TL;DR: This is a post about a personal arc of going from pro-natalist to not pro-natalist. I lay out my reasons, mainly animal welfare.
I have been a regular listener to Simone and Malcolm Collins's pro-natalism podcast since they posted about their pro-natalist cause area on EA Forum in 2022. Since maybe 2021 I've gone on an arc of
- first being fairly neutral to then
- being strongly pro-natalist,
- third being pro-natalist but not rating it as an effective cause area, and now
- entering a fourth phase where I might reject pro-natalism altogether.
I value animal welfare and at least on an intellectual level I care equally about their welfare and humanity's. For every additional human we bring into existence at a time in history where humans have never eaten more meat per capita, on expectation, you will get years of animal suffering induced by the additional consumer demand for more meat. This is known as the meat-eater problem, but I haven't seen anyone explicitly connect it to pro-natalism yet. It seems like an obvious connection to make.
The average consumer creates demand for around 25 caged chickens a year
The average American consumes 130 kg in animal flesh per year, and the average UK resident consume 80 kg per year, with the rest of Europe not far behind. In both of those countries, poultry is the most-consumed kind of meat, and factory farming (caged or barn-raised) is the predominant method of raising chickens in both those countries.
We can ball-park estimate the duration of caged chicken suffering supported by eating habits in those countries, by assuming
- 100kg meat consumed per person per year, approximating the numbers above
- 50% of meat consumed is poultry (the most common meat consumed in the UK and the US)
- About 2kg of meat per chicken
- A chicken can be expected to live around 9 weeks before slaughter
That would indicate every person on average creates economic demand for around 4 years of farmed chicken suffering for every 1 year of human life.
People in developing countries eat less meat than those in developed countries, but they are rapidly catching up with developed countries. Consumption patterns around the world differ, where pork or seafood are the leading meat type. The welfare impact of those differs from the welfare impact of eating chicken, but is not clearly better or worse to me.
Value judgements
It does seem reasonable that--depending on your view about a chicken's capacity to suffer--you might think that 4 years of farmed chicken suffering is worth a year of human life. But keep in mind that we are not here considering the value of keeping an existing human alive for an extra year, but whether to promote a cause area that will cause parents to create new human lives.
To me, 4 years of chicken suffering for every year of a new human life mitigates the value of bringing in a new human into the world down to about even. Consequently, pro-natalism seems roughly net-neutral to me. Others might place the existence exchange rate at some strongly different point and that would influence the position they take. ReThink Priorities estimates a welfare range for chickens at around 1/3 of humans, and such estimates are important when considering the pro-natal-animal-welfare trade-off. A prior analysis here on EA forum estimated a trade-off of about 1:1 of human life to poultry suffering caused.
This does not apply to the individual decisions of conscientious consumers
This is not an argument against the value of having your own kids, who you then raise with appropriate respect for the welfare of other sentient creatures. While you can't control their choices as adults, if you raise them right, your expectation they will cause large amounts of suffering will be substantially reduced, potentially enough to make it a net positive choice.
However, pro-natalism as a political movement aimed at raising birthrates at large will likely cause more animal suffering outweighing the value of human happiness it will create. For a political movement aimed at raising birthrates a good starting point seems to be that the marginal additional human life caused will result in increased meat consumption at similar marginal rates to the current rate of meat consumption.
This argument will not apply in the 'long term'
In the long term, we will hopefully invent forms of delicious meat like cultured meat that do not involve sentient animal suffering. The average person might still eat some farmed meat at the time, but hopefully, with delicious cultured meat options available, public opinion may allow for appropriate animal welfare for farmed animals, such that those farmed animals' lives are at least net positive. When that happens, pro-natalism might make more sense.
But we don't know when cultured meat will appear. It is possible that widespread adoption is several decades away, in a slower AGI timeline world or where some form of cultural or legal turn prevents the widespread adoption of cultured meat even if it is technically possible.
All-things-considered, perhaps pro-natalism might again be a net-positive (if not among the most impactful) cause area after there's a clear, continuous decline in meat consumption caused by some factor (like the appearance of good cultured meat) that seems like it will plausibly drive consumption of factory farmed meat to very low levels. This kind of transformation is likely to take a decade to complete, based on the transformation speed of past trends, and could easily be faster or slower. The speed of that transformation is an important consideration for deciding when pronatalism might again be a net-positive cause area. One must also make a value judgement based on evidence and population ethics positions (do you value maximizing average utility or total utility) about the relative value of bringing into being one new human vs. the negative value of bringing in to being the number of factory farmed chickens, pigs, fish, and shrimp that person will consume.
Increasing the population now is not a robust means of making the long-term future go well.
I anticipate some people will argue that more humans will make the long term future go well because in expectation this will create more people going into the long term. I think this is a reasonable position to take but I don't find it convincing because of the problem of moral cluelessness: there is far too much random chaos (in the butterfly effect sense of the term) for us to have any idea what the effect of more people now will be on the next few generations.
As Kevin Kuruc argues, progress happens from people (or productive person-years), not from the bare passage of time. So we should expect there's some number of productive person-years required to solve this problem. So there simply is no meat-eater problem. As a first-pass model: removing person-years from the present doesn't reduce the number of animals harmed before a solution is found; it just makes the solution arrive later.
I imagine a longer analysis would include factors like:
1. If intense AI happens in 10 to 50 years, that could do inventing afterwards.
2. I expect that a very narrow slice of the population will be responsible for scientific innovations here, if humans do it. Maybe instead of considering the policies [increase the population everywhere] or [decrease the population everywhere], we could consider more nuanced policies. Related, if one wanted to help with animal welfare, I'd expect that [pro-natalism] would be an incredibly ineffective way of doing so, for the benefit of eventual scientific progress on animals.
I think no one here is trying to use pronatalism to improve animal welfare. The crux for me is more whether pronatalism is net-negative, neutral, or net-positive, and its marginal impact on animal welfare seems to matter in that case. But the total impact of animal suffering dwarfs whatever positive or negative impact pronatalism might have.
IFF cultured meat is a technological inevitability. I don't think this is necessarily true, we could also improve the efficiency of factory farming and create a very bad future for animals.
Or if any other kind of progress (including moral progress, some of which will come from future people) will eventually abolish factory-farming. I'd be utterly shocked if factory-farming is still a thing 1000+ years from now. But sure, it is a possibility, so you could discount the value of new lives by some modest amount to reflect this risk. I just don't think that will yield the result that marginal population increases are net-negative for the world in expectation.
I doubt that is a good way to model this (for farmed animals). Consider the extremes:
So as a first approximation, we should just assume the amount of suffering in factory farms increases monotonically with the human population, since we can be fairly confident in these three data points (no suffering with no humans; lots of suffering with 8B humans; maybe more, maybe less suffering at the Malthusian limit). Of course that would be an oversimplified model. But it is a starting point, and to get from that starting point to "adding people on the margin reduces or doesn't affect expected farmed animal suffering" needs a better argument.
I think Richard is right about the general case. It was a bit unintuitive to me until I ran the numbers in a spreadsheet, which you can see here:
https://docs.google.com/spreadsheets/d/1pRW3WinG1gzJM3RER2Q4Tl5kscJRESuG8qupHGN1Wnw/edit?usp=drivesdk
Basically, yes, assume that meat eating increases with the size of human population. But the scientific effort towards ending the need to meat eat also increases with the size of the human population, assuming marginal extra people are as equally likely to go into researching the problem as the average person. Under a simple model the two exactly balance out, as you can see in the spreadsheet.
I just think real life breaks the simple model in ways I have described below, in a way that preserves a meat-eater problem.
Yeah, but as you point out below, that simple model makes some unrealistic assumptions (e.g., that a solution will definitely be found that fully eliminates farmed animal suffering, and that a person starts contributing, in expectation, to solving meat eating at age 0). So it still seems to me that a better argument is needed to shift the prior.
Fair enough.
My central expectation is that value of one more human life created is roughly about even with the amount of nonhuman suffering that life would cause (based on here https://forum.effectivealtruism.org/posts/eomJTLnuhHAJ2KcjW/comparison-between-the-hedonic-utility-of-human-life-and#Poultry_living_time_per_capita). I'm also willing to assume cultured meat is not too long away. Then the childhood delay til contribution only makes a fractional difference and I tip very slightly back into the pro natalist camp, while still accepting that the meat eater problem is relevant.
right--in that simple model, each extra marginal average person decreases the time taken to invent cultured meat at the same rate as they contribute to the problem, and there's an exact identity between those rates. But there are complicating factors that I think work against assuring us there's no meat-eater problem:
I do concede that the problem is mitigated somewhat because if we expect cultured meat to take over within the lifetime of a new person, then their harm (and impact) is scaled down proportionately, but the intrinsic hedonic value of their existence isn't similarly scaled down.
But it doesn't sound as simple as just "there's no meat-eater problem".
My best guess is that more humans reduces wild terrestrial invertebrate populations in the near term / on Earth (so ignoring space colonization), largely through agricultural land use.[1] If you think:
then increasing human populations could be good for animals in the near term, with the effect on wild animals outweighing those on farmed animals.
It's unclear to me what's going on with wild aquatic animals.
See especially Tables 3 and 4 from Attwood et al., 2008.
Net primary productivity is also typically lower in crops, across crops, based on "Land Use Change" greenhouse gas emissions from OWID / Poore & Nemecek, 2018.
Gross primary productivity decreases when replacing forest with crops, but increases if replacing grassland with crops, according to the globally representative study Krause et al., 2022.
Some other studies support increased and others decreased net productivity in crops compared to nature (Tomasik, 2013–2022, a, b)
But pesticides and fertilizers also plausibly reduce arthropod populations based on my lit reviews (but less clear in the long run with repeated use), so even if primary productivity increased, arthropod populations could still be lower overall.
Great point! Though I think it's unless clear what the impact of more humans on wild terrestrial invertebrate populations is. Developed countries have mostly stopped clearing land for human living spaces. I could imagine that a higher human population could induce demand for agriculture and increased trash output which could increase terrestrial invertebrate populations.
So this would be more food/net primary productivity available for terrestrial invertebrates to eat, and agriculture would have to increase net primary productivity overall (EDIT: or transform it into a more useful form for invertebrates), right?
Ok, I missed the citation to your source initially because the citation wasn't in your comment when you first posted it. The source does say less insect abundance in land converted to agricultural use from natural space. So then what i said about increased agricultural use supports your point rather than mine.
Yes I think so.