The Future of Humanity

Yesterday on Substack I tried something new, which was to write off the cuff, with little editing, and press the “post” button without much thought. I’m doing so because this is the first spare moment I’ve had to respond to Bassoe’s response to my review of C.M. Kosemen’s soon-to-be published book All Tomorrows, and I don't want to let this interesting conversation wither on the vine.

If you had trouble following that last sentence, it’s enough that you know this: we’re talking about the evolutionary future of humanity.

The Machine-God Scenario
Bassoe talks about “machine-gods...obsessed with tending to the well-being of an inferior species” where “the only remaining selection pressure is desire to reproduce.”

Another selective pressure would be to make ourselves adorable to the machine-gods. Perhaps the gods have a template for what they consider to be human, in which case we'll only be able to evolve in ways that don't deviate from that template. I'm reminded of a Stephen Baxter story (Mayflower II) in which humans on a generation ship turn into sub-sapient animals, but they still press buttons on the control panel because that behavior is rewarded by the ship's AI.

The Super-Tech Scenario
But I agree that even without a super-tech future where all our material needs are met, the availability of contraception means that there's a selective advantage to people who don't use contraception. There are many ways for evolution to make that happen. An instinctive desire for babies or an instinctive aversion to contraception are two such ways. I remember a Zach Weinersmith cartoon where he jokes about future humans with horns on their penises that poke holes in condoms, but of course any such physical adaptation won't be able to keep up with technological innovation. We will have to want babies.

Another option is (ala Kurt Vonnegut's Galapagos) that future humans aren't smart enough to use contraception.

The Artificial Womb Scenario
In this case, I think the most selected-for humans are the ones that are most efficiently produced by the artificial wombs. Maybe it's easier to pump out limbless grubs, which are fitted with cyborg arms (see John C. Wright's Myrmidons in his Count to the Eschaton Sequence). The form they take will depend on the parameters of the machines' programming. (see also Vanga-Vangog's The Endpoint)

The Collapse Scenario
I think this scenario is unlikely. If "life, uh, finds a way," then intelligence finds even more ways. When one resource runs out, we find another. The mere fact that you don’t know what the next resource is just means we haven’t found it yet.
But say for the sake of argument that there's a hard limit to technological progress (ala Vernor Vinge's A Deepness in the Sky) or science really is like mining, and it takes infinitely increasing resources to make the next marginal gain in technology. In both cases, you'd expect the graph of human advancement to look like a population when it hits carrying capacity. Exponential growth (we're doing that now) followed by a cycle of die-offs and re-growths, converging to a horizontal mean.

With no ability to innovate, natural selection would take over from technological progress. Once we’ve eaten all the meat and potatoes, there will be strong selection for people who can digest grass. I would expect humans in this case to diversify until our descendants occupy nearly every niche, absorbing most of the matter and energy available on Earth (at least). Whether these people are intelligent or not...probably not. Simon Roy seems to be hinting in this direction with his masterful comic series Men of Earth.

But I don't actually think collapse is likely. I bet that our population (and technological advancement) will not hit an asymptote, but will instead as progress according to a power law, as with the bacteria in Lenski's Long-Term Evolution Experiment.

The Mogul Scenario
Bessoe asks about a future in which “our cultural norms stick around indefinitely, those who generate more profit reproduce,” which I very much doubt.

In 20th century America, the more money you made, the fewer children you had. Now, it seems there's a saddle-shaped distribution, with the very poorest and the very richest women having the most children per woman. This is sure to change again, and faster than evolution can keep up. Perhaps you could say that if contraception pushes us to evolve an instinctive desire to have more children, and rich or powerful people will be in positions to gratify these instincts, then whatever traits make someone rich and powerful will be selected for.

Maybe, but now's a good time to go back to the Reich Lab's "Pervasive findings of directional selection," summarized here by the illustrious Razib Khan.

In comparing ancient to modern DNA, the Reich Lab found evidence for selective pressure in humans in Europe since the end of the Ice Age: increased intelligence, increased height, decreased organ fat, increased walking speed, decreased susceptibility to schizophrenia, increased immunity to many diseases, and, funnily, increased tendency to home-ownership and university education.

Obviously, people weren't going to college in the Chalkolithic, but whatever traits make someone likely to go to college now have been selected for since the arrival of agriculture in Europe. You can paint a plausible picture of the sort of people who were most reproductively successful in the past six thousand years, and there is even some evidence for selection in the range of 1-2 thousand years. Aside from obvious things like immunity to smallpox and Bubonic plague, Europeans have gotten paler and blonder, and more of us are able to digest lactose than in Roman times.
But the 21st century is very different from the 1st, which in turn was very different from the pre-agricultural -70th. Maybe you can say that being smart, strong, and disease resistant have always been good, and being tall and baby-faced gets you some sexual selection (almost everyone seems to have evolved shorter jaws and lost their robust brow-ridges in parallel). So we can imagine future humans who just all look gorgeous.
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I’m running out of time, but I’ll leave us with some homework. I haven’t yet had time to read:
The Urban Future by herofan135
This messageboard discussion referenced by Bessoe
Copernican’s Ecotechnic Future
John Michael Greer’s Next Billion Years
Jack L. Chalker’s Rings of the Master
Robin Hanson’s Age of Em
CaptainStroon’s Bosun’s Journal
So, let’s expand on this. Are there any scenarios I’ve missed? Logical points or facts I’ve misplaced? Or, let’s start small, what do you think will happen in the next ten thousand years?