Peter Singer is a professor of bioethics at Princeton University and one of the world's most prominent—and controversial—moral philosophers. He's written influential works on poverty, charity, and euthanasia, and is considered a founder of the modern animal rights movement. He's here to speak to you.

Singer is one the most famous ethicists alive today. He also draws the most ire, and inspires the most vociferous denunciations. Among his most influential (and argued-over) beliefs: that relatively wealthy people have a moral duty to donate relatively large amounts of money to people suffering in poverty; that "speciesism" causing mistreatment of animals is "as indefensible as the most blatant racism;" and that, in certain instances, euthanasia of profoundly disabled and suffering people is morally justifiable. (Please take the time to read Singer's own writings on these issues before leaping to attack or defend him.)

Below is an interview we conducted with Singer this month, covering many of his most famous beliefs. He is also the founder of The Life You Can Save, a group that determines which charities are most effective at helping the world's poorest people. He will be in the discussion section at the bottom of this post at 5 p.m. Eastern time to answer questions from readers. Go to it.

You're one of the world's most famous philosophers, at least among the general public. Do you feel like having a high public profile—spreading the message—is part of your ethics?

Peter Singer: Yes I do. It's because I work in ethics, and, more specifically, applied ethics, that I think it's important that if you have things to say that you think are right and you think could make the world a better place, it's important that many people read about them. Not only my colleagues in other universities or philosophy departments.

Is the desire to communicate with a wider audience lacking in the philosophy world, generally?

PS: Yes, I think it's still lacking to a significant extent. I think the situation is better now than it was 20 years ago... perhaps it's the internet that has provided [a platform] people like you who can write easily about philosophical issues for a wider audience. So I think the situation has improved. But there are structural reasons within the academic career setting that make it quite a disincentive— that you're not gonna get much credit for writing a piece in [the press], even if it's read by hundreds of thousands of people. You'll get more credit for writing a piece in a refereed journal that might be read by 500 people.

Let's talk about the issue of charity. One objection that often crops up is the tension between charity and economic development. Why the emphasis on charitable giving? Would those resources be better spent trying to build the economy in Third World nations?

PS: I don't see it as an either/ or. I think it's good for there to be investment in developing countries, and put businesses in there, and create employment, and so on. Generally speaking I think that that's a good thing. But, two things: One is a lot of the people that I'm addressing don't have that opportunity. They're ordinary people going about their jobs. They're not investors, or major capitalists, or CEOs of corporations. So if you said to them, "Let's promote economic development in Uganda or somewhere," they would say, "How do I do that?" Whereas if you say, "You can donate to the Against Malaria Foundation and you can provide bed nets," there's an easy path for them to do that.

The second thing is, I think that economic development leaves out a lot of people—and again, this is a general statement—but the evidence that I've looked at suggests that economic development does pull people out of poverty, and that's definitely an important thing, but quite often it leaves some of the poorest of the poor untouched. They don't have the skills, or sometimes they don't have the mobility, to get jobs that are created. I think we need to help them anyway. So essentially I think we need both. We need economic development, and charity.

Is there a finite pool of charitable contributions out there to be distributed? Or might some more showy forms of charity (like Batkid) be okay, because they end up pulling in more donations through their PR value?

PS: I would certainly hope that there's room for growing the amount people give to charity, and you would think that as people become more affluent, more of their income is available for non-necessity spending. You would think that the amount they give to charity ought to grow. If you look at figures for the United States, it doesn't look like it has been growing significantly, but I hope it would. The second thing is, it's a very large sum of money that we're talking about.. so if more of that were to go to highly effective charities, it would do a lot more good. So even if we can't actually grow it, which would be disappointing, we could certainly shift it towards the better charities.

What are the implications of your thoughts on charity for the arts? It seems that your position tends to cause outrage among fans of the arts who think that you're not counting the arts as a real charity.

PS: I'm not saying the arts are not a real charity, I'm just saying that in the world as it is, it's not a charity that I would give the highest priority to. I think it's great for people to promote and encourage the arts. But I do think you have to look at the world we live in. And if we could get out of the situation where we have a billion people living in extreme poverty, if we could meet basic needs... and provide some minimal education and health care and so on, then I think would be the time to say, "Yeah, let's help to promote the arts." But I just don't think that the differences you make by donating to a museum or an art gallery really compare to the differences you make by donating to the charities that fight global poverty.

Sometimes you're perceived as not having gratitude for charitable donations from the rich, i.e., saying someone like Bill Gates could donate more money. Is there a role for gratitude in your ethics?

PS: Sure. I think there's a place for—I'm not sure gratitude is quite the right word—I would say rather appreciation and recognition are what we should give to Bill Gates. And it's true that Bill Gates and Melinda Gates could give more, but I don't spend a lot of time saying that or criticizing them, because I think what they're doing is fantastic. I think they have made a huge difference to the world, they've saved millions of lives, they've set an example of what wealthy people can be doing. They're not saints or angels, but nor am I.

When it comes to an issue like climate change, which involves people balancing what are perceived to be the needs of the current generation against the needs of future generations, how do you tell people to make that calculation?

PS: I think that we have to take a long term view, even if it means some costs to the present generation. We cannot simply be oblivious to the damage we're doing, and the Russian Roulette we're playing with the future of the planet, which will have effects for centuries to come. When you talk about the costs to the present generation, I think it's important to distinguish between countries that are reasonably affluent, where virtually nobody is starving, and the sacrifices or cost for them, I think, would be relatively minor. Maybe take our standard of living back a couple of decades. But we were not living in poverty in the 1970s or 80s. We could cope with that quite well. On the other hand, other countries that still have people in extreme poverty I think are in a different situation... I think it's reasonable to say that we're the ones who should be taking the lead, and hopefully making it easier for the others to follow.

Should we treat the needs of future generations as equal to ours, or is there some discounting multiple we should put on them?

PS: I don't think we should discount them intrinsically, we should only discount for uncertainty. And there are some uncertainties... but you have to realize that if the damage is somehow irreparable, the consequences are huge, and they're huge for hundreds or thousands of years... and that's why even with a small discount for uncertainty, the shadow of the future ought to weigh very heavily on our present choices.

Inequality has finally been getting some traction in mainstream political discourse in America. Do you see inequality itself as a negative thing, or is it all dependent on its effects?

PS: It's all dependent on its effects for me. I don't see equality as an intrinsic good. I see inequality as something that has a wide range of different effects. The most obvious one for me is the law of diminishing marginal utility: the fact that if somebody is earning $100,000 and you give them an extra $1,000, you've made very little difference to their well being; if someone is struggling to live on $1,000 a year and you give them another $1,000, you've made a huge difference. So that's for me the basic problem with inequality. And obviously, that difference—the difference in the marginal utility of $1,000—is going to diminish as those extremes get closer...

There are also questions about political power that need to be discussed, and they tend to be stronger when we have fairly extreme inequality, which of course we do in the United States. The fact that you can have some billionaires putting huge amounts of money into politics, and therefore having a vastly greater influence than the average voter. If you really believe in democracy, that's difficult to reconcile with basic principles of democracy.

Should there be a maximum amount of wealth that anyone can have?

PS: I don't know that I want to say there's a maximum amount that anyone can have. I do think there are many things we could do, and used to do, to redistribute, that we don't. The move against death duties [inheritance taxes] seems to me a strange thing to have happened, because if you believe in equal opportunity, the idea that you tax someone's estate when they die seems a pretty sensible way of getting redistribution.

Is someone having an extreme amount of wealth a de facto indicator of a moral failing on their part?

PS: Well, if somebody has an extreme amount of wealth and is not using it for some good purpose, only for their own enjoyment or satisfaction, then clearly there's a moral failing in the world in which we live. But, as we were talking about the Gates before, they've done so much with a substantial part of their wealth... it would be sort of mean, failing to recognize what they've done, to say they were not good people because they still have a lot of wealth.

Let's touch on animal rights. What's your take on zoos?

PS: I think it was a mistake to get started on zoos. It was wrong to capture wild animals and confine them in captivity for people to go and gawk at them. And that's basically how zoos got started. But once you do that, and once you have animals that have been bred in captivity, you're really stuck with them in some sense. You can't return them to the wild. Many species, the skills they need to survive in the wild have to be learned... I think what we need to do is to turn the zoos around so the major purpose of them is not to provide people with an opportunity to look at animals, but to provide those animals with an opportunity to lead reasonably good lives. And then if, incidental to that, people can go and look at them while they're leading those lives, that's fine.

Let me ask you the perpetual question that arises in these animal rights conversations: "What are you gonna do with all the cows? Just let them roam free?"

PS: That question always comes up. But do these people really imagine that there are this many cows in the United States as a result of their natural reproduction? They're there because of the commercial incentives to produce them. If the market for the product disappears, then people will stop breeding them, and there won't be all these cows. We can still keep a few in some reservations.

I understand you're an atheist. Do you think religion is immoral? Is there a negative moral aspect to religious belief related to failure to seek out the truth?

PS: There are a lot of different kinds of religious belief. And very often in the discussion about the existence of god, there's [only one represented]... I suppose of the [fundamentalist, literalist] kind of religious belief, I would agree that I don't think there's evidence for such a god. I think there are actually good reasons like the Argument from Evil as to why there couldn't be an all-powerful, all-knowing, and all-good creator of the universe.

So I think there is some kind of failing to take evidence and argument seriously when people have that kind of traditional view. But there are many people who describe themselves as religious, or even as specifically Christian or Jewish or Muslim, who would not take their beliefs in that literal sort of way, but who would describe their attitude as some sort of attitude to the world... they may find participation in certain rituals as adding meaning to their lives. And if that's the case, I don't think it's a failure of rationality. It may be something that, for some people, helps to make them better people.

Can you briefly explain your position on euthanasia? It seems to be the most controversial of your positions.

PS: First of all, I do not support involuntary euthanasia, which is killing someone against their will. What I support is, firstly, voluntary euthanasia, which is killing somebody on their request, as happens legally in the Netherlands [and elsewhere]... I also will support in some cases nonvoluntary euthanasia, which is carrying out euthanasia for somebody where there is no possibility of obtaining consent or refusal either way. So, for example, we might be talking about an infant born with severe disabilities. I defend nonvoluntary euthanasia in some of those cases, where the parents, after appropriate counseling and advice, decide that that's best for them and their family. Because we already withdraw life support from some of these babies. And I don't see a big difference between [turning off a respirator keeping a baby alive], which happens every day in intensive care units, and saying, "well, given the prognosis of this baby... we think that it's better that this baby should not live. Its prospects of a life of minimally acceptable quality are too poor"... if it's okay to turn off the respirator in these cases, it ought to be okay to give the baby a lethal injection.

Considering how much controversy that one position of yours generates, do you ever question the utility of holding it?

PS: I do sometimes think that, in hindsight, it might have been better if I never addressed that topic. But it's too late now. I'm not going to change my views, and I think it would shred my credibility as a philosopher if I were now to say, "Well, this doesn't seem to be going down well with the general public, so I'm going to change my views."

To what extent do you practice what you preach in your own life?

PS: I think to a significant extent, but not fully. As I said before when we were talking about the Gates, I don't consider myself to be a saint at all... I'm totally vegetarian and largely vegan, I'm not strict about being vegan... I'm now giving about a third of my income (to charity). I've been sort of gradually working up over the years. And, you know, I think that's substantial, but sure, I'm still living very comfortably, and I could still give more, so that's one of the things I suppose I struggle with still.

For people who still need a New Year's resolution for, is there any pithy thought you have for how to live a more ethical life in 2014?

PS: I would see this as the year of deciding to make your life an effective force for good in the world. Think about: How much good am I doing? How can I do more? I want to do more good in the world in 2014 than I did in 2013, and I will then want to go on and do more still in 2015. So push yourself to your personal best, if you like.

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