Hacker News Reader

Comment by grej | Hacker News Reader

It's an interesting thought exercise, but as many of the commenters point out, the article's premise is a little ridiculous. With modern technology you don't need to send the entire population. The vast majority of the genetic diversity could be in the form of frozen sperm and eggs.

View on HN

It's a pity they went that way, because there's a different framing that is still an interesting question: How far could humanity fall and still be able to recover? It's essentially the same problem, and it's a lot easier to imagine that we're talking about a situation in which there's no longer any technology. We consider the people geographically co-located, but it's not hard to imagine a pocket of survivors of whatever $DISASTER, either.

You have to start somewhere more specific than no technology.

Like, no steel to find lying around, or no one that knows how to make charcoal and that some dirt has iron in it.

Or does anybody remember anything about agriculture?

I feel like anything like that has to be predicated on not being able to find any book. Which is certainly possible, but I feel like $DISASTER will probably leave behind some libraries and books somewhere. The people would just have to be dedicated to learning the lost info from books + experimentation.

I worry that such an event would still be devastating. One fire was all it took to lose all of the wealth of Alexandria's knowledge several thousand years ago.

A Canticle for Leibowitz is a great sci-fi thought experiment on the subject. Having survived (barely) world nuclear war, a monastery seeks to aggregate whatever fragments of information they can (notably they mysterious note "Pound pastrami, can kraut, six bagels—bring home for Emma"), and try to rebuild society without inevitably repeating the great conflagration.

"No advanced reproduction technology" is adequate for this. Even basic reproduction technology is fairly sophisticated stuff, with the exception of "the rhythm method" and basic (if very, very annoying) condoms, neither of which will affect the answers given by this analysis as only actual reproduction events matter. We assume that people can survive and procreate, and the gene pool cares little for in what style they survive and procreate in.

I see from other replies there's a bit of a misunderstanding here. This isn't an exercise in what tech levels might be used to rebuild civilization. This is an exercise in how much diversity is required to be in the gene pool for the species Homo sapiens to continue, as at that level we're still reeling from the previous near-extinction event we experienced.

Indeed, even with modern advanced technology, we are still tied to the gene pool. Until we can more easily and reliably rewrite genes before the fertilized egg begins to reproduce we're still stuck with this problem. "Designer babies" remain science fiction... tantalizingly close science fiction, close enough that the ethics debates are increasingly less abstract, but still not here yet.

Replacement rate is a big factor. Highly advanced technology won't help much if the population doesn't procreate fast enough. Japan is a surprising example: profoundly high-tech, but nowhere near enough offspring to maintain the population (as in the entire country/culture/race is on track to disappear entirely).

reproduction rates are highly tied to culture, risk (high risk = more offsprings) and wealth. How that would look in the context of high tech space ships is rather unclear.

>Highly advanced technology won't help much if the population doesn't procreate fast enough.

Japan is profoundly high-tech because they have a declining population. They desperately need to boost the productivity per individual. Advanced technology is the only thing keeping Japan afloat.

Those were my thoughts as well., I wonder though how long frozen eggs and sperm are viable. Could you really rely on then for 2000 years?

Reply on news.ycombinator.com