Hacker News Reader

Comment by powerbroker | Hacker News Reader

If you are the last woman alive, and there is one man alive, you must produce children. Contradict me, assuming you are not the alien species that tried to wipe us out.

View on HN

This completely misses the point of your hypothetical, but if you only have two humans left your descendants will inevitably die out due to inbreeding. Two individuals isn't enough genetic diversity to sustain a species.

See: https://en.m.wikipedia.org/wiki/Minimum_viable_population

I don't think that this is an absolute truth. This would depend on the genetic distance between the parents (and if parents and their childrens would procreate again).

https://en.wikipedia.org/wiki/Voluntary_Human_Extinction_Mov...

There are people who unironically belong to this movement who would urge this woman not to mate. I don't agree with their arguments, but I believe that they should not be beyond debate. I'm not smart enough to identify their values as inferior on some absolute scale, and given their values their arguments may well be sound.

If there are only two humans left, then it’s already too late. We need a breeding population of around 50, or we will suffer genetic collapse (the actual number is much higher, to be able to actually evolve, but you need at least that much to avoid catastrophic genetic drift). https://moscow.sci-hub.st/1832/d4805799591a7b5e7843531b9aeb0...

The arguments of that paper are for wild animals; it is open to question how true they would be for humans. Non-human animals get most of their adaptability from their genetics, and relatively little from culture; humans get a huge amount of their adaptability from culture. Humans may need less genetic variability to survive than other species do. It would also depend on how much of human knowledge and technology the sole surviving breeding pair would be able to retain. I don't doubt the odds would be against human survival in such a scenario, but I think we have to question how applicable research on other species is for humans – humans are capable of things no other species can do.

There's nothing to contradict as you have not provided any argument to support the claim that these two last humans must produce children.

OK, how about this: why should the human race persist? What makes humans so superior to other forms of life?

Not saying it needs to but hey, if other forms of life are procreating by default, I think humans are allowed to make that simple choice as well.

Whether or not it should, it will. You might not believe that you are under any duty to reproduce, but there are many religious ultra-conservatives in this world who believe that they have a sacred duty to do so. Given the very high birth rates of many such religious groups (the Amish, Hasidic/Haredi Jews, Quiverfull Evangelicals, Traditionalist Catholics, Salafist Muslims, etc) – and that many of them do an excellent job of retaining their children in the faith (some of these groups continue to sustain >90% retention rates even after multiple generations) – humanity isn't going anywhere. But the more that secular (and religiously moderate/liberal) people choose not to have kids, to have fewer kids, to start families at a later age – the more they are helping to create a future in which people like them are going to be outnumbered by religious ultra-conservatives, and are likely to have no choice but to make compromises with that ever-growing population which they'd rather not have to make. Unlikely you or I will live to see it–but it might be only a century or two away.

Reply on news.ycombinator.com