We all want to know how to live. That includes not only knowing how to get what we want, but knowing what to want, and what we should and shouldn’t do. Peter Singer is prepared to tell us, and because his advice would require most of us to change our lives, and because it is offered with such force and clarity, he is an important figure in moral philosophy. He has also had a larger practical impact on the world than any other philosopher of our time. His 1975 book, Animal Liberation, led to effective movements to reduce the suffering of animals in factory farming, scientific experiments, and the testing of commercial products such as cosmetics, and it has persuaded many people to become vegetarians to one degree or another.
Singer’s claims about what well-off people in affluent societies should do to help those living in poverty elsewhere in the world have had less effect so far, but he hopes to remedy that with his latest book, The Life You Can Save. “The ultimate purpose of this book,” he says, “is to reduce extreme poverty, not to make you feel guilty.” But making the reader feel guilty is one of his specialties, and a key to his effectiveness as a writer. Whether he is describing cruel and pointless experiments on heroin addiction in monkeys or the devastating effects of easily reparable obstetric fistulas on impoverished third-world women who have given birth in their teens, he acts on our emotions, and the impact is heightened by his calm, cerebral style.
Singer’s exchanges with critics in Peter Singer Under Fire cover the full range of his views, but I will start with what he says about affluence and poverty. The Life You Can Save repeats and develops an argument he originally offered in 1972, in an article that has probably been read by more students of moral philosophy than any other text, ancient or modern. He begins with an example: You are walking past a shallow pond, and you notice that a small child has fallen into the water and is about to drown. Should you wade in and rescue the child, even though it will ruin your shoes and get your clothes muddy?
Most people agree that anyone who didn’t rescue the child would be a moral monster. Even if the case is more demanding—the child has to be taken to a hospital, and that will make you miss a flight for which you have a nonrefundable ticket—it would still plainly be wrong not to save the child’s life. The next question is, what is the principle that explains why failing to rescue the child would be wrong? Singer argues that any plausible explanation of what is wrong in this case has vast implications. He offers …