Bryan Caplan asks me for a defense of utilitarianism, and specifically a reason for rejecting other strongly held moral intuitions.
Like many poorly educated people, I know little about philosophy other than that Descartes said "I think therefore I am." When people feel pain in their own bodies they instinctively think it is bad. There is no "why?" The real question is why do utilitarians think public policy should maximize aggregate utility. Before answering that question, let's consider a more basic problem. Why should I care about anyone else's pain?
Little boys famously respond to answers of "why" questions with another "but why is that," until the adult becomes exasperated. Richard Rorty said that philosophy cannot provide an ultimate justification for liberalism. He suggested that (paraphrasing Judith Shklar) all we can say is that liberals are people who believe "cruelty is the worst thing we do." Rorty did have views on where that belief comes from---he said it's the narrative arts. Think about the novels of Dickens, or Uncle Tom's Cabin, or a pro-gay film like Philadelphia. These put us in the mind of others---they make us sympathize with "the other." Milan Kundera calls Europeans "the children of the novel." The narrative arts (especially TV and film) are the principle reason why young people today are far more pro-gay rights than their parents. I'm 58, and I don't recall any gay characters on TV when I was growing up.
What Rorty called 'liberalism' I call 'utilitarianism,' a term that includes all the various forms of liberalism (classical, neo-, social democratic, etc.) But how do you get from the narrative arts and sympathy for others to utilitarianism? By adding math and logic. If you become a liberal through the narrative arts, and are also a social scientist, you think about a rigorous model for your moral intuition that pain is bad and happiness is good. And what better model than "maximize aggregate utility?"
Yes, we have lots of other moral intuitions, but they seem contingent. We once thought buying life insurance for a family member was disgusting---imagine gambling on the death of one's spouse! We thought wearing a bikini was immoral (still do in Arabia.) We thought the idea of gay marriage was preposterous. But we gave these issues a second thought, and realized "who does it really hurt if gays get married?" And "gays are people too, with their own minds and preferences, we should also care about their happiness." And who does it really hurt if a girl wears a bikini? Our hatred for pain is eternal, but our other moral intuitions are contingent on complex social factors, level of education, etc.
In a previous post I speculated that some of our bogus moral intuitions might have evolved for Darwinian reasons. I should add that they also might be cultural adaptations to one type of living environment, and inappropriate in another. Bryan Caplan correctly notes that one can make the same argument about utilitarianism:
If you aren't convinced that life is better than death, or that happiness is better than suffering, you swiftly drop out of the gene pool. And since human beings are social animals, we're evolved to value the lives and happiness of the people around us as well as our own. Should we therefore dismiss our anti-death, anti-suffering views as "illogical moral intuitions that have evolved for Darwinian reasons"?
The moral nihilist, who bites even more bullets than the utilitarian, can enthusiastically agree. Everyone else, however, has to say, "Yes, it's logically possible that we're evolved to falsely believe that life and happiness are better than death and suffering. But after calm reflection on this potential bias, I remain convinced of the merits of life and happiness." And if you use this approach for life and happiness, why not try it for murdering innocent fat guys?
His last comment is a reference to the famous trolley problem in philosophy, where most people are reluctant to push a fat man onto the tracks to stop a trolley, even if it will definitely save 5 lives further down the track. Let me take up the challenge.
I said the narrative arts put us in the minds of other people. So does standing right next to another human being. But let's say that instead I had been spending the past hour chatting with the 5 people who were chained to the track and endangered by an oncoming trolley. They've told me all about their spouses and children, their goals in life. I look to the distance and see a platform where one guy is contemplating pushing a fat man to save the 5 people I've just been speaking with. What is my moral intuition then?
PS. I'm tall and thin, and always feel guilty discussing this example. So apologies to my pleasantly plump readers. If you like, substitute an example where only by sacrificing a tall man can 5 lives be saved.
PPS. I'm not convinced that life is better than death (I view it as a plausible hypothesis), and I didn't drop out of the gene pool.
PPPS. This paper has my views on the relationship between utilitarianism and liberalism.