Yeah, those are good links. To add to that, a key issue that the value of saving lives now, and the effects this has on the future, depends on the more general concern of where the Earth is in relation to it optimum population trajectory. However, as discussed in Hilary Greaves, Optimum Population Size it’s not clear on any of a range of models whether there are too many or too few people now. Hilary discusses this assuming totalism, but the results are more general, as I discuss in chapter 2.7 of my PhD thesis. (This discussion isn’t the main point of the chapter, which is really noting and exploring the tension between believing both that the Earth is overpopulated and that saving lives is good.)
Michael, thanks for these links, I’m really enjoying reading both of them. Super interesting thesis! I am pretty puzzled by the idea of there being a single optimal population size though. Even under a totalist view,well being seems super dependent on who is alive and not just how many. E.g. if you had a world full of 20 billion people with a (learned or genetic) predisposition toward happiness, then that will look very different from a world with 20 billion people with a predisposition toward misery (and might look similar to a world with 10 or 30 billion people with a predisposition toward neutral moods). So it strikes me as strange to imagine a single inverted u function. Hillary Greaves’ piece mentions that she is considering the optimal population “under given empirical conditions,” but I’m not really sure what that means given that population could grow in any number of ways. I think that it refers to something along the lines of “the optimal population level taking the world completely as is and offering no interventions that change either who is born or how happy anyone is given that they were born” which I guess makes logical sense as an intellectual exercise but then doesn’t tell us about the ethics of any particular intervention ( offering free birth control or subsidizing births or having a baby, for example, takes us out of the world of “existing empirical conditions” and changes both who is born and how happy existing people are). I’m sure both of you considered this point though—Would it be correct to say that you believe that these considerations just don’t empirically matter that much for our practical decision making?
Hello Monica. I agree there would be different optima given different assumptions. The natural thing to do is to take the world as we, in fact, expect it to be—we’re trying to do ethics in the real world.
Hilary’s paper focuses on whether we are in relation to optimum population assuming a ‘business as usual’ trajectory, i.e. one whether we don’t try to change what will happen currently. You need to settle your view on that to know whether you think you want to encourage or discourage extra people from being born. And, as Hilary quite really points out, this is not a straightforward question to answer.
Yeah, those are good links. To add to that, a key issue that the value of saving lives now, and the effects this has on the future, depends on the more general concern of where the Earth is in relation to it optimum population trajectory. However, as discussed in Hilary Greaves, Optimum Population Size it’s not clear on any of a range of models whether there are too many or too few people now. Hilary discusses this assuming totalism, but the results are more general, as I discuss in chapter 2.7 of my PhD thesis. (This discussion isn’t the main point of the chapter, which is really noting and exploring the tension between believing both that the Earth is overpopulated and that saving lives is good.)
Michael, thanks for these links, I’m really enjoying reading both of them. Super interesting thesis! I am pretty puzzled by the idea of there being a single optimal population size though. Even under a totalist view,well being seems super dependent on who is alive and not just how many. E.g. if you had a world full of 20 billion people with a (learned or genetic) predisposition toward happiness, then that will look very different from a world with 20 billion people with a predisposition toward misery (and might look similar to a world with 10 or 30 billion people with a predisposition toward neutral moods). So it strikes me as strange to imagine a single inverted u function. Hillary Greaves’ piece mentions that she is considering the optimal population “under given empirical conditions,” but I’m not really sure what that means given that population could grow in any number of ways. I think that it refers to something along the lines of “the optimal population level taking the world completely as is and offering no interventions that change either who is born or how happy anyone is given that they were born” which I guess makes logical sense as an intellectual exercise but then doesn’t tell us about the ethics of any particular intervention ( offering free birth control or subsidizing births or having a baby, for example, takes us out of the world of “existing empirical conditions” and changes both who is born and how happy existing people are). I’m sure both of you considered this point though—Would it be correct to say that you believe that these considerations just don’t empirically matter that much for our practical decision making?
Hello Monica. I agree there would be different optima given different assumptions. The natural thing to do is to take the world as we, in fact, expect it to be—we’re trying to do ethics in the real world.
Hilary’s paper focuses on whether we are in relation to optimum population assuming a ‘business as usual’ trajectory, i.e. one whether we don’t try to change what will happen currently. You need to settle your view on that to know whether you think you want to encourage or discourage extra people from being born. And, as Hilary quite really points out, this is not a straightforward question to answer.
That makes sense, thanks Michael!
I like the framing of “optimum population trajectory”, that’s an idea I haven’t encountered before. Thanks!
yeah, it’s the natural way to think about it unless you’re only concerned about the current population.