Peter Singer is Ira W. DeCamp Professor of Bioethics in the University Center for Human Values at Princeton University and an ACE advisory Board Member. His books include Animal Liberation, Practical Ethics, The Life You Can Save, and The Point of View of the Universe. This interview is about his most recent book, The Most Good You Can Do, which provides an overview of effective altruism.

Your book provides a compelling overview of effective altruism (EA) as a philosophy and social movement. What is the most important lesson that someone not familiar with effective altruism—animal activist or otherwise—can take away?

It’s hard to boil it down to just one lesson, but if I have to do that, I’d say: stop to think before you make your choices! Whether it is a choice about where to give, what career to follow, where to volunteer, you should make sure that your head has a major role in your decision, as well as your heart.

One of the recurring questions that comes up in your book is the question of which cause to support. You seem to allow readers to draw their own conclusions about which of the main causes to support—be it poverty, animals, existential risk, or EA movement-building. But when it comes time for someone to make a donation—or choose a career—what factors should people think through in choosing a cause?

Think about where you can make the biggest difference. One of the reasons I am not prescriptive about the choices you mention is that it is so difficult to compare, say, the suffering of hens kept for their entire lives in battery cages with the suffering of a woman in a developing country with an untreated obstetric fistula. We don’t have a methodology for doing that. With existential risk, the difficult philosophical question is how to take into account the loss of the untold billions of humans who, if we do not minimize risks to the survival of our species, and the worst happens, will never come into existence.

What does the best evidence—and/or your experience—suggest are some of the best ways to create new effective altruists and/or effective animal activists?

First, get the ideas out there, through all the media you can access. Then, create groups of like-minded people who share these ideas. It’s very hard to be an effective altruist or animal activist if you are not in contact with others whose attitudes are similar to your own.

Does wild animal suffering trump farmed animal suffering as a cause that individual donors and activists should focus on? If not the average donor or activist, is there anyone who should be focusing on this cause, such as biologists? Please explain.

On the basis of the information available to us today, I don’t think wild animal suffering comes near to trumping farmed animal suffering as a cause to focus on. First, we don’t know enough about it—I mean, we don’t know how much animals do suffer in the wild. It would be good to have some more research on that.

Second, we don’t really know how to prevent wild animal suffering. Our track record for “managing” wildlife isn’t very good. Moreover, the likely ways of preventing wild animal suffering would lead to a head-on confrontation with values that many environmentalists regard as no less important than the reduction of animal suffering. We may think that the values those environmentalists hold are misguided, but for the animal activist movement and the environmentalist movement to spend all their energies fighting each other would be a disaster both for the animal movement and the environmental movement.

Should EAs specialize in a single cause? Or should they avoid overspecialization in one cause—say, by trying to keep abreast of other EA causes even if they specialize in influence with respect to one cause?

I’d say the latter—work mostly within one cause, while remaining informed about other causes, because we should keep an open mind about whether the cause we are working on is the best one to work on.

In the last chapter, you seem to suggest (p. 174) that because we need to encourage more people to be effective altruists, and since “causes like helping the global poor are more likely to draw people toward thinking and acting as effective altruists than the cause of reducing existential risk,” poverty (not x-risk) should be the public face of EA. Do you think the parallel argument works that poverty not animals should be the public face of EA? Why or why not?

No, I don’t think the situations are parallel. X-risk is a very abstract kind of concern. Most people disregard very small risks, and don’t understand the significance of, say, reducing the risk of human extinction from asteroid collision within the next century from 1 in 100,000 to 1 in 100 million. Nor do they think much about the distant future. Animal suffering, on the other hand, is something people already care about, it is happening right now, it is vivid, you can video it and show it on TV. That’s very different.

At the end of the book (p. 174), some things you say make the reduction of existential risk seem like far and away the most important cause. For one thing, unfathomable numbers of future individuals are affected (between 1018 and 1058 mind-lives, you say)—millions and millions of far future individuals for every one individual in our present or near future. Should EAs be focusing only on x-risk? Why or why not?

I’ve just given one reason—it would limit the EA movement’s appeal to the tiniest of minorities. There is also the philosophical question I mentioned earlier—how do we weigh the loss of lives that are, at present, merely potential? Thirdly, for many kinds of x-risk, it’s not clear that we have strategies that will reduce the risk. Admittedly, that is an argument for doing research into those strategies, but that should not be the only thing EAs do.

In the chapter on effective careers, you mention Henry Spira, your former student who became a leading animal activist. Does his example offer any advice about what direction today’s animal rights movement should go in or what tactics it should use?

I wrote a book about Henry and his tactics and strategies, so that animal activists would be able to follow them—it’s called Ethics Into Action: Henry Spira and the Animal Rights Movement. One of my less successful books, in terms of sales, but I think there is a lot of Henry’s wisdom to be found in it, all the same. Fortunately, today’s animal rights movement, including mainstream organizations like HSUS and PETA, is already, to significant degree, drawing on Henry’s tactics.

Thanks for your time and for your book’s excellent contribution to our intellectual culture!

Thank you for all you are doing for animals and for EA.

To learn more about the EA movement as well as Peter Singer’s latest book, please visit The Most Good You Can Do.