Bitten by the moral bulldog

Among the thick and shiny pages of a recent edition of Elle magazine, between the advertisements for Movado watches and Calvin Klein swimwear, lies the name of Peter Singer. He graces an article that discusses how much of our personal incomes we should give to developing countries: 1 per cent, as donated by the governments of the western world? a more generous biblical tithe? or a Singer-inspired 20 per cent?

Elle magazine is just the kind of showcase in which Singer is delighted to exhibit his ideas. Over his 30 years as a moral philosopher, he has striven to provide answers to particularly modern ethical problems. This engagement with "real" issues was rather a departure for moral philosophy when Singer emerged in the 1970s. Philosophers, imprisoned by the restrictions of logical positivism and linguistic analysis, believed the messy troubles of humanity to be distinctly unreal as moral questions. At first, Singer was thus a reluctant philosopher. He felt the subject was too "detached and remote an occupation". Nevertheless he took it up, and he shook it up as well. He did not invent a profound new theory but instead became a philosopher-bulldog, snapping at the world's feet with his impartialist, utilitarian viewpoint. He also turned on his peers, urging them to fulfil their duty to illuminate the public's moral darknesses rather than to add volumes more to discussion of abstract issues.

Unsanctifying Human Life is a collection of his "greatest hits" essays. For those who want to grasp essential Singer, it provides a vivid, one-volume summary of his work. The collection covers most of his philosophical forays, into issues ranging from animal welfare to the rights of infants. But it does more than this. It has sufficient diversity to reflect something of Singer's personality and the sweep of his audiences, whom he cajoles with tools ranging from tight argument to passion. Is there any other philosopher whose collected works range from an essay on "Sidgwick and the reflective equilibrium" to a recipe for red lentil dahl?

The introduction, by editor and long-time collaborator Helga Kuhse, provides a much-needed rationale for the choice of articles, which span a formidable range of intellectual levels and audiences. The book begins with some of the most abstract contributions, chosen to demonstrate how Singer has challenged moral philosophers to find workable solutions to their all-absorbing conundrums so that they can then move on to more useful matters. The first piece, "The triviality of the debate over 'is-ought' and the definition of 'moral'", published in the early 1970s when Singer was , mocks philosophers' preoccupation with the issue of the relationship between statements of fact and moral judgement. Singer finds a working solution within a few thousand words and concludes: "My complaint is that what should be regarded as something to be got out of the way in the introduction to a work of moral philosophy has become the subject matter of almost the whole of moral philosophy in the English-speaking world."

Once topics such as these have been dispatched, the collection moves on to display the public issues over which Singer has exerted so much influence.

One, in particular, gives a flavour of the man: his description of his attempts to lecture on bioethics in Germany in 1989. The story is one of demonstrations, lecture cancellations and even physical attack. His disappointment at the inability of a supposedly liberal democracy to discuss bioethics is mildly astonishing given that his subject matter was euthanasia for severely disabled newborn infants. But then one has the sense that disappointment has been a growing sensation over the decades for Singer, who wanted to change the world, but recently said that the influence of his writings has "mostly been minor".

Kuhse points out that the influence of Singer, now professor of bioethics at the University Center for Human Values, Princeton University, has been rather greater than this despondent assessment implies. He may have changed more lives than any other 20th-century philosopher, she argues. His book Animal Liberation , published in 1975, sold more than half a million copies and is credited with having triggered the modern animal rights movement. His article "Famine, affluence and morality", reproduced in this volume, is considered by some to be one of the most famous articles in moral philosophy. And his book Practical Ethics is one of the most widely used texts in applied ethics. Inevitably he is notorious rather than famous in some quarters, particularly religious ones. This is because of his relentless pursuit of his particular brand of utilitarianism - applied at first to animal welfare and our obligations towards the less well-off citizens of the global village but later also to our treatment of the terminally ill, retarded infants and embryos created by in vitro fertilisation.

Singer's central principle governs who should belong to the moral club. Rather than erect the boundary firmly around the human species - so that every human should be given moral consideration but no other animals - he redrew the line around those with the capacity to suffer pain. If you can feel pain, your interest in avoiding it should be considered by others, and that applies to many species other than our own. Conversely, if you are a human who cannot feel pain - an embryo, a foetus up to a certain age, or in a persistent vegetative state - you no longer belong within the moral circle.

In "Killing humans and killing animals", Singer addresses issues not of pain but of life and death. He says that those with the mental wherewithal to see themselves as existing over time belong to a kind of inner sanctum within this moral circle. They qualify as "persons", and it is not only wrong to cause them pain but also to take their lives. Normal adult humans, and some other animals such as the great apes, qualify as persons. Newborn infants and the severely brain-damaged do not.

Each article takes the reader more deeply into the consequences of such thoughts. In the section from which the book takes its name, we reach the most controversial pieces. Here, Singer claims that the doctrine of the sanctity of human life is an obfuscation. It absorbs much-needed funds for health care; permits painful operations on severely disabled infants who cannot protest; and keeps those alive who would be better off (or, at least, not worse off) dead. It leads people into insoluble problems regarding embryos produced by in vitro fertilisation and obstructs the efforts of the terminally ill to end their own lives. It leads us to draw a distinction between letting a patient die and actively killing him, though these, according to Singer, are morally equivalent.

These views have disturbed and disgusted many, but Singer believes it is the role of philosophers to question the basic assumptions of our age. He is all too aware that philosophical argument is only one of the available tools.

Thus he includes an account of the history of the concept of the sanctity of human life, in order to demonstrate that it is "a legacy of attitudes and beliefs that were once widespread but which few people would now try to defend". This analysis, he says, is not philosophy, but a "softening-up operation on your intuitions. Unfortunately, when a doctrine is very deeply embedded in people's moral institutions, it is sometimes necessary to do more than refute the doctrine in order to convince people that it is false."

The volume winds down with some more miscellaneous articles: the outline of a vegetarian philosophy, a consideration of environmental values and a discussion of the need to find new, non-materialist values by which people can live their lives.

Singer can sometimes seem to have lost all touch with the basic human emotions that drive many of our moral decisions. Is it entirely wrong to spend money on the private schooling of one's own children rather than on preventing the starvation of a stranger's children in Bengal? Or to rescue the most socially useful victim of a house fire while leaving one's own mother to burn? In recent years, Singer has softened his strictly impartialist approach with an acknowledgement that there is a role for partialism, for "habits or intuitive ways of thinking that can be expected, over a lifetime, to do the most good".

Critics have nevertheless been able to exploit Singer's impartialist stance by scrutinising his life to see if it matches up to his preachings. One example they have seized on is the proportion of income that he donates to the poor - 20 per cent. It may be a substantial fraction, but it is far less than Singer calls for in his writings. There, he has argued that we should give until the point of marginal utility - until to give more would reduce us to the shanty town, dollar-a-day existence of our beneficiaries. Still, there is perhaps more integrity to be found in stating the moral imperative and failing to live up to it, than in inventing a convenient moral argument to support one's own shortcomings.

Aisling Irwin is a freelance journalist specialising in science and environmental issues.