It’s applying population axiologies which are supposed to be about complete population-histories to local populations at a given time.
You’re right, my calculations only work for the full population history if population and GDP stay the same forever for each country. The main element of uncertainty is future per capita GDP, because population changes more slowly and is easier to predict. In general, since GDP per capita is likely to be higher in the future, I’m probably rating population increases too unfavorably.
But this ignores externalities which are incurred either by other countries, or the future, or both. There are a lot of different indirect effects of changes in population size, and if you start trying to account for these then you could get sensible practical rules which look quite different from critical-level utilitarianism.
Whether externalities are a major issue depends on your choice of critical level. If a country is very far from the critical level, externalities aren’t a major factor in my model (obviously if you aren’t a critical-level utilitarian they may be more important). For example, if the critical level is $300, adding an extra 1% of people with incomes of $30,000 is better than increasing everyone’s income by 4%, according to critical-level utilitarianism, because ln(30000/300) > 4. Any externalities would have to be very large to be the dominant factor here. On the other hand, if the critical level if $3,000 and the potential income is $6,000, externalities could be a much bigger deal.
I think it is plausible that externalities could be very large—and that the main mechanism for this may be changing the number of expected lives in the future. See for example discussion in section 1.1.2 of Nick Beckstead’s PhD thesis.
Thanks for the feedback!
You’re right, my calculations only work for the full population history if population and GDP stay the same forever for each country. The main element of uncertainty is future per capita GDP, because population changes more slowly and is easier to predict. In general, since GDP per capita is likely to be higher in the future, I’m probably rating population increases too unfavorably.
Whether externalities are a major issue depends on your choice of critical level. If a country is very far from the critical level, externalities aren’t a major factor in my model (obviously if you aren’t a critical-level utilitarian they may be more important). For example, if the critical level is $300, adding an extra 1% of people with incomes of $30,000 is better than increasing everyone’s income by 4%, according to critical-level utilitarianism, because ln(30000/300) > 4. Any externalities would have to be very large to be the dominant factor here. On the other hand, if the critical level if $3,000 and the potential income is $6,000, externalities could be a much bigger deal.
I think it is plausible that externalities could be very large—and that the main mechanism for this may be changing the number of expected lives in the future. See for example discussion in section 1.1.2 of Nick Beckstead’s PhD thesis.