Singer’s penchant for provocation extends to more mundane matters, like everyday charity. A recent article about Singer in The New York Times revealed that the philosopher gives one-fifth of his income to famine-relief agencies. ”From when I first saw pictures in newspapers of people starving, from when people asked you to donate some of your pocket money for collections at school,” he mused, ”I always thought, ‘Why that much — why not more?”’

Is it possible to quantify our charitable burden? In the following essay, Singer offers some unconventional thoughts about the ordinary American’s obligations to the world’s poor and suggests that even his own one-fifth standard may not be enough.

SINGER:  In the Brazilian film ”Central Station,” Dora is a retired schoolteacher who makes ends meet by sitting at the station writing letters for illiterate people. Suddenly she has an opportunity to pocket $1,000. All she has to do is persuade a homeless 9-year-old boy to follow her to an address she has been given. (She is told he will be adopted by wealthy foreigners.) She delivers the boy, gets the money, spends some of it on a television set and settles down to enjoy her new acquisition. Her neighbor spoils the fun, however, by telling her that the boy was too old to be adopted — he will be killed and his organs sold for transplantation. Perhaps Dora knew this all along, but after her neighbor’s plain speaking, she spends a troubled night. In the morning Dora resolves to take the boy back.

Suppose Dora had told her neighbor that it is a tough world, other people have nice new TV’s too, and if selling the kid is the only way she can get one, well, he was only a street kid. She would then have become, in the eyes of the audience, a monster. She redeems herself only by being prepared to bear considerable risks to save the boy.

At the end of the movie, in cinemas in the affluent nations of the world, people who would have been quick to condemn Dora if she had not rescued the boy go home to places far more comfortable than her apartment. In fact, the average family in the United States spends almost one-third of its income on things that are no more necessary to them than Dora’s new TV was to her. Going out to nice restaurants, buying new clothes because the old ones are no longer stylish, vacationing at beach resorts — so much of our income is spent on things not essential to the preservation of our lives and health. Donated to one of a number of charitable agencies, that money could mean the difference between life and death for children in need.

All of which raises a question: In the end, what is the ethical distinction between a Brazilian who sells a homeless child to organ peddlers and an American who already has a TV and upgrades to a better one — knowing that the money could be donated to an organization that would use it to save the lives of kids in need?

Of course, there are several differences between the two situations that could support different moral judgments about them. For one thing, to be able to consign a child to death when he is standing right in front of you takes a chilling kind of heartlessness; it is much easier to ignore an appeal for money to help children you will never meet. Yet for a utilitarian philosopher like myself — that is, one who judges whether acts are right or wrong by their consequences — if the upshot of the American’s failure to donate the money is that one more kid dies on the streets of a Brazilian city, then it is, in some sense, just as bad as selling the kid to the organ peddlers. But one doesn’t need to embrace my utilitarian ethic to see that, at the very least, there is a troubling incongruity in being so quick to condemn Dora for taking the child to the organ peddlers while, at the same time, not regarding the American consumer’s behavior as raising a serious moral issue.

In his 1996 book, ”Living High and Letting Die,” the New York University philosopher Peter Unger presented an ingenious series of imaginary examples designed to probe our intuitions about whether it is wrong to live well without giving substantial amounts of money to help people who are hungry, malnourished or dying from easily treatable illnesses like diarrhea. Here’s my paraphrase of one of these examples:

Bob is close to retirement. He has invested most of his savings in a very rare and valuable old car, a Bugatti, which he has not been able to insure. The Bugatti is his pride and joy. In addition to the pleasure he gets from driving and caring for his car, Bob knows that its rising market value means that he will always be able to sell it and live comfortably after retirement. One day when Bob is out for a drive, he parks the Bugatti near the end of a railway siding and goes for a walk up the track. As he does so, he sees that a runaway train, with no one aboard, is running down the railway track. Looking farther down the track, he sees the small figure of a child very likely to be killed by the runaway train. He can’t stop the train and the child is too far away to warn of the danger, but he can throw a switch that will divert the train down the siding where his Bugatti is parked. Then nobody will be killed — but the train will destroy his Bugatti. Thinking of his joy in owning the car and the financial security it represents, Bob decides not to throw the switch. The child is killed. For many years to come, Bob enjoys owning his Bugatti and the financial security it represents.

Now you, too, have the information you need to save a child’s life. How should you judge yourself if you don’t do it? Think again about Bob and his Bugatti. Unlike Dora, Bob did not have to look into the eyes of the child he was sacrificing for his own material comfort. The child was a complete stranger to him and too far away to relate to in an intimate, personal way. Unlike Dora, too, he did not mislead the child or initiate the chain of events imperiling him. In all these respects, Bob’s situation resembles that of people able but unwilling to donate to overseas aid and differs from Dora’s situation.

If you still think that it was very wrong of Bob not to throw the switch that would have diverted the train and saved the child’s life, then it is hard to see how you could deny that it is also very wrong not to send money to one of the organizations listed above. Unless, that is, there is some morally important difference between the two situations that I have overlooked.

Is it the practical uncertainties about whether aid will really reach the people who need it? Nobody who knows the world of overseas aid can doubt that such uncertainties exist. But Unger’s figure of $200 to save a child’s life was reached after he had made conservative assumptions about the proportion of the money donated that will actually reach its target.

One genuine difference between Bob and those who can afford to donate to overseas aid organizations but don’t is that only Bob can save the child on the tracks, whereas there are hundreds of millions of people who can give $200 to overseas aid organizations. The problem is that most of them aren’t doing it. Does this mean that it is all right for you not to do it?

Suppose that there were more owners of priceless vintage cars — Carol, Dave, Emma, Fred and so on, down to Ziggy — all in exactly the same situation as Bob, with their own siding and their own switch, all sacrificing the child in order to preserve their own cherished car. Would that make it all right for Bob to do the same? To answer this question affirmatively is to endorse follow-the-crowd ethics — the kind of ethics that led many Germans to look away when the Nazi atrocities were being committed. We do not excuse them because others were behaving no better.

We seem to lack a sound basis for drawing a clear moral line between Bob’s situation and that of any reader of this article with $200 to spare who does not donate it to an overseas aid agency. These readers seem to be acting at least as badly as Bob was acting when he chose to let the runaway train hurtle toward the unsuspecting child. In the light of this conclusion, I trust that many readers will reach for the phone and donate that $200. Perhaps you should do it before reading further.

Now that you have distinguished yourself morally from people who put their vintage cars ahead of a child’s life, how about treating yourself and your partner to dinner at your favorite restaurant? But wait. The money you will spend at the restaurant could also help save the lives of children overseas! True, you weren’t planning to blow $200 tonight, but if you were to give up dining out just for one month, you would easily save that amount. And what is one month’s dining out, compared to a child’s life? There’s the rub. Since there are a lot of desperately needy children in the world, there will always be another child whose life you could save for another $200. Are you therefore obliged to keep giving until you have nothing left? At what point can you stop?

Hypothetical examples can easily become farcical. Consider Bob. How far past losing the Bugatti should he go? Imagine that Bob had got his foot stuck in the track of the siding, and if he diverted the train, then before it rammed the car it would also amputate his big toe. Should he still throw the switch? What if it would amputate his foot? His entire leg?

As absurd as the Bugatti scenario gets when pushed to extremes, the point it raises is a serious one: only when the sacrifices become very significant indeed would most people be prepared to say that Bob does nothing wrong when he decides not to throw the switch. Of course, most people could be wrong; we can’t decide moral issues by taking opinion polls. But consider for yourself the level of sacrifice that you would demand of Bob, and then think about how much money you would have to give away in order to make a sacrifice that is roughly equal to that. It’s almost certainly much, much more than $200. For most middle-class Americans, it could easily be more like $200,000.

Isn’t it counterproductive to ask people to do so much? Don’t we run the risk that many will shrug their shoulders and say that morality, so conceived, is fine for saints but not for them? I accept that we are unlikely to see, in the near or even medium-term future, a world in which it is normal for wealthy Americans to give the bulk of their wealth to strangers. When it comes to praising or blaming people for what they do, we tend to use a standard that is relative to some conception of normal behavior. Comfortably off Americans who give, say, 10 percent of their income to overseas aid organizations are so far ahead of most of their equally comfortable fellow citizens that I wouldn’t go out of my way to chastise them for not doing more. Nevertheless, they should be doing much more, and they are in no position to criticize Bob for failing to make the much greater sacrifice of his Bugatti.

At this point various objections may crop up. Someone may say: ”If every citizen living in the affluent nations contributed his or her share I wouldn’t have to make such a drastic sacrifice, because long before such levels were reached, the resources would have been there to save the lives of all those children dying from lack of food or medical care. So why should I give more than my fair share?” Another, related, objection is that the Government ought to increase its overseas aid allocations, since that would spread the burden more equitably across all taxpayers.

Yet the question of how much we ought to give is a matter to be decided in the real world — and that, sadly, is a world in which we know that most people do not, and in the immediate future will not, give substantial amounts to overseas aid agencies. We know, too, that at least in the next year, the United States Government is not going to meet even the very modest Umited Nations-recommended target of 0.7 percent of gross national product; at the moment it lags far below that, at 0.09 percent, not even half of Japan’s 0.22 percent or a tenth of Denmark’s 0.97 percent. Thus, we know that the money we can give beyond that theoretical ”fair share” is still going to save lives that would otherwise be lost. While the idea that no one need do more than his or her fair share is a powerful one, should it prevail if we know that others are not doing their fair share and that children will die preventable deaths unless we do more than our fair share? That would be taking fairness too far.

Thus, this ground for limiting how much we ought to give also fails. In the world as it is now, I can see no escape from the conclusion that each one of us with wealth surplus to his or her essential needs should be giving most of it to help people suffering from poverty so dire as to be life-threatening. That’s right: I’m saying that you shouldn’t buy that new car, take that cruise, redecorate the house or get that pricey new suit. After all, a $1,000 suit could save five children’s lives.

Now, evolutionary psychologists tell us that human nature just isn’t sufficiently altruistic to make it plausible that many people will sacrifice so much for strangers. On the facts of human nature, they might be right, but they would be wrong to draw a moral conclusion from those facts. If it is the case that we ought to do things that, predictably, most of us won’t do, then let’s face that fact head-on. Then, if we value the life of a child more than going to fancy restaurants, the next time we dine out we will know that we could have done something better with our money. If that makes living a morally decent life extremely arduous, well, then that is the way things are. If we don’t do it, then we should at least know that we are failing to live a morally decent life — not because it is good to wallow in guilt but because knowing where we should be going is the first step toward heading in that direction.

When Bob first grasped the dilemma that faced him as he stood by that railway switch, he must have thought how extraordinarily unlucky he was to be placed in a situation in which he must choose between the life of an innocent child and the sacrifice of most of his savings. But he was not unlucky at all. We are all in that situation.