CEA statement on Nick Bostrom's email

Yeah, I think there are a bunch of different ways to answer this question, and active research on it, but I feel like the answer here does indeed depend on empirical details and there is no central guiding principle that we are confident in that gives us one specific answer. 

Like, I think the correct defense is to just be straightforward and say "look, I think different people are basically worth the same, since cognitive variance just isn't that high". I just don't think there is a core principle of EA that would prevent someone from believing that people who have a substantially different cognitive makeup would also deserve less or more moral consideration (though the game-theory here also often makes it so that you should still trade with them in a way that evens stuff out, though it's not guaranteed).

I personally don't find hedonic utilitarianism very compelling (and I think this is true for a lot of EA), so am not super interested in valence-based approaches to answering this question, though I am still glad about the work  Rethink is doing since I still think it helps me think about how to answer this question in-general. 

Ah okay, sorry, I thought you meant the opposite.  Thank you!

This list is a good example of the sort of arguments that look persuasive to those already opposed to HBD, but can push people on the fence towards accepting it, so it may be net-negative from your perspective. This is what has happened to me, and I'll elaborate on why – so that you may rethink your approach, if nothing else.

Disclaimer: I am a non-Western person with few traits worth mentioning. I identify with the rationalist tradition as established on LW, feel sympathy for the ideal of effective altruism, respect Bostrom despite some disagreements, have donated to GiveWell charities on EA advice, but I have not participated more directly. Seeing the drama, people expressing disappointment and threatening to leave the community, and the volume of meta-discussion, I feel like clarifying a few details that may be hard to notice from within your current culture, and hopefully helping you mend the fracture that is currently getting filled with the race-iq stuff.

All else being equal, people who hang around such communities prefer consistent models (indeed, utilitarianism itself is a radical solution to inconsistencies in other ethical theories). This discourse is suffused with intellectual inconsistency, on many levels of varying contentiousness.

• On the faint level of moral intuitions, there's the strange beeline from the poorly supported prior that normalization of beliefs like Bostrom's will lead to bad effects like discrimination, to the consequentialist decision against entertaining them. It is not clear that Bostrom's beliefs are harmful in this way, or more likely to encourage a net increase in discrimination than their negation. Arguments from historical precedent have big problems with them: they do not address the direction of causality, or the fact that different cultures can have different reactions to the same information. As it is not considered normal in the modern culture to equate moral worth and ability for individuals of any group, it can be expected that the same will hold should the difference in ability between groups be acknowledged. Arguments from personal distress of users are valid points with regard to community health, but obviously (I hope) incommensurate with the question of global utility, and do not directly weigh on it. So the consequentialist case for not taking Bostrom's belief in good faith is already suspect.
• Perhaps the most obvious level is that specific failings Bostrom is credibly accused of (racist attitude, belief in the racial IQ difference, belief in the validity of IQ measurement) do not depend on HBD. (He has done himself no favors by bringing up eugenics). So it's bizarre to see many people denounce his beliefs in toto, but support this denunciation with environmentalist explanations of the IQ gap – in effect, conceding the specific factual claim in Bostrom's old email, or at least demonstrating that it is not beyond the pale by their own standard. To be clear: it is not in doubt that the IQ gap between Black and White Americans exists; and that it is as predictive of outcomes associated with cognitive capacity as IQ measurement is (which is to say, highly predictive – and this, too, is mainstream consensus). People who act indignant about such statements send a huge red flag, demonstrating either general unwillingness to educate themselves or irrational ideological bias on this specific matter. People who bring up irrelevant anti-HBD talking points demonstrate confused reasoning.
• Less obviously, the problem is portraying this as an open-and-shut case – a portrayal which doesn't really survive scrutiny. I don't know how to put this nicely, but what your list most reminds me of is polemics of sophisticated Creationists in the heyday of New Atheism. It's a mix of true but irrelevant, misleadingly phrased, blatantly misinterpreting and patently false claims. Instrumentally they are gotchas; structurally, opening moves aimed at people who are not familiar with the debate and are not aware that all those issues had long been answered, and the debate is incredibly mature. Of course, in all such debates both sides can assert that they've solved every vulnerability, and this forum isn't some HBD Central. So I won't compete in citations, and will just address things a total layman, provided he's minimally erudite, napkin-numerate, capable of critical thought and aware of basic logical fallacies, could spot, if he were so inclined. You way "Now you might want to attack one of these (and feel free to send me a message), but even if you're right, that would still leave more than enough reasons to stay away from HBD." What if we go through every one of these?

1. Human biodiversity is actually pretty low. Homo sapiens has been through a number of bottlenecks. – maybe true but vacuous. "Pretty" low relative to what baseline? How would we even tell – do we have anything like IQ for other species? Does this genetic fact establish some prior for the magnitude in differences in measurable phenotypic traits between groups? What about individuals? What we do know that people with a priori negligible "biodiversity" – as in, children in ethnically endogamous marriages, even in isolated villages – routinely have large differences in all traits of interest. So how much diversity is needed, really, to introduce some measurable population-level divergence? Likewise for the point about bottlenecks, what of it? Should our layman just conclude that this is an authoritative-sounding technical term?
2. Human migrations over the last thousand years have been such that literally everyone on Earth is a descendant of literally everyone that lived 7000 years ago whose offspring didn't die out. This is known as the Identical Ancestors Point. – grossly misleading/false, and doesn't pass basic sanity check. Is every single unadmixed Indigenous Australian really a descendant of "literally everyone" 7000 years ago, same as every single Han Chinese? But, looking it up, National Geographic says that "Aboriginal Australians are all related to a common ancestor who was a member of a distinct population that emerged on the mainland about 50,000 years ago", which implies people of other populations are not all related to him. Aha, here's where your figure comes from: "Rohde, Olson and Chang showed through simulations that, given the false assumption of random mate choice without geographic barriers, the Identical Ancestors Point for all humans would be surprisingly recent, on the order of 5,000-15,000 years ago." But it is indeed false, there were barriers for the entire history of our species, such as oceans; and how do migrations of the last millenium negate it? More importantly, it's a quantitative issue. Your link goes on to say: "Thus, even though the Norwegian and Japanese person share the same set of ancestors, these ancestors appear in their family tree in dramatically different proportions. A Japanese person in 5000 BC with present-day descendants will likely appear trillions of times in a modern-day Japanese person's family tree, but might appear only one time in a Norwegian person's family tree." Seeing as every specimen can have novel genetic variants, this should allow for arbitrary magnitude of divergence, no?
3. Africans have more genetic diversity than literally every other ethnicity on earth taken together, so any classification that separates "Africans" from other groups is going to be suspect. – misleading. The money quote is: "Tishkoff and her colleagues studied DNA markers from around the planet, identifying 14 "ancestral clusters" for all of humanity. Nine of those clusters are in Africa. "You're seeing more diversity in one continent than across the globe," Tishkoff said." Okay, let's assume that those 9 clusters are meaningfully different (as are the other 5). When people talk of "Africans", in practice, whom do they refer to? Looking it up,

"The very-diverse are hunter-gatherer populations who live in clusters scattered across Central and Southern Africa, in Namibia, Botswana, the Congo and a dozen other nations. They include the Khoi, the San, the Mbuti, the Mbenga, the Twa and the Hadza. [...] Save for that isolated half-million very-diverse hunter-gatherer minority, all Sub-Saharan Africans constitute the genetically in-between group of 1.14 billion not-very-diverse humans. [...] The founder population of today’s genetically not-very-diverse Sub-Saharan Africans shows signatures of a population crash, probably with a toll of 50% and probably from an effective breeding population of something like 50,000 people down to 25,000. So out of a founding population on the scale of a very small city 60,000-120,000 years ago, today’s 1.14 billion Sub-Saharan Africans have gone on to people every habitable space of that hugely varied continent. They are significantly more genetically diverse than their relatives on five other continents, but nowhere near as diverse as the neighbors in their midst. [...] 93-98.5% of the ancestry of humans outside of Sub-Saharan Africa (among those with no recent Sub-Saharan African ancestry, obviously) derives from a breeding population of 1,000 to 10,000, which expanded rapidly 60,000 years ago."
So this tells us that a) this measure of diversity is mostly sensitive to minimal sizes of ancient populations, b) people descending from most of those diverse clusters constitute a tiny fraction of African population, and are thus non-central cases of colloquial "Africans", c) the overwhelming majority of people of SSA ancestry descend from a single breeding population, which can be distinguished from other populations – including the one that had left Africa. The story is more complex, but the point is that this diversity appears not to be a good reason to not recognize [the majority of] Africans as a specific separate group.

4. Race isn't a valid construct, genetically speaking. It's not well defined". – but aren't we already talking of genomic ancestry? So this is a true but irrelevant objection. Now, people are of course free to believe that conventional self-reported "races", which are, as is often correctly said, social constructs, do not correspond to continental-level ancestry – although noisily in many cases. I think this is pretty absurd on its face, but anyway, Googling tells us "In mothers self-identified as Black and White, the imputed ancestry proportions were 77.6% African and 75.1% European respectively" in a "diverse" NYC sample, and I'd expect less cosmopolitan groups to show higher figures. However unfit race is for purposes of cutting-edge research, in the aggregate data it is robustly aligned with ancestry, which is well-defined.

5. Intelligence is not well defined. There's no single definition of intelligence on which people from different fields can agree. – blatantly misinterpreting. The cited paper states: "...Nevertheless, some definitions are clearly more concise, precise and general than others. Furthermore, it is clear that many of the definitions listed above are strongly related to each other and share many common features" and goes on to propose a unified definition: “Intelligence measures an agent’s ability to achieve goals in a wide range of environments.” Features such as the ability to learn and adapt, or to understand, are implicit in the above definition as these capacities enable an agent to succeed in a wide range of environments. Also it is not clear why we'd even need people from different fields (in this case, psychology and AI research!) to agree on a definition of intelligence to have a useful measurement of human smarts. And this is what has happened with IQ:

6. IQ has a number of flaws. It is by definition Gaussian without having appeared empirically first and the g construct itself has almost certainly no neurological basis and is purely an artifact of factor analysis. – this is just some Gish Gallop. To begin with, I don't see your link supporting your summarization – except the vague "number of flaws". If I may, where have you taken this list from? In any case, anything but God has a number of flaws; your link says that "According to Weiten, "IQ tests are valid measures of the kind of intelligence necessary to do well in academic work."" and "clinical psychologists generally regard IQ scores as having sufficient statistical validity for many clinical purposes". It doesn't seem like there's any scientific objection as to the validity of IQ as a measurement of what's casually called smarts and understood to be smarts in the context of this discussion – even though there are weird attempts to drown this fact in caveats. Why is the part about assumed Gaussian even relevant? What would it mean for g to have a neurological basis, and why would that matter in the discussion of HBD? ...And the part about g being "purely an artifact of factor analysis" is plain false, far as I can tell. It comes from Cosma Shalizi's essay that misstates the reason for the existence of positive manifold. "If I take any group of variables which are positively correlated, there will, as a matter of algebraic necessity, be a single dominant general factor... Since intelligence tests are made to correlate with each other, it follows trivially that there must appear to be a general factor of intelligence." This is just a lie: a great deal of effort has been devoted to making cognitive tests comprehensive and diverse assessments of ability, but positive correlations pop out on their own, even in research informed by Shalizi's assumptions, e.g. "The WJ-R was developed based on the idea that the g factor is a statistical artifact with no psychological relevance. Nevertheless, all of its subtests are intercorrelated and, when factor analyzed, it reveals a general factor that is no less prominent than those of more traditional IQ tests". And "...All 861 correlations are positive. Subtests of each IQ battery correlate positively not only with each other but also with the subtests of the other IQ batteries. This is, of course, something that the developers of the three different batteries could not have planned – and even if they could have, they would not have had any reason to do so, given their different theoretical presuppositions."

7. Twin studies are flawed in methodology. Twins, even identical twins, simply do not have exactly the same DNA. – again, misinterpreting; there are flaws but the method is not summarily "flawed" just because a section about flaws exists. The first link is a list of objections but in no way does it show or argue that they are decisive, or even apply at all to current methods (there are "responses to critiques" subsections). The second is apparently irrelevant, and was already addressed by another user.

8. Evolution isn't just mutations and natural selection. Not every trait is an adaptation. (a link to Wiki on "Evolution – Evolutionary processes") – ...okay but how does this even support your case? I'm honestly unsure what the idea here is. Taken literally, your summary suggests that evolution can produce maladaptive changes, so we cannot assume that all (or any) populations will be maximally fit (for their environment). This is a pro-eugenicist take, if anything. Whereas the page itself discusses mechanisms of change in allele frequency and does not have any clear impact on the validity of HBD one way or another.

9. Heritability does not imply genetic determinism. Many things are heritable and do not involve genes. These include epigenetic mechanisms, microbiota, or even environmental stress on germinal cells. – irrelevant/false. The link is to "Heritability – Controversies" with some nitpicks of unclear truth value. The second is a general overview of possible issues with heritability estimates. It does not weigh in on HBD and accepts the premise of variable genetic contributions to human intelligence: As a case in point, consider that both genes and environment have the potential to influence intelligence. Heritability could increase if genetic variation increases, causing individuals to show more phenotypic variation, like showing different levels of intelligence. On the other hand, heritability might also increase if the environmental variation decreases, causing individuals to show less phenotypic variation. This says, concretely, that in more equal environments we will observe more true genetic effects on variation in intelligence, so whatever differences in genetic effects on this trait there are between groups, they will become more pronounced. By the way this is terrible for the anti-HBD position because it means that the state of perfect environmental equality – one could say equality of opportunity – will collapse into genetic determinism (modulo random noise). Your own idea seems to be that non-genetic mechanisms of apparent heritability can be interrupted by a positive environmental intervention. What share of "heritable" variance can it explain, at a maximum? Like, concretely, to what extent do you think the racial IQ gap is explained by microbiota, epigenetic mechanisms and environmental stress on germinal cells? Those are all quantifiable and falsifiable claims, but you just gesture at them. At this point, a dedicated layman looks it up and sees that they can explain very little indeed.

10. We don't mate randomly, which is an assumption in many genetics studies. – irrelevant applause lights, "genetics bad". Which studies, and does this matter for HBD? I've watched the video; it discusses interactions between psychiatric disorders and such, and states that genetic correlations between traits may be inflated by assortative mating (i.e. people high in trait X marry people high in trait Y). Genetic correlation "is defined as the proportion of the heritability that is shared between two traits divided by the square root of the product of the heritability for each trait". What is meant here, concretely? Ancestry is not really a "heritable trait", is it? And race is just a category, plus a bad proxy for ancestry, as far as HBD is concerned.

11. HBD is not generally accepted in academia. – this is just an appeal to authority, plus misleading. It's a single highly technical paper by some Kevin Bird, "Department of Horticulture Michigan State University", can it be considered an authoritative source on what academia thinks? And from the abstract, it attacks a very strong form of HBD reasoning, using data that cannot plausibly be conclusive: Evidence for selection was evaluated using an excess variance test. Education associated variants were further evaluated for signals of selection by testing for excess genetic differentiation (Fst). Does it strike you as plausible that we know enough about "education associated variants" to impute effects of prehistoric selection on intelligence? This ought to mean that the science of genetics of intelligence is vastly more mature than people think, than you suggest, too, and that within-group intelligence heritability is understood really well! Why hasn't this made the news yet? (And how does this address obvious low-tech HBD arguments, such as admixture studies and adoption studies?)

12. Many public HBD figures have been found guilty of fraud. Cyril Burt would literally forge results, while Lynn would take the average of two neighboring countries' IQ in order to derive "data" from a country's unknown national IQ. – That's an isolated demand for rigor. What field doesn't commit fraud? Were public anti-HBD figures never found guilty of fraud? Is the fraud rate different enough to affect our priors? And your link does not show that Burt's forgery was positively proven, but it admits that figures of heritability arrived at by independent researchers do not differ from Burt's, so why should we care? Assuming that a layman could track it down from here, I'll allow myself to quote Richard Haier (The Neuroscience of Intelligence, Cambridge University press, 2017): Subsequent twin studies done by different investigators around the world with large samples arrive at an average value for the correlation of intelligence scores among identical twins raised apart of .75 (Plomin & Petrill, 1997). Burt’s value was .77. For comparison, based on 19 studies ranging in sample sizes between 26 and 1,300 identical twin pairs, the average value for identical twins raised together is about .86 (see Loehlin & Nichols, 1976, table 4.10, p. 39)... Thus, the .771 “fraud” ends with recognition of overwhelming data from independent researchers that are fully consistent with Burt’s analyses, flawed as they may have been. Any single study, or any one researcher, can be flawed, but the basic conclusion that genes play an important role in intelligence is consistently supported by data from numerous studies of twins, adoptees, and adopted twins. This is an excellent example of looking at the weight of evidence (recall my three laws from the Preface: no story is simple; no one study is definitive; it takes many years to sort out conflicting and inconsistent findings and establish a weight of evidence). ... The weight of evidence summarized in this chapter leaves no reasonable doubt. Only extreme ideologues are still in denial. As for Lynn's country data, well, the same logic applies. Do we have any more trustworthy data? Does it refute Lynn's? Then why not just refer to it instead? Please don't say that it's not very interesting and nobody has bothered to collect proper measurements, IQ and race (or rather, ethnicity) is literally the most painful question in modern science, and it's evident from such dramas that a great many researchers are emotionally invested in proving the relationship wrong.

Ultimately, exposure to this sort of content has done for me what it has done for this person:

[…] Well, OK, I could believe that; visible traits consistent over entire populations like skin color might differ systematically because of sexual selection or something, but why not leave IQ following the exact same bell curve in each population? There was no specific thing here that made me start to wonder, more a gradual undermining (Gould’s work like The Mismeasure of Man  being completely dishonest is one example - with enemies like that…) as I continued to read studies and wonder why Asian model minorities did so well, and a lack of really convincing counter-evidence like one would expect the last two decades to have produced - given the politics involved - if the idea were false. And one can always ask oneself: suppose that intelligence was meaningful, and did have a large genetic component, and the likely genetic ranking East Asians > Caucasian > Africans; in what way would the world, or the last millennium (eg the growth of the Asian tigers vs Africa, or the different experiences of discriminated-against minorities in the USA), look different than it does now?
But having said that, and admiring things like Plantinga’s free will defense, and the subtle logical issues in formulating it and the lack of any really concrete evidence for or against Jesus’s existence, do I take the basic question of God seriously? No. The theists’ rearguard attempts and ever more ingenious explanations and indirect pathways of reasons and touted miracles fundamentally do not add up to an existing whole. The universe does not look anything like a omni-benevolent/powerful/scient god was involved, a great deal of determined effort has failed to provide any convincing proof, there not being a god is consistent with all the observed processes and animal kingdom and natural events and material world we see, and so on. The persistence of the debate reflects more what motivated cognition can accomplish and the weakness of existing epistemology and debate.[…]

I want to make it perfectly clear: those question marks in my point-by-point do not actually indicate uncertainty. They could as well have been references to papers. The field really is about as advanced as Bird's study suggests – only in the direction he disapproves of. But this isn't the place for it, surely people can go to some edgier venue and ask for receipts. The point I'm trying to make is: you say "Okay, if there's anyone here who actually believes in HBD, here's a couple reasons why you shouldn't." On an ignorant but moderately skeptical person your little list can, and likely will, have an effect that's the opposite of what you intend to achieve. To "who actually believes in HBD", it's utterly unconvincing. If I may be so blunt, it's almost as sad as quasi-scientific gotchas of flat earthers.

And this is how all of anti-HBD rhetoric is, in my experience. It crumbles under basic scrutiny, links do not show what they are purported to show, there are simple misunderstandings of what terms mean, there is no coherent epistemology or a single model, there's suppression of inconvenient evidence, there's substitution of evidence with confident op-eds in Vox from people who are supposed to be experts (but whose legitimate work doesn't support their confident claims), there are cascades of internally inconsistent Gish Gallops and other fallacies; worst of all, the reader is assumed to just not be all that bright. It's a collection of purely reactive objections that might come across as persuasive to like-minded people, but are not battle-tested – and indicate general unwillingness to test one's beliefs.

I expect very little payoff from this labor. But it would be nice if EAs were to become a little more reserved on this topic, and at least stopped turning off potential recruits with irrefutable displays of irrationality.

Adding on to this with regards to IQ in particular, I recommend this article and it's followup by academic intelligence researchers debunking misconceptions about their field. To sum up some of their points:

• IQ test scores are significantly affected by socio-economic and other environmental factors, to the point where one study found adoption from a poor family to a rich one causes a 12-18 point jump in IQ score.
• The average IQ of the whole populace jumped 18 points in 50 years due to the Flynn effect.
• The gap in test scores between races has been dropping for decades, including a 5 point drop in the IQ test score gap over 30 years. 
• With the above points in mind, the remaining IQ test score gap of 9.5 points does not seem particularly large, and does not seem to require any genetic explanation. 

I don’t think one of the claims, that “Twin studies are flawed in methodology. Twins, even identical twins, simply do not have exactly the same DNA”, is true. As I see, it is not supported by the link and the study.

The difference of 5.2 out of 6 billion letters that identical twins have on average is not something that makes their DNA distinct enough to make the correlations between being identical tweens or not and having something in common more often to be automatically invalid.

One of the people involved in the study is cited: “Such genomic differences between identical twins are still very rare. I doubt these differences will have appreciable contribution to phenotypic [or observable] differences in twin studies.”

Twin studies being something we should be able to rely on seems like a part of the current scientific view, and some EA decisions might take such studies into consideration.

I think it’s important not to compromise our intellectual integrity even when we debunk foundations for awful and obviously wrong beliefs that are responsible for so much unfairness and suffering that exist in our world and for so many deaths.

I think if the community uses words that are persuasive but don’t contain actually good evidence, then even if we’re arguing for the truth that’s important and impactful to spread, in the long-term, this might lead to people putting less trust in any of our words arguing for the truth and more people believing something harmful and untrue. And on the internet, there are a lot of words containing bad arguments for the truth because it’s easy for people to be in the mode of finding persuasive arguments, which don’t necessarily have to be actually good evidence.

I think it’s really important for the EA community to be epistemically honest and talk about the actual reasons we have for believing something, instead of trying to find the most persuasive list of reasons for believing in what we believe in and just copying it without verifying that all the reasons are good and should update people in the claimed direction.

Bob Jacobs @ 2023-01-14T09:00 (+1)

These are two separate links for two separate claims. 'Twin studies are flawed in methodology.' and 'Twins, even identical twins, simply do not have exactly the same DNA.', both of which are true. The confidence in the proposed HBD conclusions is simply not warranted by the evidence.

Many twin studies have the assumption that they share 100% of their DNA (which is false) and that they share the exact same environment (which is also false). This leads to underestimating environmental factors  and underestimating non-genetic biological factors.
Furthermore, separated twin pairs, identical or fraternal, are generally separated by adoption. This makes them unrepresentative of twins as a whole and there can be some issues of undetected behaviors in the case of behaviors that many people keep secret presently or in their earlier lives.

Samin @ 2023-01-14T10:11 (+6)

Oops! Sorry, I only discovered the second link; but before writing my comment, I looked up the first myself.

I’m not a biologist and will probably defer to any biologist entering this thread and commenting on the twin studies.

Twins (mostly, as the linked study shows) do not have exactly the same DNA. But it doesn’t seem to be relevant. The relevant assumption is that there’s almost no difference between the DNAs of “identical” twins and a large difference between the DNAs of non-identical reared-together twins, which is true despite a couple of random mutations per 6 billion letters.

The next two linked articles are paywalled. Is there somewhere to read them?

The third is a review of a short book, available after a sign-up, and it says that “some studies on twins are good, some bad”, and the author feels, but “doesn’t actually know” that the reviewed one is good. The reviewed book performed a study on twins and noticed there isn’t much of a difference between the correlation of the similarity of many personality traits with whether people are identical twins, and concluded that, since you’d expect to see a difference if the traits have different degree of heritability, many personality traits are results of the environment.

How is this an evidence that twin studies are flawed and shouldn’t be used? If that’s a correct study, it’s just evidence that personality traits are mostly formed by environment (which is something I already believe and have believed for the most of my life), but, e.g., why would this be relevant for a discussion of whether or not some disease has a genetic component to it, when a twin study shows that there is?

It’s important to carefully compare the numbers; but obviously there are things that identical twins have in common more often then non-identical twins, because these things are heritable at to larger or lesser degree; like hair color or height.

Of course, any study makes some underrepresentation of humanity. But if your study is about the degree of heredity of something and not about twins, why would this matter? If there’s a difference between adopted identical and non-identical twins that’s better explained by genetics (e.g., non-identical twins would have a different height more often), why does it matter how well they represent twins in general? Unless you’re studying how likely people are to be adopted, I don’t understand the claim.

The last link is paywalled, but again, why would this affect the difference between identical twins and non-identical twins? Until a year ago, I kept secret that I’m bi and would’ve kept it secret from scientists; but I don’t think this kind of thing affects conclusions you’d make if identical twins answered identically to some question more often than non-identical twins (e.g., imagine a society where people with green eyes are persecuted and a lot of them use contact lenses. Some would still say the truth, in confidence, to scientists; and the number of identical twins telling the same answer would be greater than the amount of non-identical twins telling the same answer, and the scientists will correctly infer this to be evidence for the heritability of eye color, even though a lot of twins would lie about their eye color).

So while it’s possible to just compare full DNAs and account for lots of different factors (all sorts of various environmental conditions that might be different between the subjects of the study) to find out whether DNA correlates with eye color, it’s much easier to do a twin study, and a strong correlation there will be a strong evidence

Bob Jacobs @ 2023-01-14T10:28 (+1)

Oops! Sorry, I only discovered the second link

It's fine.
Studies don't just use identical twins but twins in general. You are equating my two claims and attacking claims that I haven't even made, I never talked about "whether or not some disease has a genetic component to it, when a twin study shows that there is?". I made a claim that twins, even identical twins, don't share exactly the same DNA and provided a link to an article that gave more information, and I made a second claim that twin studies were flawed and provided that claim with a link to an article with more information about that. All this stuff about that it can't help us find diseases or that twin studies "shouldn’t be used" are claims I never made.

EDIT: 

I’m not a biologist and will probably defer to any biologist entering this thread

For the record my study has some biostatistics, but it isn't my strongest field and I'm mostly  leaning on stuff my professors have explained:

 I will also probably defer to a biologist/biostatistician.

As a different perspective to your list, I'd like to reference this thread of 25 threads, which provides extensive research in the opposite direction. Like you, I do not claim that this is all correct (I'm not an expert on this topic), but the evidence is certainly much less clear-cut than one might think from just reading the pieces you provided.

Comment erased due to formatting error; apologies. The correct version is here.

You and I have a very opposite reflection of the Sam Harris vs Ezra Klein fiasco.

I'd like to hear what you think about Klein's point that environmental factors explain may >100% of the black-white iq gap, and yet this is alien in the race realism discourse.  https://forum.effectivealtruism.org/posts/ALzE9JixLLEexTKSq/cea-statement-on-nick-bostrom-s-email?commentId=YN85c93DD3EiNLFfo

counterproductive for the goal of fighting racism to stake your case on scientific claims that could turn out to be false.

There is so much evidence at this point against race realism/ HBD. There is no possibility of it "could be false" without evoking some grand conspiracy. Can we never call it pseudoscience? My goal is to fight for scientific truth, not some anti-racist agenda. Check out Ben Jacob's great resources.

Whether or to which extent it is hurtful is indeed unclear.