Dean Spears and Mark Budolfson have just published a paper with what appears to be a very important result. It's not yet on Sci-Hub and the academic login details a friend had shared with me expired, so I can't access it, though this seems to be a precursor to it. [Update: a user kindly sent me a copy of the paper, which you can download from here.] I haven't stayed abreast of recent developments in population ethics, so I'd be curious to hear what folks more knowledgeable in this area than I am have to say about it.
The population ethics literature has long focused on attempts to avoid the repugnant conclusion. We show that a large set of social orderings that are conventionally understood to escape the repugnant conclusion do not in fact avoid it in all instances. As we demonstrate, prior results depend on formal definitions of the repugnant conclusion that exclude some repugnant cases, for reasons inessential to any “repugnance” (or other meaningful normative properties) of the repugnant conclusion. In particular, the literature traditionally formalizes the repugnant conclusion to exclude cases that include an unaffected sub-population. We relax this normatively irrelevant exclusion, and others. Using several more inclusive formalizations of the repugnant conclusion, we then prove that any plausible social ordering implies some instance of the repugnant conclusion. This understanding—that it is impossible to avoid all instances of the repugnant conclusion—is broader than the traditional understanding in the literature that the repugnant conclusion can only be escaped at unappealing theoretical costs. Therefore, the repugnant conclusion provides no methodological guidance for theory or policy-making, because it does not discriminate among candidate social orderings. So escaping the repugnant conclusion should not be a core goal of the population ethics literature.
I'm neither a philosopher nor familiar with the formal methods Spears & Budolfson use, but here is my understanding of the paper, which understanding may well be wrong.
Normally, the repugnant conclusion says that a very large population with only barely positive lives is better than a small population of really great lives. I don't think Spears & Budolfson deny the fact that, in this particular situation, average utilitarianism (to take one example) does say that the small population of really great lives is in fact better than the alternative. Instead, they rephrase the problem to say something like that, for any one population, you can always make those people really unhappy if you only add enough additional lives to counterbalance it. Even average utilitarianism aggregates, so a large number of slightly happy members will outweigh a small group of very unhappy members. In any case, so long as you can add an arbitrary number to a population, & so long as you aggregate utility, a very large number of small differences can outweigh a small number of large differences.
I take them to say that Parfit & others were looking not for forms of utilitarianism that avoided any repugnant conclusion, but for ones that avoided some specific repugnant conclusion for some specific hypothetical populations (such as those originally described by Parfit). But there are still, for all forms of utilitarianism – including those that solve Parfit's original problem – other repugnant conclusions for other hypothetical populations. And because the particular hypothetical populations that produce repugnant conclusions are different in different variants of utilitarianism, they cannot easily be compared & repugnant conclusions are therefore not a good measure.
They also argue that there are repugnant conclusions for non-aggregative forms of utilitarianism. As I interpret it, they argue that, for any suffering population, you can always distribute some fixed amount of utility by giving a tiny amount to each existing member & distributing the rest over a very large number of additional members, such that all original members are still suffering & all new members are, too. But at every step we only added utility & therefore made everyone better off, so even if we don't aggregate utility, the final population should still be preferable to the original population. (To be clear, as I understand it, they are still discussing only utilitarian systems & their discussion doesn't apply to for example Kantian or virtue ethics.)
So I think the suggestion is that one shouldn't look at repugnancy as a binary category, but instead some sort of continuum, though the precise measuring of it is yet to be worked out.
Hi! Thanks for your careful read of our paper and thougthful summary. I think this paragraph is especially good: "I take them to say that Parfit & others were looking not for forms of utilitarianism that avoided any repugnant conclusion, but for ones that avoided some specific repugnant conclusion for some specific hypothetical populations (such as those originally described by Parfit). But there are still, for all forms of utilitarianism – including those that solve Parfit's original problem – other repugnant conclusions for other hypothet... (read more)