One of the common critiques of total utilitarianism is Parfit’s The Repugnant Conclusion. It was originally formulated:
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.
It is my contention that this is a lot less interesting than people think it is.
This is a chart I made in Paint. Essentially, what the repugnant conclusion means is that total utilitarians are indifferent between any point on the red line. We are equally okay with a world of trillions of people with lives barely worth living, a world of billions of people with pretty good lives, or a world of millions of people with ecstatically happy lives.
This means that the repugnant conclusion could just as well be phrased “for any population of ten billion people, all with a very high quality of life, there is some imaginable smaller population with a much much higher quality of life which, if other things were equal, is preferable.”
First, there is nothing in total utilitarianism that says that you have to prefer the high-population-lower-utility to the low-population-higher-utility. You could very well say that, if the population * utility of two states of the world are equal, people should prefer the happier one.
Second, the Repugnant Conclusion depends on the assumption that lives cost less than happiness does. Think about it this way: one implication of the Repugnant Conclusion is that if you could devote all the resources of the earth to make a single, ecstatically happy human, trillions of times happier than any human has ever been before, then it would be ethical to do so. This is not particularly interesting to total utilitarians, because obviously we cannot devote all the resources of the world to create a single ecstatically happy human. They would be tremendously lonely and having all of Europe doesn’t do you much good once you already have all of America.
Similarly, the actual Repugnant Conclusion depends on this unstated premise: if you have X amount of resources, you could use that to either make two people who have 1 utility each, or one person who has 1.9 utility, and therefore it is always ethical to devote those resources to creating more people and no one gets to have more than 1 utility. Without this assumption, the Repugnant Conclusion is as trivial as the conclusion that we ought to create a single human with trillions of utility. If you can use your X resources to create two people who have 1 utility each, or one person with 4 utility, it is obviously better to create the single person, and the Repugnant Conclusion is nothing but an amusing parlor trick.
However, this premise seems dubious. It is possible to increase both population and utility per person (for instance, by curing diseases or preventing famines): quality of life has improved tremendously over the past couple centuries, even as the population has soared.
Furthermore, one may look into less resource-intensive ways of making a life worth living. Having more resources does not necessarily make people happier. New Yorkers use fewer resources than most Americans; their carbon footprint is 30% of the average American’s. The claim that a New Yorker’s life has 30% of the utility of an average American’s seems, at best, dubious.
A total utilitarian utopia may be one where everyone lives in a dense urban environment, takes the subway to work, only eats meat on special occasions, and takes vacations a few days away from where they live. However, they can still have interesting work, deep and meaningful relationships, access to the world’s great art and music, and a sense of contributing to the world. That is an unusual definition of “life barely worth living”.
Furthermore, at current margins, it costs fewer resources to make a person happier than to create a person (although not by much). Therefore, we can guess that– whatever the ideal point of trading off putting-resources-into-lives and putting-resources-into-utility is– it is probably not too far below where the median person on Earth is now. Total utilitarianism may require a population of ten or twelve billion people; but it is unlikely to call for a population of thirty or forty billion.