Comment by RhysU | Hacker News Reader

Comment by RhysU | Hacker News Reader

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Thank you for the detailed response.

> Humans are a K-selected species - the optimal strategy for passing on our genes is to invest as many resources as possible into the smallest viable number of offspring.

It's certainly fashionable these days in the West. I don't know that I would call it optimal. Optimal now for passing along genes is probably donating at a sperm bank after getting into a regionally swanky university. A joke, of course, but notice it stacks! Certainly the donating to the sperm bank plus what you profess dominates what you profess in isolation. Since I just improved the strategy, it wasn't optimal.

> People reproduced much more when food, medicine, and housing were much more scarce.

Yet the population was smaller. You're talking per capita rates and I am not.

We successfully produce more viable adults now in absolute terms than ever before, the number of live births notwithstanding. Otherwise, global population would drop. Which it hasn't. Definitely slower growth but not shrinking: https://www.worldometers.info/world-population/#growth rate

That site says "The latest world population projections indicate that world population will reach 10 billion persons in the year 2060 and 10.2 billion in 2100."

> Humans are quite a bit different from micro-organisms

Humans increasingly inhabit inhabitable parts of the Earth with increasing density. This species-wide growth, regardless of the optimal reproductive strategy for any single individual, is like a microorganism spreading across a petri dish. We're starting to run into the edges of the dish so we're slowing down a tad. But, likely growth for at least the next 75 projected years per the above 10.2B people in 2100 projection.

Going back a step: My point is there's no end in sight for needs around housing, food, and medicine. Human beings aren't special. We consume all available resources, in part due to population growth. I did not expect population growth to be such a controversial topic. Population, it grows.

> Since I just improved the strategy, it wasn't optimal.

You did not improve on the strategy.

> You're talking per capita rates and I am not.

Because per capita rates are all that matters. specifically your concern was "Suppose only 5% of the population breeds like rabbits in the presence of food, medicine, and housing." This requires individuals to have more children per capita.

Population growth has been dominated by demographic momentum. Because a few generations ago infant mortality fell, those generations that had high birthrates produced much larger subsequent generations than thir immediate predecessors. These later generations had much lower per capita birthrates but they were larger, so as you say, they have more aggregate children. Subsequent generations after this have very similar numbers of children, but these generations are replacing smaller generations from when the infant mortality rate was higher. Once you get far enough from industrialization that no one from before the infant mortality decrease is left to be replaced, the population stops growing, at least from births. In the developed world which is now well over 100 years from this transition, population growth is purely from immigration, and in fact without this immigration the populations would be decreasing (as it is in a few less desirable locales like eastern europe). East Asia which went through this transition about 60 years ago is plateauing now. World population growth is only continuing in parts of the world where infant mortality is still falling, particularly sub-Saharan Africa.

You conveniently failed to mention in your link that it shows the world population dropping to 10.2 billion in 2100 after peaking in the 2080s.

> Humans increasingly inhabit inhabitable parts of the Earth with increasing density.

False. Huge potentially inhabitable parts of the earth remain uninhabited and are unlikely to ever be inhabited, and population densities in most inhabited areas are falling. There are a few distinct areas, namely urban centers, where population density is large and increasing, but this only proves that population density is not resource constrained.

> We're starting to run into the edges of the dish so we're slowing down a tad.

False. Resources are more abundant than ever, and our rate of production is growing faster than ever. Places with the most resources, the most petri dish available, have the lowest birthrates.

> But, likely growth for at least the next 75 projected years per the above 10.2B people in 2100 projection.

57 years based on the above projection

> We consume all available resources, in part due to population growth.

False. See above.

> I did not expect population growth to be such a controversial topic. Population, it grows.

Because you were uninformed on the topic.

> My point is there's no end in sight for needs around housing, food, and medicine.

There very clearly is an end in sight for the need for higher levels of housing, food production, and medicine production. Specifically it's in decades, not centuries, barring some future demographic shift comparable to the reduction in infant mortality during industrialization.

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