During most of the 20th century, most secular moral philosophers considered natural law ethics to be a lifeless medieval relic, preserved only in Roman Catholic schools of moral theology. In the late 20th century the chief proponents of natural law ethics continued to be Roman Catholic, but they began to defend their position with arguments that made no explicit appeal to religious beliefs. Instead, they started from the claim that there are certain basic human goods that should not be acted against in any circumstances. The list of goods offered by John Finnis in the aforementioned Natural Law and Natural Rights, for example, included life, knowledge, play, aesthetic experience, friendship, practical reasonableness, and religion. The identification of these goods is a matter of reflection, assisted by the findings of anthropologists. Furthermore, each of the basic goods is regarded as equally fundamental; there is no hierarchy among them.

It would, of course, be possible to hold a consequentialist ethics that identified several basic human goods of equal importance and judged actions by their tendency to produce or maintain these goods. Thus, if life is a good, any action that led to a preventable loss of life would, other things being equal, be wrong. Proponents of natural law ethics, however, rejected this consequentialist approach; they insisted that it is impossible to measure the basic goods against each other. Instead of relying on consequentialist calculations, therefore, natural law ethics assumed an absolute prohibition of any action that aims directly against any basic good. The killing of the innocent, for instance, is always wrong, even in a situation where, somehow, killing one innocent person is the only way to save thousands of innocent people. What is not adequately explained in this rejection of consequentialism is why the life of one innocent person cannot be measured against the lives of a thousand innocent people—assuming that nothing is known about any of the people involved except that they are innocent.

Natural law ethics recognizes a special set of circumstances in which the effect of its absolute prohibitions would be mitigated. This is the situation in which the so-called doctrine of double effect would apply. If a pregnant woman, for example, is found to have a cancerous uterus, the doctrine of double effect allows a doctor to remove it, notwithstanding the fact that such action would kill the fetus. This allowance is made not because the life of the woman is regarded as more valuable than the life of the fetus, but because in removing the uterus the doctor is held not to aim directly at the death of the fetus; instead, its death is an unwanted and indirect side effect of the laudable act of removing a diseased organ. In cases where the only way of saving the woman’s life is by directly killing the fetus, the doctrine provides a different answer. Before the development of modern obstetric techniques, for example, the only way of saving a woman whose fetus became lodged during delivery was to crush the fetus’s skull. Such a procedure was prohibited by the doctrine of double effect, for in performing it the doctor would be directly killing the fetus. This position was maintained even in cases where the death of the mother would certainly also bring about the death of the fetus. In these cases, the claim was made that the doctor who killed the fetus directly would be guilty of murder, but the deaths from natural causes of the mother and the fetus would not be his doing. The example is significant, because it indicates the lengths to which proponents of natural law ethics were prepared to go in order to preserve the absolute nature of their prohibitions.

Virtue ethics

In the last two decades of the 20th century, there was a revival of interest in the Aristotelian idea that ethics should be based on a theory of the virtues rather than on a theory of what one ought to do. This revival was influenced by Elizabeth Anscombe and stimulated by Philippa Foot, who in essays republished in Virtues and Vices (1978) explored how acting ethically could be in the interest of the virtuous person. The Scottish philosopher Alasdair MacIntyre, in his pessimistic work After Virtue (1980), lent further support to virtue ethics by suggesting that what he called “the Enlightenment Project” of giving a rational justification of morality had failed. In his view, the only way out of the resulting moral confusion was to ground morality in a tradition, such as the tradition represented by Aristotle and Aquinas.

Virtue ethics, in the view of its proponents, promised a reconciliation of morality and self-interest. If, for example, generosity is a virtue, then a virtuous person will desire to be generous; and the same will hold for the other virtues. If acting morally is acting as a virtuous human being would act, then virtuous human beings will act morally because that is what they are like, and that is what they want to do. But this point again raised the question of what human nature is really like. If virtue ethicists hope to develop an objective theory of the virtues, one that is valid for all human beings, then they are forced to argue that the virtues are based on a common human nature; but, as was noted above in the discussion of naturalism in ethics, it is doubtful that human nature can serve as a standard of what one would want to call morally correct or desirable behaviour. If, on the other hand, virtue ethicists wish to base the virtues on a particular ethical tradition, then they are implicitly accepting a form of ethical relativism that would make it impossible to carry on ethical conversations with other traditions or with those who do not accept any tradition at all.

A rather different objection to virtue ethics is that it relies on an idea of the importance of moral character that is unsupported by the available empirical evidence. There is now a large body of psychological research on what leads people to act morally, and it points to the surprising conclusion that often very trivial circumstances have a decisive impact. Whether a person helps a stranger in obvious need, for example, largely depends on whether he is in a hurry and whether he has just found a small piece of change. If character plays less of a role in determining moral behaviour than is commonly supposed, an ethics that emphasizes virtuous character to the exclusion of all else will be on shaky ground.

Feminist ethics

In work published from the 1980s, feminist philosophers argued that the prevalent topics, interests, and modes of argument in moral philosophy reflect a distinctively male point of view, and they sought to change the practice of the discipline to make it less male-biased in these respects. Their challenge raised questions in metaethics, normative ethics, and applied ethics. The feminist approach received considerable impetus from the publication of In a Different Voice (1982), by the American psychologist Carol Gilligan. Gilligan’s work was written in response to research by Lawrence Kohlberg, who claimed to have discovered a universal set of stages of moral development through which normal human beings pass as they mature into adulthood. Kohlberg claimed that children and young adults gradually progress toward more abstract and more impartial forms of ethical reasoning, culminating in the recognition of individual rights. As Gilligan pointed out, however, Kohlberg’s study did not include females. When Gilligan studied moral development in girls and young women, she found less emphasis on impartiality and rights and more on love and compassion for the individuals with whom her subjects had relationships. Although Gilligan’s findings and methodology were criticized, her suggestion that the moral outlook of women is different from that of men led to proposals for a distinctly feminist ethics—an “ethics of care.” As developed in works such as Caring (1984), by the American feminist philosopher Nel Noddings, this approach held that normative ethics should be based on the idea of caring for those with whom one has a relationship, whether that of parent, child, sibling, lover, spouse, or friend. Caring should take precedence over individual rights and moral rules, and obligations to strangers may be limited or nonexistent. The approach emphasized the particular situation, not abstract moral principles.

Not all feminist moral philosophers accepted this approach. Some regarded the very idea that the moral perspective of women is more emotional and less abstract than that of men as tantamount to accepting patriarchal stereotypes of women’s thinking. Others pointed out that, even if there are “feminine” values that women are more likely to hold than men, these values would not necessarily be “feminist” in the sense of advancing the interests of women. Despite these difficulties, feminist approaches led to new ways of thinking in several areas of applied ethics, especially those concerned with professional fields like education and nursing, as well as in areas that male philosophers in applied ethics had tended to neglect, such as the family.

Ethical egoism

All of the normative theories considered so far have had a universal focus—i.e., the goods they seek to achieve, the character traits they seek to develop, or the principles they seek to apply pertain equally to everyone. Ethical egoism departs from this consensus, because it asserts that moral decision making should be guided entirely by self-interest. One great advantage of such a position is that it avoids any possible conflict between self-interest and morality. Another is that it makes moral behaviour by definition rational (on the plausible assumption that it is rational to pursue one’s own interests).

Two forms of egoism may be distinguished. The position of the individual egoist may be expressed as: “Everyone should do what is in my interests.” This is indeed egoism, but it is incapable of being universalized (because it makes essential reference to a particular individual); thus, it is arguably not an ethical principle at all. Nor, from a practical perspective, is the individual egoist likely to be able to persuade others to follow a course of action that is so obviously designed to benefit only the person who is advocating it.

Universal egoism is expressed in this principle: “Everyone should do what is in his own interests.” Unlike the principle of individual egoism, this principle is universalizable. Moreover, many self-interested people may be disposed to accept it, because it appears to justify acting on desires that conventional morality might prevent one from satisfying. Universal egoism is occasionally seized upon by popular writers, including amateur historians, sociologists, and philosophers, who proclaim that it is the obvious answer to all of society’s ills; their views are usually accepted by a large segment of the general public. The American writer Ayn Rand is perhaps the best 20th-century example of this type of author. Her version of egoism, as expounded in the novel Atlas Shrugged (1957) and in The Virtue of Selfishness (1965), a collection of essays, was a rather confusing mixture of appeals to self-interest and suggestions of the great benefits to society that would result from unfettered self-interested behaviour. Underlying this account was the tacit assumption that genuine self-interest cannot be served by lying, stealing, cheating, or other similarly antisocial conduct.

As this example illustrates, what starts out as a defense of universal ethical egoism very often turns into an indirect defense of consequentialism: the claim is that everyone will be better off if each person does what is in his own interest. The ethical egoist is virtually compelled to make this claim, because otherwise there is a paradox in the fact that he advocates ethical egoism at all. Such advocacy would be contrary to the very principle of ethical egoism, unless the egoist stands to benefit from others’ becoming ethical egoists. If his interests are such that they would be threatened by others’ pursuing their own interests, then he would do better to advocate altruism and to keep his belief in egoism a secret.

Unfortunately for ethical egoism, the claim that everyone will be better off if each person does what is in his own interests is incorrect. This is shown by thought experiments known as “prisoner’s dilemmas,” which played an increasingly important role in discussions of ethical theory in the late 20th century (see game theory). The basic prisoner’s dilemma is an imaginary situation in which two prisoners are accused of a crime. If one confesses and the other does not, the prisoner who confesses will be released immediately and the prisoner who does not will be jailed for 20 years. If neither confesses, each will be held for a few months and then released. And if both confess, each will be jailed for 15 years. It is further stipulated that the prisoners cannot communicate with each other. If each of them decides what to do purely on the basis of self-interest, he will realize that it is better for him to confess than not to confess, no matter what the other prisoner does. Paradoxically, when each prisoner acts selfishly—i.e., as an egoist—the result is that both are worse off than they would have been if each had acted cooperatively.

Although the example might seem bizarre, analogous situations occur quite frequently on a larger scale. Consider the dilemma of the commuter. Suppose that each commuter finds his private car a little more convenient than the bus, but when each commuter drives a car, the traffic becomes extremely congested. So everyone is better off in the situation where everyone takes the bus than in the situation where everyone drives a car. Because private cars are somewhat more convenient than buses, however, and because the overall volume of traffic is not appreciably affected by one more car on the road, it is in the interests of each commuter to continue driving. At least on the collective level, therefore, egoism is self-defeating—a conclusion well brought out by the English philosopher Derek Parfit in Reasons and Persons (1984).

The fact that ethical egoism is collectively self-defeating does not mean that it is wrong. An ethical egoist might still maintain that it is right for each person to pursue his own interests, even if this would bring about worse consequences for everyone. His position would not be self-contradictory, though it would be “self-effacing,” since it would require him to avoid promoting egoism in public and to keep his true ethical beliefs a secret.