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The world's most famous utilitarian on whether all carnivorous animals should be killed

Dylan Matthews is a senior correspondent and head writer for Vox's Future Perfect section and has worked at Vox since 2014. He is particularly interested in global health and pandemic prevention, anti-poverty efforts, economic policy and theory, and conflicts about the right way to do philanthropy.

Most philosophers dream of having one big, deeply influential idea. Peter Singer has had three. His 1975 book Animal Liberation served as the founding text of the animal rights movement, and provided a powerful ethical rationale for vegetarianism. In Practical Ethics and Rethinking Life and Death, he challenged traditional ideas about personhood and offered a vigorous defense of abortion and, in some cases, infanticide. His 1972 essay "Famine, Affluence, and Morality" used a simple thought experiment to back up a powerful conclusion: people in rich countries, he thinks, are morally obligated give away a big portion of their income to poor people in the developing world.

His latest book, The Most Good You Can Do, follows up on "Famine, Affluence, and Morality" and argues for effective altruism, the idea that charitable giving should be directed toward the most worthy, cost-effective causes, as determined through rigorous evaluation. Singer is an active member of the effective altruist community, leading the group The Life You Can Save (also the name of one of his books) and championing other organizations like GiveWell that evaluate charities and support highly effective ones. At the moment, the Against Malaria Foundation, GiveDirectly, Schistosomiasis Control Initiative, and Deworm the World Initiative top the list; you can click the links to donate.

I recently spoke to Singer about everything from the ethics of meat-eating to the risk that artificial intelligence will kill us all to the 2011 US intervention in Libya. A transcript — edited and condensed for clarity and length — follows.

Are animals just much, much more important than humans?

Dylan Matthews:You're probably the best-known animal rights advocate in the United States. There's an argument to be made that given the sheer number of non-human animals on the planet, their concerns totally swamp those of humans in terms of overall importance, even if one regards them as less morally important than humans. Why do you suggest giving to charities helping humans, then? Why not animals?

Peter Singer: My position is that the moral status of animals is such that their interests should get equal consideration with the similar interests of humans. I think actually most people in the effective altruism movement would probably agree with that. The question they would ask would be, "How much do they suffer in these conditions? How do we know how much chickens suffer when they're confined in cages to lay their eggs? Or how much do breeding sows suffer when they're kept in stalls where they can't even turn around?"

That's the difficulty. I think it's obvious that they suffer a lot, and I think it's obvious that the benefits of keeping them that way are negligible, or they're actually harms to us, not benefits at all. So I think some of those cases are fairly easy, to say that these are bad practices. If you then say, "How do I compare the value I get by donating to an organization fighting against them with giving to an organization fighting on behalf of the global poor?" That's a lot harder. I think the best you can do is to give a range of plausible estimates, and then see how the value compares. That's what I talk about in the chapter of the book that discusses animals.

Some of these practices are so inexpensive to fight. For example, to get somebody to stop eating animal products for a year, it maybe only costs a few dollars, and it benefits the animals and it will benefit the humans in terms of reducing climate change and making more grain available to feed humans. Some of those things do look like they're a very good value, but you do need somewhere in this range to say, "This is how I weigh in the animal suffering."

Dylan Matthews:How do you think about the suffering of animals in the wild? Jeff McMahan has written a few interesting papers and essays implying that the controlled extinction of carnivorous species might be morally necessary, if it's even ecologically possible. Should we care about improving preyed-upon animals' lives, just as we care about animals in captivity?

Peter Singer: I welcome the discussion of that question. I think it's a good thing that people are taking this seriously and looking at it. What I think should be done about it at the moment is that people should keep thinking and talking about it and doing research into it. I don't think at the moment we've got to the point where we know enough about the suffering of wild animals, and I also don't think there's actually much of a constituency there for doing a lot about it at the moment. So I think that the research and discussion thing is where that issue should be at the moment.

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Dylan Matthews:How would we come to know more about wild animals suffering? There are obviously facts about their nervous systems and sensory capabilities, but we can't really know what, subjectively, it's like to be bat. Does that limit what we can know?

Peter Singer: There are some things that just factual questions, I suppose, that will vary with the species. What percentage of the animals die within hours or days of birth? How long do they take to die? Is it that a predator gets them and then they're killed very rapidly? Or is it that they starve to death and die more slowly? Those are factual questions, and they're relevant questions.

But you're right: then you have to make some judgment. If it's the case that there are large numbers that die slowly from starvation, you would still need some judgment as to what they're actually feeling. So that would be a difficult question. Then, of course, once you did bring that up as a political issue — that is what I meant by saying I don't think there's a constituency of this — then you would have a lot of environmentalists saying, "Well, that's natural, so therefore it's good. And we shouldn't interfere with it because that would be humans changing the environment, and we shouldn't do that."

I don't, myself, accept that "it's natural and therefore good" argument. Obviously we don't really apply that to ourselves. We didn't think that smallpox was natural, and therefore good, and leave it to kill millions of people. I think you would need to have that discussion with people in the environmental movement and try to get some support for doing something about this. Otherwise you're going to get into a pretty nasty sort of political battle in which a lot of energy is going to be wasted and nothing is going to be achieved.

Dylan Matthews:I've heard some effective altruists make the argument that the best thing to do if you're concerned with animal suffering is not to be a vegetarian, but instead to buy humanely raised, free-range meat, on the grounds that that is likely a better life than being in the wild — and, further, that creating a market for humanely raised meat moves the industry in that direction, and maybe has more of a marginal impact on animals' lives than abstaining from meat. What do you make of that line of reasoning?

Peter Singer: Obviously I think it would be far better if people were only eating products from free-ranging animals. As far as the animals are concerned, they would have much better lives. If you could really stick to that, and if you could get some real standards that show they did have good lives, and there wasn't constant commercial pressure for people to cut corners and do things that are harmful to the animals, because that way they can compete better on the marketplace — then that would be a reasonable strategy, I would say, as far as animal welfare is concerned.

One of the other problems, of course, with raising animals is the contribution it makes to the climate change. Particularity if you're talking about beef, it actually makes it worse to buy grass-fed beef. Yeah, it's a better life for the animals, but it's a worse contribution to the climate. I think that's a very powerful reason for not supporting even free-range meat from ruminant animals, which is basically beef and lamb in the US.

The ethics of humanitarian war

Dylan Matthews:You wrote a bit about humanitarian intervention in your book One World. I was curious about your current thoughts on that and on how to think about the ethics of intervention in places like Libya and Syria.

Peter Singer: Just on the general question, I think it's interesting that since I wrote One World, the United Nations has accepted the idea of "responsibility to protect." I think what was then a controversial principle, about the morality of humanitarian intervention, has actually become less controversial as a general principle. So the idea that if a nation is failing to protect its citizens from genocide or war crimes or crimes against humanity, that other nations have, through the United Nations, a responsibility to protect those people. It's something that is now accepted and was the basis, for example, for UN support of the intervention in Libya.

But the intervention in Libya unfortunately went beyond the mandate the UN had given it. It extended to not just protecting civilians in Benghazi or wherever, but to overthrowing the Qaddafi regime. So that's now made Russia and China, in particular, much more suspicious of humanitarian intervention, and it's going to be hard to get Security Council support for it for some time to come. That makes it more difficult.

I think that intervention in Syria earlier on would have been justified, but now it seems like it's such a mess it's very difficult to see the way out. I think humanitarian intervention against the Islamic State is justified. I guess that's more or less where I am on the current military interventions and suggested possible military interventions.

Liu Jin — Pool/Getty Images

Dylan Matthews:When the Libya intervention happened, a few people — me, Ezra Klein, Matthew Yglesias — raised the point that if the goal of the intervention is to save lives, donating bednets is probably a more cost-effective way to do that than deploying the US military. How should an effective altruist think about that kind of trade-off?

Peter Singer: One thing is that the US military is going to be spending money whether it intervenes in Libya or not. There are additional expenses involved in intervening in Libya; you have to replace the missiles that are fired, and so on. But it's not likely that the money that comes out of that budget would have gone to foreign aid. While in theory it might be true that we could save more lives in other ways, it probably, in practice, wasn't going to happen.

The other thing that needs to be taken into account here, but again is more difficult to assess, is that I think it's important that the world stands by principles of intervention against genocide, crimes against humanity, etc. In other words, that it stands for the responsibility to protect. For that to have some buy-in, you need to do something about it now and again. Otherwise it would be like saying, "Yeah, we have a law against murder, but we're not going to stop people murdering others," or, "We're not going to try to catch the murderers and punish them in some way."

I think it would be a good thing, in the long run, if people who might otherwise commit some of these crimes realize that there is likely to be intervention against them, that they are likely to end up in front of the International Criminal Court or to be punished in some other way. It's not so easy to calculate how much it's worth spending in order to achieve that goal.

How to think about the end of the world

Dylan Matthews:You talk about existential risks in your latest book — big threats that have a chance of wiping out all of humanity. Which of those, if you had to pick one or two, concerns you the most? Is there one where the story of how a disaster would unfold is particularly compelling?

Peter Singer: It's not just that the disaster story is more compelling, but that there is a reasonably compelling story as to how we can reduce that risk. When it comes to collision with an asteroid, there is a reasonable story about how we could reduce that risk. First we need to discover whether asteroids are on a collision path, and NASA is already doing that, and then we would need to think about how we could deflect it from Earth. So that, I can kind of understand.

Some of the others, it's hard to know exactly what we could do. Bioterrorism, I guess we can develop ways of making things more secure and making it harder for bioterrorists. But it's not going to be easy to find exactly what the best strategy is. Things like the singularity — the takeover by artificial intelligence, or something like that — it's very hard to see exactly, at this stage, anyway, what you could do that would reduce that risk. I don't know.

I find some of the stories more compelling. I still think there are nuclear risks even though we may think they've been reduced — the risk of existential nuclear risks, rather than simply a local nuclear accident or terrorist attack. I still think there's some risk with the tension between Russia and the United States. That's inched up a notch over what it was before, though it's still nowhere near Cold War levels. I think those things are worth thinking about as well.

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Don Davis / NASA

Dylan Matthews:A large part of the appeal of working on big extinction threats is that you'd save the lives of billions if not trillions if not quadrillions of future people. But there's a lot of disagreement about how we should treat people who don't actually exist yet, morally speaking. How do you think about that? Do all future persons count equally to those of us alive now?

Peter Singer: I find that one of the most difficult ethical questions in this whole area, really. I certainly do think that the well-being of future individuals who do not now exist has to be taken into consideration. There are some people who are only interested in beings who either exist now or who are definitely going to exist at some point. Although I can see the appeal of that position, I don't accept it. I think that you do have to take account of the well-being of future individuals who might not exist, if, for example, we become extinct.

But does that mean I weigh it as much as the well-being of existing individuals? Is the discount only one for uncertainty as to whether they will or will not exist, and what difference we can make? I'm not sure. I kind of suspect that maybe the most consistent answer is, "Yes, the only discounting you're entitled to do is for uncertainty." I wouldn't say that I have a settled position on that question.

Abortion and infanticide

Dylan Matthews:You're a utilitarian, and there's a good argument that utilitarians should prefer a world where there are, say, 100 billion people with lives barely worth living to a world with 1 billion people who are all marvelously happy, if the former would have more total happiness. That'd imply that people have a moral duty to procreate.

Do you think that's right? Do we have an obligation to grow the population as much as possible until we reach that miserable tipping point?

Peter Singer: I think it's reasonably plausible that there is such an obligation, yes. Although it often sounds counterintuitive, all of the other alternatives that people have put up seem to have worse counterintuitive implications. There is no good view where you can just say, "Well here's a theory that is both coherent, consistent, and in accord with several intuitions." It seems to me that there isn't such a theory. So maybe the idea of maximizing total happiness is the best answer that we can come up with.

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Dylan Matthews:You've defended the morality of abortion and, in certain cases, infanticide, in the past. Isn't there a tension between thinking that people might have a moral obligation to procreate and supporting reproductive freedom for women?

Peter Singer: I don't think there is really a tension. I think that the world we're in at the moment, there is no implication of the idea that we ought to have the maximum population that will produce the greatest long-term, sustainable happiness. I think we are either at or have exceeded that level. So I think in the present situation, there's no argument to say it's a good thing to have more children because of that.

The other question, then, is, does it go the other way? Does the fact that we do have more people than we can sustainably give good lives mean we should encourage people not to have children even if they wish to do that? I think the first thing we ought to do is to make sure that every woman has access to contraception. There's still, according to World Health Organization, 225 million women who don't. So that's a win for reproductive freedom, and a win for avoiding an unsustainably large population on the planet. That's obviously the first thing we should do.

Once we've done that, should we encourage people not to have large families? I'm inclined to think, yes, we should, and we should see how that goes. But exactly what forms of encouragement we talk about is a question. We obviously start off with incentives that could not been seen as coercive, and see how that works. If we still found the population was growing faster than we felt was going to lead to sustainable planet, we might consider different kinds of incentives. I think that would be something to be tried out and discussed on the basis of information about what actually does influence people's reproductive behavior.

Dylan Matthews:We've learned a lot about pregnancy and early childhood since you've started writing about abortion and infanticide, and the age at which fetuses can be viable outside the womb has gotten earlier due to medical advances. Have those developments led your views to evolve in any way?

Peter Singer: Not really, I don't think. If we're talking about abortion, I don't think viability is the distinguishing feature that makes the moral difference. When the fetus is sentient, or maybe is able to feel pain, is relevant. Maybe we've made some progress in that direction. The research seems to suggest that it might actually be a little later than we thought. We were seeing people that talked about 18 or 20 weeks. I think perhaps now there's reason to think it's somewhat later than that, which is good in terms of saying that abortion is not necessarily harming a sentient being. But otherwise, I don't think that those changes have made a big difference to my thinking.

The best way to donate

Dylan Matthews:Getting back to your book, what makes effective altruism new and different? Don't most philanthropists think they're doing the most good they can do?

Peter Singer: There's a sense in which the ideas are not really new, and some people trace them to an article I wrote in the 1970s, "Famine, Affluence, and Morality." The kernel of the stuff is already there. But what's new is there are now a lot of people putting this into action, making this a part of their lives. That's never happened until, really, the past five years.

Maybe now and again you'd find an isolated individual, but the idea that there's a whole movement who know about this, who talk about this, that there are websites online when people discuss it. People are using it as part of their career choice. There are websites that are giving well-researched information on which are the most effective charities to donate to. All of that didn't exist 10 years ago. That's a really important shift.

Dylan Matthews:Earlier in your career, you urged readers to donate to big charities like UNICEF and Oxfam, whereas effective altruists tend to recommend smaller, more focused groups like the Against Malaria Foundation. Do you still think the big organizations are worth supporting?

Peter Singer: I still do support Oxfam, among many others, because I think large, diverse organizations are very difficult to evaluate. That doesn't mean that they're not effective organizations. It just means it's hard to prove their effectiveness. But effective altruism is about evidence, and having evidence for what you're doing.

So I have switched a significant amount of my support to areas where there is good evidence, like those groups recommended by GiveWell: the Against Malaria Foundation, the deworming organizations, and GiveDirectly. Those organizations basically do just one thing, and then you can do trials about the one thing they do. If that works well, you can cost it and say, "Here, your money can do this, and it'll be a good thing to do, and it'll be highly cost-effective."

With Oxfam they do a mix of direct aid, some humanitarian relief in disasters, which is a little harder to estimate, and some advocacy work that's very hard to estimate. Some of that might actually have big payoffs. In the book, I used the example of working with civil society organizations in Ghana to make sure that a significant amount of the country's oil revenue is going to develop agriculture for the poor. My estimate is that was a huge payoff for a small amount of money. I think those things are worth supporting, but just some of them are more speculative as to what you're achieving than others.


Dylan Matthews:One frequent criticism you hear is that if everyone donated like an effective altruist, all kinds of popular institutions — museums and the arts, private universities, nonprofits work on illnesses in rich countries — would see funding dry up. What's your counter?

Peter Singer: I don't think that effective altruism is ever going to be the way in which 100 percent of individuals donate to charities. There is a certain kind of person who is open to what effective altruism is suggesting, and thinks that way. I think there's still going to be significant numbers of people who will perhaps give in a more emotionally directed way, and then others who want to give to causes that effective altruists would probably think are not good, but that are geared to the hearts of other people — like the arts, perhaps.

I think what you're likely to see, and what indeed I hope will happen, is that we'll have a significant turning toward the most effective charities, and we'll do more good, and then more charities will see that they need to demonstrate the good that they're doing in order to get money, and they will do that. So it will have an effect that spreads to a large segment of the charitable movement, but I don't think support for other causes is going to completely dry up. I think it will, rather, diminish.

Dylan Matthews:I was interested when you brought up the advocacy work that Oxfam does, since that's another critique you sometimes hear: that effective altruism is not sufficiently political, that it's too focused on what individuals can do and not as much on collective action.

Peter Singer: I think the question is to try to see what the odds are that Oxfam's advocacy work is actually changing things, that it's going to make a difference. Very often it's just very tough, especially given American politics. It's extremely tough to make a difference.

Look, for example, at the Farm Bill, which is very poor for peasant farmers in developing countries, because it makes it difficult or impossible for them to sell their products. They're competing with products that actually initially would be more expensive than theirs, but because of the subsidies they're cheaper. Then there's all the opposition because the subsidies are a waste of taxpayer funds and contribute to obesity and — there are dozens of good reasons why the Farm Bill should disappear, should not be reauthorized. And yet, the politics of it means that it keeps going on.

If you're asking, "Should I support an organization's advocacy work against that?" you would have to say, "It's a very high-risk venture." It would have a big payoff if it succeeded. Maybe one day it will succeed. I think you really need to know what's changed since the last time that makes it more plausible to think a battle against the Farm Bill might succeed.

There's also a quite different kind of advocacy — Oxfam does stuff on behalf of local people who are put at a disadvantage by mining companies that go into developing countries. There, I think there probably is evidence of effectiveness in a number of different cases where they've been able to empower people and local civil society organizations to make a difference. Again, you would want to look at the track record and say, "Yeah. This is something that is helping people."

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