In Defense of Animals
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In Defense of Animals

The Second Wave

Peter Singer, Peter Singer

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eBook - ePub

In Defense of Animals

The Second Wave

Peter Singer, Peter Singer

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About This Book

Bringing together new essays by philosophers and activists, In Defense of Animals: The Second Wave highlights the new challenges facing the animal rights movement.

  • Exciting new collection edited by controversial philosopher Peter Singer, who made animal rights into an international concern when he first published In Defence of Animals and Animal Liberation over thirty years ago
  • Essays explore new ways of measuring animal suffering, reassess the question of personhood, and draw highlight tales of effective advocacy
  • Lays out "Ten Tips for Activists", taking the reader beyond ethical theory and into the day-to-day campaigns for animal rights
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Part I

The Ideas


Utilitarianism and Animals

Gaverick Matheny
In North America and Europe, around 17 billion land animals were raised and killed during 2001 to feed us. Somewhere between 50 and 100 million other animals were killed in laboratories, while another 30 million were killed in fur farms. The vast majority of these animals were forced to live and die in conditions most of us would find morally repugnant. Yet their use – and the use of comparable numbers of animals every year – has been justified by the belief that nonhuman animals do not deserve significant moral consideration. Several plausible ethical theories argue that this belief is mistaken. Utilitarianism is one such theory that condemns much of our present use of animals. If this theory is reasonable, then most of us should change the way we live.


There is broad consensus within both religious and secular ethics that an ethical life respects virtues like fairness, justice, and benevolence. At the heart of these virtues lies a more basic principle: I cannot reasonably claim that my interests matter more than yours simply because my interests are mine. My interests may matter more to me, but I cannot claim they matter more in any objective sense. From the ethical point of view, everyone’s interests deserve equal consideration.
In the Judeo-Christian tradition, this sentiment is embodied in “The Golden Rule” attributed to Moses: “Love your neighbor as you love yourself” (Matthew 22:39) and in the Talmud, “What is hateful to you, do not to your fellow men” (Shabbat 31a). In the secular tradition, this sentiment is embodied in the “principle of equal consideration of interests”: “Act in such a way that the like interests of everyone affected by your action are given equal weight.” This phrase may lack the elegance of Scripture but conveys the same general idea. The principle of equal consideration of interests asks that we put ourselves in the shoes of each person affected by an action and compare the strengths of her or his interests to those of our own – regardless of whose interests they are. To be fair, just, and benevolent, any ethical rule we adopt should respect this principle.


Utilitarianism is an ethical theory with the rule, “act in such a way as to maximize the expected satisfaction of interests in the world, equally considered.” This rule is a logical extension of the principle of equal consideration of interests in that it says I should sum up the interests of all the parties affected by all my possible actions and choose the action that results in the greatest net satisfaction of interests. Another way of thinking about this is to imagine which actions I would choose if I had to live the lives of all those affected by me. Because the rule of utilitarianism represents a simple operation upon a principle of equality, it is perhaps the most minimal ethical rule we could derive. Utilitarianism is said to be universalist, welfarist, consequentialist, and aggregative. Each of these properties needs some explanation.
Utilitarianism is universalist because it takes into account the interests of all those who are affected by an action, regardless of their nationality, gender, race, or other traits that we find, upon reflection, are not morally relevant. The rule “act in such a way as to maximize the expected satisfaction of interests” is one we would be willing to have everyone adopt. Some writers have even claimed, forcefully, this is the only such rule.
Utilitarianism is welfarist because it defines what is ethically “good” in terms of people’s welfare, which we can understand as the satisfaction (or dissatisfaction) of people’s interests. Most of us are interested in good health, a good job, and our friends and family, among other things. We could reduce many if not all of these interests to something more general, such as an interest in a happy, pleasurable, relatively painless life. I will use the word “interests” to describe whatever it is that we value here – all those things that matter to us. We can safely say we all have an interest, at a minimum, in a pleasurable life, relatively free of pain. And from experience, we know when our happiness is decreased, as when we suffer acute pain, any other interests we may have tend to recede into the background. That being so, utilitarianism promotes an ethical rule that seeks to satisfy our interests, particularly those in a pleasurable, relatively painless life.
Utilitarianism is consequentialist because it evaluates the rightness or wrongness of an action by that action’s expected consequences: the degree to which an action satisfies interests. These consequences can often be predicted and compared accurately with little more than common sense.
Finally, utilitarianism is said to be aggregative because it adds up the interests of all those affected by an action. To make a decision, I need to weigh the intensity, duration, and number of interests affected by all of my possible actions. I choose the action that results in the greatest net satisfaction of interests – “the greatest good for the greatest number.” Utilitarian decisions thus involve a kind of accounting ledger, with our like interests serving as a common currency. This is no easy exercise. But, as we’ll see, in many of our most important moral judgments, even a rough comparison of interests is enough to make a wise decision.

The Advantages of Utilitarianism

Utlitarianism has several advantages over other ethical theories. First, its consequentialism encourages us to make full use of information about the world as it is. If you have access to the same information as I do, you can argue with me about how I ought to act. This lends utilitarianism a greater degree of empirical objectivity than most ethical theories enjoy.
Some ethical theories hold less regard for consequences than does utilitarianism and address their ethical rules either to actions themselves or to the motivations prompting them. These rules would often lead to misery if they were followed without exception. For instance, we would not have praised Miep Gies, the woman who hid Anne Frank and her family from the Nazis, had she followed the rule “never tell a lie” and turned the Franks over to the Nazis. Most of us believe the kind of deception Gies engaged in was justified, even heroic. So when should you tell a lie? When the consequences of not telling the lie are worse than the consequences of telling it. To decide otherwise would be to engage in a kind of rule worship at the expense of other people’s interests. Because we are often forced to choose between the lesser of two evils, any rule about particular actions – lying, promising, killing, and so on – can lead to terrible results.
At the same time, it would be foolhardy to live without any general principles. I would not be an efficient utilitarian if, every time I approached a stoplight, I weighed the consequences of respecting traffic laws. This would waste time and regularly lead to poor results. It would be best if I adopted “rules of thumb” that, in general, promote the greatest satisfaction of interests by guiding my actions in ordinary situations. Such rules of thumb would likely include most of our common views about right and wrong. However, in extraordinary situations, these rules of thumb should be overridden, as in the case of Miep Gies. In this way, utilitarianism supports most of our common moral intuitions while, at the same time, overriding them in important cases where following them could be catastrophic.
Utilitarianism’s aggregative properties offer additional advantages. Our moral decisions regularly benefit one individual at the expense or neglect of another. For instance, in North America and Europe, some citizens are taxed in order to provide financial support to the disabled, among others. Is it ethical to benefit one group with this tax while another suffers some expense? While such conflicts arise regularly in public policy, they also arise in our personal choices. In deciding to spend $1,000 on a piece of artwork instead of on a donation to a charity, I know a charity now has less money with which to help those in need than it would had I given it my $1,000. Is it ethical to have benefited myself while neglecting others? Utilitarianism, in allowing some exchange of costs and benefits, can help us answer questions like these, whereas many other ethical theories cannot.
Many of the moral stances implied by utilitarianism are familiar and widely accepted. Historically, utilitarians were among the most outpoken opponents of slavery and the strongest proponents of women’s suffrage, public education, public health, and other social democratic institutions. In recent years, utilitarians have advanced some of the strongest moral arguments for charity to the poor and sick. At the same time, however, utilitarianism leads us to moral views many of us do not already accept. Prominent among these are moral views regarding nonhuman animals.

Do Any Nonhumans Have Interests?

By the principle of equal consideration of interests, interests matter, regardless of whose interests they are. We can agree that we all have an interest, at a minimum, in a pleasurable life, relatively free of pain. Pleasure and pain matter to all of us who feel them. As such, it follows that we are obliged to consider, at a minimum, the interests of all those who are capable of feeling pleasure and pain – that is, all those who are sentient. We can then say that sentience is a sufficient condition for having interests and having those interests considered equally.
Are any nonhuman animals sentient? That is, are any nonhumans biologically capable of feeling pleasure and pain? There are few people today, including biologists, who seriously doubt the answer is yes. For most of us, our common sense and experience with animals, especially dogs and cats, are sufficient to let us answer affirmatively. However, our common sense and experience cannot always be trusted, and so we should look for further evidence that animals other than ourselves are sentient.
How do we know that other human beings are sentient? We cannot know for certain. My friend who shrieks after burning himself on the stove could be a very sophisticated robot, programmed to respond to certain kinds of stimuli with a shriek. But, because my friend is biologically similar to me, his awareness of pain would offer a biological advantage, his behavior is similar to my own when I am in pain, and his behavior is associated with a stimulus that would be painful for me, I have good reason to believe my friend feels pain.
We have similar reasons for believing that many nonhuman animals feel pain. Human beings evolved from other species. Those parts of the brain involved in sensing pleasure and pain are older than human beings and common to mammals and birds, and probably also to fish, reptiles, and amphibians. For most of these animals, awareness of pain would serve important functions, including learning from past mistakes.
Like my potentially robotic friend, these animals also respond to noxious stimuli much the same way we do. They avoid these stimuli and shriek, cry, or jerk when they can’t escape them. The stimuli that cause these behaviors are ones we associate with pain, such as extreme pressure, heat, and tissue damage. These biological and behavioral indications do not guarantee sentience, but they are about as good as those that we have for my human friend.
Whether invertebrates such as insects feel pain is far less certain, as these animals do not possess the same equipment to feel pain and pleasure that we have; and, by their having short life-cycles in stereotyped environments, the biological advantages of being sentient are less obvious.
That some nonhuman animals feel pain needn’t imply that their interests in not feeling pain are as intense as our own. It’s possible that ordinary, adult humans are capable of feeling more intense pain than some nonhumans because we are self-conscious and can anticipate or remember pain with greater fidelity than can other animals. It could also be argued, however, that our rationality allows us to distance ourselves from pain or give pain a purpose (at the dentist’s office, for instance) in ways that are not available to other animals. Moreover, even if other animals’ interests in not feeling pain are less intense than our own, the sum of a larger number of interests of lesser intensity (such as 100,000 people’s interests in $1 each) can still outweigh the sum of a smaller number of interests of greater intensity (such as my interest in $100,000).
So it is possible, even in those cases where significant human interests are at stake, for the interests of animals, considered equally, to outweigh our own. As we will see, however, in most cases involving animals, there are no significant human interests at stake, and the right course of action is easy to judge.

Some Rebuttals

Philosophers have never been immune to the prejudices of their day. In the past, some advanced elaborate arguments against civil rights, religious tolerance, and the abolition of slavery. Similarly, some philosophers today seek to justify our current prejudices against nonhuman animals, typically not by challenging the claim that some nonhumans are sentient, but rather by arguing that sentience is not a sufficient condition for moral consideration. Common to their arguments is the notion that moral consideration should be extended only to those individuals who also possess certain levels of rationality, intelligence, or language, or to those capable of reciprocating moral agreements, which likewise implies a certain level of rationality, intelligence, or language.
It is not clear how these arguments could succeed. First, why would an animal’s lack of normal human levels of rationality, intelligence, or language give us license to ignore her or his pain? Second, if rationality, intelligence, or language were necessary conditions for moral consideration, why could we not give moral preference to humans who are more rational, intelligent, or verbose than other humans? Third, many adult mammals and birds exhibit greater rationality and intelligence than do human infants. Some nonhuman animals, such as apes, possess language, while some humans do not. Should human infants, along with severely retarded and brain-damaged humans, be excluded from moral consideration, while apes, dolphins, dogs, pigs, parrots, and other nonhumans are included? Efforts to limit moral consideration to human beings based on the possession of certain traits succeed neither in including all humans nor in excluding all nonhuman animals.
The most obvious property shared among all human beings that excludes all nonhuman animals is our membership of a particular biological group: the species Homo sapiens. What is significant about species membership that could justify broad differences in moral consideration? Why is the line drawn at species, rather than genus, subspecies, or some other biological division? There have been no convincing answers to these questions. If species membership is a justification for excluding sentient animals from moral consideration, then why not race or gender? Why could one not argue that an individual’s membership of the biological group “human female” excludes that individual from moral consideration? One of the triumphs of modern ethics has been recognizing that an individual’s membership of a group, alone, is not morally relevant. The cases against racism and sexism depended upon this point, as the case against speciesism does now.
If a nonhuman animal can feel pleasure and pain, then that animal possesses interests. To think otherwise is to pervert the sense in which we understand pleasure and pain, feelings that matter to us and to others who experience them. At a minimum, a sentient animal has an interest in a painless, pleasurable life. And if he or she possesses this interest, then he or she deserves no less consideration of his or her interests than we give to our own. This view, while modern in its popularity, is not new. The utilitarian Jeremy Bentham held it at a time when black slaves were treated much as we now treat nonhuman animals:
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 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? (1988 [1823]: 1988: 310–11)
The principle of equal consideration of interests requires we count the interests of any individual equally with the like interests of any other. The racist violates this rule by giving greater weight to the interests of members of her own race. The sexist violates this rule by giving greater weight to the interests of members of his own sex. Similarly, the speciesist violates this rule by giving greater weight to the interests of members of his own species.
If an animal is sentient and if sentience is a sufficient condition for having interests, then we should consider that animal’s interests equal to our own when making ethical decisions. The essays in this book by James Mason and Mary Finelli, by Richard Ryder, and by Miyun Park show that we fall far short. Animals are used in a wide range of human activities, including agriculture, product testing, medical and scientific research, entertainment, hunting and fishing, the manufacture of clothing, and as our pets. In most of these activities, we treat animals in ways that do not show proper regard for their interests and thereby are unethical. I will limit discussion here to our treatment of animals in agriculture, laboratories, and the wild.


Other essays in this book discusses factory farming practices in detail. It is difficult, however, to convey these conditions in print, so I encourage you either to visit a factory farm or to watch video footage from these facilities at the website listed at the end of this essay. Factory farm conditions are believed by many to be so inhumane that it would be better if animals living in these facilities had not existed. Deciding what makes a life worth living is no simple matter, but we can think how we consider whether or not to euthanize a hopelessly sick dog or cat.
The pain experienced by animals in factory farms is likely greater than that experienced by many of those sick dogs and cats we choose to euthanize, as factory-farmed animals often experience an entire lifetime of pain, compared with a few weeks or months. If, for instance, we knew that our dog or cat would have no choice but to be confined in a cage so restrictive that turning around or freely stretching limbs is difficult if not impossible; live in his own excrement; be castrated or have her teeth, tail, or toes sliced off without anesthesia, I suspect most of us would believe that euthanizing the animal is the humane choice. It would be better, then, if farmed animals who endure these conditions did not exist.
One is hard-pressed to find, even among philosophers, any attempt to justify these conditions or the practice of eating factory-farmed animals. We have no nutritional need for animal products. In fact, vegetarians are, on average, healthier than those who eat meat. The overriding interest we have in eating animals is the pleasure we get from the taste of their flesh. However, there are a variety of vegetarian foods available, including ones that taste like animal products, from meat to eggs to milk, cheese, and yogurt. So, in order to justify eating animals, we would have to show that the pleasure gained from consuming them minus the pleasure gained from eating a vegetarian meal is greater than the pain caused by eating animals.
Whatever pleasure we gain from eating animals cannot be discounted. However, equal consideration of interests requires that we put ourselves in the place of a farmed animal as well as in the place of a meat-eater. Does the pleasure we enjoy from eating a chicken outweigh the pain we would endure were we to be raised and killed for that meal? We would probably conclude that our substantial interest in not being raised in a factory farm and slaughtered is stronger than our trivial interest in eating a chicken instead of chickpeas. There is, after all, no shortage of foods that we can eat that don’t require an animal to suffer in a factory farm or slaughterhouse. That our trivial interest in the taste of meat now trumps the pain endured by 17 billion farmed animals may be some measure of how far we are from considering their interests equally.
Accordingly, equal consideration of interests requires that we abstain, at a minimum, from eating factory-farmed products – particularly poultry and eggs, products that seem to cause the most pain per unit of food. Ideally, we should not consume products from any animal that we believe is sentient. This is the least we can do to have any real regard for the pain felt by other animals. Eating animals is a habit for most of us and, like other habits, can be challenging to break. But millions of people have made the switch to a vegetarian diet and, as a result, have enjoyed better health and a clearer conscience.
The use of animals for food is by far the largest direct cause of ani...

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Citation styles for In Defense of Animals
APA 6 Citation
Singer, P. (2013). In Defense of Animals (1st ed.). Wiley. Retrieved from (Original work published 2013)
Chicago Citation
Singer, Peter. (2013) 2013. In Defense of Animals. 1st ed. Wiley.
Harvard Citation
Singer, P. (2013) In Defense of Animals. 1st edn. Wiley. Available at: (Accessed: 14 October 2022).
MLA 7 Citation
Singer, Peter. In Defense of Animals. 1st ed. Wiley, 2013. Web. 14 Oct. 2022.