An extremely brief and reductive summary of this book goes like this:

Part One: Genetic differences between individuals exist and they are meaningfully involved in having an effect on life outcomes.

Part Two: Because individual genetic differences exist and have a meaningful effect on life outcomes they ought to be taken into consideration.

Despite the many examples Harden provides of the potential pitfalls involved, she remains optimistic that addressing these issues is preferable to not doing so. To me it seems to be the sort of gambit that is expecting long term net gains and acknowledges the significant potential downsides. It's certainly to her credit that these negatives are included, as all too often people want to exclude anything that detracts and remain unwaveringly positive in hopes of persuading their audience. That's not without reason, as a significant amount of people seem to not appreciate such inclusions, and indeed see them as devaluing in general.

To be clear, this book says that genetics should be considered in addition to, rather than as a replacement. Individual genetic differences matters, but so do many other variables. A considerable portion is devoted to trying to convince ostensible allies that the author isn't the enemy, though I have to wonder how much of an effect that has. Sometimes it seems to not matter how often one tries to allay the concerns of another.

Along those considerations, considerable effort is put towards this being an accessible and readable work. I'm of mixed opinion on the inclusion of memes and pop culture references, but if they successfully serve their purpose, I'm all for them.

John Rawls is the philosopher whose ideas are most frequently referenced and employed. I really ought to read his works someday considering how relevant they seem to me and for other personal reasons.

Overall I found this to be generally agreeable, though I did have various concerns about how specific comparisons may come across, and other pragmatic considerations.

From what I've looked of what others have thought about this, what isn't included seems to have a greater concern that what is included.

Certain groups of those on "left" seem to think that it doesn't go far enough in addressing racism and is misguided in general as it isn't the preferred method. Harden repeatedly states in various ways that "there is zero evidence that genetics explains racial differences in outcomes like education." To which the response seems be along the lines of asking why it it matters if it isn't addressing a systemic and institutionalized social problem. To which I say, the collective matters, but so do the individuals within that collective, which is what this is much more about. Psychology is much more about the individual and Sociology isn't. Both approaches are valid.

From the "right", well, it's far more fundamental in disagreement, and too much for me to write about here and far too easy for me to fall into caricature.


And now for excerpts and thoughts:

As Eric Turkheimer, Dick Nisbett, and I warned: If people with progressive political values, who reject claims of genetic determinism and pseudoscientific racialist speculation, abdicate their responsibility to engage with the science of human abilities and the genetics of human behavior, the field will come to be dominated by those who do not share those values.

The main problem I see with this is that this may be seen as being preferable so it's not a very persuasive argument. After all, if no one who shares their values is in the field then there's no chance of friendly fire occurring. Having to determine whether someone is a friend or foe can be such a bother, let alone allowing for something that isn't a dichotomy.

no matter how strongly those genetic differences influence the development of human characteristics, no matter whether those characteristics are physiological or psychological, we are still not absolved of the responsibility to arrange society to the benefit of all people, not just the tiny slice of global genetic diversity that is people of predominantly European ancestry.

These sort of fundamental arguments are definite source of contention and there isn't anything reasonable that can be done about that really.

Although the term “executive functions” is plural, children who tend to do well on a test of one executive function tend to do well on all the other tests. This positive correlation among test scores means that performance on all of them can be aggregated statistically into a single overall score that we call general EF.
...this nearly perfectly heritable trait is a surprisingly good predictor of how well students do on their state-mandated academic achievement tests.
...general EF was correlated at 0.4 to 0.5 with students’ test scores.

There was a lot I didn't already know, or hadn't heard of it in here, and this was one of the more interesting parts.

The SNPs correlated with non-cognitive skills were correlated with higher risk for several mental disorders, including schizophrenia, bipolar disorder, anorexia nervosa, and obsessive-compulsive disorder.

Such "trade-offs" as they could be called, may yet well stymie any sort of genetic editing for a long time to come. The concerns about it are probably alarmist. It does make for compelling science fiction though.

Their propaganda is this: if genetic differences between people cause differences in their life outcomes, then social change will be possible only by editing people’s genes, not by changing the social world.

It certainly can be frustrating when others set your goals for you and tell you how you have to proceed.


The following excerpt explain in some ways how the environmental conditions can prevent reaching individual potential. This is also a fundamental point of contention in US politics.

This pattern of results—where heritability is higher in good environments than in bad ones—can be counterintuitive. But we can build up an intuition about them using a classic thought experiment from the biologist Richard Lewontin. Imagine two gardens. One has nutrient-rich soil, bright sunlight, and plenty of water, whereas the other is rocky, dark, and parched. Now imagine that both gardens are sown with genetically diverse corn seeds. Within the lavishly resourced garden, each plant has the opportunity to reach its maximal height. Moreover, because the conditions of the garden are exactly uniform across plants, the variation among the plants in their heights will be primarily due to genetic differences between the seeds.

Here, the power of the family environment is spotlighted: children with high polygenic indices but whose parents had the lowest socioeconomic status still ended up, on average, worse off as adults than children who had low polygenic indices but had wealthy parents.

The economists Kevin Thom and Nicholas Papageorge came to a similar conclusion in their analysis of college graduation rates: 27 percent of rich children with the lowest polygenic indices graduated from college, compared with 24 percent of poor children with the highest polygenic indices.

...born into poverty, even the most genetically advantaged children will still have a lower socioeconomic status in adulthood than children who have no genetic advantages but were born to wealth. As the social scientist Ben Domingue summarized, “genetics are a useful mechanism for understanding why people from relatively similar backgrounds end up different.… But genetics is a poor tool for understanding why people from manifestly different starting points don’t end up the same.”

end selection of quotes on this topic

Genes are not always a problem to be fixed, or the only problem to be fixed. People are not the problem to be fixed. The problem to be fixed is society’s recalcitrant unwillingness to arrange itself in a way that allows them to participate.

This of course is a very political notion, especially in the United States. It's difficult for me to know what degree the "average person" would endorse this, as I have a very skewed view. I think most would accept accommodations for the physically disabled, and some forms of mental disability, but not much more than that.

For example, we would consider it unfair to measure family income just so that we can deny university admission to low-income students on the grounds that they are less likely to graduate from college.

A lot of the "we" statements statements really depend on who "we" is. Maybe outright statements like this would be, but there are plenty of ways that obscure the same result with the same method and are thought of as fair.

When one considers aviation or another sort of high-stakes profession, where failure can kill people, choosing applicants on their “merits” has obvious benefits for everyone in society. We want pilots to be selected for their ability to fly planes, not their social connections. We want surgeons, engineers, pharmacists, teachers, plumbers, etc., to be people who will operate, build, dispense, teach, and fix skillfully.
...What is considered “meritorious” is simply what brings about the social consequences that we desire.

This is certainly an interesting way to think about it, and I like it, but I would think it's a minority opinion. For now anyway with any hope.