Friday, May 27, 2022

Interpersonal Utility Comparisons

One common criticism of utilitarianism is that we have no way of way of trading off utility gains to one person against utility losses to another in order to say whether the net change is an increase or decrease in total utility. That is not a problem for much of economic theory, which can be done not only without interpersonal comparisons but without assuming anything more than individual preferences. But it is a problem for the idea of economic efficiency, a criterion of goodness derived from Marshall’s definition of an economic improvement. Marshall, a utilitarian, offered the concept of an economic improvement as corresponding, albeit imperfectly, to a change that increased total utility.

We can and do make interpersonal utility comparisons, although not very well. A parent making decisions that affect his children is implicitly asking himself whether doing something one child wants to do and the other doesn't will increase the former's happiness more than it decreases the latter. Someone deciding which friend to give a gift to is doing it in part on which he thinks will be made happier by it. I signal my feelings, including preferences, in facial expressions, voice tones, and the like; others appear to do the same, giving me some idea of the strength as well as the ordering of their preferences and comparing to mine.

I cannot know another person’s preferences with certainty but I have no serious doubt that the disutility to a random stranger of being tortured to death is greater than the disutility to me of stubbing my toe.

10 Comments:

At 10:44 AM, May 30, 2022, Anonymous William H. Stoddard said...

The trouble with utilitarianism as an ethic is that it allows, and indeed requires, that harm be inflicted on one person either for the greater benefit of another person, or for small benefits to a sufficiently large number of other people. See Ursula Le Guin's classic parable "The Ones Who Walk Away from Omelas" for what this implies. I prefer Ayn Rand's concept of a nonsacrificial ethic. Indeed, it seems to me that a nonsacrificial ethic is essentially compatible with libertarianism, but a utilitarian one seems to lead us downward to socialism.

 
At 10:05 PM, May 30, 2022, Anonymous Anonymous said...

《I signal my feelings, including preferences, in facial expressions, voice tones, and the like; others appear to do the same, giving me some idea of the strength as well as the ordering of their preferences and comparing to mine.》

Do I not know that my own preferences are wilfully intransitive, and others give me daily evidence that their preferences are also intransitive, thus invalidating all of orthodox microeconomics?

 
At 3:20 AM, May 31, 2022, Blogger BTRBT said...

William, why would utilitarian ethics lead us to socialism? Do you think that socialist policies actually provide a net benefit over cost to peaceful people?
If so, that's *quite* the tacit endorsement, and one which I would be highly skeptical of.

In any case, anecdotally I've found that some level of "harm for benefit" is pragmatically unavoidable. Detractors usually disregard this point by redefining harm to mean only that which they oppose. Obvious examples of broadly acceptable harms in lieu of net utility:
- Any judiciary process, in which a person is subject to unusual discomfort for the sake of clarity. Some percentage of those who go through this are innocent.
- Critique of socialism causing emotional discomfort to its proponents.
- Subjecting pedestrians to some degree of risk when driving on an adjacent road.

Of course, there's many more.

 
At 4:48 AM, June 01, 2022, Blogger Modern Mugwump said...

@BTRBT agreed re socialism - if utilitarianism leads to socialism, that's a pretty good endorsement of socialism. But I don't think it does. Theory aside, every socialist country to date has been pretty miserable - more or less linearly with socialism.

Unless you interpret "socialism" the way the Chinese Communist Party (post-Mao) and Elon Musk do - as meaning "whatever is good for the people as a whole". Few argue with that (other than quibbling over the name). Free markets and property rights seem to be good for the people as a whole.

@DavidFriedman The traditional answer to utilitarianism is the idea of "rights". People have "rights" that others can't legitimately infringe. That prevents torture for the sake of entertainment (even if it's economically efficient). You can go whole hog on utilitarianism so long as you don't infringe on anybody's rights.

Rights are a good idea - we should do more of that.

 
At 11:01 PM, June 01, 2022, Blogger David Friedman said...

The comments appear to be about whether utilitarianism is a correct philosophy. You are welcome to argue about that, but it doesn't have much to do with my post.

What I am arguing is that interpersonal utility comparisons are possible, something many people deny. That leaves open the question of what they are good for.

 
At 8:54 AM, June 04, 2022, Blogger Powers said...

This comment has been removed by the author.

 
At 8:56 AM, June 04, 2022, Blogger Powers said...

Hi David,

I've been a little puzzled about this lately; maybe you can be of some help. Ignoring, at first the issue of interpersonal utility comparisons, I'm actually confused about what a personal utility judgement would be. Suppose I am trying to decide whether to eat some ice cream. Is the thought: 'will eating this ice cream make me happier than not?' synonymous with 'will eating this ice cream increase my utility?'.

If that is the case, how is one judging happiness, and when? Ice cream may give short-term pleasure, but perhaps at a longer-term cost. If I make a judgment to eat the ice cream, am I making an intrapersonal utility judgment that 'me' in the present benefits more from the short-term pleasure than 'me' in the future suffers from the potential long-term harm?

Thank you

 
At 2:52 PM, June 24, 2022, Blogger BTRBT said...

Modern Mugwump,

Your re: misrepresents my position. I am not arguing that utilitarianism leads to socialism and that this consequently makes socialism good. To the contrary, I am presenting a reductio ad absurdum.

eg: Concluding that Alice would like my cookie more than Bob does not make me a socialist. Neither does the "harm" incurred by saying "Sic semper tyrannis" to people who really want to tyrannize me.

---
Powers,

I'm not David, but I don't think that utility is restricted to short-term happiness. Rather, that short-term happiness is a subset of utility.

So when when you're deciding whether to have ice cream, that's based on your understanding of the ice cream's nature with respect to yourself, and how its consumption will interact with your values.

If you value long-term health very highly, and feel you've been eating too much ice cream lately, you will forgo the ice cream, deeming its consumption a disutility. Or at the very least, a suboptimal gain in utility, relative to other things (eg: Eating some food which is less fattening, but similarly tasty).

 
At 9:26 PM, June 24, 2022, Anonymous Anonymous said...

《I cannot know another person’s preferences with certainty but I have no serious doubt that the disutility to a random stranger of being tortured to death is greater than the disutility to me of stubbing my toe.》

Doesn't revealed preference theory indicate that most of us tolerate torture of others much more than personal injuries? Is Assange in jail because his revealed preference actually proves he cared more about tortured others than his own freedom?

In other words does the disutility of acting on news of a random stranger being tortured outweigh the disutility of ignoring a stubbed toe? In practice?

 
At 1:45 PM, June 26, 2022, Blogger David Friedman said...

@Anonymous:
Interpersonal comparison isn't about comparing the utility of my getting something to the utility to me of your getting something. It's about comparing the utility to me of my getting something to the utility to you of you getting something.

 

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