The boys at Catallarchy are having a little dust-up on the subject of interpersonal utility comparisons (IUCs). Are such comparisons possible? Brandon Berg, Jonathan Wilde, and Patri Friedman say yes; Brian Doss defends the conventional economic wisdom and says no.
Without offering too much in the way of justification, I’ll just say that philosophically I tend to agree with Brian. Making interpersonal utility comparisons is a kind of category error, akin to trying to add degrees and pounds. I don’t have a logical proof of this point; it just seems intuitively right to me. You can’t add my utility to yours, because my utility and your utility are just different sorts of thing. And appealing to objective measures, like dopamine levels or endorphins in the brain, seems to me to miss the point. We’ve got different brains, and an endorphin in my brain just ain’t the same as an endorphin in yours. I suspect there’s some connection here to Rawls’s “separateness of persons” objection to utilitarianism.
But on the other hand, as defenders of IUCs are fond of pointing out, we make such comparisons all the time. If you win a baby doll at the fair and give it to your daughter instead of your son, in the expectation that your daughter will enjoy it more, you’re making an IUC. Right? And if you’ll donate money to a homeless person rather than George Soros, on grounds that the homeless person will obtain greater benefit from it, you’re making an IUC. Right?
Since we make these comparisons all the time, they’re clearly not impossible. In that sense, the debate is suffering from ill-chosen language. The question is not whether we can make such comparisons, but whether they possess philosophical or scientific validity. People make IUCs, but they make lots of other mistakes, too. They say things like, “Mary is fatter than John is tall,” a statement that makes less and less sense the more your scrutinize it.
If we’re going to make sense of real-world IUCs, I think we have to reconstruct them more carefully. I think most of them can be understood as imagined “standing in the shoes of” comparisons. If you have a baby doll to give to one of your children, you imagine yourself as a girl with a baby doll, and then you imagine yourself as a boy with a baby doll, and you imagine your satisfaction with each situation. If you have a philosopher gene, you might even imagine that you have a 50% chance of occupying each child’s position. And then you think, “Which of these imaginings was the more satisfying?” Or if you have an economist gene, you might imagine that you also have a toy truck to give away, and realize that the daughter would prefer the doll to the truck and the boy would prefer the truck to the doll.
Similarly, if you have a dollar to give away, you imagine yourself as a homeless person gifted with one more dollar, and then as Soros gifted with one more dollar. In which of these imagined situations did you experience the greater “lift”? You might – again with the economist gene – imagine each of these persons as a possible future you, and then ask in which future you’d prefer to have that extra dollar. That is the sort of imagining that moves people to buy insurance.
Am I just slipping IUCs in the back door by this “imaginings” method? Maybe, but I think not. I am not claiming that the comparisons made by this method possess an objective reality. The comparisons are filtered through an internal, subjective assessment process, which is unavoidably connected to my particular background and character (though I might try to set aside my personal circumstances as much as possible). And that means people who perform such imaginings will naturally reach different conclusions in some cases. This is not because one evaluator is right and another is wrong, but because there is not an objective answer to the question.
Nevertheless, there will exist a range of cases where, despite the non-existence of an objective answer, most everyone will arrive at the same answer. That is, they reach intersubjective agreement. This is what makes the examples given by the IUC-defenders so intuitive; the examples are selected precisely because they fall into the regions where intersubjective agreement is easily reached. On the other hand, there exist other comparisons where different people will honestly reach different conclusions. The IUC-defenders wish to treat these as cases where the utility numbers are just too close to call, and thus people make mistakes. I would counter that in such cases, the differences are not merely honest but also accurate, being based on differing evaluative processes. (And yes, I realize that intersubjectivity is a post-modernist notion, so maybe Scott Scheule’s concerns are well-placed. But even if post-modernism is usually full of crap, even a stopped clock is correct twice a day.)
All this might seem odd coming from a confessed utilitarian like myself. I assure you that I have a fascinating and compelling account of how my positions are consistent, but it will have to wait.