Building a better utility monster

Back in March, Tyler Cowen encouraged bloggers to list the books that most influenced them. I didn’t think I could come up with a list that was a) plausible and b) would make me look cool, so I did not participate. But I enjoyed reading other people’s lists, and I noted, along with Steve Landsburg, that Derek Parfit’s Reasons and Persons seemed to be the most frequently cited book. Vowing that I will be prepared the next time the influential books meme comes around, I got a copy, which I finished this evening.

I found the book interesting throughout, but Part III on personal identity really stood out. I found it exhilarating and metaphysically challenging. I have spent the last couple weeks badgering my friends incessantly about corpus callosotomy (split-brain surgery), which results in two separate streams of consciousness.

The parts of the book that challenge classical utilitarianism are also interesting (though perhaps a little repetitive at times). The standard counterexample to utilitarianism is Nozick’s utility monster. This is a creature that, in economic jargon, has increasing marginal utility of wealth. If at least one utility monster exists, then the optimal utilitarian distribution of wealth is for one utility monster to have all the wealth. This is supposed to be abhorrant, but the standard reply, of course, is that no such creature exists, or is even imaginable. Utilitarians can bite this bullet with no real-world consequences.

Parfit tries to create a utility monster that is imaginable. His utility monster takes the form of the Repugnant Conclusion:

For any possible population of at least ten billion people, all with a very high quality of life, there must be some much larger imaginable population whose existence, if other things are equal, would be better, even though its members have lives that are barely worth living.

In classical utilitarian terms, a gazillion Muzak-and-potatoes lives are better than ten billion high quality lives. Parfit spends most of Part IV trying to avoid the Repugnant Conclusion. I think Cowen resolves the issue with his Ideal Participant construct, and in any case, a gazillion lives is scarcely more imaginable than the utility monster.

[Caution: untrained philosopher. Proceed at your own risk.]

Can we come up with a better utility monster? I propose, as an imaginable, realistic challenge to utilitarianism: abortion. I think the utilitarian position on abortion has implications that no one—whether pro-life, pro-choice, or ambivalent—would accept.

Let’s start with some assumptions. First, assume that the unwanted fetus will grow into a person who has a life well worth living. This life will be marginally worse if it is born to a 14-year old mother than if it is born to an older, economically-established mother. Whether or not the fetus is aborted, the mother will also have a life worth living. At least in some cases, this life will be somewhat worse if she gives birth to the child, though in all cases her reduction in utility from giving birth is less than the gain in utility to the born child. Assume also that no one is substantially harmed by the existence of any of these people.

Under these assumptions, isn’t the utility-maximizing outcome for the mother to always give birth to the child? No. It depends on how many children the mother is otherwise planning to have, or whether the child is a marginal or inframarginal child. If we suppose that a woman is planning to have two children in her life, and she gets pregnant with one of them at age 14, the utility-maximizing outcome would be for her to abort the child and then have two children when she is ready for them. She and the children she does have will have better lives than she and the children she does not have would have had. However, if a woman is planning to have two children in her life, has them, and then becomes pregnant for a third time, the utility-maximizing outcome would be for her to give birth to the child. This third person will not otherwise be replaced later on by someone else who will have as much or more utility.

To sum up, under utilitarianism, the abortion of inframarginal pregnancies is permissible, but the abortion of marginal pregnancies is not. Pro-lifers would not accept that the abortion of inframarginal pregnancies is permissible. Pro-choicers would not accept that abortion is impermissible in the case of marginal pregnancies. But the oddest result comes if we contrast a woman who is planning to have two children with a woman who is not planning to have any. Suppose they both get pregnant at age 14. It is permissible for the woman who wants children to have an abortion, but it is impermissible for the woman who does not want children to have an abortion. This seems like it would conflict with everyone’s intuitions.

Does my example work? Can you find an acceptable utilitarian solution to this dilemma?