Imagine intelligent aliens discover Earth. We're in complete awe at the elegance of their language, their art, technology, and their wisdom. But shortly after they arrive, the aliens begin to put us in cramped stalls. They force females to breed（使繁殖）, take their babies away, and drink their milk. They force us to eat from morning to night so that we're so fat that even as children we can't stand on our own. Finally, as teenagers, we're carted off to factories to be slaughtered（屠宰） on assembly（集合） lines.

  We protest, but the aliens don't understand our outrage（暴行）. They're far too intellectually（理智地） superior（上级的）, and they like the way we taste. Of course, we wouldn't agree with the aliens' behavior, but would it be morally wrong? When we gaze（盯） into the heavens, we might sometimes wonder how our actions will be perceived throughout eternity. Some people would think that the question of what is right or wrong is entirely subjective, that it's up to me. What I think is right or wrong is what counts, and what you may have some completely different view, and we're just exchanging preferences, just like maybe you like Indian food, and I prefer Chinese food.

  I don't believe that that's true. Peter Singer at Princeton University is one of the most influential（有影响的） philosophers（哲学家） today. I believe that there is scope（范围） for reason and argument in discussing ethics, and at the very least that there are many people who hold（拿住） positions that they haven't thought about, haven't reflected on, and that when they do reflect on it, they find that many of their beliefs are not really consistent. Peter Singer's worldview centers on the doctrine（主义） of utilitarianism. It is trying to weigh up the net（纯粹的） balance of pleasure versus（对） pain or happiness versus（对） suffering, and to maximize（取…最大值） that. So the right action for utilitarian（功利的） is the action that has the best consequences for all of those affected, and best consequences here means promoting the greatest amount of well-being for all of those affected.

  If we took a utilitarian perspective and had to decide between several possible actions, we would have to consider how each will affect the happiness of all those involved. Let's say we're expecting 10 guests for dinner, three of them like roast beef, seven like chicken. What should we cook? As a doctor, should we give（做） preference to other doctors in a disaster so that we can work（使工作） together to save more people? Should we help the tobacco（烟草） lobbyist who asks for directions to the German parliament even if he's likely to cause great social harm with the extra office time he gains by getting there quickly? As utilitarians, we calculate what each possible action would contribute to the total happiness in the universe.

  Then we choose the one that maximizes it. We direct the lobbyists to the woods, prioritize the other doctor, and naturally we'd make（使） chicken. That's the way utilitarianism works, but Peter Singer has taken it a step further. He asks, what about the interests of the chicken? You can't draw the line between the species because I don't believe that species is itself a morally relevant criterion any more than I believe that race or sex is a morally relevant criterion. If you want to move to something that may be a morally relevant criterion, like capacities of various kinds, mental life, then you're always going to get the possibility of an overlap between humans who lack these capacities because of brain damage or genetic abnormality（异常） and animals who have these capacities, therefore to a higher degree, than those particular abnormal humans.

  If we look back in time, we can see how the concept of a species has no clear boundary（分界线）. Imagine you take your mother by the hand and she takes her mother's hand and her mother takes her mother's hand back through the family tree. You follow it down for thousands and millions of years and there's a chimpanzee somewhere in Africa doing the same thing. He takes his mother's hand and the mother takes her mother's hand back into the past until you find a common mother. The chain of human beings and primates（首领） would be about 1,000 kilometers long. You and the chimpanzee are distant cousins reaching out to each other across the ages.

  If species were a moral boundary, then at some point there would be a mother and a child. One would be human and the other animal. One would be our moral equivalent and the other not at all. We humans are far closer to a chimpanzee than a chimpanzee is even to a dog, let alone to an oyster（[动]牡蛎） or something that's not even a vertebrate（脊椎动物）. But our legal system traditionally recognizes only one distinction（区别） in the animal kingdom（王国）, homo（人） sapiens（（拉）现代人的） and everyone else. Well, here are our choices.

  I could sit here in the witness box and the metaphor is that I'm a witness testifying（证明） for animals. Gary Francione is professor of law and philosophy. Or I could sit here in the jury box and I'm one of the jurors or he pioneered（开辟） teaching animal rights in the 1980s. I could sit up here where the judges sit. He's closely examined the history of the relationship between animals and the law. Your choice.

  In the West, before the 19th century, animals were largely excluded from the moral and legal community altogether. They were regarded as things. I mean, you had people like Descartes who did not believe that animals were sentient（有感觉力的）. So he didn't think that anything he did to them mattered because they didn't have any interests. And so he used to cut the animals up and the animals would scream. And he dismissed this as being this is just a machine made by God, but it's really no different from a machine made by humans that needs oil.

  When a machine made by humans needs oil, it makes a squeaking noise. When a machine made by God is adversely（不利地） affected in some way, it makes a screaming noise. But there's no pain perception there. There's no mind. There's no sort of mind that has a preference or want or desire for that pain to stop. Today, many countries have animal protection laws.

  They forbid causing animals unnecessary suffering. The thing is, is that because animals are property, our moral thinking is tremendously skewed in a very bizarre（奇异的(指态度）, weird direction. Gary Francione explains what he sees as a contradiction（矛盾） in animal protection law. The laws that provide for the protection of animals are interpreted in a way that reflect their status as chattel property. And it means, in essence（本质）, that the laws can't really apply to them in a meaningful（ 意味深长的） way because the laws don't permit us to look at use. The concept of property means that the owner is able to use it, but they can't without violence.

  If a person wants to keep livestock（牲畜）, the animals must be confined（限制）, and those who want to eat animals must kill them. Then the only question becomes, is the treatment necessary, given uses that may not be necessary? Because the reality is, we don't need to eat animals. By declaring animals as property, the law puts economic interests in competition with animal interests. That's why we accept that female pigs can be left in narrow cages for weeks, and that 23 hens can live in one square meter, and turkeys, who are so overfed, they can't stand up. We cut off the pigs' tails, and turkeys' beaks.

  We separate newborn calves（[解剖] 腓肠） from their mothers, and simply accept that pigs in stockyards scream for their lives before they're slaughtered. We accept it all because we have to in order to use animals effectively. So what does it mean to say we shouldn't inflict（造成） unnecessary suffering on food animals? What does that mean? It means that we shouldn't inflict unnecessary, unnecessary suffering on animals. We shouldn't inflict gratuitous（免费的） suffering on animals.

  The laws assume that institutionalized exploitation（开发） is a legitimate（合法的） exercise of property rights. So what you end up with are cases where kids are lighting dogs on fire, cats in microwave ovens. That's what you have for animal cruelty. All right. Have a safe week, everybody. Francione says there's only one way to end the routine torture（折磨） of livestock（牲畜）.

  Animals need rights. I subscribe to a rights position. That is, I'm not a utilitarian, and I believe that all sentient beings have the right not to be regarded as property. He believes in inalterable rights and responsibilities that always apply. In deontology, the ethics of duty and obligation, there's no weighing the good and bad consequences of inaction.