My claims are mostly about median income, not average. I am not making strong 99.9% confident claims; I am making my best estimates. So even if I cannot prove that any future physics will limit economic value per atom, I can use our best understanding of physics today to estimate such limits.
Strong security might allow high median income in the nations that limit population, but that would not assure the global median remained high.
On your capital argument, I think you need to learn more econ growth theory.
Your meme argument would apply to any non-meme-pushing use of resources whatsoever. And why can't having kids be a good way to push memes?
The demarcation of distinct "capita" for purposes of "per capita" wealth offers a lot of room for flexibility. If we assess wealth on a per-cell basis (in energy, food, etc), then human wealth is comparable to bacterial wealth within a couple orders of magnitude by some metrics. But if we assess at the level of an 'organism' human wealth is astronomically greater.
Future intelligences may demarcate identity in such a way that the members of the 'proletariat' are just components of 'capita,' without independent desires. Or labor might be ...
Under the theory of eternal inflation new universes keep being created at an exponentially growing rate. If we could find a way to keep sending our surplus population to different universes we could have unlimited growth.
A "world government" and "unlimited growth" I can understand.
However:
Memes are not really a solution to Malthus's dilemma. They are just a different type of substrate for inheritance. The world filling with memes might indeed prevent the world from filling up with DNA - but then you have the exact same Malthusian problem all over again with the new medium of inheritance.
The "Disease or Warfare" scenario apparently retains the essential undesirable element of Malthus's scenario of resource limitation - namely the failure of much of the population to survive to reproduce. The standard of living for those that remain could be high, though.
From what I've heard, people don't try to have as many children as possible-- they try to have as many children as will be able to inherit their niche. This could explain why those who can afford college for their children put money into that for a small number of children rather than into having as many children as possible.
We already have something like Psychohistorian's nudges. There's a lot more pressure to not leave a child home alone, and that raises the cost of raising children.
The other observed fact is that birth rates drop when women get rights....
How about simple spontaneous population stability... I live in a country with negative birth rate but the population is increasing due to immigration nevertheless. This state of affairs hasn't been legislated into existence, it just happened, and may be a natural behaviour of large human populations. Perhaps once the whole world reaches western standards of living the whole world will stop growing exponentially, with pockets of negative growth being compensated by low but positive growth in others... in the long term the trend could even be for decreasing population...
Notice how little evidence we have for most human societies in history to be really close to Malthusian population bounds.
It's really incompatible with evidence unless you take "extreme long term view" like Robin, in which case it becomes essentially non-empirical.
This is like most of the responses to Robin on OB; extreme examples of wishful thinking. None of the responses, here or there, are stable or address Robin's point that in the very long term population will probably grow until it reaches the level of subsistence.
I'd add:
Superstimuli - New technology creates activities that are so enjoyable that most people just don't bother having children, or don't want to have many children.
Default birth control - all individuals (of at least one gender) are implanted with effective birth control at birth/onset of puberty. It's easy to turn off, and anyone who wants to turn it off can, but you can't conceive without taking making an affirmative decision to do so. This could lower birthrates enough to hit replacement.
Nudges - like default birth control, but through other mechanis...
Population doubling takes place in alternative branches of a coherent quantum superposition, so that each single branch has plenty of capital. Parents don't get to talk to their children much, but everyone maintains a higher standard of living - in exchange, perhaps, for lower measure.
"Singleton
A world government or superpower imposes a population control policy over the whole world."
If predicting the far future is very difficult, why should "future people will be very rich" be different from "future people will be very poor"? Shouldn't it be just as hard to be sure of one as the other?
The big one:
Memetic instability, aka Hanson's assumptions are just wrong.
It's quite easy for an armchair evolutionary psychologist to say, "X group reproduces more than not-X. Therefore, by 2150, everyone will be Mormon because they'll be selected for!" Yes, I'm exaggerating a bit, but the actual argument is about as absurd. There aren't any large population subgroups with extremely high fertility as a subcultural norm. Given the substantial hedonistic sacrifice involved in high fertility, this is not surprising. It seems unlikely, barring kids b...
Also: Nothing. We'll be fine.
Hanson's assumptions require extremely strong memetic stability, or at least high and consistent prevalence for high-fertility. Since fertility, at the relevant margin, seems principally memetic (rather than genetic), this seems unlikely, particularly if it entails a significant sacrifice of material well-being. If it doesn't require a significant sacrifice of material well-being, then it will not likely coincide with falling standards of living. In other words, when it becomes clear that the next generation will be worse off t...
People interested in malthusian theories focus on calories
Which is of course total nonsense, as number of calories consumer per capita varies extremely little over huge differences in GDP. some data
So quality of life as measured by things other than food may have become high in 1300, but the famine of 1315-1317 suggests that the food situation was precarious.
Not at all. Even if there's plenty of unused land lying around, if you get unusually low yields, you can get famine. Few civilizations farmed spare land and threw away food, just in case the spare food might be useful, so food margins have nothing to do with availability of free land or lack of it. It takes some time to get new land into use, one year at the very least, more realistically many years to cut forests, build settlements, gather people, animals, and seed and move there, make agricultural tools etc. It's a major project, and conditions of famine do not help at all.
I think the adoption of the high calorie-per-acre potato is correlated with low productivity
Potato was widely adopted in 18th century, the Eastern vs Western divide refers to Late Middle ages/Early Modern period, which took place long before it. During that time Poland and other countries became major exporters of wheat to Western Europe, using particularly nasty forms of serf labour.
No, it just says it about 1000-1250.
That's not what I meant about 1350. Clearly if land was plentiful in 1000-1250, it must have been even more plentiful in 400-1000, and yet population wasn't expanding back to its Roman levels.
Raiders were Vikings / Muslim / Hungarians / etc. and they were raiding entire Europe. There was no distinction between raidable and not raidable lands. Here's map of Viking raids. Other groups raided other regions. Most of Europe, especially coastal areas were repeatedly raided, these lands were definitely inhabited all the time.
We know that in the right circumstances, such as colonial America, population can double each generation.
It can, and also GDP/capita was increasing while population was increasing. For pretty much any country you try. Malthusian theory suggests ridiculously high starting GDP/capita, which would then gradually go down as population increased, which is completely wrong.
People interested in malthusian theories focus on calories
Which is of course total nonsense, as number of calories consumer per capita varies extremely little over huge differences in GDP. some data
I'm sorry if I wasn't clear, but I reject GDP for this purpose. I suspect that Braudel and the conventional wisdom about 1300 are like saying that people today are as kings, for they have the greatest musicians of the century at their beck and call on youtube. GDP tells how nice are the luxuries, but it doesn't tell if someone is starving.
Malthusians claim...
This is an attempt to list all of the possible ways in which humanity may avoid scenarios where the average standard of living is close to subsistence, in response to Robin Hanson's recent series of posts on Overcoming Bias, where he argues that such an outcome is likely in the long run.
I'll start with six, some suggested by myself, and others collected from comments on Overcoming Bias and Robin's own posts. If anyone provides additional ideas, I'll add them to the list.
(I have a more general point here, BTW, which is that predicting the far future is very difficult. Before thinking that some outcome is inevitable or highly likely, it's a good idea to repeatedly ask oneself "This is all the ways that I can think of why it may fail to come true. Am I sure that all of them have low probability and that I'm not missing anything?" There may be some scenario with a non-negligible probability that your brain simply overlooked when you first asked it.)
Singleton
A world government or superpower imposes a population control policy over the whole world.
Strong Security
Strong defensive technologies and doctrines (such as Mutually Assured Destruction) allow nations, communities, and maybe tribes and families to unilaterally limit their populations within their own borders, while holding off hordes of would-be invaders and immigrants.
Non-Human Capital
Maximizing the wealth and power of a nation requires an optimal mix of human and non-human capital. Nations that fail to adopt population controls find their relative wealth and power fade over time as their mixes deviate from the optimum (i.e., they find themselves spending too much resources on raising humans, and not enough on building machines), and either move to correct this or are taken over by stronger powers. (I believe that historically this was the reason China adopted its one-child policy.)
Unlimited Growth
We don't completely understand the laws of physics, nor the nature of value. There turns out to be some way for economic growth to continue without limit. (Robin himself once wrote "I know of no law limiting economic value per atom" but apparently changed his mind later.)
Selfish Memes
Memes that manage to divert people's resources away from biological reproduction and towards memetic reproduction will have an advantage over memes that don't. On the other hand, genes that manage to block such memes will have an advantage over genes that don't. Memes manage to keep the upper hand in this struggle (or periodically regain the upper hand).
Disease, Warfare, Natural Disasters, Aliens, Keeper of the Simulation
One or more of these come along regularly to keep the human population in check and per capita incomes above subsistence.