The first time I opened Peter Singer's ''Animal Liberation,'' I was dining alone at the Palm, trying to enjoy a rib-eye steak cooked medium-rare. If this sounds like a good recipe for cognitive dissonance (if not indigestion), that was sort of the idea. Preposterous as it might seem, to supporters of animal rights, what I was doing was tantamount to reading ''Uncle Tom's Cabin'' on a plantation in the Deep South in 1852.
Singer and the swelling ranks of his followers ask us to imagine a future in which people will look back on my meal, and this steakhouse, as relics of an equally backward age. Eating animals, wearing animals, experimenting on animals, killing animals for sport: all these practices, so resolutely normal to us, will be seen as the barbarities they are, and we will come to view ''speciesism'' -- a neologism I had encountered before only in jokes -- as a form of discrimination as indefensible as racism or anti-Semitism.
Even in 1975, when ''Animal Liberation'' was first published, Singer, an Australian philosopher now teaching at Princeton, was confident that he had the wind of history at his back. The recent civil rights past was prologue, as one liberation movement followed on the heels of another. Slowly but surely, the white man's circle of moral consideration was expanded to admit first blacks, then women, then homosexuals. In each case, a group once thought to be so different from the prevailing ''we'' as to be undeserving of civil rights was, after a struggle, admitted to the club. Now it was animals' turn.
That animal liberation is the logical next step in the forward march of moral progress is no longer the fringe idea it was back in 1975. A growing and increasingly influential movement of philosophers, ethicists, law professors and activists are convinced that the great moral struggle of our time will be for the rights of animals.
So far the movement has scored some of its biggest victories in Europe. Earlier this year, Germany became the first nation to grant animals a constitutional right: the words ''and animals'' were added to a provision obliging the state to respect and protect the dignity of human beings. The farming of animals for fur was recently banned in England. In several European nations, sows may no longer be confined to crates nor laying hens to ''battery cages'' -- stacked wired cages so small the birds cannot stretch their wings. The Swiss are amending their laws to change the status of animals from ''things'' to ''beings.''
Though animals are still very much ''things'' in the eyes of American law, change is in the air. Thirty-seven states have recently passed laws making some forms of animal cruelty a crime, 21 of them by ballot initiative. Following protests by activists, McDonald's and Burger King forced significant improvements in the way the U.S. meat industry slaughters animals. Agribusiness and the cosmetics and apparel industries are all struggling to defuse mounting public concerns over animal welfare.
Once thought of as a left-wing concern, the movement now cuts across ideological lines. Perhaps the most eloquent recent plea on behalf of animals, a new book called ''Dominion,'' was written by a former speechwriter for President Bush. And once outlandish ideas are finding their way into mainstream opinion. A recent Zogby poll found that 51 percent of Americans believe that primates are entitled to the same rights as human children.
What is going on here? A certain amount of cultural confusion, for one thing. For at the same time many people seem eager to extend the circle of our moral consideration to animals, in our factory farms and laboratories we are inflicting more suffering on more animals than at any time in history. One by one, science is dismantling our claims to uniqueness as a species, discovering that such things as culture, tool making, language and even possibly self-consciousness are not the exclusive domain of Homo sapiens. Yet most of the animals we kill lead lives organized very much in the spirit of Descartes, who famously claimed that animals were mere machines, incapable of thought or feeling. There's a schizoid quality to our relationship with animals, in which sentiment and brutality exist side by side. Half the dogs in America will receive Christmas presents this year, yet few of us pause to consider the miserable life of the pig -- an animal easily as intelligent as a dog -- that becomes the Christmas ham.
We tolerate this disconnect because the life of the pig has moved out of view. When's the last time you saw a pig? (Babe doesn't count.) Except for our pets, real animals -- animals living and dying -- no longer figure in our everyday lives. Meat comes from the grocery store, where it is cut and packaged to look as little like parts of animals as possible. The disappearance of animals from our lives has opened a space in which there's no reality check, either on the sentiment or the brutality. This is pretty much where we live now, with respect to animals, and it is a space in which the Peter Singers and Frank Perdues of the world can evidently thrive equally well.
Several years ago, the English critic John Berger wrote an essay, ''Why Look at Animals?'' in which he suggested that the loss of everyday contact between ourselves and animals -- and specifically the loss of eye contact -- has left us deeply confused about the terms of our relationship to other species. That eye contact, always slightly uncanny, had provided a vivid daily reminder that animals were at once crucially like and unlike us; in their eyes we glimpsed something unmistakably familiar (pain, fear, tenderness) and something irretrievably alien. Upon this paradox people built a relationship in which they felt they could both honor and eat animals without looking away. But that accommodation has pretty much broken down; nowadays, it seems, we either look away or become vegetarians. For my own part, neither option seemed especially appetizing. Which might explain how I found myself reading ''Animal Liberation'' in a steakhouse.
This is not something I'd recommend if you're determined to continue eating meat. Combining rigorous philosophical argument with journalistic description, ''Animal Liberation'' is one of those rare books that demand that you either defend the way you live or change it. Because Singer is so skilled in argument, for many readers it is easier to change. His book has converted countless thousands to vegetarianism, and it didn't take long for me to see why: within a few pages, he had succeeded in throwing me on the defensive.
Singer's argument is disarmingly simple and, if you accept its premises, difficult to refute. Take the premise of equality, which most people readily accept. Yet what do we really mean by it? People are not, as a matter of fact, equal at all -- some are smarter than others, better looking, more gifted. ''Equality is a moral idea,'' Singer points out, ''not an assertion of fact.'' The moral idea is that everyone's interests ought to receive equal consideration, regardless of ''what abilities they may possess.'' Fair enough; many philosophers have gone this far. But fewer have taken the next logical step. ''If possessing a higher degree of intelligence does not entitle one human to use another for his or her own ends, how can it entitle humans to exploit nonhumans for the same purpose?''
This is the nub of Singer's argument, and right around here I began scribbling objections in the margin. But humans differ from animals in morally significant ways. Yes they do, Singer acknowledges, which is why we shouldn't treat pigs and children alike. Equal consideration of interests is not the same as equal treatment, he points out: children have an interest in being educated; pigs, in rooting around in the dirt. But where their interests are the same, the principle of equality demands they receive the same consideration. And the one all-important interest that we share with pigs, as with all sentient creatures, is an interest in avoiding pain.
Here Singer quotes a famous passage from Jeremy Bentham, the 18th-century utilitarian philosopher, that is the wellspring of the animal rights movement. Bentham was writing in 1789, soon after the French colonies freed black slaves, granting them fundamental rights. ''The day may come,'' he speculates, ''when the rest of the animal creation may acquire those rights.'' Bentham then asks what characteristic entitles any being to moral consideration. ''Is it the faculty of reason or perhaps the faculty of discourse?'' Obviously not, since ''a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant.'' He concludes: ''The question is not, Can they reason? nor, Can they talk? but, Can they suffer?''
Bentham here is playing a powerful card philosophers call the ''argument from marginal cases,'' or A.M.C. for short. It goes like this: there are humans -- infants, the severely retarded, the demented -- whose mental function cannot match that of a chimpanzee. Even though these people cannot reciprocate our moral attentions, we nevertheless include them in the circle of our moral consideration. So on what basis do we exclude the chimpanzee?
Because he's a chimp, I furiously scribbled in the margin, and they're human! For Singer that's not good enough. To exclude the chimp from moral consideration simply because he's not human is no different from excluding the slave simply because he's not white. In the same way we'd call that exclusion racist, the animal rightist contends that it is speciesist to discriminate against the chimpanzee solely because he's not human.
But the differences between blacks and whites are trivial compared with the differences between my son and a chimp. Singer counters by asking us to imagine a hypothetical society that discriminates against people on the basis of something nontrivial -- say, intelligence. If that scheme offends our sense of equality, then why is the fact that animals lack certain human characteristics any more just as a basis for discrimination? Either we do not owe any justice to the severely retarded, he concludes, or we do owe it to animals with higher capabilities.
This is where I put down my fork. If I believe in equality, and equality is based on interests rather than characteristics, then either I have to take the interests of the steer I'm eating into account or concede that I am a speciesist. For the time being, I decided to plead guilty as charged. I finished my steak.
But Singer had planted a troubling notion, and in the days afterward, it grew and grew, watered by the other animal rights thinkers I began reading: the philosophers Tom Regan and James Rachels; the legal theorist Steven M. Wise; the writers Joy Williams and Matthew Scully. I didn't think I minded being a speciesist, but could it be, as several of these writers suggest, that we will someday come to regard speciesism as an evil comparable to racism? Will history someday judge us as harshly as it judges the Germans who went about their ordinary lives in the shadow of Treblinka? Precisely that question was recently posed by J.M. Coetzee, the South African novelist, in a lecture delivered at Princeton; he answered it in the affirmative. If animal rightists are right, ''a crime of stupefying proportions'' (in Coetzee's words) is going on all around us every day, just beneath our notice.
It's an idea almost impossible to entertain seriously, much less to accept, and in the weeks following my restaurant face-off between Singer and the steak, I found myself marshaling whatever mental power I could muster to try to refute it. Yet Singer and his allies managed to trump almost all my objections.
My first line of defense was obvious. Animals kill one another all the time. Why treat animals more ethically than they treat one another? (Ben Franklin tried this one long before me: during a fishing trip, he wondered, ''If you eat one another, I don't see why we may not eat you.'' He admits, however, that the rationale didn't occur to him until the fish were in the frying pan, smelling ''admirably well.'' The advantage of being a ''reasonable creature,'' Franklin remarks, is that you can find a reason for whatever you want to do.) To the ''they do it, too'' defense, the animal rightist has a devastating reply: do you really want to base your morality on the natural order? Murder and rape are natural, too. Besides, humans don't need to kill other creatures in order to survive; animals do. (Though if my cat, Otis, is any guide, animals sometimes kill for sheer pleasure.)
This suggests another defense. Wouldn't life in the wild be worse for these farm animals? ''Defenders of slavery imposed on black Africans often made a similar point,'' Singer retorts. ''The life of freedom is to be preferred.''
But domesticated animals can't survive in the wild; in fact, without us they wouldn't exist at all. Or as one 19th-century political philosopher put it, ''The pig has a stronger interest than anyone in the demand for bacon. If all the world were Jewish, there would be no pigs at all.'' But it turns out that this would be fine by the animal rightists: for if pigs don't exist, they can't be wronged.
Animals on factory farms have never known any other life. Singer replies that ''animals feel a need to exercise, stretch their limbs or wings, groom themselves and turn around, whether or not they have ever lived in conditions that permit this.'' The measure of their suffering is not their prior experiences but the unremitting daily frustration of their instincts.
O.K., the suffering of animals is a legitimate problem, but the world is full of problems, and surely human problems must come first! Sounds good, and yet all the animal people are asking me to do is to stop eating meat and wearing animal furs and hides. There's no reason I can't devote myself to solving humankind's problems while being a vegetarian who wears synthetics.
But doesn't the fact that we could choose to forgo meat for moral reasons point to a crucial moral difference between animals and humans? As Kant pointed out, the human being is the only moral animal, the only one even capable of entertaining a concept of ''rights.'' What's wrong with reserving moral consideration for those able to reciprocate it? Right here is where you run smack into the A.M.C.: the moral status of the retarded, the insane, the infant and the Alzheimer's patient. Such ''marginal cases,'' in the detestable argot of modern moral philosophy, cannot participate in moral decision making any more than a monkey can, yet we nevertheless grant them rights.
That's right, I respond, for the simple reason that they're one of us. And all of us have been, and will probably once again be, marginal cases ourselves. What's more, these people have fathers and mothers, daughters and sons, which makes our interest in their welfare deeper than our interest in the welfare of even the most brilliant ape.
Alas, none of these arguments evade the charge of speciesism; the racist, too, claims that it's natural to give special consideration to one's own kind. A utilitarian like Singer would agree, however, that the feelings of relatives do count for something. Yet the principle of equal consideration of interests demands that, given the choice between performing a painful medical experiment on a severely retarded orphan and on a normal ape, we must sacrifice the child. Why? Because the ape has a greater capacity for pain.
Here in a nutshell is the problem with the A.M.C.: it can be used to help the animals, but just as often it winds up hurting the marginal cases. Giving up our speciesism will bring us to a moral cliff from which we may not be prepared to jump, even when logic is pushing us.
And yet this isn't the moral choice I am being asked to make. (Too bad; it would be so much easier!) In everyday life, the choice is not between babies and chimps but between the pork and the tofu. Even if we reject the ''hard utilitarianism'' of a Peter Singer, there remains the question of whether we owe animals that can feel pain any moral consideration, and this seems impossible to deny. And if we do owe them moral consideration, how can we justify eating them?
This is why killing animals for meat (and clothing) poses the most difficult animal rights challenge. In the case of animal testing, all but the most radical animal rightists are willing to balance the human benefit against the cost to the animals. That's because the unique qualities of human consciousness carry weight in the utilitarian calculus: human pain counts for more than that of a mouse, since our pain is amplified by emotions like dread; similarly, our deaths are worse than an animal's because we understand what death is in a way they don't. So the argument over animal testing is really in the details: is this particular procedure or test really necessary to save human lives? (Very often it's not, in which case we probably shouldn't do it.) But if humans no longer need to eat meat or wear skins, then what exactly are we putting on the human side of the scale to outweigh the interests of the animal?
I suspect that this is finally why the animal people managed to throw me on the defensive. It's one thing to choose between the chimp and the retarded child or to accept the sacrifice of all those pigs surgeons practiced on to develop heart-bypass surgery. But what happens when the choice is between ''a lifetime of suffering for a nonhuman animal and the gastronomic preference of a human being?'' You look away -- or you stop eating animals. And if you don't want to do either? Then you have to try to determine if the animals you're eating have really endured ''a lifetime of suffering.''
Whether our interest in eating animals outweighs their interest in not being eaten (assuming for the moment that is their interest) turns on the vexed question of animal suffering. Vexed, because it is impossible to know what really goes on in the mind of a cow or a pig or even an ape. Strictly speaking, this is true of other humans, too, but since humans are all basically wired the same way, we have excellent reason to assume that other people's experience of pain feels much like our own. Can we say that about animals? Yes and no.
I have yet to find anyone who still subscribes to Descartes's belief that animals cannot feel pain because they lack a soul. The general consensus among scientists and philosophers is that when it comes to pain, the higher animals are wired much like we are for the same evolutionary reasons, so we should take the writhings of the kicked dog at face value. Indeed, the very premise of a great deal of animal testing -- the reason it has value -- is that animals' experience of physical and even some psychological pain closely resembles our own. Otherwise, why would cosmetics testers drip chemicals into the eyes of rabbits to see if they sting? Why would researchers study head trauma by traumatizing chimpanzee heads? Why would psychologists attempt to induce depression and ''learned helplessness'' in dogs by exposing them to ceaseless random patterns of electrical shock?
That said, it can be argued that human pain differs from animal pain by an order of magnitude. This qualitative difference is largely the result of our possession of language and, by virtue of language, an ability to have thoughts about thoughts and to imagine alternatives to our current reality. The philosopher Daniel C. Dennett suggests that we would do well to draw a distinction between pain, which a great many animals experience, and suffering, which depends on a degree of self-consciousness only a few animals appear to command. Suffering in this view is not just lots of pain but pain intensified by human emotions like loss, sadness, worry, regret, self-pity, shame, humiliation and dread.
Consider castration. No one would deny the procedure is painful to animals, yet animals appear to get over it in a way humans do not. (Some rhesus monkeys competing for mates will bite off a rival's testicle; the very next day the victim may be observed mating, seemingly little the worse for wear.) Surely the suffering of a man able to comprehend the full implications of castration, to anticipate the event and contemplate its aftermath, represents an agony of another order.
By the same token, however, language and all that comes with it can also make certain kinds of pain more bearable. A trip to the dentist would be a torment for an ape that couldn't be made to understand the purpose and duration of the procedure.
As humans contemplating the pain and suffering of animals, we do need to guard against projecting on to them what the same experience would feel like to us. Watching a steer force-marched up the ramp to the kill-floor door, as I have done, I need to remind myself that this is not Sean Penn in ''Dead Man Walking,'' that in a bovine brain the concept of nonexistence is blissfully absent. ''If we fail to find suffering in the [animal] lives we can see,'' Dennett writes in ''Kinds of Minds,'' ''we can rest assured there is no invisible suffering somewhere in their brains. If we find suffering, we will recognize it without difficulty.''
Which brings us -- reluctantly, necessarily -- to the American factory farm, the place where all such distinctions turn to dust. It's not easy to draw lines between pain and suffering in a modern egg or confinement hog operation. These are places where the subtleties of moral philosophy and animal cognition mean less than nothing, where everything we've learned about animals at least since Darwin has been simply . . . set aside. To visit a modern CAFO (Confined Animal Feeding Operation) is to enter a world that, for all its technological sophistication, is still designed according to Cartesian principles: animals are machines incapable of feeling pain. Since no thinking person can possibly believe this any more, industrial animal agriculture depends on a suspension of disbelief on the part of the people who operate it and a willingness to avert your eyes on the part of everyone else.
From everything I've read, egg and hog operations are the worst. Beef cattle in America at least still live outdoors, albeit standing ankle deep in their own waste eating a diet that makes them sick. And broiler chickens, although they do get their beaks snipped off with a hot knife to keep them from cannibalizing one another under the stress of their confinement, at least don't spend their eight-week lives in cages too small to ever stretch a wing. That fate is reserved for the American laying hen, who passes her brief span piled together with a half-dozen other hens in a wire cage whose floor a single page of this magazine could carpet. Every natural instinct of this animal is thwarted, leading to a range of behavioral ''vices'' that can include cannibalizing her cagemates and rubbing her body against the wire mesh until it is featherless and bleeding. Pain? Suffering? Madness? The operative suspension of disbelief depends on more neutral descriptors, like ''vices'' and ''stress.'' Whatever you want to call what's going on in those cages, the 10 percent or so of hens that can't bear it and simply die is built into the cost of production. And when the output of the others begins to ebb, the hens will be ''force-molted'' -- starved of food and water and light for several days in order to stimulate a final bout of egg laying before their life's work is done.
Simply reciting these facts, most of which are drawn from poultry-trade magazines, makes me sound like one of those animal people, doesn't it? I don't mean to, but this is what can happen when . . . you look. It certainly wasn't my intention to ruin anyone's breakfast. But now that I probably have spoiled the eggs, I do want to say one thing about the bacon, mention a single practice (by no means the worst) in modern hog production that points to the compound madness of an impeccable industrial logic.
Piglets in confinement operations are weaned from their mothers 10 days after birth (compared with 13 weeks in nature) because they gain weight faster on their hormone- and antibiotic-fortified feed. This premature weaning leaves the pigs with a lifelong craving to suck and chew, a desire they gratify in confinement by biting the tail of the animal in front of them. A normal pig would fight off his molester, but a demoralized pig has stopped caring. ''Learned helplessness'' is the psychological term, and it's not uncommon in confinement operations, where tens of thousands of hogs spend their entire lives ignorant of sunshine or earth or straw, crowded together beneath a metal roof upon metal slats suspended over a manure pit. So it's not surprising that an animal as sensitive and intelligent as a pig would get depressed, and a depressed pig will allow his tail to be chewed on to the point of infection. Sick pigs, being underperforming ''production units,'' are clubbed to death on the spot. The U.S.D.A.'s recommended solution to the problem is called ''tail docking.'' Using a pair of pliers (and no anesthetic), most but not all of the tail is snipped off. Why the little stump? Because the whole point of the exercise is not to remove the object of tail-biting so much as to render it more sensitive. Now, a bite on the tail is so painful that even the most demoralized pig will mount a struggle to avoid it.