricked into dropping the 13/50 stat: