第 1 章
Ethics in the Crosshairs: Singer's Radical Rethinking of Right and Wrong
When Peter Singer's "Practical Ethics" first appeared in 1980, it didn't just spark academic debate-it ignited firestorms. Translated into fifteen languages and taught in universities worldwide, the book has also faced fierce opposition, with protests so intense they've led to canceled lectures and even death threats. Why? Because Singer dares to challenge our most deeply held moral assumptions, particularly the notion that human life has inherent, sacred value simply because it's human. This Australian philosopher, now at Princeton University, has been called both "the most influential living philosopher" by The New Yorker and "the most dangerous man in the world" by his critics. His willingness to follow ethical arguments wherever they lead-even to conclusions many find deeply unsettling about abortion, euthanasia, and animal rights-has made him a lightning rod in culture wars across continents. Yet his clear, accessible writing style and commitment to reason over emotion have also made his work essential reading for anyone serious about ethical thinking in the modern world.
第 2 章
Beyond Moral Platitudes: What Ethics Really Is
Ethics isn't primarily about sexual behavior, despite mid-20th century preoccupations. While sexual decisions may involve ethical considerations like honesty and avoiding harm, the same applies to everyday activities like driving-which actually raises far more serious moral questions from safety and environmental perspectives. Today's ethical discourse properly focuses on weightier issues like global poverty and climate change rather than obsessing over sexual conduct.
The common claim that ethics is "good in theory but not in practice" fundamentally misunderstands ethics' purpose. If an ethical judgment proves useless in practice, it must be theoretically flawed, since guiding practice is ethics' very purpose. This misconception stems from viewing ethics as simple rules like "Do not lie" that inevitably conflict in complex situations. Sophisticated ethical frameworks address this through either nuanced rule systems (deontology) or by focusing on outcomes rather than rules (consequentialism). Utilitarianism, for instance, judges actions by whether they produce more happiness than alternatives, allowing for contextual flexibility rather than rigid idealism.
Ethics stands independent of religion. The claim that "good" simply means "what God approves" was refuted by Plato thousands of years ago: either God approves actions because they're already good (meaning goodness exists independently), or divine approval is arbitrary. The traditional religious motivation for ethics-heavenly reward and hellish punishment-is unnecessary, as everyday observation shows ethical behavior without religious belief and vice versa. Instead, our moral faculties evolved from social mammalian ancestors, developing intuitions about right and wrong that we share with primates like chimpanzees, who also demonstrate reciprocity and rudimentary justice. These evolved intuitions, however, don't necessarily provide the right answers for today's ethical challenges.
Ethics isn't merely relative to society or subjective opinion. While specific ethical judgments may vary by context, this superficial relativism doesn't undermine universal principles like "increase happiness and reduce suffering." The more fundamental relativism that emerged from 19th-century anthropological discoveries-suggesting morality merely reflects societal customs-creates insurmountable problems. It can't explain moral disagreement or reform, since reformers would necessarily be wrong until they convince society otherwise. Simple subjectivism similarly fails by making genuine ethical disagreement impossible.
At its core, ethics requires justification that goes beyond self-interest, addressing a larger audience with a universal point of view. From Moses's Golden Rule to Kant's categorical imperative to utilitarian impartiality, ethical theories share this universality despite their differences. When thinking ethically, I cannot give my own preferences greater weight simply because they're mine. This universalizing of self-interested decision-making leads naturally to preference utilitarianism-doing what furthers the preferences of all affected-as a minimal ethical position. Going beyond this requires substantial moral argument, as our intuitions may be unreliable evolutionary artifacts.
第 3 章
Equality's True Foundation: Equal Consideration of Interests
Since World War II, moral attitudes have shifted dramatically regarding equality-especially racial equality. While racist views once dominated European thought, they've become publicly unacceptable. But what does human equality actually mean when humans clearly differ in countless ways-height, intelligence, athletic ability, moral character and emotional capacity?
The true basis for equality isn't factual but ethical: the principle of equal consideration of interests. This means giving equal weight to like interests regardless of whose they are-"an interest is an interest." This principle rejects racism, sexism, and hierarchies based on intelligence or disability, not by denying differences between individuals, but by refusing to make arbitrary distinctions in how we consider interests.
Equal consideration doesn't mandate equal treatment. After an earthquake, if I have two shots of morphine and encounter two victims-one with a crushed leg in agony and another with a gashed thigh in slight pain-giving both one shot would be equal treatment but not equal consideration. The person with the crushed leg would still suffer tremendously, while giving her both shots would produce more overall relief. When following the principle of declining marginal utility (additional units of something provide less benefit as one accumulates more), equal consideration often leads to more egalitarian outcomes-as with income distribution.
Genetic differences between individuals or groups don't undermine equality. Even if evidence confirmed genetic factors in group IQ differences, this wouldn't justify racism or undermine equality, for three reasons: First, we should still work to eliminate environmental disadvantages; second, group averages say nothing about individuals (substantial overlap exists between groups); and third, most fundamentally, equality isn't based on factual claims about intelligence or other characteristics. As Thomas Jefferson wrote, "whatever be their degree of talent, it is no measure of their rights."
Our society accepts large income differences as fair if they arise under conditions of equal opportunity. But this view is superficial. True equality of opportunity would require equalizing not just schools but home environments, parental influence, and even genetic endowments. The ultimate objection is that equality of opportunity rewards those lucky enough to inherit abilities valued by society while penalizing the unlucky. This system distributes rewards based on genetic inheritance rather than desert or need.
While complete equalization of income faces practical barriers, there remains significant scope for reducing pay differentials in affluent Western nations. The assumption that high salaries are necessary to motivate people to become doctors or professors is dubious-many would choose these professions over lower-status jobs regardless of pay differences. As psychologist Jeffrey Gray notes, paying people differently for jobs requiring different innate abilities is often "wasteful use of resources" that either tempts people beyond their capabilities or unnecessarily rewards them for what they would do anyway.
第 4 章
Animal Equality: The Case Against Speciesism
The principle of equal consideration of interests that grounds human equality logically extends beyond our species. Human speciesists don't accept that pain is as bad when felt by animals as when felt by humans. This doesn't mean animal and human suffering are always equivalent. Humans with greater awareness may suffer more in some circumstances, like cancer, due to mental anguish. But this requires careful comparison of interests across species rather than invalidating the equality principle.
Sometimes the differences work in reverse-animals may suffer more due to their limited understanding, as they can't comprehend that capture doesn't mean death. While precise comparisons between species are impossible, this doesn't prevent us from preventing animal suffering when human interests aren't comparably affected.
For most urbanized people, eating animals represents our primary interaction with them and forms the foundation of viewing animals as things for our use. In industrialized societies, eating meat isn't necessary for survival or health-humans can live healthy lives on plant-based diets (though vegans need B12 supplements). Animal agriculture is inefficient, converting only one-quarter to one-tenth of plant nutrients into meat, and contributes more to global warming than the entire transport sector.
Factory farming treats sentient beings as mere flesh-producing machines, confining them in cramped conditions their entire lives. Competition forces producers to minimize costs regardless of animal suffering. By purchasing these products, we support practices that sacrifice major animal interests for minor human taste preferences.
Animal experimentation reveals speciesism most clearly, as experimenters often justify their work by claiming it provides insights about humans-acknowledging crucial similarities between species while treating them differently. Not all animal experiments serve vital medical purposes. The LD50 test (determining lethal doses that kill 50% of test animals) is still used for products like Botox Cosmetic, where mice slowly suffocate as their respiratory muscles become paralyzed-suffering that isn't necessary to prevent human suffering.
Several objections to extending equal consideration to animals persist. We can never directly experience another being's pain, whether human or animal. Our certainty about animal pain comes from the same basis as our belief in human pain-behavior. Animals in pain behave similarly to humans, providing sufficient justification for believing they feel pain. Though they cannot verbalize their suffering, neither can human babies. Supporting this behavioral evidence, the nervous systems of all vertebrates, especially birds and mammals, are fundamentally similar to ours.
The argument that "animals eat each other, so why shouldn't we eat them?" fails for several reasons. First, predatory animals must kill to survive, while humans can thrive without animal flesh. Second, it's inconsistent to normally condemn animal behavior as "beastly" yet selectively imitate it when convenient. Most decisively, nonhuman animals cannot reflect on dietary ethics or consider alternatives, making it impossible to hold them morally responsible for their actions.
第 5 章
The Ethics of Taking Life: Beyond Species Boundaries
Is taking the life of a rational, self-conscious being more serious than taking the life of a merely sentient being? A self-conscious being aware of itself as a distinct entity with past and future can form desires about its future. To kill such a being thwarts these forward-looking desires, which are central to most mature humans' lives.
For preference utilitarians, since an action contrary to any being's preference is wrong unless outweighed by contrary preferences, killing someone who prefers to live is wrong. The fact that victims aren't around afterward to lament their thwarted preferences is irrelevant-the wrong occurs when the preference is thwarted. Taking a person's life violates not just one preference but a wide range of central preferences, often nullifying everything the victim has been trying to achieve.
Since killing a person is considered more seriously wrong than killing a non-person, we must ask whether any nonhuman animals qualify as persons-rational, self-conscious beings aware of themselves as distinct entities with past and future.
Language experiments with apes provide compelling evidence. Washoe the chimpanzee learned 350 signs, used 250 correctly, formed simple sentences, and identified herself in mirrors. Other apes like Koko the gorilla developed vocabularies exceeding 500 signs. These animals demonstrate time-awareness by referring to past and future events.
Even without language, animals show conceptual thought. Julia the chimpanzee solved complex sequential puzzles requiring backward reasoning. Wild chimpanzees demonstrate planning and deception-hiding sexual behavior from dominant males and coordinating to bypass electric fences. Pigs strategically conceal food locations from stronger competitors, and Santino the chimpanzee collects stones hours before visitors arrive to throw at them. Most remarkably, scrub jays cache food based on anticipated future desires rather than current preferences.
This evidence strongly suggests some nonhuman animals are indeed persons with self-awareness, memory, expectations, and intentions-contradicting philosophers who claimed animals lack concepts of order or future. If the special significance of human life derives from personhood rather than species membership, then nonhuman persons deserve the same protection.
The wrongness of killing might be better understood as a matter of degree rather than a binary distinction. While some nonhumans qualify as persons under basic definitions, philosophers like Gary Varner propose more demanding criteria, such as having a "biographical sense of self" that requires sophisticated language. The moral significance of killing might therefore depend on whether a being is fully a person, a near-person, or lacks self-awareness entirely, and on the extent and centrality of their future-directed desires.
第 6 章
Abortion and the Status of Early Life
The ethics of abortion and embryo research have been fiercely contested for decades, with little success in changing opponents' views. The ethical challenge stems from the gradual development of human life. A fertilized egg begins as a single cell with no human features, gradually developing into an embryo and eventually a human being. This continuous development creates difficulty in determining when destroying early human life becomes morally wrong.
The central conservative argument against abortion is straightforward: it's wrong to kill innocent human beings, and a human fetus is an innocent human being, therefore killing a fetus is wrong. Conservatives challenge liberals to identify any morally significant dividing line in the continuum from fertilized egg to child. Birth doesn't work as such a line because the fetus/baby remains the same entity whether inside or outside the womb. Viability (when the fetus could survive outside the womb) fails as a criterion because it varies with medical technology and location rather than reflecting any intrinsic change in the fetus itself.
The term "human" conflates two distinct concepts: membership in the species Homo sapiens and personhood. If "human" means "person," the second premise fails because fetuses lack rationality and self-consciousness. If "human" merely means "member of our species," then the first premise fails because species membership lacks moral significance. This transforms the abortion debate: we should evaluate fetuses based on their actual characteristics rather than species membership.
Once a fetus develops consciousness (though not yet self-consciousness), abortion requires more serious moral consideration. Scientific evidence suggests the earliest point for fetal consciousness is around eighteen weeks gestation, when the cerebral cortex develops synaptic connections necessary for pain perception. Before this stage, there's no evidence of consciousness. Even between eighteen and thirty weeks, the fetus appears to be in a persistent sleep state. Most abortions (over 85% in the US) occur during the first trimester, well before this threshold.
The argument that killing a fetus is wrong because it's a potential human being fails scrutiny. There's no general rule that potential entities deserve the same rights as what they might become-Prince Charles doesn't have the rights of a king, nor does destroying an acorn equal cutting down an oak tree. The reasons we value persons' lives-their self-awareness, autonomy, and ability to see themselves as continuing entities-don't apply to fetuses.
Laboratory embryos present unique moral questions that can't be resolved by women's bodily autonomy arguments. The early embryo's status as an individual is questionable since it can split into twins up to fourteen days after fertilization. When an embryo divides, we cannot say which resulting embryo is the "original" individual-suggesting we shouldn't consider pre-fourteen-day embryos as distinct individuals at all.
第 7 章
Euthanasia: When Is Death a Blessing?
The sanctity-of-life argument against abortion inevitably leads to questions about euthanasia. While opponents point to the Hippocratic Oath's prohibition against giving "deadly medicine" and invoke Nazi extermination programs as warnings, accepting certain forms of killing isn't horrific but sometimes morally necessary once we abandon unsupportable doctrines about the sanctity of human life.
Voluntary euthanasia occurs at the explicit request of a mentally competent, adequately informed person. It can remain voluntary even when the person is no longer competent at the time of death if they previously made and periodically reaffirmed written requests specifying conditions under which they would wish to die. In the Netherlands, a series of court cases during the 1980s established a doctor's right to assist patients in dying, and in 2002, the Dutch parliament legalized voluntary euthanasia under specific guidelines.
Nonvoluntary euthanasia applies to those incapable of understanding the choice between life and death-including severely disabled infants and people who have permanently lost decision-making capacity through accident, illness, or age. The Samuel Linares case exemplifies this: after an infant was left comatose on life support for eight months, his father disconnected the respirator and held him until death.
Since characteristics like rationality and self-awareness-not merely being human-determine the wrongness of killing, and infants lack these traits, killing them cannot be equated with killing normal human beings. For disabled infants, the considerations include the expected quality of life and parental attitudes. While parents of normal infants develop natural affection, parents of severely disabled infants may regret the birth, making the child's death potentially beneficial rather than harmful to them.
Many hospitals care for accident victims whose brains are permanently damaged beyond recovery. These patients may survive in vegetative states for decades, like Rita Greene who remained unconscious from age 24 until her death at 63. An estimated 10,000-40,000 Americans exist in persistent vegetative states at any given time. These patients are "alive biologically but not biographically." Their lives have no intrinsic value, as there's no advantage to surviving in a comatose state when death without recovery is certain.
Where euthanasia remains illegal, doctors who help terminally ill patients die risk criminal charges despite jury reluctance to convict. Voluntary euthanasia advocates propose changing laws to allow doctors to respond to patients' desires to die without further suffering. Critics argue doctors can make mistakes in terminal diagnoses. However, this small risk must be weighed against the significant, pointless suffering of genuinely terminal patients. Rational people may choose to avoid overwhelming suffering that will almost certainly end in death, even with a tiny chance of survival.
The conclusions reached challenge Western ethics' fundamental tenet that killing innocent humans is always wrong. However, this view represents less radical departure from existing practice than it might seem. Medical cases illustrate accepted practices of allowing severely disabled infants to die-often through prolonged suffering. This reveals a troubling inconsistency-we treat animals more humanely than humans. A suffering dog would receive a swift, painless lethal injection rather than being left to die slowly. Having chosen death, we should ensure it comes in the best possible way.
第 8 章
Global Poverty and Our Moral Responsibility
World Bank researchers interviewing 60,000 people in extreme poverty across 73 countries found consistent themes: constant food shortages, inability to save money, borrowing at exploitative interest rates, inability to educate children, unstable housing requiring frequent rebuilding, and lack of safe drinking water. Beyond material deprivation, extreme poverty brings humiliation, powerlessness and shame.
The World Bank defines extreme poverty as lacking income to meet basic human needs, calculated at purchasing power equivalent to US$1.25 per day. An estimated 1.4 billion people live below this absolute poverty line-not merely relative poverty as in industrialized nations, but a deadly condition. According to UNICEF, 8.8 million children under five (24,000 daily) died from preventable poverty-related causes in 2008.
In stark contrast to absolute poverty stands "absolute affluence"-having income significantly beyond what's needed for basic necessities. The absolutely affluent choose food for pleasure not hunger, buy clothes for fashion not warmth, upgrade housing for space or neighborhood not shelter, and still have money for entertainment and vacations. Most citizens of Europe, North America, Japan, Australia, New Zealand and oil-rich Middle Eastern states qualify as absolutely affluent, along with hundreds of millions in emerging economies like China, India and Brazil.
Despite possessing wealth they could transfer without threatening their basic welfare, the affluent give relatively little. In 1970, the UN set a modest target for foreign aid from rich nations: 0.7 percent of Gross National Income. Forty years later, only Denmark, Luxembourg, The Netherlands, Norway and Sweden had reached this level. The United States and Japan gave just 0.19 percent in 2008.
If I pass a shallow pond where a child is drowning, I ought to wade in and save them despite ruining my clothes or missing a lecture. This reflects a principle: if we can prevent something very bad without sacrificing anything of comparable moral significance, we ought to do it. This principle applies not just to drowning children but to those living in absolute poverty. The argument is simple: (1) If we can prevent something bad without sacrificing anything comparably significant, we ought to do it; (2) Extreme poverty is bad; (3) We can prevent some extreme poverty without comparable sacrifice; therefore, we ought to prevent some extreme poverty. This isn't charity but obligation.
Many argue we should help those near us-our families and fellow citizens-before addressing distant poverty. While we instinctively prefer helping those close to us, distance or community membership makes no moral difference to our obligations. Just as we'd reject prioritizing based on race, we should reject prioritization based solely on citizenship. The truth in "taking care of our own" lies in the efficiency of recognized responsibility systems within families and communities. But this modest preference for family is outweighed when others face extreme poverty while our own families already enjoy comfortable lives and luxuries.
第 9 章
Climate Change: The Greatest Moral Challenge
Today, we are connected globally in ways our ancestors couldn't imagine, and climate change has revealed new ways we harm one another. According to the World Health Organization, global warming already caused 140,000 additional deaths in 2004 compared to baseline temperatures-equivalent to a 9/11 attack every week. Low-lying regions like the Sunderbans in India and Pacific nations like the Maldives are already losing land to rising seas.
Our atmosphere resembles a village drain with seemingly limitless capacity that we've suddenly discovered is full. Before the industrial revolution, atmospheric carbon dioxide was only 270 parts per million (ppm); by 2010, it reached 390 ppm and continues rising at 2 ppm annually. Most scientists previously agreed that exceeding 450 ppm (which we'll reach by 2040) risks dangerous temperature increases beyond 2C. However, recent evidence suggests even this is too high-warming is exceeding predictions, and feedback loops like arctic ice melt and thawing permafrost accelerate the process.
At a 2009 UN Summit, Rwanda's President Kagame proposed that every human being should be entitled to an equal share of the atmosphere. Under a plausible target of two tons of carbon dioxide per person annually (to stay below 450 ppm), the implications would be dramatic: the US, Canada and Australia would need to reduce emissions by 90% from their twenty tons per person, Germany by 80% from eleven tons, while China would need to halve its four tons. India (at one ton) and Sri Lanka (two-thirds of a ton) could actually increase emissions while staying within their shares.
Philosopher Henry Shue proposed distinguishing between "subsistence emissions" (like methane from rice paddies in poor countries) and "luxury emissions" (like those from recreational vehicles in rich nations). China later adopted this language at a 2007 UN debate, arguing that "emissions of subsistence" and "development emissions" of poor countries should be accommodated while "luxury emissions" of rich countries should be restricted.
Considering the various principles of climate justice-equal per capita shares, historical responsibility, and development needs-it's clear that rich nations cannot justify their continued high greenhouse gas emissions under any plausible ethical framework. At a 2007 African Union summit, Uganda's President Museveni characterized these emissions as "aggression" against Africa. Though this terminology shocks us, it has merit. While rich nations aren't deliberately attacking other countries, their actions may prove more devastating than conventional warfare.
When considering our individual responsibilities regarding climate change, the situation differs from our obligations toward global poverty. With poverty, individual donations can have a discernible impact on specific lives. With climate change, individual actions seem less significant. If I reduce my annual carbon emissions from twenty tons to two tons by changing my lifestyle, will anyone notice the difference? This raises the philosophical question about imperceptible harms and collective responsibility.
