Peter Singer on Sentience, Effective Altruism, and the Ethics of Doing Good

Peter Singer

Thank you, Sean. Great to be with you.

Peter Singer

I do think that there is something objective and real, although obviously a lot of our moral intuitions are evolved intuitions that have helped our ancestors to survive. So I don't really trust those moral intuitions, but I think that reason has something to say about ethics, and that's where the objectivity or reality comes in.

This is not a view that I've always held. I started out as what philosophers call a non-cognitivist — something that basically holds that there's nothing to be known, that there's no moral knowledge. The view I held that was quite popular when I was an undergraduate in the '60s was that moral judgments are expressions of our emotions, our feelings. I moved a little bit when I got to Oxford and studied with R.M. Hare, who thought that moral judgments are prescriptions — that's like commands — but also that when you think ethically they are governed by the need to make those prescriptions universalizable. That is essentially something like the golden rule. If you say this is the right moral thing to do, and perhaps on this occasion you benefit from it, you also have to stick to the same judgment when the roles are reversed. Your judgments can't just say, well, because I'm Peter Singer I can do this to you, but because you're Sean Carroll you can't do that to me.

So that brought in an element of reason, but for Hare it was just part of the grammar of the moral language, and that wasn't really enough for me. After struggling with that for a few years, I came to a view I took from the late 19th-century philosopher Henry Sidgwick: that there are rational judgments, that we are capable of looking at things from a broader point of view than our own. He called it the point of view of the universe — although he wasn't saying that the universe is a being with a point of view. That produces an element of reasoning, and I think objectivity, in moral judgments.

Peter Singer

Yes, I think that's right. The term moral realism suggests that in some way this is part of the furniture of the universe, that we could discover it as we discover other galaxies. Clearly that's not the case. But I think it's objective in the sense that any being capable of reasoning could understand the reasons we give for acting in the ways we say you ought to act. That's what makes it larger than just ourselves or even our species.

Peter Singer

When you say that, you're denying the fact that others aren't like you, and claiming you're justified in ignoring that fact. You're missing some fact about the situation, or not giving it attention or weight. If we're going to talk ethically, that's not justifiable. Yes, there's a selfish way of reasoning you can engage in, but you're looking at it from a narrower perspective — one our ancestors may have evolved and survived by taking. We can look at things from a broader perspective, this point of view of the universe. Is it a bad thing that somebody is suffering? When we understand what suffering is, we can say, yes, that is a bad thing. And that's something you're ignoring when you only look at Sean Carroll's suffering, and not at the suffering of others that you're causing.

Peter Singer

There's some sense in which some beings might have a higher status — they might be able to suffer more, for example. Some non-human animals are certainly agents; we might even say moral agents in some cases. But maybe they have more limited cognitive capacities, and possibly they're not capable of suffering or enjoying life as much. In one sense they matter less than we do. So I'm not saying every moral agent is of equal worth in some deep sense. But I am saying that any being capable of having conscious experience matters and ought not to be ignored.

Peter Singer

I'm a consequentialist, and I have been for my entire career. A consequentialist thinks the right actions are those that have the best consequences. A deontologist essentially denies that — says sometimes an action is right even though, all things considered and for everybody affected, it will have worse consequences than some other action. Virtue ethics, I think, is compatible in some form with consequentialism, because it simply says you should be the kind of being who has a virtuous character. Then we have to define what virtuous means, and a consequentialist will say the virtues one should have are those that in the long run tend to produce the best consequences. So I don't really see virtue ethics as a completely independent moral view.

Peter Singer

That's right. You can think of consequentialism as the genus and utilitarianism as the species. Consequentialists might value a wide range of things — they might say freedom, autonomy, knowledge, or justice are independent goods, things of intrinsic value even if they don't produce more happiness and less suffering. Whereas utilitarians say the only thing of intrinsic value is the well-being of sentient beings, desirable states of consciousness. All these other things are important, but instrumentally — as a means to producing, in the long run, a society that leads to more happiness for all sentient beings.

Peter Singer

Yes, I'm now a classical hedonist — a hedonistic utilitarian. That means I regard happiness and pleasure, desirable states of consciousness, the kinds of states you like to have for their own sake, as good, and undesirable states — pain, misery, suffering — as bad. For some years I was a preference utilitarian, somewhat under the influence of Hare, because his view was that moral judgments have to be universalizable, and that means putting ourselves in the position of others and taking on their preferences. But the problem is that people may be misinformed. They may want something and not realize it's actually going to be quite bad. Sidgwick anticipated all of this in the 19th century: if you're talking about the preferences you would have if you were rational, then you have to ask whether there's some reason for thinking that happiness is good and other preferences are not. That was one reason I shifted to a hedonistic viewpoint. The most definitive statement of it is a book I co-authored with the Polish philosopher Katarzyna de Lazari-Radek called The Point of View of the Universe.

Peter Singer

A utilitarian doesn't have to believe we actually can measure it in any precise way. But that it exists, yes. There's some state of happiness you're in that I cannot directly access, and it might be greater or lesser than mine. But I think that's something we all have to do anyway. Suppose you and a few people are going out for dinner and deciding which restaurant. You love spicy Sichuan food, two others enjoy it, and someone else says, I really hate spicy food, I can't take it. You have to decide whether your preference and the others' will outweigh that of the person who'll have to order plain boiled rice. We do that kind of thing all the time in group choices. So I don't think the utilitarian has to say more than: we try to do that as accurately as we can.

Peter Singer

There are many such objections. I tend to think the answer is: if you specify that this is a hypothetical, and we know the slight happiness of the many will outweigh the greater unhappiness of the few, and there are no further bad consequences, then that could well be what we ought to do. But let me add — to decide the slight happiness of the many outweighs the greater unhappiness of the one, we need a scale on which to compare suffering with happiness. It's not obvious that scale runs an equal distance from the neutral point in both directions. I sometimes ask my audiences: suppose a fairy says, I can grant you an hour of the greatest pleasure you've ever experienced, but the price is an hour of the greatest pain you've ever experienced. Would you like that wish? Most of the audience says no. I conclude that we think the worst pains we suffer are further from the neutral point than the greatest pleasures we enjoy. So we have to be careful about making one person miserable, because that might outweigh a very large amount of mild enjoyments.

Peter Singer

Yes, I think that's the standard view. Some people have toyed with a declining marginal utility of utility itself, particularly on the puzzles of population ethics. You're perhaps familiar with the examples we owe mostly to Derek Parfit: for any world with, say, a billion extremely happy people, you could imagine a much larger world in which everybody is just barely above the level at which life is worth living. Parfit called it a life of muzak and potatoes — you only get potatoes, and the only music is the stuff that comes out of elevators. Some people say that with very large populations the value of the additional utility falls away. But it's not clear why, or what the discount rate is. So I think it's better just to say: if happiness is good, and the happiness of two people is good, then the happiness of four people at the same level is twice as good.

Peter Singer

Yes. The underlying reason is that our intuitions have arisen in ways that suggest they are not likely to be tracking moral truth. Some are cultural — we were brought up in a certain ethic, perhaps influenced by a dominant religion, which very often solidified centuries ago in circumstances quite different from our own. I'm an atheist, so I don't think religious teachings have authority as such. And some people say there are near-universal judgments everybody shares — for example, that incest is wrong. But that may be an evolved intuition: incestuous reproduction might lead to inferior children, so groups that had an inhibition against it did better. That's not, today, a reason against incest, because we have reliable contraception. Jonathan Haidt has an example of adult siblings, alone on holiday, who decide to have sex once, enjoy it, use contraception, and remain close afterwards. His subjects nearly all said it was wrong, but when asked why, they couldn't explain it — they just had a deep instinct. We can explain why they have that intuition, but it doesn't give us any reason for thinking what the couple did was wrong.

Peter Singer

What you're describing sounds like the idea of reflective equilibrium that John Rawls put forward in A Theory of Justice — we develop a foundation for a moral theory, test it against our intuitions, and either tweak the theory or tweak the intuitions to match. Rawls likened it to a scientist producing a theory to match the data. But I think that's a mistaken view of what we're doing in morality, because I don't think there is the solid data there might be in science. So I'm more of a foundationalist. I try to get the foundations as clear as I can, take the most rational point of view — the point of view of the universe rather than our own — and find what is intrinsically good and bad. Desirable states of consciousness are intrinsically good, undesirable ones intrinsically bad. That seems to me a more solid foundation than relying on moral intuitions.

Peter Singer

That's a simplified overall perspective. But it's not that everybody should do that in daily life all the time — I simply don't think that would work. We have evolved as beings who love and care for our children and have close relationships with kin and friends. I don't think we can set all that aside and say I'm going to deal with strangers exactly the way I deal with my children or my partner. We have to show some partiality. So although in one sense the well-being of every sentient being counts as much as my own, in practice we have to take account of the fact that we and others will only do well in close personal relationships that necessarily involve some partiality.

Peter Singer

We should care about strangers because they are capable of having the mental states that are intrinsically good or bad. It's a better universe if most sentient beings — not only humans — do not have the really bad states, states of agony, and it's good if they have the positive states of happiness and fulfilment. If we say, well, they're far away and I'm only going to care about those close to me, we're using a distinction that may have had practical value. People used to say, I know better what those close to me want and can help them better — and that was clearly true before we could know what was happening on the other side of the world. It's less so now. So we'd be invoking a difference of distance when it's not really relevant to what is intrinsically good and bad — the states of consciousness that sentient beings can have.

Peter Singer

Yes, it does, if that's going to be positive in its consequences. If they're just going to get angry and end the friendship and not listen at all, then obviously that's not a good thing to do. There's this idea of the busybody interfering in other people's business, and often people do that wrongly. John Stuart Mill said everybody is the best judge and guardian of their own interests. I don't actually think that's right — Mill would have opposed some laws we now take for granted, like requiring seat belts. You can go too far in interfering, but some forms of intervention are clearly justified.

Peter Singer

You use the language "I have the right", and some people take that as ending the discussion completely, because they think rights are absolute and inviolable. Consequentialists talk about rights differently. We may think we should establish systems of rights — things people should virtually never do, a high barrier against violating somebody's rights — but that's not the end of the discussion. Suppose you're riding a motorbike and say, I like my long hair streaming in the wind, I know I'm taking a risk. You could argue it's better to let people take responsibility for choices that don't harm others. But we can still discuss it — have you seen people in hospital with brain injuries from motorbikes, lying there making a few noises? Is it really worth the risk? Or suppose somebody wealthy buys a great painting and says, I've decided to cut it into small pieces and use it to wallpaper my bedroom. We might say, you own it, perhaps you have the right — but don't you think you're damaging something millions have wanted to see, even after your ownership is over? So saying "I have a right" is not the end of the discussion.

Peter Singer

I'd like people to see that if they're part of the affluent world — not at the very bottom, but middle class or above — the additional marginal utility that money has to them is very small compared to the marginal utility it has to somebody living in extreme poverty. The World Bank defines extreme poverty as close to $3 a day, and says around 800 million people live at that level — about 10% of the world's population, which is historically a very low figure. If you're living on $3 a day and could get an extra $1,000, that's roughly your annual income doubled. You might buy a corrugated iron roof for a dwelling that until now has been thatched and leaks — which is actually cheaper in the long run because thatch has to be replaced frequently, but you could never accumulate the cost. You could send your children to school, get basic health care that might be life-saving, sleep under malaria nets so your small children don't get bitten. A whole range of things that would transform your life. And what's a thousand dollars to middle-class people in affluent societies? Maybe a slightly less luxurious holiday. It's not a big deal. If people really think about what it's like to live in extreme poverty, and how much better life can be, more would be prepared to say, that's something good I can do — and perhaps find their own lives more meaningful because they're having a positive influence on others.

Peter Singer

There's an in-between alternative — companies. This is a rough estimate, but the profits of companies worldwide are roughly $10 trillion. If companies tithed 10% of their profits, that could be the trillion dollars needed to bring everybody out of extreme poverty. So there are really three options: individuals, companies, and governments. In one way it would be fairest if governments did it, because they have progressive taxation, so the wealthiest would do the most. But it's very difficult politically. No government gives much more than 1% of gross national product — the United States gives about a quarter of 1%, Australia, where I'm from, is around that deplorably low level, and although some European states are higher, none is really above 1%. There's also a question about whether government aid is as effectively directed as non-government organizations; for many years Iraq was the number one country for US aid, though it was certainly not the poorest. So while it would be nice to increase government aid, that's a long shot. Individuals can give relatively easily, and I direct a lot of my argument towards them. I wrote a book, first published in 2009, called The Life You Can Save, about the most effective organizations to give to. The Life You Can Save is now also an organization; it's distributed about $120 million so far. GiveWell does research on the most effective organizations, supported by what used to be called Open Philanthropy, now Coefficient Giving, backed by Dustin Moskovitz and Cari Tuna. So this moral argument has had a sizable impact — not of the trillion-dollar range, but it's affected very large numbers of people for the better. I've also recently co-founded an organization called Profit for Good, looking at the company side; people can go to profitforgood.com.

Peter Singer

It's a little unfair to say they said give money to them — they might have said give to think tanks they're working for.

Peter Singer

Okay, good — I thought you might be suggesting they were siphoning off the money, which of course was suggested about Sam Bankman-Fried. That's one reason effective altruism took a hit: he'd been a kind of pin-up boy, the world's richest person under 30, who said he was going to give it away to effective causes. Then it turned out there was a fraud, that he was using clients' trust funds, and he's currently in prison. Obviously the loss of money that could have gone to good causes is the greatest tragedy. But it's not representative of the movement as a whole — there are other very wealthy people giving really effectively, and I think the movement has recovered.

Yes, quite a number of people in the movement are interested in preventing our species from becoming extinct, including reducing the risk that AI will take us over. I have mixed feelings. Global poverty is a more immediate cause where we can know with greater certainty that we're having good consequences. Animal welfare, especially combatting factory farming, is another practical, immediate concern. Whereas reducing the risk of extinction by super-intelligent AI is much more speculative — that you're actually going to succeed. But the counterargument is that we're not just talking about 8 billion people; we're talking about vast numbers who will exist, possibly colonizing other planets — quintillions of people who might exist and won't if we don't survive the next century. As a utilitarian I have to value happy consciousness, and it would be tragic if that were lost. So it's not obvious they're wrong to treat extinction risk as a high priority — I just think it's very difficult to know how we're contributing to reducing that particular one. Other extinction risks, like bioterrorism or nuclear war, I take much more seriously as things we can actually have an impact on.

Peter Singer

We can distinguish between what we'd do if we were ideal beings purely motivated by the utilitarian idea, and what we can reasonably ask of human beings given the way they've evolved. If we were all saints, then yes, we would give away down to that level of marginal utility. But we're not. So what we ought to be asking is what will actually bring about the best consequences. If I say to somebody, to live an ethical life you have to give away everything down to the point where you'd be as poor as the poorest person you're giving to, and they throw up their hands and say, if that's what ethics requires, I'm giving up ethics — then you get nothing. Whereas with a more modest scale of giving, still significant, you get a lot more. In The Life You Can Save I draw up a scale of giving that's progressive, like a tax scale — people at modest incomes give 1% or 2%, and by the time you're earning millions a year it suggests giving a third, which is still modest, because you're still very wealthy. So that's a reasonable scale, and I'm hoping it will actually maximize the total amount people give.

Peter Singer

Yes, exactly. Asking people to give is itself an action, and utilitarians weigh actions by their consequences. So you have to frame the ask in the way that will have the best consequences.

Peter Singer

Yes, absolutely, and Jonathan Birch is doing exactly that. The Jeremy Coller Centre for Animal Sentience at LSE, which he directs, is remarkably effective. There was philosophical and scientific work on the sentience of cephalopods — octopuses and squid — and decapod crustaceans, basically lobsters and crabs, which had an immediate legislative effect in the UK. When the UK was part of the EU, animals had always been recognized as sentient beings under EU law. When the UK left, the animal movement protested this would be lost, and Boris Johnson said, don't worry, I'll bring in a law to say they're sentient — a promise he actually kept. The House of Lords amended it to include cephalopods and decapod crustaceans. It doesn't mean they're protected the same way as other animals, but there's a legal basis for courts and government policies to give them weight now.

Peter Singer

Although they're not as separate as you might think, because there are moves to factory-farm octopuses. There's a proposal in the Canary Islands, part of Spain, for a large underwater factory farm producing millions of octopuses. So don't assume your octopus had a happy life in the sea. I think factory farming is really one of the great moral atrocities going on right now, and the reason is that the scale is so mind-bogglingly enormous. For land-based factory farms it's probably something like 70 to 80 billion animals a year. Including factory farms for fish, it probably goes up to something like 200 billion vertebrate animals a year — crowded together in conditions solely directed to producing their flesh, eggs, or milk in the cheapest possible manner, with no independent concern for their welfare. Those conditions thwart a lot of basic instincts — social instincts to be in a group small enough to recognize other individuals, which chickens and turkeys might do with 20 or 30 or 50, but not when you have 20,000 birds in a single shed; instincts to play, which young pigs, playful intelligent animals, have; instincts to move around freely and root around. There's a huge amount of suffering, and it's completely unnecessary — it doesn't produce more food. It actually dramatically reduces the food available to human beings, because when we feed grain or soybeans to animals we get back only a small fraction of the food value — perhaps less than 10% in the case of grain fed to beef cattle, and always less than half.

Peter Singer

Unfortunately that's largely a false impression, though it depends where you are. In the EU and the UK, since Animal Liberation came out in 1975 — just over 50 years ago — there's been some progress. Not that producers are trying to be nicer, but that the animal movement has succeeded in getting laws that reduce suffering, though only marginally. You can no longer keep laying hens in small wire cages where they can't stretch their wings, or veal calves in individual stalls where they can't turn around, or mother pigs in stalls too narrow to turn around. But in the United States, except for some states like California, these are still standard practices — in Iowa, North Carolina, Nebraska, the states that produce most of the animals, there are no such laws. And China has dramatically increased its production of animal products, all through factory farming with pretty much no welfare constraints. So globally I would not say there's been an improvement; there have been some regional improvements.

Peter Singer

There certainly are advocacy efforts, in many countries including the US, and to some extent in India. Much less in China, where the animal welfare movement is mostly focused on dogs and cats. And there are a lot of myths. If you ask Americans whether they eat products from factory farms, the proportion who say, oh, I only eat free-range or welfare-friendly animals, vastly outnumbers the actual production. In chicken meat, the number of chickens not in factory farms is two in every thousand — 99.8% of chickens produced in the US are in factory farms — yet the number who say they only eat free-range is maybe 10% of the population.

Peter Singer

Somewhat easier. In the EU and the UK you can get eggs properly labelled free-range. In the US it's quite easy to get eggs labelled cage-free, but cage-free doesn't mean free-range — they might still be confined in a big shed with thousands of birds. Here in Australia we now have producers who put the number of hens per hectare on the box. You can't call eggs free-range with more than 10,000 birds per hectare, and some are right at 10,000 while others have just 1,200 — obviously a significant difference in quality of life for the hens.

Peter Singer

Yes, absolutely. The unifying thread of the things I've worked on most intensively — not only as a philosopher but as an advocate — is trying to eliminate pointless or unnecessary suffering. The suffering of factory farming is pointless because it doesn't produce more food. The suffering of people in extreme poverty is unnecessary because we have the means to end it. And on a much smaller scale, the suffering of people who are terminally ill, who understand they're not going to survive very long and don't want to go through those last days or weeks, is completely unnecessary and pointless. I'm thinking of it from the point of view of those people who want to die, who are making a rational choice given that their prospects are very poor, and yet in many jurisdictions are still not able to have medical assistance in dying. I'm pleased to say that over the years I've worked on this, it has been legalized in more and more countries, starting with the Netherlands in the 1980s, and now a growing number of US states.

Peter Singer

I would advocate that under certain conditions — they need good reasons. I would not like to see anybody able to do this if they're just temporarily depressed with every prospect of recovering, or lovesick teenagers whose partner has broken up with them. We need a certain amount of paternalism here — not absolute autonomy overriding everything. But if they can give us good reasons, that's something I would allow them to choose.

Peter Singer

Yes. I retired from Princeton in 2024, and one thing that gave me more time to do was a podcast, with the Polish philosopher I mentioned, with whom I co-authored The Point of View of the Universe and a book on utilitarianism for Oxford's Very Short Introduction series. We're both interested in what it is to live well, and we're both hedonistic utilitarians presenting that point of view. But we thought it would be interesting to get a range of guests — people who have something to say about what enables people to live well, or who've just led interesting lives. We started with the late psychologist Daniel Kahneman, a Nobel laureate. We recently had Paul Simon the musician, and Judy Collins the folk singer, and Yuval Harari, author of Sapiens, and a range of people living more ordinary lives — some activists, like Ingrid Newkirk from PETA. We had Kakenya Ntaiya, a Maasai woman from Kenya who made a deal with her father: she would go through the genital mutilation ceremony typical for girls in her culture if he allowed her to go to high school, which girls usually didn't do — they usually married at 13 or 14. She ended up going to college in the United States and started a movement called Kakenya's Dream to give other girls that kind of future. So it's a wide range of people who've led rich and fulfilling lives.

Peter Singer

It's called Lives Well Lived. You can find it on Apple Podcasts, Spotify, or wherever you get your podcasts — including, of course, Mindscape.

Peter Singer

Thanks a lot, Sean. It's been great talking to you.