Dr. Peter Singer, a tenured professor of the Center for Human Values at Princeton University, is one of the world's most famous and influential philosophers. He's best known for his most infamous idea: that parents who aren't able to care for their newborn baby—healthy or not—should have the right to kill it.

No one would accept such a horrific idea, right? Wrong. Singer's "utilitarian" theories have a growing following. His numerous books and articles have appeared in countless translations all over the world, and his writing style appeals to a wide range of audiences, from the most intellectual to the most popular.

Singer’s mother had reached a point in her life where she did not meet his definition of a person.

What is Utilitarianism? It's a philosophy that says we have a moral duty to decrease the level of suffering and increase the level of pleasure experienced by as many people as possible, at all costs. Moral absolutes—against killing, in some cases—shouldn't be allowed to stand in the way of this goal.

There are utilitarians, for instance, who think killing some humans is—ethically—the right thing to do if it achieves the overall goal of reducing suffering and increasing pleasure. How can they justify this reasoning? Many utilitarian-minded ethicists who believe it's okay to kill some humans agree with an unquestioned assumption of contemporary bioethics—that some members of the human species are not persons. Their term for these humans is "non-person humans."

Singer makes a clear-cut distinction between a biological definition of humanity, and a definition of persons based on conscious activity. (Practical Ethics, Cambridge UP, 1993, 85-87). He doesn't doubt or deny, but in fact strongly affirms, that from the moment of conception human embryos are human beings, as are all of the other humans he's willing to kill. From a genetic/biological point of view—especially with our advanced technology—it would be absurd to deny that any of these are members of the species "Homo sapiens."

When does a member of the human species also count as a person? To answer that question Singer develops the teachings of the philosophers John Locke and Joseph Fletcher, whom he rightly refers to as the forefathers of this view, saying, "I propose to use [the term] 'person', in the sense of a rational and self-conscious being" (Practical Ethics, 87). And so, a "non-person human" is a being who is undeniably a member of our species based on biology and genetics, but who is incapable of the conscious activities typical of those members when they are alert: thinking, feeling, hoping, experiencing pleasure and pain, etc.

In a striking and revolting text, Singer makes explicit his position: "If we compare a severely defective human infant with a nonhuman animal, a dog or a pig, for example, we will often find the nonhuman to have superior capacities, both actual and potential, for rationality, self-consciousness, communication, and anything else that can plausibly be considered morally significant."(Sanctity of Life or Quality of Life, Pediatrics (1983) Vol. 27: 128-29). In other texts he asserts that healthy infants are sentient beings who are neither rational nor self-conscious, and therefore do not count as persons and may be killed (See for example, Practical Ethics, 170 - 74).

Singer criticized Mother Teresa because she had a love for individuals rather than a 'love for mankind.'

One way to understand this reasoning would be to recall the argument pro-abortion advocates used to make—that an embryo "isn't even human, it's just a blob of tissue." No one says that anymore, thanks to advances in genetic and DNA research. You could say that when utilitarians lost the battle on a scientific level—they can't claim any longer that an embryo isn't human—they switched to the idea that embryos and other vulnerable forms of biologically human life are not persons.

To counter some of Singer's ideas, last year I wrote and presented a paper contrasting the idea of human suffering as described by Pope John Paul II with that of Peter Singer. I sent the paper to Singer, and to my surprise he wrote back. Although his response was cordial, and in some respects helpful, ultimately it was disappointing. Singer's views often elicit strong negative emotions in those who disagree with him. Yet his writing style makes it difficult to pin down the reasons why his conclusions are wrong; I hope to identify some of those reasons here.

In his book, The Expanding Circle (Oxford: Clarendon Press, 1981), Professor Singer criticized Blessed Mother Teresa of Calcutta because she described her love for others as love for each of a succession of individuals rather than as "love for mankind merely as such." "If we were more rational," he says, "we would use our resources to save as many lives as possible, irrespective of whether we do it by reducing the road toll or by saving specific, identifiable lives" (p. 157). His idea seems to be that since Blessed Teresa was not, for example, spending her energy calculating auto accident rates against various speed limit options, she was irrational, because in doing so she could help more people.

Yet, there is a difference between the love of Blessed Teresa for each person she met and the love Singer calls "love of mankind." Let's call Blessed Teresa's love, "love of the individual." Love of the individual involves a one-to-one relationship based on an attitude of care and respect that demands your full attention before moving on to the next person. "Love of mankind," on the other hand, is not a focus on one individual, but rather on the sum total of all people.

Singer's view implies that face-to-face relationships sap time and energy that could be put to better use in lowering the overall suffering of mankind. This idea tends to separate individual people from suffering so you can get a measurable thing called "overall suffering." After that, you do whatever it takes to decrease suffering, even if it sometimes means killing an innocent person.

Of course, Blessed Teresa also wanted the overall suffering of humanity to be reduced, but she never tried to achieve that goal by killing someone. In fact, she believed that in addition to the terrible violation of the individual killed, doing so would inevitably lead to more suffering in the long run.

In principle, Singer is open to killing anyone as long as that single death will reduce overall suffering, but he focuses on fetuses, newborn babies, and elderly people suffering from dementia, since, as mentioned above, they lack certain abilities that healthy adults have.

Love opens our eyes to the true source of the worth of a person.

Something interesting happens, however, when the individual in question is a family member. Peter Singer broke all of his own rules when his mother became ill with Alzheimer's disease. Michael Specter reported on this in a profile of Singer titled, The Dangerous Philosopher (The New Yorker, September 6, 1999). Singer's mother had reached a point in her life where she no longer recognized Singer, his sister, or her grandchildren, and she had lost the ability to reason. In this state, according to Singer's theory, she did not meet the definition of a person. According to his ethical theory, she ought to have been killed or left to die. Certainly no money should have been spent on her care, since the money could be better spent lowering the suffering of the greatest number of other people. Instead, Singer and his sister hired a team of home health-care aides to look after their mother, spending tens of thousands of dollars in the process.

What's fascinating is that it is precisely when Singer gets into the position of reuniting suffering with a specific individual person, one whom he loves, that he reverses—in his actions—what he insists upon in his books.

Many people have asked Singer about this contradiction between his behavior and his theory, and in many of those instances he has responded in ways consistent with his theory. Yet, when Michael Specter pressed him on the point, Singer said, "I think this has made me see how the issues of someone with these kinds of problems are really very difficult... Perhaps it is more difficult than I thought before, because it is different when it's your mother." (The New Yorker, 55)

The difference, when the sufferer is your mother, is that you love her. And it is love that opens our eyes to the true source of the worth of persons: their inner preciousness, unrepeatability, and uniqueness. It is precisely a glimpse of the unrepeatable uniqueness of another human person that inspires love. Once this glimpse is achieved and love springs forth in the soul—as it does like a surprising gift—that love then has the remarkable power of allowing you to see more clearly and deeply the unique preciousness, as well as the humanity, of the person you love. That vision in turn inspires more love. When that happens, there is no philosophical argument that can make you kill the one you love—or in any other way abandon her.

Of course, some people believe it's merciful to kill someone who is in pain; that, however, is not love, but abandonment and murder. The request to be killed is actually a plea for two basic things: to be loved and to find pain relief. As soon as a person feels loved and/or has their pain managed, they no longer ask to be killed (and they're grateful that their request was not heeded). Pain is the trump card used by pro-euthanasia activists to promote their cause, but in our high-tech world we have the ability to eliminate this reason for the request to be killed. As for the other reason—feeling like an unloved nuisance—we must rise to the challenge presented by the recognition that loving each person is an infinitely higher value than cost management and perfect physical health.

It's very important to point out that while the love you have for someone is one reason why you would never kill him, it isn't the deepest reason. The deepest reason is the inner worth of the person. Your love for him is inside of you, but his humanity, uniqueness, and preciousness are inside of him. When you love someone you can more clearly see his inner worth. The person has this inner worth whether or not you love him, so no one should kill him—but unless love is in the picture you might have trouble knowing about his inner worth.

Singer did not kill his mother because he loves her.

This brings us to Dr. Singer's surprising—and alas disappointing—response when I pointed out the discrepancy between his life and his philosophy. He shared with me an article he wrote that has since appeared in The Ethics of Assistance (Cambridge UP, 2004), a book edited by Deen Chatterjee, and gave me permission to quote it. In the article he defends his theories against those who would use his behavior to refute them. The many people who wrote against Singer said, in effect: "Look, you didn't follow your rules when it came to your own mother, doesn't that mean your rules are wrong?" Paraphrasing, his answer is basically this: "No, that doesn't mean my rules are wrong, it only means that I disobeyed them in the case of my mother, and acted unethically."

Here are his words: "Suppose, however, that it were crystal clear that the money could do more good elsewhere. Then I would be doing wrong in spending it on my mother, just as I do wrong when I spend, on myself or my family, money that could do more good if donated to an organization that helps people in much greater need than we are. I freely admit to not doing all that I should; but I could do it, and the fact that I do not do it does not vitiate the claim that it is what I should do" (p. 29).

This answer is frustrating because he equates two unequal ideas: on the one hand, donating money to the poor in the form of tithing, and on the other hand, killing someone and then donating the money you gained from that to the poor. I would ask Dr. Singer to answer the following questions:

Has he learned from this experience and made a firm intention not to make this moral error in the future? For example, when his wife, children, or sister become debilitated, will he do what he believes to be the "right thing" and kill them?

If it is the case that his action toward his mother, while in direct opposition to his written work, does not negate his theories, how many such actions would it take to negate them?

If he is convinced that he did an objective wrong against the greater good when he cared for his mother, does he also think that he has thereby incurred moral guilt by caring for her?

Most people don't respect a teacher who doesn't live according to the demands he makes on others. To remain consistent, Singer should have written: "I want to apologize to all my followers for my error, I am sorry I failed, and I assure you that if this same situation happens with any other family members of mine, I will not let you down again!" But he didn't write that. He very well may act in just the same way with other ill family members: he may care for them—only time will tell. Why is it, we could wonder, that the leader of this movement can do the exact opposite of what he preaches—and boldly admit it—while adding that none of this undercuts his theoretical assertions?

In making this defense, however, Singer forgot to look on page 2 of his book Practical Ethics, where he asserts, "...ethics is not an ideal system that is noble in theory but no good in practice. The reverse is closer to the truth: an ethical judgment that is no good in practice must suffer from a theoretical defect..." It seems that not only his critics think his action towards his mother negates his ethical theory, he does too! Will he take his own advice and admit that his ethical theory must suffer from theoretical defects, since it is no good in his very own practice?

These questions and the contradictions in Singer's thought are important, but even they don't approach the real problem, expressed in the following question: Why can't Singer take the step from his experience with his mother to see that Blessed Teresa's way of life is the most rational? She acted in the same way he did towards his mother with every person she met. Her noble effort never to abandon anyone springs from an insight that Singer rejects over and over again: No person is replaceable, and no person ever loses his worth. Love, which clarifies the vision of the beloved, is an experience common to believers and non-believers alike, and so even though Singer is an atheist, these insights, which guided Blessed Teresa's life, are available to him through his experience with his mother.

Will he take his own advice and admit that his ethical theory must suffer from theoretical defects, since it is no good in his very own practice?

In addition, since utilitarian ethics allows for the killing and abandonment of individual persons to achieve its stated goal of reducing overall suffering, it has actually doomed itself to failure from the outset. The link between the legalization of euthanasia and large-scale killing is not correctable through "guidelines," but follows from an inner and unavoidable logic. Not only has large-scale killing followed on the coattails of legalized euthanasia historically, but the logical connection between the two can also be demonstrated. I would formulate that reason like this: To kill or abandon one single human person, is in a certain sense just as horrible as killing or abandoning thousands. Since persons are irreplaceably precious, killing one of them represents an infinite crime, and so killing many is not a "greater" evil in a quantitative sense, such that when you reach a certain number, say 100,000, only then does immorality kick in.

My friend, Dr. Maria Fedoryka, put it this way: "Killing many persons should be understood as a 'greater' evil in the sense that it is repeating many times over an already infinite crime of violating a unique person." And so, if the killing of any person becomes allowed, then the only foundation on which mass killing could be opposed has been stripped from the equation. Only a person who understands this can truly bring about what Pope John Paul II calls a "civilization of love." On March 20, 2004 Pope John Paul II announced the following to participants at an international conference titled, Life-Sustaining Treatments and Vegetative State: Scientific Advances and Ethical Dilemmas:

"I feel the duty to reaffirm strongly that the intrinsic value and personal dignity of every human being do not change, no matter what the concrete circumstances of his or her life. A man, even if seriously ill or disabled in the exercise of his highest functions, is and always will be a man, and he will never become a 'vegetable' or an 'animal.' Even our brothers and sisters who find themselves in the clinical condition of a 'vegetative state' retain their human dignity in all its fullness" (Zenit.org, April 5, 2004).

Suffering is an unavoidable and overwhelming fact of life. John Paul II also says that one of the deepest meanings to be found within it is its ability to "unleash love," which if realized in individual cases, will eventually result in an entire civilization of love (Salvifici Doloris, Nos. 28-30). Yet, we can be strongly tempted to think people who are sick have lost their worth and do not deserve love and care. It is for this reason, it seems to me, that the Catechism of the Catholic Church insists, "Those whose lives are diminished or weakened deserve special respect" (No. 2276). This is not because they are worth more than the healthy, but because it is too easy for the healthy to forget they still have all of their personal dignity. As soon as love comes into the picture, however, the right attitude toward individuals returns.

Despite his experience with his mother, Singer has yet to admit this in his writing. His answer—that he did wrong when he cared for his mother, as one of my students, Maria Scarnecchia, put it, "excuses his action, but does not express the motive for it." His critics are looking for that motive, and so I will suggest one: He did not kill his mother because he loves her, and this love made him see the reasons within her being for which she should not be killed.

If utilitarians are sincere in their desire to bring about the greatest good for the greatest number of people, let them strive to achieve a civilization of love on the only basis possible: the inviolable preciousness of every person.