PETER SINGER

Peter Singer (b. 1946) is the Ira W. DeCamp Professor of Bioethics at Princeton University. A native of Australia, he is a graduate of the University of Melbourne and Oxford University and the author or editor of more than two dozen books, including Animal Liberation (1975), Practical Ethics (1979), Rethinking Life and Death (1995), and One World: The Ethics of Globalization (2002). He has written on a variety of ethical issues, but he is especially known for caring about the welfare of animals.

This essay originally appeared in the New York Review of Books (April 5, 1973), as a review of Animals, Men and Morals, edited by Stanley and Roslind Godlovitch and John Harris.

Animal Liberation

I

We are familiar with Black Liberation, Gay Liberation, and a variety of other movements. With Women’s Liberation some thought we had come to the end of the road. Discrimination on the basis of sex, it has been said, is the last form of discrimination that is universally accepted and practiced without pretense, even in those liberal circles which have long prided themselves on their freedom from racial discrimination. But one should always be wary of talking of “the last remaining form of discrimination.” If we have learned anything from the liberation movements, we should have learned how difficult it is to be aware of the ways in which we discriminate until they are forcefully pointed out to us. A liberation movement demands an expansion of our moral horizons, so that practices that were previously regarded as natural and inevitable are now seen as intolerable.

206

Animals, Men and Morals is a manifesto for an Animal Liberation movement. The contributors to the book may not all see the issue this way. They are a varied group. Philosophers, ranging from professors to graduate students, make up the largest contingent. There are five of them, including the three editors, and there is also an extract from the unjustly neglected German philosopher with an English name, Leonard Nelson, who died in 1927. There are essays by two novelist/critics, Brigid Brophy and Maureen Duffy, and another by Muriel the Lady Dowding, widow of Dowding of Battle of Britain fame and the founder of “Beauty without Cruelty,” a movement that campaigns against the use of animals for furs and cosmetics. The other pieces are by a psychologist, a botanist, a sociologist, and Ruth Harrison, who is probably best described as a professional campaigner for animal welfare.

Whether or not these people, as individuals, would all agree that they are launching a liberation movement for animals, the book as a whole amounts to no less. It is a demand for a complete change in our attitudes to nonhumans. It is a demand that we cease to regard the exploitation of other species as natural and inevitable, and that, instead, we see it as a continuing moral outrage. Patrick Corbett, Professor of Philosophy at Sussex University, captures the spirit of the book in his closing words:

We require now to extend the great principles of liberty, equality, and fraternity over the lives of animals. Let animal slavery join human slavery in the graveyard of the past.

The reader is likely to be skeptical. “Animal Liberation” sounds more like a parody of liberation movements than a serious objective. The reader may think: We support the claims of blacks and women for equality because blacks and women really are equal to whites and males — equal in intelligence and in abilities, capacity for leadership, rationality, and so on. Humans and nonhumans obviously are not equal in these respects. Since justice demands only that we treat equals equally, unequal treatment of humans and nonhumans cannot be an injustice.

5 This is a tempting reply, but a dangerous one. It commits the nonracist and nonsexist to a dogmatic belief that blacks and women really are just as intelligent, able, etc., as whites and males — and no more. Quite possibly this happens to be the case. Certainly attempts to prove that racial or sexual differences in these respects have a genetic origin have not been conclusive. But do we really want to stake our demand for equality on the assumption that there are no genetic differences of this kind between the different races or sexes? Surely the appropriate response to those who claim to have found evidence for such genetic differences is not to stick to the belief that there are no differences, whatever the evidence to the contrary; rather one should be clear that the claim to equality does not depend on IQ. Moral equality is distinct from factual equality. Otherwise it would be nonsense to talk to the equality of human beings, since humans, as individuals, obviously differ in intelligence and almost any ability one cares to name. If possessing greater intelligence does not entitle one human to exploit another, why should it entitle humans to exploit nonhumans?

207

Jeremy Bentham expressed the essential basis of equality in his famous formula: “Each to count for one and none for more than one.” In other words, the interests of every being that has interests are to be taken into account and treated equally with the like interests of any other being. Other moral philosophers, before and after Bentham, have made the same point in different ways. Our concern for others must not depend on whether they possess certain characteristics, though just what that concern involves may, of course, vary according to such characteristics.

Bentham, incidentally, was well aware that the logic of the demand for racial equality did not stop at the equality of humans. He wrote:

The day may come when the rest of the animal creation may acquire those rights which never could have been withholden from them but by the hand of tyranny. The French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormentor. It may one day come to be recognized that the number of the legs, the villosity of the skin, or the termination of the os sacrum, are reasons equally insufficient for abandoning a sensitive being to the same fate. What else is it that should trace the insuperable line? Is it the faculty of reason, or perhaps the faculty of discourse? But a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week, or even a month, old. But suppose they were otherwise, what would it avail? The question is not, Can they reason? nor Can they talk? but, Can they suffer?¹

Surely Bentham was right. If a being suffers, there can be no moral justification for refusing to take that suffering into consideration, and, indeed, to count it equally with the like suffering (if rough comparisons can be made) of any other being.

So the only question is: Do animals other than man suffer? Most people agree unhesitatingly that animals like cats and dogs can and do suffer, and this seems also to be assumed by those laws that prohibit wanton cruelty to such animals. Personally, I have no doubt at all about this and find it hard to take seriously the doubts that a few people apparently do have. The editors and contributors of Animals, Men and Morals seem to feel the same way, for although the question is raised more than once, doubts are quickly dismissed each time. Nevertheless, because this is such a fundamental point, it is worth asking what grounds we have for attributing suffering to other animals.

It is best to begin by asking what grounds any individual human has for supposing that other humans feel pain. Since pain is a state of consciousness, a “mental event,” it can never be directly observed. No observations, whether behavioral signs such as writhing or screaming or physiological or neurological recordings, are observations of pain itself. Pain is something one feels, and one can only infer that others are feeling it from various external indications. The fact that only philosophers are ever skeptical about whether other humans feel pain shows that we regard such inference as justifiable in the case of humans.

208

10 Is there any reason why the same inference should be unjustifiable for other animals? Nearly all the external signs which lead us to infer pain in other humans can be seen in other species, especially “higher” animals such as mammals and birds. Behavioral signs — writhing, yelping, or other forms of calling, attempts to avoid the source of pain, and many others — are present. We know, too, that these animals are biologically similar in the relevant respects, having nervous systems like ours which can be observed to function as ours do.

So the grounds for inferring that these animals can feel pain are nearly as good as the grounds for inferring other humans do. Only nearly, for there is one behavioral sign that humans have but nonhumans, with the exception of one or two specially raised chimpanzees, do not have. This, of course, is a developed language. As the quotation from Bentham indicates, this has long been regarded as an important distinction between man and other animals. Other animals may communicate with each other, but not in the way we do. Following Chomsky,² many people now mark this distinction by saying that only humans communicate in a form that is governed by rules of syntax. (For the purposes of this argument, linguists allow those chimpanzees who have learned a syntactic sign language to rank as honorary humans.) Nevertheless, as Bentham pointed out, this distinction is not relevant to the question of how animals ought to be treated, unless it can be linked to the issue of whether animals suffer.

This link may be attempted in two ways. First, there is a hazy line of philosophical thought, stemming perhaps from some doctrines associated with Wittgenstein, which maintains that we cannot meaningfully attribute states of consciousness to beings without language. I have not seen this argument made explicit in print, though I have come across it in conversation. This position seems to me very implausible, and I doubt that it would be held at all if it were not thought to be a consequence of a broader view of the significance of language. It may be that the use of a public, rule-governed language is a precondition of conceptual thought. It may even be, although personally I doubt it, that we cannot meaningfully speak of a creature having an intention unless that creature can use a language. But states like pain, surely, are more primitive than either of these, and seem to have nothing to do with language.

Indeed, as Jane Goodall points out in her study of chimpanzees, when it comes to the expression of feelings and emotions, humans tend to fall back on nonlinguistic modes of communication which are often found among apes, such as a cheering pat on the back, an exuberant embrace, a clasp of hands, and so on.³ Michael Peters makes a similar point in his contribution to Animals, Men and Morals when he notes that the basic signals we use to convey pain, fear, sexual arousal, and so on are not specific to our species. So there seems to be no reason at all to believe that a creature without language cannot suffer.

The second, and more easily appreciated way of linking language and the existence of pain is to say that the best evidence that we can have that another creature is in pain is when he tells us that he is. This is a distinct line of argument, for it is not being denied that a non-language-user conceivably could suffer, but only that we could know that he is suffering. Still, this line of argument seems to me to fail, and for reasons similar to those just given. “I am in pain” is not the best possible evidence that the speaker is in pain (he might be lying) and it is certainly not the only possible evidence. Behavioral signs and knowledge of the animal’s biological similarity to ourselves together provide adequate evidence that animals do suffer. After all, we would not accept linguistic evidence if it contradicted the rest of the evidence. If a man was severely burned, and behaved as if he were in pain, writhing, groaning, being very careful not to let his burned skin touch anything, and so on, but later said he had not been in pain at all, we would be more likely to conclude that he was lying or suffering from amnesia than that he had not been in pain.

209

15 Even if there were stronger grounds for refusing to attribute pain to those who do not have a language, the consequences of this refusal might lead us to examine these grounds unusually critically. Human infants, as well as some adults, are unable to use language. Are we to deny that a year-old infant can suffer? If not, how can language be crucial? Of course, most parents can understand the responses of even very young infants better than they understand the responses of other animals, and sometimes infant responses can be understood in the light of later development.

This, however, is just a fact about the relative knowledge we have of our own species and other species, and most of this knowledge is simply derived from closer contact. Those who have studied the behavior of other animals soon learn to understand their responses at least as well as we understand those of an infant. (I am not referring to Jane Goodall’s and other well-known studies of apes. Consider, for example, the degree of understanding achieved by Tinbergen from watching herring gulls.⁴) Just as we can understand infant human behavior in the light of adult human behavior, so we can understand the behavior of other species in the light of our own behavior (and sometimes we can understand our own behavior better in the light of the behavior of other species).

The grounds we have for believing that other mammals and birds suffer are, then, closely analogous to the grounds we have for believing that other humans suffer. It remains to consider how far down the evolutionary scale this analogy holds. Obviously it becomes poorer when we get further away from man. To be more precise would require a detailed examination of all that we know about other forms of life. With fish, reptiles, and other vertebrates the analogy still seems strong, with molluscs like oysters it is much weaker. Insects are more difficult, and it may be that in our present state of knowledge we must be agnostic about whether they are capable of suffering.

If there is no moral justification for ignoring suffering when it occurs, and it does occur in other species, what are we to say of our attitudes toward these other species? Richard Ryder, one of the contributors to Animals, Men and Morals, uses the term “speciesism” to describe the belief that we are entitled to treat members of other species in a way in which it would be wrong to treat members of our own species. The term is not euphonious, but it neatly makes the analogy with racism. The nonracist would do well to bear the analogy in mind when he is inclined to defend human behavior toward nonhumans. “Shouldn’t we worry about improving the lot of our own species before we concern ourselves with other species?” he may ask. If we substitute “race” for “species” we shall see that the question is better not asked. “Is a vegetarian diet nutritionally adequate?” resembles the slaveowner’s claim that he and the whole economy of the South would be ruined without slave labor. There is even a parallel with skeptical doubts about whether animals suffer, for some defenders of slavery professed to doubt whether blacks really suffer in the way whites do.

210

I do not want to give the impression, however, that the case for Animal Liberation is based on the analogy with racism and no more. On the contrary, Animals, Men and Morals describes the various ways in which humans exploit nonhumans, and several contributors consider the defenses that have been offered, including the defense of meat-eating mentioned in the last paragraph. Sometimes the rebuttals are scornfully dismissive, rather than carefully designed to convince the detached critic. This may be a fault, but it is a fault that is inevitable, given the kind of book this is. The issue is not one on which one can remain detached. As the editors state in their Introduction:

Once the full force of moral assessment has been made explicit there can be no rational excuse left for killing animals, be they killed for food, science, or sheer personal indulgence. We have not assembled this book to provide the reader with yet another manual on how to make brutalities less brutal. Compromise, in the traditional sense of the term, is simple unthinking weakness when one considers the actual reasons for our crude relationships with the other animals.

20 The point is that on this issue there are few critics who are genuinely detached. People who eat pieces of slaughtered nonhumans every day find it hard to believe that they are doing wrong; and they also find it hard to imagine what else they could eat. So for those who do not place nonhumans beyond the pale of morality, there comes a stage when further argument seems pointless, a stage at which one can only accuse one’s opponent of hypocrisy and reach for the sort of sociological account of our practices and the way we defend them that is attempted by David Wood in his contribution to his book. On the other hand, to those unconvinced by the arguments, and unable to accept that they are merely rationalizing their dietary preferences and their fear of being thought peculiar, such sociological explanations can only seem insultingly arrogant.

II

The logic of speciesism is most apparent in the practice of experimenting on nonhumans in order to benefit humans. This is because the issue is rarely obscured by allegations that nonhumans are so different from humans that we cannot know anything about whether they suffer. The defender of vivisection cannot use this argument because he needs to stress the similarities between man and other animals in order to justify the usefulness to the former of experiments on the latter. The researcher who makes rats choose between starvation and electric shocks to see if they develop ulcers (they do) does so because he knows that the rat has a nervous system very similar to man’s, and presumably feels an electric shock in a similar way.

Richard Ryder’s restrained account of experiments on animals made me angrier with my fellow men than anything else in this book. Ryder, a clinical psychologist by profession, himself experimented on animals before he came to hold the view he puts forward in his essay. Experimenting on animals is now a large industry, both academic and commercial. In 1969, more than 5 million experiments were performed in Britain, the vast majority without anesthetic (though how many of these involved pain is not known). There are no accurate U.S. figures, since there is no federal law on the subject, and in many cases no state law either. Estimates vary from 20 million to 200 million. Ryder suggests that 80 million may be the best guess. We tend to think that this is all for vital medical research, but of course it is not. Huge numbers of animals are used in university departments from Forestry to Psychology, and even more are used for commercial purposes, to test whether cosmetics can cause skin damage, or shampoos eye damage, or to test food additives or laxatives or sleeping pills or anything else.

211

A standard test for foodstuffs is the “LD50.” The object of this test is to find the dosage level at which 50 percent of the test animals will die. This means that nearly all of them will become very sick before finally succumbing or surviving. When the substance is a harmless one, it may be necessary to force huge doses down the animals, until in some cases sheer volume or concentration causes death.

Ryder gives a selection of experiments, taken from recent scientific journals. I will quote two, not for the sake of indulging in gory details, but in order to give an idea of what normal researchers think they may legitimately do to other species. The point is not that the individual researchers are cruel men, but that they are behaving in a way that is allowed by our speciesist attitudes. As Ryder points out, even if only 1 percent of the experiments involve severe pain, that is 50,000 experiments in Britain each year, or nearly 150 every day (and about fifteen times as many in the United States, if Ryder’s guess is right). Here then are two experiments:

O. S. Ray and R. J. Barrett of Pittsburgh gave electric shocks to the feet of 1,042 mice. They then caused convulsions by giving more intense shocks through cup-shaped electrodes applied to the animals’ eyes or through pressure spring clips attached to their ears. Unfortunately some of the mice who “successfully completed Day One training were found sick or dead prior to testing on Day Two.” [Journal of Comparative and Physiological Psychology, 1969, vol. 67, pp. 110–116]

At the National Institute for Medical Research, Mill Hill, London, W. Feldberg and S. L. Sherwood injected chemicals into the brains of cats — “with a number of widely different substances, recurrent patterns of reaction were obtained. Retching, vomiting, defecation, increased salivation and greatly accelerated respiration leading to panting were common features.” . . .

The injection into the brain of a large dose of Tubocuraine caused the cat to jump “from the table to the floor and then straight into its cage, where it started calling more and more noisily whilst moving about restlessly and jerkily . . . finally the cat fell with legs and neck flexed, jerking in rapid clonic movements, the condition being that of a major [epileptic] convulsion . . . within a few seconds the cat got up, ran for a few yards at high speed, and fell in another fit. The whole process was repeated several times within the next ten minutes, during which the cat lost faeces and foamed at the mouth.”

212

This animal finally died thirty-five minutes after the brain injection. [Journal of Physiology, 1954, vol. 123, pp. 148–167]

25 There is nothing secret about these experiments. One has only to open any recent volume of a learned journal, such as the Journal of Comparative and Physiological Psychology, to find full descriptions of experiments of this sort, together with the results obtained — results that are frequently trivial and obvious. The experiments are often supported by public funds.

It is a significant indication of the level of acceptability of these practices that, although these experiments are taking place at this moment on university campuses throughout the country, there has, so far as I know, not been the slightest protest from the student movement. Students have been rightly concerned that their universities should not discriminate on grounds of race or sex, and that they should not serve the purposes of the military or big business. Speciesism continues undisturbed, and many students participate in it. There may be a few qualms at first, but since everyone regards it as normal, and it may even be a required part of a course, the student soon becomes hardened and, dismissing his earlier feelings as “mere sentiment,” comes to regard animals as statistics rather than sentient beings with interests that warrant consideration.

Argument about vivisection has often missed the point because it has been put in absolutist terms: Would the abolitionist be prepared to let thousands die if they could be saved by experimenting on a single animal? The way to reply to this purely hypothetical question is to pose another: Would the experimenter be prepared to experiment on a human orphan under six months old, if it were the only way to save many lives? (I say “orphan” to avoid the complication of parental feelings, although in doing so I am being overfair to the experimenter, since the nonhuman subjects of experiments are not orphans.) A negative answer to this question indicates that the experimenter’s readiness to use nonhumans is simple discrimination, for adult apes, cats, mice, and other mammals are more conscious of what is happening to them, more self-directing, and, so far as we can tell, just as sensitive to pain as a human infant. There is no characteristic that human infants possess that adult mammals do not have to the same or a higher degree.

(It might be possible to hold that what makes it wrong to experiment on a human infant is that the infant will in time develop into more than the nonhuman, but one would then, to be consistent, have to oppose abortion, and perhaps contraception, too, for the fetus and the egg and sperm have the same potential as the infant. Moreover, one would still have no reason for experimenting on a nonhuman rather than a human with brain damage severe enough to make it impossible for him to rise above infant level.)

The experimenter, then, shows a bias for his own species whenever he carries out an experiment on a nonhuman for a purpose that he would not think justified him in using a human being at an equal or lower level of sentience, awareness, ability to be self-directing, etc. No one familiar with the kind of results yielded by these experiments can have the slightest doubt that if this bias were eliminated the number of experiments performed would be zero or very close to it.

213

III

30 If it is vivisection that shows the logic of speciesism most clearly, it is the use of other species for food that is at the heart of our attitudes toward them. Most of Animals, Men and Morals is an attack on meat eating — an attack which is based solely on concern for nonhumans, without reference to arguments derived from consideration of ecology, macrobiotics, health, or religion.

The idea that nonhumans are utilities, means to our ends, pervades our thought. Even conservationists who are concerned about the slaughter of wildfowl but not about the vastly greater slaughter of chickens for our tables are thinking in this way — they are worried about what we would lose if there were less wildlife. Stanley Godlovitch, pursuing the Marxist idea that our thinking is formed by the activities we undertake in satisfying our needs, suggests that man’s first classification of his environment was into Edibles and Inedibles. Most animals came into the first category, and there they have remained.

Man may always have killed other species for food, but he has never exploited them so ruthlessly as he does today. Farming has succumbed to business methods, the objective being to get the highest possible ratio of output (meat, eggs, milk) to input (fodder, labor costs, etc.). Ruth Harrison’s essay “On Factory Farming” gives an account of some aspects of modern methods, and of the unsuccessful British campaigns for effective controls, a campaign which was sparked off by her Animal Machines (London: Stuart, 1964).

Her article is in no way a substitute for her earlier book. This is a pity since, as she says, “Farm produce is still associated with mental pictures of animals browsing in the fields . . . of hens having a last forage before going to roost. . . .” Yet neither in her article nor elsewhere in Animals, Men and Morals is this false image replaced by a clear idea of the nature and extent of factory farming. We learn of this only indirectly, when we hear of the code of reform proposed by an advisory committee set up by the British government.

Among the proposals, which the government refused to implement on the grounds that they were too idealistic, were: “Any animal should at least have room to turn around freely.”

35 Factory farm animals need liberation in the most literal sense. Veal calves are kept in stalls 5 feet by 2 feet. They are usually slaughtered when about four months old, and have been too big to turn in their stalls for at least a month. Intensive beef herds, kept in stalls only proportionately larger for much longer periods, account for a growing percentage of beef production. Sows are often similarly confined when pregnant, which, because of artificial methods of increasing fertility, can be most of the time. Animals confined in this way do not waste food by exercising, nor do they develop unpalatable muscle.

“A dry bedded area should be provided for all stock.” Intensively kept animals usually have to stand and sleep in slatted floors without straw, because this makes cleaning easier.

“Palatable roughage must be readily available to all calves after one week of age.” In order to produce the pale veal housewives are said to prefer, calves are fed on an all-liquid diet until slaughter, even though they are long past the age at which they would normally eat grass. They develop a craving for roughage, evidenced by attempts to gnaw wood from their stalls. (For the same reason, their diet is deficient in iron.)

214

“Battery cages for poultry should be large enough for a bird to be able to stretch one wing at a time.” Under current British practice, a cage for four or five laying hens has a floor area of 20 inches by 18 inches, scarcely larger than a double page of the New York Review of Books. In this space, on a sloping wire floor (sloping so the eggs roll down, wire so the dung drips through) the birds live for a year or eighteen months while artificial lighting and temperature conditions combine with drugs in their food to squeeze the maximum number of eggs out of them. Table birds are also sometimes kept in cages. More often they are reared in sheds, no less crowded. Under these conditions all the birds’ natural activities are frustrated, and they develop “vices” such as pecking each other to death. To prevent this, beaks are often cut off, and the sheds kept dark.

How many of those who support factory farming by buying its produce know anything about the way it is produced? How many have heard something about it, but are reluctant to check up for fear that it will make them uncomfortable? To nonspeciesists, the typical consumer’s mixture of ignorance, reluctance to find out the truth, and vague belief that nothing really bad could be allowed seems analogous to the attitudes of “decent Germans” to the death camps.

40 There are, of course, some defenders of factory farming. Their arguments are considered, though again rather sketchily, by John Harris. Among the most common: “Since they have never known anything else, they don’t suffer.” This argument will not be put by anyone who knows anything about animal behavior, since he will know that not all behavior has to be learned. Chickens attempt to stretch wings, walk around, scratch, and even dustbathe or build a nest, even though they have never lived under conditions that allowed these activities. Calves can suffer from maternal deprivation no matter at what age they were taken from their mothers. “We need these intensive methods to provide protein for a growing population.” As ecologists and famine relief organizations know, we can produce far more protein per acre if we grow the right vegetable crop, soy beans for instance, than if we use the land to grow crops to be converted into protein by animals who use nearly 90 percent of the protein themselves, even when unable to exercise.

There will be many readers of this book who will agree that factory farming involves an unjustifiable degree of exploitation of sentient creatures, and yet will want to say that there is nothing wrong with rearing animals for food, provided it is done “humanely.” These people are saying, in effect, that although we should not cause animals to suffer, there is nothing wrong with killing them.

There are two possible replies to this view. One is to attempt to show that this combination of attitudes is absurd. Roslind Godlovitch takes this course in her essay, which is an examination of some common attitudes to animals. She argues that from the combination of “animal suffering is to be avoided” and “there is nothing wrong with killing animals” it follows that all animal life ought to be exterminated (since all sentient creatures will suffer to some degree at some point in their lives). Euthanasia is a contentious issue only because we place some value on living. If we did not, the least amount of suffering would justify it. Accordingly, if we deny that we have a duty to exterminate all animal life, we must concede that we are placing some value on animal life.

215

This argument seems to me valid, although one could still reply that the value of animal life is to be derived from the pleasures that life can have for them, so that, provided their lives have a balance of pleasure over pain, we are justified in rearing them. But this would imply that we ought to produce animals and let them live as pleasantly as possible, without suffering.

At this point, one can make the second of the two possible replies to the view that rearing and killing animals for food is all right so long as it is done humanely. This second reply is that so long as we think that a nonhuman may be killed simply so that a human can satisfy his taste for meat, we are still thinking of nonhumans as means rather than as ends in themselves. The factory farm is nothing more than the application of technology to this concept. Even traditional methods involve castration, the separation of mothers and their young, the breaking up of herds, branding or earpunching, and of course transportation to the abattoirs and the final moments of terror when the animal smells blood and senses danger. If we were to try rearing animals so that they lived and died without suffering, we should find that to do so on anything like the scale of today’s meat industry would be a sheer impossibility. Meat would become the prerogative of the rich.

45 I have been able to discuss only some of the contributions to this book, saying nothing about, for instance, the essays on killing for furs and for sport. Nor have I considered all the detailed questions that need to be asked once we start thinking about other species in the radically different way presented by this book. What, for instance, are we to do about genuine conflicts of interest like rats biting slum children? I am not sure of the answer, but the essential point is just that we do see this as a conflict of interests, that we recognize that rats have interests too. Then we may begin to think about other ways of resolving the conflict — perhaps by leaving out rat baits that sterilize the rats instead of killing them.

I have not discussed such problems because they are side issues compared with the exploitation of other species for food and for experimental purposes. On these central matters, I hope that I have said enough to show that this book, despite its flaws, is a challenge to every human to recognize his attitudes to nonhumans as a form of prejudice no less objectionable than racism or sexism. It is a challenge that demands not just a change of attitudes, but a change in our way of life, for it requires us to become vegetarians.

Can a purely moral demand of this kind succeed? The odds are certainly against it. The book holds out no inducements. It does not tell us that we will become healthier, or enjoy life more, if we cease exploiting animals. Animal Liberation will require greater altruism on the part of mankind than any other liberation movement, since animals are incapable of demanding it for themselves, or of protesting against their exploitation by votes, demonstrations, or bombs. Is man capable of such genuine altruism? Who knows? If this book does have a significant effect, however, it will be a vindication of all those who have believed that man has within himself the potential for more than cruelty and selfishness.