By Peter Singer

Edited by Tom Regan and Peter Singer. Second edition
Englewood Cliffs, NJ, Prentice Hall, 1989
ISBN # 0-13-036864-4

In recent years a number of oppressed groups have campaigned vigorously for equality. The classic instance is the Black Liberation movement, which demands an end to the prejudice and discrimination that has made blacks second-class citizens. The immediate appeal of the black liberation movement and its initial, if limited, success made it a model for other oppressed groups to follow. We became familiar with liberation movements for Spanish-Americans, gay people, and a variety of other minorities. When a majority group—women—began their campaign, some thought we had come to the end of the road. Discrimination on the basis of sex, it has been said, is the last universally accepted form of discrimination, practiced without secrecy or pretense even in those liberal circles that have long prided themselves on their freedom from prejudice against racial minorities.

One should always be wary of talking of "the last remaining form of discrimination." If we have learnt anything from the liberation movements, we should have learnt how difficult it is to be aware of latent prejudice in our attitudes to particular groups until this prejudice is forcefully pointed out.

A liberation movement demands an expansion of our moral horizons and an extension or reinterpretation of the basic moral principle of equality. Practices that were previously regarded as natural and inevitable come to be seen as the result of an unjustifiable prejudice. Who can say with confidence that all his or her attitudes and practices are beyond criticism? If we wish to avoid being numbered amongst the oppressors, we must be prepared to re-think even our most fundamental attitudes. We need to consider them from the point of view of those most disadvantaged by our attitudes, and the practices that follow from these attitudes. If we can make this unaccustomed mental switch we may discover a pattern in our attitudes and practices that consistently operates so as to benefit one group—usually the one to which we ourselves belong—at the expense of another. In this way we may come to see that there is a case for a new liberation movement. My aim is to advocate that we make this mental switch in respect of our attitudes and practices towards a very large group of beings: members of species other than our own—or, as we popularly though misleadingly call them, animals. In other words, I am urging that we extend to other species the basic principle of equality that most of us recognize should be extended to all members of our own species.

All this may sound a little far-fetched, more like a parody of other liberation movements than a serious objective. In fact, in the past the idea of "The Rights of Animals" really has been used to parody the case for women's rights. When Mary Wollstonecraft, a forerunner of later feminists, published her Vindication of the Rights of Women in 1792, her ideas were widely regarded as absurd, and they were satirized in an anonymous publication entitled A Vindication of the Rights of Brutes. The author of this satire (actually Thomas Taylor, a distinguished Cambridge philosopher) tried to refute Wollstonecraft's reasonings by showing that they could be carried one stage further. If sound when applied to women, why should the arguments not be applied to dogs, cats, and horses? They seemed to hold equally well for these "brutes"; yet to hold that brutes had rights was manifestly absurd; therefore the reasoning by which this conclusion had been reached must be unsound, and if unsound when applied to brutes, it must also be unsound when applied to women, since the very same arguments had been used in each case.

One way in which we might reply to this argument is by saying that the case for equality between men and women cannot validly be extended to nonhuman animals. Women have a right to vote, for instance, because they are just as capable of making rational decisions as men are; dogs, on the other hand, are incapable of understanding the significance of voting, so they cannot have the right to vote. There are many other obvious ways in which men and women resemble each other closely, while humans and other animals differ greatly. So, it might be said, men and women are similar beings and should have equal rights, while humans and nonhumans are different and should not have equal rights.

The thought behind this reply to Taylor's analogy is correct up to a point, but it does not go far enough. There are important differences between humans and other animals, and these differences must give rise to some differences in the rights that each have. Recognizing this obvious fact, however, is no barrier to the case for extending the basic principle of equality to nonhuman animals. The differences that exist between men and women are equally undeniable, and the supporters of Women's Liberation are aware that these differences may give rise to different rights. Many feminists hold that women have the right to an abortion on request. It does not follow that since these same people are campaigning for equality between men and women they must support the right of men to have abortions too. Since a man cannot have an abortion, it is meaningless to talk of his right to have one. Since a pig can't vote, it is meaningless to talk of its right to vote. There is no reason why either Women's Liberation or Animal Liberation should get involved in such nonsense. The extension of the basic principle of equality from one group to another does not imply that we must treat both groups in exactly the same way, or grant exactly the same rights to both groups. Whether we should do so will depend on the nature of the members of the two groups. The basic principle of equality, I shall argue, is equality of consideration; and equal consideration for different beings may lead to different treatment and different rights.

So there is a different way of replying to Taylor's attempt to parody Wollstonecraft's arguments, a way which does not deny the differences between humans and nonhumans, but goes more deeply into the question of equality and concludes by finding nothing absurd in the idea that the basic principle of equality applies to so-called "brutes." I believe that we reach this conclusion if we examine the basis on which our opposition to discrimination on grounds of race or sex ultimately rests. We will then see that we would be on shaky ground if we were to demand equality for blacks, women, and other groups of oppressed humans while denying equal consideration to nonhumans.

When we say that all human beings, whatever their race, creed, or sex, are equal, what is it that we are asserting? Those who wish to defend a hierarchical, inegalitarian society have often pointed out that by whatever test we choose, it simply is not true that all humans are equal. Like it or not, we must face the fact that humans come in different shapes and sizes; they come with differing moral capacities, differing intellectual abilities, differing amounts of benevolent feeling and sensitivity to the needs of others, differing abilities to communicate effectively, and differing capacities to experience pleasure and pain. In short, if the demand for equality were based on the actual equality of all human beings, we would have to stop demanding equality. It would be an unjustifiable demand.

Still, one might cling to the view that the demand for equality among human beings is based on the actual equality of the different races and sexes. Although humans differ as individuals in various ways, there are no differences between the races and sexes as such. From the mere fact that a person is black, or a woman, we cannot infer anything else about that person. This, it may be said, is what is wrong with racism and sexism. The white racist claims that whites are superior to blacks, but this is false—although there are differences between individuals, some blacks are superior to some whites in all of the capacities and abilities that could conceivably be relevant. The opponent of sexism would say the same: a person's sex is no guide to his or her abilities, and this is why it is unjustifiable to discriminate on the basis of sex.

This is a possible line of objection to racial and sexual discrimination. It is not, however, the way that someone really concerned about equality would choose, because taking this line could, in some circumstances, force one to accept a most inegalitarian society. The fact that humans differ as individuals, rather than as races or sexes, is a valid reply to someone who defends a hierarchical society like, say, South Africa, in which all whites are superior in status to all blacks. The existence of individual variations that cut across the lines of race or sex, however, provides us with no defense at all against a more sophisticated opponent of equality, one who proposes that, say, the interests of those with I.Q. ratings above 100 be preferred to the interests of those with I.Q.s below 100. Would a hierarchical society of this sort really be so much better than one based on race or sex? I think not. But if we tie the moral principle of equality to the factual equality of the different races or sexes, taken as a whole, our opposition to racism and sexism does not provide us with any basis for objecting to this kind of inegalitarianism.

There is a second important reason why we ought not to base our opposition to racism and sexism on any kind of factual equality, even the limited kind which asserts that variations in capacities and abilities are spread evenly between the different races and sexes: we can have no absolute guarantee that these abilities and capacities really are distributed evenly, without regard to race or sex, among human beings. So far as actual abilities are concerned, there do seem to be certain measurable differences between both races and sexes. These differences do not, of course, appear in each case, but only when averages are taken. More important still, we do not yet know how much of these differences is really due to the different genetic endowments of the various races and sexes, and how much is due to environmental differences that are the result of past and continuing discrimination. Perhaps all of the important differences will eventually prove to be environmental rather than genetic. Anyone opposed to racism and sexism will certainly hope that this will be so, for it will make the task of ending discrimination a lot easier; nevertheless it would be dangerous to rest the case against racism and sexism on the belief that all significant differences are environmental in origin. The opponent of, say, racism who takes this line will be unable to avoid conceding that if differences in ability did after all prove to have some genetic connection with race, racism would in some way be defensible.

It would be folly for the opponent of racism to stake his whole case on a dogmatic commitment to one particular outcome of a difficult scientific issue which is still a long way from being settled. While attempts to prove that differences in certain selected abilities between races and sexes are primarily genetic in origin have certainly not been conclusive, the same must be said of attempts to prove that these differences are largely the result of environment. At this stage of the investigation we cannot be certain which view is correct, however much we may hope it is the latter.

Fortunately, there is no need to pin the case for equality to one particular outcome of this scientific investigation. The appropriate response to those who claim to have found evidence of genetically-based differences in ability between the races or sexes is not to stick to the belief that the genetic explanation must be wrong, whatever evidence to the contrary may turn up: instead we should make it quite clear that the claim to equality does not depend on intelligence, moral capacity, physical strength, or similar matters of fact. Equality is a moral ideal, not a simple assertion of fact. There is no logically compelling reason for assuming that a factual difference in ability between two people justifies any difference in the amount of consideration we give to satisfying their needs and interests. The principle of the equality of human beings is not a description of an alleged actual equality among humans: it is a prescription of how we should treat animals.

Jeremy Bentham incorporated the essential basis of moral equality into his utilitarian system of ethics in the formula: "Each to count for one and none for more than one." In other words, the interests of every being affected by an action are to be taken into account and given the same weight as the like interests of any other being. A later utilitarian, Henry Sidgwick, put the point in this way: "The good of any one individual is of no more importance, from the point of view (if I may say so) of the Universe, than the good of any other.''1 More recently, the leading figures in contemporary moral philosophy have shown a great deal of agreement in specifying as a fundamental presupposition of their moral theories some similar requirement which operates so as to give everyone's interests equal consideration—although they cannot agree on how this requirement is best formulated.2

It is an implication of this principle of equality that our concern for others ought not to depend on what they are like, or what abilities they possess—although precisely what this concern requires us to do may vary according to the characteristics of those affected by what we do. It is on this basis that the case against racism and the case against sexism must both ultimately rest; and it is in accordance with this principle that speciesism is also to be condemned. If possessing a higher degree of intelligence does not entitle one human to use another for his own ends, how can it entitle humans to exploit nonhumans?

Many philosophers have proposed the principle of equal consideration of interests, in some form or other, as a basic moral principle; but, as we shall see in more detail shortly, not many of them have recognized that this principle applies to members of other species as well as to our own. Bentham was one of the few who did realize this. In a forward-looking passage, written at a time when black slaves in the British dominions were still being treated much as we now treat nonhuman animals, Bentham wrote:

The day may come when the rest of the animal creation may acquire those rights which never could have been witholden 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 sarrum, 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 reasons nor Can they talk? but, Can their suffer?3

In this passage Bentham points to the capacity for suffering as the vital characteristic that gives a being the right to equal consideration. The capacity for suffering—or more strictly, for suffering and/or enjoyment or happiness—is not just another characteristic like the capacity for language, or for higher mathematics. Bentham is not saying that those who try to mark "the insuperable line" that determines whether the interests of a being should be considered happen to have selected the wrong characteristic. The capacity for suffering and enjoying things is a prerequisite for having interests at all, a condition that must be satisfied before we can speak of interests in any meaningful way. It would be nonsense to say that it was not in the interests of a stone to be kicked along the road by a schoolboy. A stone does not have interests because it cannot suffer. Nothing that we can do to it could possibly make any difference to its welfare. A mouse, on the other hand, does have an interest in not being tormented, because it will suffer if it is.

If a being suffers, there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that its suffering be counted equally with the like suffering—in so far as rough comparisons can be made—of any other being. If a being is not capable of suffering, or of experiencing enjoyment or happiness, there is nothing to be taken into account. This is why the limit of sentience (using the term as a convenient, if not strictly accurate, shorthand for the capacity to suffer or experience enjoyment or happiness) is the only defensible boundary of concern for the interests of others. To mark this boundary by some characteristic like intelligence or rationality would be to mark it in an arbitrary way. Why not choose some other characteristic, like skin color?

The racist violates the principle of equality by giving greater weight to the interests of members of his own race, when there is a clash between their interests and the interests of those of another race. Similarly the speciesist allows the interests of his own species to override the greater interests of members of other species.4 The pattern is the same in each case. Most human beings are speciesists. l shall now very briefly describe some of the practices that show this.

For the great majority of human beings, especially in urban, industrialized societies, the most direct form of contact with members of other species is at mealtimes: we eat them. In doing so we treat them purely as means to our ends. We regard their life and well-being as subordinate to our taste for a particular kind of dish. l say "taste" deliberately—this is purely a matter of pleasing our palate. There can be no defense of eating flesh in terms of satisfying nutritional needs, since it has been established beyond doubt that we could satisfy our need for protein and other essential nutrients far more efficiently with a diet that replaced animal flesh by soy beans, or products derived from soy beans, and other high-protein vegetable products.5

It is not merely the act of killing that indicates what we are ready to do to other species in order to gratify our tastes. The suffering we inflict on the animals while they are alive is perhaps an even clearer indication of our speciesism than the fact that we are prepared to kill them.6 In order to have meat on the table at a price that people can afford, our society tolerates methods of meat production that confine sentient animals in cramped, unsuitable conditions for the entire durations of their lives. Animals are treated like machines that convert fodder into flesh, and any innovation that results in a higher "conversion ratio" is liable to be adopted. As one authority on the subject has said, "cruelty is acknowledged only when profitability ceases."7 . . .

Since, as l have said, none of these practices cater for anything more than our pleasures of taste, our practice of rearing and killing other animals in order to eat them is a clear instance of the sacrifice of the most important interests of other beings in order to satisfy trivial interests of our own. To avoid speciesism we must stop this practice, and each of us has a moral obligation to cease supporting the practice. Our custom is all the support that the meat-industry needs. The decision to cease giving it that support may be difficult, but it is no more difficult than it would have been for a white Southerner to go against the traditions of his society and free his slaves: if we do not change our dietary habits, how can we censure those slaveholders who would not change their own way of living?

The same form of discrimination may be observed in the widespread practice of experimenting on other species in order to see if certain substances are safe for human beings, or to test some psychological theory about the effect of severe punishment on learning, or to try out various new compounds just in case something turns up....

In the past, 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 perform his experiment on an orphaned human infant, if that were the only way to save many lives? (I say "orphan" to avoid the complication of parental feelings, although in doing so l am being overfair to the experimenter, since the nonhuman subjects of experiments are not orphans.) If the experimenter is not prepared to use an orphaned human infant, then his readiness to use nonhumans is simple discrimination, since adult apes, cats, mice, and other mammals are more aware of what is happening to them, more self-directing and, so far as we can tell, at least as sensitive to pain, as any human infant. There seems to be no relevant characteristic that human infants possess that adult mammals do not have to the same or a higher degree. (Someone might try to argue that what makes it wrong to experiment on a human infant is that the infant will, in time and if left alone, develop into more than the nonhuman, but one would then, to be consistent, have to oppose abortion, since the fetus has the same potential as the infant—indeed, even contraception and abstinence might be wrong on this ground, since the egg and sperm, considered jointly, also have the same potential. In any case, this argument still gives us no reason for selecting a nonhuman, rather than a human with severe and irreversible brain damage, as the subject for our experiments).

The experimenter, then, shows a bias in favor of 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 most experiments on animals can have the slightest doubt that if this bias were eliminated the number of experiments performed would be a minute fraction of the number performed today.

Experimenting on animals, and eating their flesh, are perhaps the two major forms of speciesism in our society. By comparison, the third and last form of speciesism is so minor as to be insignificant, but it is perhaps of some special interest to those for whom this article was written. I am referring to speciesism in contemporary philosophy.

Philosophy ought to question the basic assumptions of the age. Thinking through, critically and carefully, what most people take for granted is, I believe, the chief task of philosophy, and it is this task that makes philosophy a worthwhile activity. Regrettably, philosophy does not always live up to its historic role. Philosophers are human beings, and they are subject to all the preconceptions of the society to which they belong. Sometimes they succeed in breaking free of the prevailing ideology: more often they become its most sophisticated defenders. So, in this case, philosophy as practiced in the universities today does not challenge anyone's preconceptions about our relations with other species. By their writings, those philosophers who tackle problems that touch upon the issue reveal that they make the same unquestioned assumptions as most other humans, and what they say tends to confirm the reader in his or her comfortable speciesist habits.

I could illustrate this claim by referring to the writings of philosophers in various fields—for instance, the attempts that have been made by those interested in rights to draw the boundary of the sphere of rights so that it runs parallel to the biological boundaries of the species homo sapiens, including infants and even mental defectives, but excluding those other beings of equal or greater capacity who are so useful to us at mealtimes and in our laboratories. l think it would be a more appropriate conclusion to this article, however, if I concentrated on the problem with which we have been centrally concerned, the problem of equality.

It is significant that the problem of equality, in moral and political philosophy, is invariably formulated in terms of human equality. The effect of this is that the question of the equality of other animals does not confront the philosopher, or student, as an issue itself—and this is already an indication of the failure of philosophy to challenge accepted beliefs. Still, philosophers have found it difficult to discuss the issue of human equality without raising, in a paragraph or two, the question of the status of other animals. The reason for this, which should be apparent from what I have said already, is that if humans are to be regarded as equal to one another, we need some sense of "equal" that does not require any actual, descriptive equality of capacities, talents or other qualities. If equality is to be related to any actual characteristics of humans, these characteristics must be some lowest common denominator, pitched so low that no human lacks them—but then the philosopher comes up against the catch that any such set of characteristics which covers all humans will not be possessed only by humans. In other words, it turns out that in the only sense in which we can truly say, as an assertion of fact, that all humans are equal, at least some members of other species are also equal—equal, that is, to each other and to humans. If, on the other hand, we regard the statement "All humans are equal" in some non-factual way, perhaps as a prescription, then, as I have already argued, it is even more difficult to exclude non-humans from the sphere of equality.

This result is not what the egalitarian philosopher originally intended to assert. Instead of accepting the radical outcome to which their own reasonings naturally point, however, most philosophers try to reconcile their beliefs in human equality and animal inequality by arguments that can only be described as devious.

As a first example, I take William Frankena's well-known article "The Concept of Social Justice." Frankena opposes the idea of basing justice on merit, because he sees that this could lead to highly inegalitarian results. Instead he proposes the principle that

all men are to be treated as equals, not because they are equal, in any respect, but simply because they are human. They are human because they have emotions and desires, and are able to think, and hence are capable of enjoying a good life in a sense in which other animals are not.8

But what is this capacity to enjoy the good life which all humans have, but no other animals? Other animals have emotions and desires and appear to be capable of enjoying a good life. We may doubt that they can think—although the behavior of some apes, dolphins, and even dogs suggests that some of them can—but what is the relevance of thinking? Frankena goes on to admit that by "the good life" he means "not so much the morally good life as the happy or satisfactory life," so thought would appear to be unnecessary for enjoying the good life; in fact to emphasize the need for thought would make difficulties for the egalitarian since only some people are capable of leading intellectually satisfying lives, or morally good lives. This makes it difficult to see what Frankena's principle of equality has to do with simply being human. Surely every sentient being is capable of leading a life that is happier or less miserable than some alternative life, and hence has a claim to be taken into account. In this respect the distinction between humans and nonhumans is not a sharp division, but rather a continuum along which we move gradually, and with overlaps between the species, from simple capacities for enjoyment and satisfaction, or pain and suffering, to more complex ones.

Faced with a situation in which they see a need for some basis for the moral gulf that is commonly thought to separate humans and animals, but can find no concrete difference that will do the job without undermining the equality of humans, philosophers tend to waffle. They resort to highsounding phrases like "the intrinsic dignity of the human individual";9 they talk of the "intrinsic worth of all men" as if men (humans?) had some worth that other beings did not,10 or they say that humans, and only humans, are "ends in themselves," while "everything other than a person can only have value for a person.''11

This idea of a distinctive human dignity and worth has a long history; it can be traced back directly to the Renaissance humanists, for instance to Pico delta Mirandola's Oration on the Dignity of Man. Pico and other humanists based their estimate of human dignity on the idea that man possessed the central, pivotal position in the "Great Chain of Being" that led from the lowliest forms of matter to God himself; this view of the universe, in turn, goes back to both classical and Judeo-Christian doctrines. Contemporary philosophers have cast off these metaphysical and religious shackles and freely invoke the dignity of mankind without needing to justify the idea at all. Why should we not attribute "intrinsic dignity" or "intrinsic worth" to ourselves? Fellow-humans are unlikely to reject the accolades we so generously bestow on them, and those to whom we deny the honor are unable to object. Indeed, when one thinks only of humans, it can be very liberal, very progressive, to talk of the dignity of all human beings. In so doing, we implicitly condemn slavery, racism, and other violations of human rights. We admit that we ourselves are in some fundamental sense on a par with the poorest, most ignorant members of our own species. It is only when we think of humans as no more than a small sub-group of all the beings that inhabit our planet that we may realize that in elevating our own species we are at the same time lowering the relative status of all other species.

The truth is that the appeal to the intrinsic dignity of human beings appears to solve the egalitarian's problems only as long as it goes unchallenged. Once we ask why it should be that all humans—including infants, mental defectives, psychopaths, Hitler, Stalin, and the rest—have some kind of dignity or worth that no elephant, pig, or chimpanzee can ever achieve, we see that this question is as difficult to answer as our original request for some relevant fact that justifies the inequality of humans and other animals. In fact, these two questions are really one: talk of intrinsic dignity or moral worth only takes the problem back one step, because any satisfactory defence of the claim that all and only humans have intrinsic dignity would need to refer to some relevant capacities or characteristics that all and only humans possess. Philosophers frequently introduce ideas of dignity, respect, and worth at the point at which other reasons appear to be lacking, but this is hardly good enough. Fine phrases are the last resource of those who have run out of arguments.

In case there are those who still think it may be possible to find some relevant characteristic that distinguishes all humans from all members of other species, I shall refer again, before I conclude, to the existence of some humans who quite clearly are below the level of awareness, self-consciousness, intelligence, and sentience, of many non-humans. l am thinking of humans with severe and irreparable brain damage, and also of infant humans. To avoid the complication of the relevance of a being's potential, however, I shall henceforth concentrate on permanently retarded humans.

Philosophers who set out to find a characteristic that will distinguish humans from other animals rarely take the course of abandoning these groups of humans by lumping them in with the other animals. It is easy to see why they do not. To take this line without re-thinking our attitudes to other animals would entail that we have the right to perform painful experiments on retarded humans for trivial reasons; similarly it would follow that we had the right to rear and kill these humans for food. To most philosophers these consequences are as unacceptable as the view that we should stop treating nonhumans in this way.

Of course, when discussing the problem of equality it is possible to ignore the problem of mental defectives, or brush it aside as if somehow insignificant.12 This is the easiest way out. What else remains? My final example of speciesism in contemporary philosophy has been selected to show what happens when a writer is prepared to face the question of human equality and animal inequality without ignoring the existence of mental defectives, and without resorting to obscurantist mumbo jumbo. Stanley Benn's clear and honest article "Egalitarianism and Equal Consideration of Interests''13 fits this description.

Benn, after noting the usual "evident human inequalities" argues, correctly I think, for equality of consideration as the only possible basis for egalitarianism. Yet Benn, like other writers, is thinking only of "equal consideration of human interests." Benn is quite open in his defence of this restriction of equal consideration:

. . . not to possess human shape is a disqualifying condition. However faithful or intelligent a dog may be, it would be a monstrous sentimentality to attribute to him interests that could be weighed in an equal balance with those of human beings . . . if, for instance, one had to decide between feeding a hungry baby or a hungry dog, anyone who chose the dog would generally be reckoned morally defective, unable to recognize a fundamental inequality of claims.
This is what distinguishes our attitude to animals from our attitude to imbeciles. It would be odd to say that we ought to respect equally the dignity or personality of the imbecile and of the rational man . . . but there is nothing odd about saying that we should respect their interests equally, that is, that we should give to the interests of each the same serious consideration as claims to considerations necessary for some standard of well-being that we can recognize and endorse.

Benn's statement of the basis of the consideration we should have for imbeciles seems to me correct, but why should there be any fundamental inequality of claims between a dog and a human imbecile? Benn sees that if equal consideration depended on rationality, no reason could be given against using imbeciles for research purposes, as we now use dogs and guinea pigs. This will not do: "But of course we do distinguish imbeciles from animals in this regard," he says. That the common distinction is justifiable is something Benn does not question; his problem is how it is to be justified. The answer he gives is this:

The final sentence of this passage gives the argument away. An imbecile, Benn concedes, may have no characteristics superior to those of a dog; nevertheless this does not make the imbecile a member of "a different species" as the dog is. Therefore it would be "unfair" to use the imbecile for medical research as we use the dog. But why? That the imbecile is not rational is just the way things have worked out, and the same is true of the dog—neither is any more responsible for their mental level. If it is unfair to take advantage of an isolated defect, why is it fair to take advantage of a more general limitation? I find it hard to see anything in this argument except a defense of preferring the interests of members of our own species because they are members of our own species. To those who think there might be more to it, I suggest the following mental exercise. Assume that it has been proven that there is a difference in the average, or normal, intelligence quotient for two different races, say whites and blacks. Then substitute the term "white" for every occurrence of "men" and "black" for every occurrence of "dog" in the passage quoted; and substitute "high l.Q." for "rationality" and when Benn talks of "imbeciles" replace this term by "dumb whites"—that is, whites who fall well below the normal white l.Q. score. Finally, change "species" to "race." Now retread the passage. It has become a defense of a rigid, no-exceptions division between whites and blacks, based on l.Q. scores, not withstanding an admitted overlap between whites and blacks in this respect. The revised passage is, of course, outrageous, and this is not only because we have made fictitious assumptions inour substitutions. The point is that in the original passage Benn was defending a rigid division in the amount of consideration due to members of different species, despite admitted cases of overlap. If the original did not, at first reading strike us as being as outrageous as the revised version does, this is largely because although we are not racists ourselves, most of us are speciesists. Like the other articles, Benn's stands as a warning of the ease with which the best minds can fall victim to a prevailing ideology.


  1. The Methods of Ethics (7th Ed.), p. 382.
  2. For example, R. M. Hare, Freedom and Reason (Oxford, 1963) and J. Rawls, A Theory of Justice (Harvard, 1972); for a brief account of the essential agreement on this issue between these and other positions, see R. M. Hare, "Rules of War and Moral Reasoning," Philosophy and Public Affairs, vol. 1, no. 2 (1972).
  3. Introduction to the Principles of Morals and Legislation, ch. XVII.
  4. I owe the term speciesism to Richard Ryder.
  5. In order to produce 1 lb. of protein in the form of beef or veal, we must feed 21 Ibs. of protein to the animal. Other forms of livestock are slightly less inefficient, but the average ratio in the United States is still 1:8. It has been estimated that the amount of protein lost to humans in this way is equivalent to 90 percent of the annual world protein deficit. For a brief account, see Frances Moore Lappe, Diet for a Small Planet (Friends of The Earth/Ballantine, New York 1971), pp. 4—11.
  6. Although one might think that killing a being is obviously the ultimate wrong one can do to it, l think that the infliction of suffering is a clearer indication of speciesism because it might be argued that at least part of what is wrong with killing a human is that most humans are conscious of their existence over time and have desires and purposes that extend into the future see, for instance, M. Tooley, "Abortion and Infanticide," Philosophy and Public Affairs, vol . 2, no. I (1972). Of course, if one took this view one would have to hold—as Tooley does—that killing a human infant or mental defective is not in itself wrong and is less serious than killing certain higher mammals that probably do have a sense of their own existence over time.
  7. Ruth Harrison, Animal Machines (Stuart, London, 1964). For an account of farming conditions, see my Animal Liberation (New York Review Company, 1975) from which "Down on the Factory Farm," is reprinted in this volume.
  8. In R. Brandt (ed.), Social Justice (Prentice Hall, Englewood Cliffs, 1962), p. 19.
  9. Frankena, op. cit. p. 23.
  10. H. A. Bedau, "Egalitarianism and the Idea of Equality," in Nomos IX: Equality, ed. J. R. Pennock and J. W. Chapman, New York, 1967.
  11. C. Vlastos, "Justice and Equality," in Brandt, Social Justice, p. 48.
  12. For example, Bernard Williams, "The Idea of Equality," in Philosophy, Politics, and Society (second series), ed. P. Laslett and W. Rundman (Blackwell, Oxford, 1962), p. 118; J. Rawls, A Theory of Justice, pp. 509—10.
  13. Nomos IX: Equality; the passages quoted are on p. 62ff.

Peter Singer is Director of the Center for Human Bioethics at Monash University, Australia. His many writings in ethics include Practical Ethics (Cambridge University Press, 1979) and, as editor, In Defense of Animals (Blackwell, 1986).

From Philosophic Exchange, vol. 1, no. 5 (Summer 1974). Parts of this article appeared in a review of Animals, Men and Morals, Codlovitch and Harris (eds.), in The New York Review of Books, April 5, 1973.

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