Tuesday, July 20, 2021

New Introduction to Population Ethics

I recently took over as the lead editor for utilitarianism.net, where we've just published a new introduction to population ethics.  Check it out!  (And feel free to email me with any suggestions or corrections.)

My favourite bit was translating Johan Gustafsson's critical range view into the colloquial idiom of "meh" lives and "value blur" (with thanks to Helen for suggesting the term 'meh').  Here's a selection, minus footnotes and illustrations...

Adding an individual makes an outcome better to the extent that their wellbeing exceeds the upper end of a critical range, and makes an outcome worse to the extent that their wellbeing falls below the lower limit of the critical range. [...]

What about lives that fall within the critical range? Life within this range may strike us as meh: neither good nor bad, but also not precisely equal to zero in value, either. After all, some meh lives (those toward the upper end of the range) are better than others (those toward the lower end), so it cannot be that adding any life in this range results in an equally valuable outcome. Instead, the outcome’s value must be incomparable or on a par with that of the prior state: neither better, nor worse, nor precisely equal in value. Note that it may be better to add an upper-range meh life to the world than to add a lower-range meh life, even though adding either life is merely "meh", or results in an outcome that is incomparable with the world in which neither life is added.

To further develop this view, we may think of the value of a life as having two dimensions. In addition to the familiar negative-vs-positive dimension, there is a second dimension of what we might call value blur. When there is zero blur, the resulting values are perfectly precise and comparable: any positive life, however barely so, then constitutes an intrinsic improvement to the world. But as we increase blur, the resulting value becomes increasingly "meh", or incomparable. If life's value had infinite blur, then all lives would be meh. (We will consider such a view in the next section.) Alternatively, if we think that life's value admits of just moderate blur, then sufficient positive (or negative) value may overcome this blurriness to qualify the life in question as one that would be in itself good (or bad) to add to the world.

The key implication of this critical range theory (with moderate value blur) is that an intrinsically good life must contain significantly more welfare than an intrinsically bad life, because between these two levels there is a moderate range of lives that are meh, as illustrated below [...]

The resulting view, while theoretically complex, seems less susceptible to severe objections than the other views we have surveyed. In particular, it can simultaneously avoid both the repugnant conclusion and the sadistic conclusion. But it is worth noting that it cannot accommodate the strong “anti-repugnance” intuition that the idyllic world A is strictly better than the repugnant world Z. Critical range theories instead regard the two worlds as incomparable, due to the immense value blur introduced by all those meh lives in world Z.

Or, on narrow person-affecting views:

Most people would prefer [mostly-good] world A over an empty world B. But the simple procreative asymmetry would seem, perversely, to favor the empty world B since it counts the many good lives in world A for nothing while the few bad lives dominate the decision. On this view, there are no worthwhile trade-offs between good and bad lives. It would be better, supposedly, to have no lives at all.

To help address these problems, we may consider a more complex person-affecting view—one analogous to the critical range theory, discussed above, but with infinite value blur, yielding the result that all (positive) lives are "meh". On such a view, it is better to create a flourishing life than a mediocre one... but either choice is merely on a par with creating neither.

But this brings us to a deeper problem with the procreative asymmetry, which is that it has trouble accounting for the idea that we should be positively glad that the world (with all its worthwhile lives) exists. Granted, the immense incomparability introduced by all the putatively "meh" lives in A at least blocks the perverse conclusion that we must outright prefer the empty world B. Even so, holding the two worlds to be incomparable or “on a par” also seems wrong.

We should recognize that A is better. But to do that, we must reject the strict procreative asymmetry and hold that there is an upper limit to the “critical range” of lives that are merely meh. And this is independently plausible. After all, when thinking about what makes some possible universe good, the most obvious answer is that it contains a predominance of awesome, flourishing lives. How could that not be better than a barren rock? Any view that denies this verdict is arguably too nihilistic and divorced from humane values to be worth taking seriously.

Big thanks to everyone who helped contribute to the article!  My hope is that it will be the best intro to population ethics available on the web.  If you find it useful, feel free to share it widely!  (And again, any suggestions to further improve it are always welcome...) 


  1. In regards to the "impossibility" theorems, it seems like rejecting Mere Addition and accepting the Sadistic Conclusion matches the way that human moral intuitions work in practical scenarios. People often go to great lengths to avoid having children, including having expensive and unpleasant medical procedures, and using devices that decrease their sexual pleasure. This indicates that people are willing to forgo pleasure and inflict pain on themselves in order to avoid "mere addition" of new people. The Sadistic Conclusion merely concentrates this pain and foregone pleasure into a small group of lives not worth living, rather than spreading it out among the general population.

    The way people naturally behave in the day to day world implicitly accepts the Sadistic Conclusion. It also implicitly rejects Parfit's Mere Addition Principle, and Heumer's Benign Addition Principle.

    In regards to the first paragraph of "Tolerating the Intuition:" I think there is an easy way to debunk the accusation that people reject the Repugnant Conclusion because it is hard for human beings to imagine such a large amount of lives. We merely need to note that people intuitively reject Total utilitarianism and Mere Addition for much smaller-scale moral dilemmas. Most people think it is wrong to kill someone, even if you also create a new person to replace them. Most people would rather have one healthy child be born than twins with Huntington's disease, even if the combined lifespan of the twins equals or slightly exceeds the lifespan of the healthy child. Most people think that women should avoid becoming pregnant if the risk of the pregnancy killing them is sufficiently high, they do not act like the new child can just replace the dead mother. It is relatively easy to frame these realistic, small-scale scenarios as "Mere Addition" type problems, but people reject them anyway, which suggests we should reject Mere Addition.

    My suspicion is that most people reject the Repugnant Conclusion because they tend to view people as valuable in and of themselves and reject the principle that Parfit articulated at the end of his discussion of the non-Identity Problem, that "Personal identity does not matter, what matters is the total quantity of whatever makes life worth living." To use the "value receptacle" metaphor, most people would rather have fewer receptacles that each contain more value, rather than a larger amount of receptacles with a smaller amount of value in each, because they value the receptacles, not just the quantity. (To make it clear, I do not think this is a person-affecting view. My example of 1 healthy child vs twins with Huntington's shows that people hold such views, even in cases where all involved individuals don't exist yet).

    1. Hi Evan, it doesn't seem that your examples actually involve "mere addition" (which requires that no existing people be detrimentally affected, and also that no better lives be prevented from coming to exist in their place). For example, people who don't want kids more specifically don't want to themselves become parents. They surely couldn't care less if someone else had more kids (assuming no negative externalities, etc.).

      I take your point that adding 2 okay lives seems less good than adding one flourishing life, so this suggests that we reject small-scale analogues of the repugnant conclusion, even when we can fully grasp the numbers involved. That's a neat response to the "large numbers" defense. But that's not yet to show that rejecting mere addition is intuitive. That would require showing that people don't think you should add a mediocre life to no-one else's detriment. And that seems surprising (hence the mere addition "paradox" -- one may ultimately conclude that rejecting mere addition is the best way out of it, but it's not an entirely intuitive starting point)!

    2. Hi Richard,

      I think there are a decent number of examples of people morally condemning random strangers they heard about in the news or town gossip; strangers who chose to have children with suboptimal lives, even if those lives were technically worth living. You occasionally hear someone talk about how some people shouldn't be allowed to have kids, or should have to take a test before they have them.

      Some of that is probably hyperbole, and probably some of that is motivated by a fear that the kids will generate negative externalities. Some of that might also be condemning the opportunity cost of not waiting until you are better prepared to have kids. But I think people do have an instinctive sense that adding other people adding lives of much lower than average welfare is sometimes bad in some way, even though I think if you asked them they'd admit that the kids in questions didn't have lives that were literally so bad that they were better off never born.

      I am not saying that the kind of people who say things like that are necessarily making a correct moral judgement. People often underestimate the positive externalities new people generate. And the psychological effect of bad parenting on long term wellbeing may be exaggerated. But if I was to guess, I think such people might be working off some sort of crude implicit theory that is a sort of hybrid of virtue ethics and critical level utilitarianism, where the critical level for a child is "Whatever level of welfare the parents could generate for their child if they exert a 'reasonable' level of conscientiousness and effort during their child rearing." I don't know if such a theory is coherent or reasonable or not, but I have to admit I find it more appealing than pure total utilitarianism. What I am trying to establish is that lots of people do seem to intuitively reject "mere addition" under some circumstances.

      More generally, you are absolutely correct that the way people handle having kids in real life isn't 100% analogous to the thought experiment of "mere addition." But the point of "mere addition" is that you can get to the Repugnant Conclusion down a garden path using transitivity. The way people have children today isn't true "mere addition," but it doesn't seem that much further down the garden path using transitivity. The next step beyond "adding lives barely worth living without harming existing people is "adding lives slightly above barely worth living while mildly harming existing people." Or maybe since people do undergo hardships to avoid having children, the most accurate description would be "adding lives slightly above barely worth living while causing some harms and some benefits to existing people." You're right that its not a perfect analogy to mere addition, but I still think that it reveals some strong moral intuitions that are easily extrapolated into opposition to "mere addition."


Visitors: check my comments policy first.
Non-Blogger users: If the comment form isn't working for you, email me your comment and I can post it on your behalf. (If your comment is too long, first try breaking it into two parts.)

Note: only a member of this blog may post a comment.