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Can a college course in moral philosophy convince people to eat less meat?

One study found that sitting in a discussion section on the ethics of meat led students to lower their meat consumption.

In the NBC TV show The Good Place, Chidi Anagonye (William Jackson Harper) attempts to teach moral philosophy to Eleanor Shellstrop (Kristen Bell), to mixed results.
Ron Batzdorff/NBCU Photo Bank/NBCUniversal via Getty Images

One of my favorite running debates within moral philosophy as a discipline is whether moral philosophy, as a discipline, is any good or not.

The latest salvo in the debate is an actual randomized evaluation of the effects of moral philosophy instruction. Describing their work in the journal Cognition, the authors — University of California Riverside’s Eric Schwitzgebel, University of Kansas’s Bradford Cokelet, and Princeton’s Peter Singer— describe it as “the first controlled experiment testing the real-world behavioral consequences of university-level philosophy instruction.” In other words: Does sitting in a moral philosophy class actually nudge you toward more moral decisions?

The argument over the moral effects of philosophy dates to the ancient Greeks or earlier, but in recent decades a foundational article is Elizabeth Anscombe’s “Does Oxford Moral Philosophy Corrupt Youth?”

Published in 1957 and commenting on the evolving nature of philosophical instruction in England’s premier university, Anscombe’s essay was an allusion to the criminal charge against Socrates — that he “corrupted the youth” of Athens — that led to his execution. And while Anscombe was an Oxford moral philosopher, she was also a devout Catholic. Her conclusion was that Oxford’s moral philosophy instruction could not corrupt the young elites of Britain any more than the base and vile culture of their upbringing had already corrupted them.

More recently, the philosophers Annette Baier and Kieran Setiya have argued that the corruption charge was justified based on the fact that introductory moral philosophy courses, in particular, teach students that the discipline has come to no shared conclusions on the nature of morality.

Instead, it has split into competing factions. There are some utilitarians and some Kantians (arguing that morality derives from the nature of rational thought), and some Aristotelians (emphasizing character and pursuit of the virtues), and learning about the profound differences between each can lead students to conclude we know nothing about the nature of morality — and thus that anything goes.

In Baier’s words, “We, in effect, give courses in comparative moral theory, and like courses in comparative religion, their usual effect on the student is loss of faith in any of the alternatives presented. We produce relativists and moral skeptics, persons who have been convinced by our teaching that whatever they do in some difficult situation, some moral theory will condone it, another will condemn it.” In other words, students learn that experts disagree about the nature of right and wrong, which leads them to lose faith that there is a firm difference between the two.

To date, the debate has mostly centered around individual philosophy professors — people who have much expertise but whose judgments are inevitably partial and contradict each other frequently. So I was pleased to see that three philosophers have actually conducted a large-scale randomized experiment to see if moral philosophy can alter student’s moral decision-making — and in what direction.

Schwitzgebel, Cokelet, and Singer do not look at abstract outcomes, like how well students do after a class on tests of moral reasoning capacity. They instead look at a very concrete outcome: Do students eat less meat after learning about philosophical arguments against factory farming?

Tracking students’ meat spending after philosophy class

The experiment was conducted with 1,332 UC Riverside students across four different introductory philosophy courses. All the classes had small discussion sections (each capped at 25 students) run by graduate student teaching assistants.

One week, the sections focused either on the ethics of charity (the control group) or the ethics of eating meat (the treatment group); students were informed that this was part of a “teaching experiment.” Neither of these topics was covered in lectures, so the discussion sections were the whole treatment.

The study authors chose meat-eating for several reasons, but a key one was that “among philosophers who write on the issue there is widespread (though not perfect) consensus that it is generally morally better for the typical North American to eat less factory farmed meat.” Few ethical areas have that degree of consensus, but factory-farmed meat is so bad for humans and animals alike that it’s hard to construct a defense (though some have tried). That allows the authors to test if the instruction “worked” by seeing if the discussion caused people to eat less meat.

And it worked! Not only were students in the meat ethics sections likelier to say they thought eating factory-farmed meat is unethical, analysis of their dining cards — basically debit cards issued as part of UC Riverside’s meal plan that students can use to buy meals on campus — suggested that they bought less meat too. Fifty-two percent of dining card purchases for both the control and treatment groups were of meat products before the class. After the class, the treatment group’s percentage fell to 45 percent.

This effect wasn’t driven by a few students becoming vegetarians, but by all students buying slightly less meat. It’s possible this effect was temporary; the authors only had a few weeks of data. But it at least lasted for several weeks.

This result is somewhat surprising. One of the authors, Schwitzgebel, has conducted surveys suggesting that the moral views and behaviors of moral philosophers aren’t appreciably different from those of other philosophers and non-philosophy academics (one exception to this trend appears to be meat-eating). Despite being “experts” on morality, ethicists don’t seem to behave differently or have different moral opinions than people in other fields, which arguably casts some doubt on the existence of moral expertise.

In an email announcing the paper, Singer said that Schwitzgebel expected a null result on the new experiment too: that is, he didn’t think the moral instruction would do anything.

“It’s an encouraging result for those challenging the ethics of eating meat, because it shows that what happens in a classroom can persuade people to eat less meat (even if the difference isn’t as sharp as I would have wished),” Singer concluded.

I hope this is only the beginning of a large literature on the effectiveness of philosophical instruction. But it’s a promising start.

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