It seems to me that there’s a simpler argument for the same conclusion with the same premises. Consider any small population-changing intervention. If it’s small then it’s approximately reversible. Either it or its reverse will have positive rather than negative impact. It such interventions are cheap enough, the impact will still be positive after accounting for cost. If you got staggeringly unlucky and picked an intervention of near-zero net impact, pick a different one instead.
Of course all the premises are somewhat questionable, but that’s true whichever formulation of the argument one uses.
It’s not obvious to me why small interventions should be reversible—can you explain? The fact that lives of type X (e.g. people born in a particular place) are cheap to create and prevent doesn’t mean it should be done independent of your population ethics: if you think X-type lives are neutral, it’s not worth changing the number of them. It needs to be cheap to create/prevent at least two different types of lives which are clearly different in expected utility. That way, someone who thinks that one type is neutral will find the other type highly non-neutral and be in favor of changing its population size.
For example, even if it’s cheap to change the number of people living on $500 per year, someone who thinks those lives are barely worth living wouldn’t do it. But if it’s also cheap to change the number living on $50,000 per year, then the same person would be in favor of increasing that number. The idea is that nobody should view both types of lives as neutral, since they are very different and most people think it’s very good to improve an existing person’s income by 100-fold.
It’s not obvious to me why small interventions should be reversible
Because it seems like it would be an awful coincidence if the current situation were right at the end of the range of the available possibilities. That would mean, e.g., that there’s a small gap between where we are now and one more child being born in Bhutan, but a really big gap between where we are now and one fewer child being born in Bhutan.
That’s by no means a watertight argument. It could be, e.g., that for some reason it’s really easy to get people to have more children and really hard to get them to have fewer, or vice versa. But it seems really unlikely.
The fact that lives of type X [...] are cheap to create and prevent doesn’t mean it should be done independent of your population ethics
For the avoidance of doubt: I didn’t think it does, nor did I think you think it does.
[...] at least two different types of lives which are clearly different in expected utility.
That’s pretty much exactly what I meant by “If you got staggeringly unlucky … pick a different one instead”. My apologies if that was too cryptic.
It could be, e.g., that for some reason it’s really easy to get people to have more children and really hard to get them to have fewer, or vice versa. But it seems really unlikely.
Seems really likely to me. For instance, having more children is associated with poverty. It’s a lot easier to make many people poor than to make many people rich.
It seems to me that there’s a simpler argument for the same conclusion with the same premises. Consider any small population-changing intervention. If it’s small then it’s approximately reversible. Either it or its reverse will have positive rather than negative impact. It such interventions are cheap enough, the impact will still be positive after accounting for cost. If you got staggeringly unlucky and picked an intervention of near-zero net impact, pick a different one instead.
Of course all the premises are somewhat questionable, but that’s true whichever formulation of the argument one uses.
It’s not obvious to me why small interventions should be reversible—can you explain? The fact that lives of type X (e.g. people born in a particular place) are cheap to create and prevent doesn’t mean it should be done independent of your population ethics: if you think X-type lives are neutral, it’s not worth changing the number of them. It needs to be cheap to create/prevent at least two different types of lives which are clearly different in expected utility. That way, someone who thinks that one type is neutral will find the other type highly non-neutral and be in favor of changing its population size.
For example, even if it’s cheap to change the number of people living on $500 per year, someone who thinks those lives are barely worth living wouldn’t do it. But if it’s also cheap to change the number living on $50,000 per year, then the same person would be in favor of increasing that number. The idea is that nobody should view both types of lives as neutral, since they are very different and most people think it’s very good to improve an existing person’s income by 100-fold.
Because it seems like it would be an awful coincidence if the current situation were right at the end of the range of the available possibilities. That would mean, e.g., that there’s a small gap between where we are now and one more child being born in Bhutan, but a really big gap between where we are now and one fewer child being born in Bhutan.
That’s by no means a watertight argument. It could be, e.g., that for some reason it’s really easy to get people to have more children and really hard to get them to have fewer, or vice versa. But it seems really unlikely.
For the avoidance of doubt: I didn’t think it does, nor did I think you think it does.
That’s pretty much exactly what I meant by “If you got staggeringly unlucky … pick a different one instead”. My apologies if that was too cryptic.
Seems really likely to me. For instance, having more children is associated with poverty. It’s a lot easier to make many people poor than to make many people rich.