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The term evolutionary ethics refers to three different fields of inquiry that share a concern for the relationship between ethics and evolutionary theory. First is the question of how the human capacity for ethics could have arisen through natural selection—the evolution of ethics. Second is the issue of how the process of evolution appears to exacerbate the problem of natural evil and theodicy—the ethics of evolution. Third is the question of what implications Darwinian theory has for ethical understanding and whether it is possible to derive an ethical system from evolutionary biology—ethics from evolution.

Evolution of ethics

Charles Darwin (1809–1882) speculated on, but did not resolve, the question of how ostensibly sacrificial social cooperation, and especially human morality, could be established by natural selection, which entails the preferential transmission of biological characteristics that confer reproductive advantage to their possessor. In the 1970s, breakthroughs in the application of Darwinian theory to animal social behavior by the emerging discipline of sociobiology shed light on this problem through the notion of reciprocal altruism, suggesting that organisms sacrifice for others in proportion to the likelihood of a compensatory return. Some species, such as social insects, achieve high cooperation in large group sizes, at the cost of rigid and therefore predictable behaviors. Other species, such as nonhuman primates, can achieve high cooperation with significant behavioral flexibility, within the constraints of small group sizes where relational history can be monitored. Human morality is widely viewed as facilitating the unique capacity for significant cooperation in the context of both high behavioral flexibility and large group sizes. Morality not only urges us, but in a sense enables us, to be kind to strangers.

Far from settling the biological origin of ethics however, these notions have stimulated vigorous debate. One controversy is over whether ethical behavior can be understood as invariably benefiting the actor's or others' reproduction; that is, is morality an individual or group level adaptation? Extending the influential ideas of George Williams and Richard Dawkins, in his seminal work, The Biology of Moral Systems (1987), Richard Alexander maintains that moral acts, even those not directly paid back, benefit the individual by indirect reciprocity or reputational enhancement. We are as morally good as it takes to enhance our social standing, and conscience is a reputation alarm that goes off when we are cheating in a way likely to get caught. Conversely, David Wilson and Christopher Boehm argue that human evolution has established the capacity for moral acts that entail uncompensated personal sacrifice and benefit the group relative to competing groups.

Another debate waged both within and outside evolutionary biology involves the question of whether morality is adequately explainable by natural selection at all. One view considers morality not as an evolutionary adaptation but as a byproduct of other biologically adaptive capacities, such as intelligence and the capacity for group cooperation. Another position, coevolutionary or hierarchy theory, views moral systems and other higher cognitive functions as influenced by nongenetic evolutionary processes that are not constrained by natural selection. Proponents reject genetic reductionism and affirm both genuine moral freedom and radical outgroup sacrifice. Scientific and theological critics maintain it is dualistic, even Gnostic, in viewing beneficence as a nonmaterial imposition on an innately selfish human biology. These disputes mirror longstanding theological differences over embodiment and the work of grace.

Ethics of evolution

In his 1893 Romanes lectures, Thomas Henry Huxley (1825–1895) reflected on the relationship between natural evil and evolutionary ethics. While natural evil is considered by many religious and wisdom traditions, evolutionary theory has been viewed as intensifying the quandary in three ways. First, it extends the temporal and biological scope of suffering and death. They become primal features rather than post-hoc additions to creation; moreover, death ravages not only individuals but also entire species, previously considered fixed in divine providence. Second, the role of natural evil changes from an ancillary intrusion upon God's mode of creation to the central driving force of the process itself. The very engines of creation seem to be the competition and selective carnage of natural selection. Third, not just the process but the products of natural selection raise ethical questions: In many representations, the Darwinian picture of the world is colored by dominant hues of self-interest and an utter absence of natural beneficence. A century after Huxley, George Williams argued that evolutionary theory and sociobiology paint an even bleaker picture.

Some theodicies respond to this view of the world by affirming eschatological extrapolations of evolutionary progress. Others criticize the picture itself. Darwin maintained death was most often swift, and selection favored pleasure over pain in behavioral motivation. Moreover, natural selection is actually not driven by selective mortality, but by differential fecundity. Finally, symbiotic cooperation may be as important in evolution as competitive displacement. Whether the most apt metaphor for evolution is "nature is red in tooth and claw" or "exuberant in youth and bough" is an object of ongoing debate, and the controversy itself has significant theological implications.

Ethics from evolution

The relationship of evolution to ethical theory is debated along two main lines. First is the metaethical question of whether a naturalistic origin of ethics makes divine command theory, or any form of moral realism, untenable. Michael Ruse argues that evolution entails moral relativism because what seems right is merely what happens to work in conferring reproductive success. Conversely, Nancy Murphy and some process thinkers argue that the universe operates in such a way that what works actually tends toward the right and good.

Another controversy involves the normative ethical question of whether evolution can inform moral understanding. Advocates of this view, such as Ruse and natural law proponent Larry Arnhart, argue evolution can contribute, first, by elucidating what is biologically impossible in light of natural selection and therefore errant to command. Ruse thus claims the New Testament's radical love command is biologically perverse. Second, if we understand the evolutionary function of human behavioral traits, we can discern what is most likely to facilitate or subvert fulfillment, and therefore inform ethical judgments. Critics argue that limiting our ethical vision to what conforms with prevailing views of the natural dismisses the work of grace in redeeming, or moral imagination in reforming, nature. Especially since the evolutionarily natural may not be so good, we are cautioned to avoid the naturalistic fallacy of attempting to infer a moral ought from a brute is. Furthermore, evolution-based ethics cannot adjudicate between conflicting impulses: If the function of all behavior is reproductive advantage, then slavery is not ethically preferable to benevolence, assuming both sustainably maximize fitness. Huxley's Evolution and Ethics (1894) made these criticisms of Herbert Spencer's (1820–1903) evolutionary ethics, and the debates continue to this day.

See also ECOLOGY, ETHICS OF; EVOLUTION, BIOCULTURAL; EVOLUTIONARY EPISTEMOLOGY; NATURE; NATURE VERSUS NURTURE; SOCIOBIOLOGY

JEFFREY P. SCHLOSS