[I read this quickly, so sorry if I missed something]
First, on the scope of the argument. When you talk about “Traditional neartermist interventions”, am I right in thinking you *only* have life-saving interventions in mind? Because there are “traditional neartermist interventions”, such as alleviating poverty, that not only do not save lives, but also do not appear to have large effects on future population size.
If your claim applies only to the traditionally near-term interventions which increase the population size (in the near term), then you should make that clear. (Aside, I found the “TLIs” and “TNIs” thing really confusing because the two are so similar and this would be a further reason to change them).
Second, on your argument itself. It seems to rest on this speculative claim.
Those children will go on to have children, and those children will have children, and so on, following an exponential curve. The more time goes by, the more the number of descendants will accelerate until there are millions, billions, or even more future people.
But, as an empirical matter, this is highly unlikely. If you look at the UN projections for world population, it looks like this will peak around 2100. As countries get richer, fertility—the number of children each woman has—goes down. Fertility rates are below 2 in nearly every rich country (e.g. see this), which is below the ‘Replacement level fertility’ of 2.1, the average number of children per woman you need to keep the population constant over time. As poorer countries get richer, we can expect fertility to come down there too. So, your claim might be true if the Earth’s population was set to keep growing in perpetuity, but it’s not. On current projections, saving a life in a high fertility county might lead to one to two generations of above replacement level fertility. (You mention interstellar colonisation, but it’s pretty unclear what relationship that would have with Earth’s population size).
All this is really before you get into debates about optimum population, a topic there is huge uncertainty about.
We don’t need to be certain the UN projections are wrong to have some credence that world population will continue to grow. If that credence is big enough, the Charlemagne Effect can still win.
Hi Michael, thanks for the feedback and the interest in this post! I’ll try to respond to both of your points below:
I discuss the Charlemagne Effect as one of the most obvious and easy-to-illustrate examples of long-term effects of traditionally neartermist interventions (TNIs), but mention that there are likely many other significant long-term effects that would require more thought and research to better define.
As I write: “The Charlemagne Effect, whereby present people will reproduce and create huge numbers of future people, is at least one highly significant long-term effect of TNIs.”
Easy to miss, but I also discuss these nuances in greater depth in Footnotes 13 and 17, and the Considering Potential Impactions section.
Regarding population growth, I respond to your concerns in the section Counterargument: Carrying Capacities. Additionally, Footnote 29 directly addresses this point, and my comment responding to Gregory Lewis touches on many of the same concerns. But to briefly summarize here, if it is true that we hit a global carrying capacity by 2100, you’re right that the Charlemagne Effect is unlikely to have much impact. But if many other scenarios occur (space colonization, very slow but not completely static growth, or cyclic growth), then it will absolutely matter. But of course we won’t know what actually will happen until it happens, but this uncertainty is similar to the uncertainty that accompanies making investments in traditionally longtermist interventions (TLIs) like AI safety or pandemic prevention — we can’t really know how much we are reducing existential risk, we can only give our best estimates.
The hope of this post is not to argue that TNIs are more impactful than TLIs, but rather to make the case that people could reasonably disagree about which are more impactful based on any number of assumptions and forecasts. And therefore, that even within a longtermist utilitarian analysis, it is not obviously better to invest only in TLIs.
[I read this quickly, so sorry if I missed something]
First, on the scope of the argument. When you talk about “Traditional neartermist interventions”, am I right in thinking you *only* have life-saving interventions in mind? Because there are “traditional neartermist interventions”, such as alleviating poverty, that not only do not save lives, but also do not appear to have large effects on future population size.
If your claim applies only to the traditionally near-term interventions which increase the population size (in the near term), then you should make that clear. (Aside, I found the “TLIs” and “TNIs” thing really confusing because the two are so similar and this would be a further reason to change them).
Second, on your argument itself. It seems to rest on this speculative claim.
But, as an empirical matter, this is highly unlikely. If you look at the UN projections for world population, it looks like this will peak around 2100. As countries get richer, fertility—the number of children each woman has—goes down. Fertility rates are below 2 in nearly every rich country (e.g. see this), which is below the ‘Replacement level fertility’ of 2.1, the average number of children per woman you need to keep the population constant over time. As poorer countries get richer, we can expect fertility to come down there too. So, your claim might be true if the Earth’s population was set to keep growing in perpetuity, but it’s not. On current projections, saving a life in a high fertility county might lead to one to two generations of above replacement level fertility. (You mention interstellar colonisation, but it’s pretty unclear what relationship that would have with Earth’s population size).
All this is really before you get into debates about optimum population, a topic there is huge uncertainty about.
We don’t need to be certain the UN projections are wrong to have some credence that world population will continue to grow. If that credence is big enough, the Charlemagne Effect can still win.
Hi Michael, thanks for the feedback and the interest in this post! I’ll try to respond to both of your points below:
I discuss the Charlemagne Effect as one of the most obvious and easy-to-illustrate examples of long-term effects of traditionally neartermist interventions (TNIs), but mention that there are likely many other significant long-term effects that would require more thought and research to better define.
As I write: “The Charlemagne Effect, whereby present people will reproduce and create huge numbers of future people, is at least one highly significant long-term effect of TNIs.”
Easy to miss, but I also discuss these nuances in greater depth in Footnotes 13 and 17, and the Considering Potential Impactions section.
Regarding population growth, I respond to your concerns in the section Counterargument: Carrying Capacities. Additionally, Footnote 29 directly addresses this point, and my comment responding to Gregory Lewis touches on many of the same concerns. But to briefly summarize here, if it is true that we hit a global carrying capacity by 2100, you’re right that the Charlemagne Effect is unlikely to have much impact. But if many other scenarios occur (space colonization, very slow but not completely static growth, or cyclic growth), then it will absolutely matter. But of course we won’t know what actually will happen until it happens, but this uncertainty is similar to the uncertainty that accompanies making investments in traditionally longtermist interventions (TLIs) like AI safety or pandemic prevention — we can’t really know how much we are reducing existential risk, we can only give our best estimates.
The hope of this post is not to argue that TNIs are more impactful than TLIs, but rather to make the case that people could reasonably disagree about which are more impactful based on any number of assumptions and forecasts. And therefore, that even within a longtermist utilitarian analysis, it is not obviously better to invest only in TLIs.