Should Our Priors Make Us Doubt Ethical Veganism?

No, they shouldn't.

At first glance, it might seem that ethical veganism has low prior probability. About 92% of people worldwide eat animals. Ninety-seven percent eat animal byproducts like eggs and dairy. Even a majority of applied ethicists say that eating animal products is permissible under normal circumstances. If the experts in a particular field are telling us that something isn’t true, then we should probably assign a low prior probability to that thing being true.

The above data may seem strange to someone who’s familiar with the philosophical literature, since there just aren’t any good arguments that defend factory farming. The most prominent, by Tim Hsiao, denies that there’s a distinction between moral agency and moral patiency and equates the harms done to animals to the “harms” that can be done to plants and inanimate objects, like failing to change the oil in your car. (How and why your car might care that you haven’t changed its oil, I’m not sure!) As Michael Huemer puts it, whenever defenders of animal agriculture argue against ethical veganism, their objections are really lame and just don’t hold up to intellectual scrutiny.

All of this might force us to consider a Fermi-like “where are they?” paradox in animal ethics: Unless we have some very good reasons to think that most people on Earth—and most applied ethicists—are wrong, and not just wrong, but fantastically wrong about eating animals, then we should expect there to be at least one good argument in the literature in favor of factory farming. Yet no such argument is forthcoming.

We might think that there are three possible answers here:

1. Huemer and I are just wrong, and there are plenty of good arguments for eating animals that we either haven’t heard or dismiss too quickly.

2. Ethical veganism is correct, but the prior probability of veganism is low because the only way to learn much about the issue is to study the literature.

3. The prior probability of ethical veganism isn’t as low as we think, and we just haven’t considered some relevant data point(s) that might explain why most people are wrong.

Explanation 2 can be dismissed almost out of hand. If eating factory farmed animals is wrong, then why wouldn’t there be anything outside the world of philosophy to suggest that it’s wrong, or to explain why people don’t accept the philosophical arguments? Philosophy may be an ivory tower, but it’s not a hermetically sealed bunker.

Explanation 1 is more plausible. But the arguments for factory farming really just don’t seem to be there. Hsiao notes that, besides himself, “only one philosopher (Carruthers 1992) has attempted to defend the specific permissibility of industrial farming against an almost unanimous condemnation in the ethical literature.” Carruthers’s contractarian view makes a similar mistake as Hsiao by assuming that the only beings who can be protected by our moral rules are those who can make them. But, as Donald VanDeVeer observes, the social contract affords protection to plenty of moral stakeholders who wouldn’t be in a position to write the moral rules.

Even if we believe Carruthers and Hsiao’s arguments are plausible, moreover, they’re a tiny minority in the literature. The contradiction posed by a literature that is nearly unanimous against factory farming, when the body of experts widely says it’s permissible, is only slightly less vexing than the contradiction posed by a literature that is literally unanimous.

I think we should lean toward explanation 3. The most likely reason that we see considerable support for factory farming, even among applied ethicists, is that people aren’t perfectly knowledgeable and rational about factory farming, but they’re often irrational in pretty predictable ways. A few obvious cases:

• A lot of people haven’t been exposed to the truth about factory farming or the philosophical arguments for veganism. (I’m doubtful that this one matters much, since the number of vegans per capita has barely changed after decades of vegan outreach.)

• A lot of people who are exposed to the philosophical arguments either reject them because they don’t want to feel guilty for eating animals, or they accept them but still don’t change their behavior because meat-eating is so engrained in the culture.

• Consider also that applied ethicists—who should be more inclined to make costly behavioral changes based on philosophical arguments—are far more accepting of ethical veganism than the lay public.

• If we’re living through an ongoing moral catastrophe, most people probably wouldn’t know until it’s about to end. Consider it a welcome sign, then, that it’s now mainstream to acknowledge that future generations will probably regard our treatment of farmed animals as atrocious.

When you account for all of these factors, the prior probability of ethical veganism starts to look pretty good. You could likely say all the same things about Effective Altruism, which is similarly niche and widely disliked despite the poverty of arguments against it.