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Comment by Will_Parker | Hacker News Reader

The counter to this is, we're a uniquely complex species where culture is vastly more important than genetics. (If you doubt it, consider what in our genetics makes us different than cave painters 30,000 years ago).

I see humans who don't reproduce as analogous to cells in the human body that don't contribute to the germ line. Is the reproductive system the most important part of the body? Of course not. The brain is important too, even though none of those cells will have direct descendants that outlive you.

You might think evolution would weed out people with this attitude over time. But not necessarily so! It's quite possible to do things that help a population or a lineage, and the multiplier effect can have more impact on the frequency of your genes than directly reproducing would. (Because your culture impact can affect many people instead of just your offspring.)

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>consider what in our genetics makes us different than cave painters 30,000 years ago

A tremendous amount has changed in that time. Height, immune system changes, lactose tolerance, blue eyes, different hair colors, digestive system changes. There's strong evidence for significant changes in IQ, time preference, and other psychological traits. A cave painter from 30,000 years ago would probably act like an undisciplined, impulsive child because of genetic predisposition to high time preference and low intelligence.

It's a myth that evolution takes millions of years. With sufficient and realistic selection pressures, something like IQ or height can shift several percent every generation. This is how there's only a few thousand years between even the most different dog breeds. 30,000 years is more than enough time for massive shifts in a gene pool.

And this is even assuming your cave painter is human. If it's 30,000 years ago, he may not be!

[1] News article on genetic changes post agricultural revolution.

>I see humans who don't reproduce as analogous to cells in the human body that don't contribute to the germ line

One basic insight of the selfish gene is that a gene can be regarded as being in several places at once if it has copies in those places. It acts as the same gene, not separate copies.

Since all cells in the body have the same genes, if you have a biological child, they all contribute to the germ line since, in terms of outcomes, they are all the same unified entity. And if you don't, none of them do.

>It's quite possible to do things that help a population or a lineage, and the multiplier effect can have more impact on the frequency of your genes than directly reproducing would.

Definitely true! Hence the human predisposition towards ethnic nationalism and tribalism.

Here's a thought: Perhaps one reason for our rising identitarian tribalism isn't just increasing ethnic diversity, but is also the fact that increasing numbers of childless people are expressing their reproductive instincts through tribal aggression instead of direct childbearing.

[1] https://www.sciencealert.com/ancient-dna-suggests-agricultur...

Disclaimer: I have no particular expertise on this topic.

> A tremendous amount has changed in that time. Height, immune system changes, lactose tolerance, blue eyes, different hair colors, digestive system changes.

None of those are tremendous changes. We're talking about a single mutation that disables a certain gene in most cases above, right? Also they aren't universally spread among humans, and it seems like many people from divergent genetic lines can adapt to a modern culture just fine.

I know Jared Diamond makes a strong claim that the human brain really isn't that different across humans, citing, e.g. friends from New Guinea tribes who could happily and easily learn to use computers when they were exposed to them.

> There's strong evidence for significant changes in IQ, time preference, and other psychological traits.

Any citation for that first claim in particular?

I know that (though the strong social norm is to avoid these topics at all cost), e.g. the population of Ashkenazi Jews has a higher average IQ than the mean. But individual variation is still far more important. And it's not clear how "significant" the difference is, if we're talking about the magnitude of changes that make culture and language possible vs impossible. E.g. if maybe 1% of the population could be math PhDs vs 0.2%, is that so significant?

> One basic insight of the selfish gene is that a gene can be regarded as being in several places at once if it has copies in those places. It acts as the same gene, not separate copies.

But this is true across populations too. So, it may not have been in the best interest of your genes to directly reproduce, vs spending the effort to help your family or tribe.

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