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Evolutionary Ethics


Evolutionary theory came of age with the publication of Charles Darwin's Origin of Species (1859), in which he argued that all organisms, living and dead, including humans, are the end result of a long, slow, natural process of development from one or a few simple life forms. Believing this new world history to be the death knell of traditional ways of thinking, many were inspired to find evolutionary parallels in other fields, including ethicsin both evolution of appropriate guides for proper human conduct (substantive ethics) as well as the justificatory foundations for all such social behavior (metaethics).

At the substantive level the evolutionary ethicist's usual point of departure was Darwin's own suggested mechanism of changethe "natural selection" of the "fittest" organisms in the struggle for existenceseeking to find an analogue in human conduct. Although this philosophy became known as Social Darwinism, its widespread popularity, especially in America, owed less to Darwin himself and more to the voluminous writings of his countryman Herbert Spencer, a notorious enthusiast for extreme libertarian laissez-faire social and economic policies.

In later writings Spencer tempered the harshness of his philosophy, seeing a definiterole for cooperation in society, and this ambiguity about his real position led to his followers making contradictory claims, all in the name of the same philosophy. At one end of the spectrum there were supporters like the sociologist J. B. Sumner, who saw a place only for the success of the successful, and at the other end were American Marxists who saw in biology, as interpreted by Spencer, the true rules of moral conduct. Softer and more subtle forms of Social Darwinism tried to combine social responsibility with enlightened capitalism.

In this century the debt to Spencer is ignored and unknown, and the term Social Darwinism, burdened by history, is avoided. Nevertheless, particularly among biologists and politicians, the tradition has continued of seeking rules of conduct in what are believed to be the sound principles of the evolutionary process. At the beginning of the century there was the exiled Russian anarchist, Prince Peter Kropotkin, who argued that all animals are subject to a cooperating tendency toward "mutual aid" and that this can and will function once we dismantle the apparatus of the modern state. Later, the English biologist Julian Huxley became the first director general of UNESCO and based his policies on a biologically oriented religion of humanity directed toward the survival of the human species. And today we have the Harvard entomologist and sociobiologist Edward O. Wilson, who urges the preservation of the rain forests lest humans, who live in symbiotic relation with the rest of nature, fade and die. It is less than obvious, from a historical or conceptual point of view, that some of the more racist ideologies of this century owe much to evolutionary biology. The Nazis, for instance, shrank from the implication that all humans have a common origin, ultimately simian (although they were happy with the idea that within the human species there were biological differences).

Evolutionary ethics has long fallen from favor in philosophical circles, chiefly because of its supposed metaethical inadequacy. In his Principia Ethica (1903), G. E. Moore penned the classic critique, complaining that systems like that of Spencer commit the "naturalistic fallacy," trying to define the nonnatural property of goodness in terms of natural properties, in Spencer's case the happiness supposedly produced by the evolutionary process. Psychologically, however, enthusiasts for evolutionary ethics find this critique most unconvincing. It is more effective to point to the earlier attack of Thomas Henry Huxley (Julian's grandfather), who argued that systems deriving morality from evolution invariably rely on the hiddenand dubiouspremise that evolution is in some sense progressive and that value is thus increased as one goes up the scale. Recently, with the increased biological interest in the evolution of animal social behavior ("sociobiology"), there has been renewed interest by philosophers in the possibility of fruitful connections between biology and morality. In his influential A Theory of Justice, John Rawls suggested that social contract theorists might explore fruitfully the possibility that in real life morality is end result of the evolutionary process rather than the construct of a hypothesized group of rational beings. Rawls drew attention to the similarities between his own beliefs in "justice as fairness" and the results of such sociobiological mechanisms as "reciprocal altruism."

This position taken by Rawls and others is a naturalistic position on ethics. If the science fails, then so does the philosophy. Have we any reason to think thateven if we agree that a Rawlsian type of situation is that which could and would be maintained by selectionthat this position would ever come into being? This position of Rawls is an option for intelligent agents rather than beings that are basically under the control of the genes and hence, in crucial respects, might not be planning at all for themselves. There are various ways in which one might start to approach the empirical questions. Much interest has been shown in our close relatives, the chimpanzees. Students of their behavior argue strongly that we do find actions strongly suggestive of cooperation that simulates the moral.

Another naturalistic approach focuses on game theory. Models drawn from game theory are now showing that some kind of justicelike reciprocation can evolve among humans, even when no prior planning is involved. To see this, let us introduce two important concepts. The first is the notion of a Nash equilibrium, which posits that if there are two players in a game who are fighting over a fixed sum, and if they together demand more than the sum, neither will get anything. Given that both players know what the other will do, what is the most rational move for this first player? Suppose, for instance, that there are 100 units to be divided and player 1 knows that player 2 will demand 70 units. Then the most rational demand for player 1 is 30 units. An equilibrium holds if the distribution is 30:70player 1 cannot do better than this, and could do worse. The second notion is that of an Evolutionarily Stable Strategy, whereby no one mutantation or variation can gain predominate over or eliminate all others in the population. Selection for rarity will lead to such an equilibrium because if the variation gets more common, it will be under heavier selection pressure, and conversely.

Now fairness would seem to demand that the two players agree to divide 50:50, but why should this result evolve given that it could be rational to go 30:70, given the greediness (but not irrationality) of player 2? The philosopher Brian Skyrms has shown that in fact only a 50:50 distribution is an evolutionarily stable situation. His insight is that if anyone coming into a population asked for less than 50 units, where the inhabitants asked for 50 units, then the invaders would do less well. If they asked for more than 50 units in such a population, they would always get nothing. Conversely, if the inhabitants asked for less than 50 units, the invaders asking for 50 units would spread. In his conclusion, where everyone asked for less than 50 units, one would always get less than one might have had. But if one asks for more, then too often one will end up getting nothing at all. So a kind of justice as fairness result comes out of the evolutionary process.

Suppose we grant all of this. You may still complain, legitimately, that we do not have morality. We have beings behaving as if they were moral. Morality, however, involves a sense of moral obligation. At this point, obviously, the Darwinian ethicist supposesthat is, makes an empirical assumptionthat this sense of obligation is something put in place by selection to make us work together, to make us altruists who respect fairness. Normally we are self-centered. That is the way that selection has made us. So we look to our own needs when it comes to food and sex and so forth. But we are social animals also, and there are advantages to being social. So we have this moral sentiment that makes us reach beyond ourselves. Morality in this sense is an adaptation, just like any other.

Work is now proceeding at an empirical level showing how moral sentiments emerge in games of strategy. But, at the general level, the most obvious empirical support for the suggestion that ethics (substantive ethics) is an adaptation is that it fits in with the general Darwinian picture. We do have biological inclinations to selfishnesswe want food and mates for ourselvesand so, if cooperation is of value, we need adaptations to let us break through the selfishness. A moral sense is just what is needed. Substantive ethics is a kind of quick and dirty solution to the question of cooperation. It gets you to act quickly, even though (as with quick and dirty solutions) it might not always be the best answer.

Thinking of evolutionary ethics at the metaethical level also, we find that there has been renewed thought. Because the search for foundations seems so misguidedcommitting what Moore called the "naturalistic fallacy," could it not be that the evolutionist is directed toward some noncognitivist "ethical skepticism," where there simply are no foundations at all? This is the approach taken by Wilson collaborating with the philosopher Michael Ruse. Following up on the thinking of the late John L. Mackie, they suggest that ethics might be simply a collective illusion of our genes, put in place by natural selection to make humans into good cooperators. To this they add that the reason ethics works is that our biology makes us "objectify" our moral sentiments; thus, we are psychologically convinced that morality, despite its lack of real foundation, is more than mere subjective sentiment.

See also Altruism; Darwin, Charles Robert; Darwinism; Human Nature; Huxley, Thomas Henry; Kropotkin, Pëtr Alekseevich; Mackie, John Leslie; Metaethics; Moore, George Edward; Moral Motivation; Rawls, John; Self-Interest; Social Contract; Wilson, Edward O.


Huxley, T. H. Evolution and Ethics [1894]. Princeton, NJ, 1989.

Mackie, J. L. "The Law of the Jungle." Philosophy 53 (215) (1978), 553573.

Moore, G. E. Principia Ethica. Cambridge, U.K.: Cambridge University Press, 1903.

Richards, R. J. Darwin and the Emergence of Evolutionary Theories of Mind and Behavior. Chicago, 1987.

Ruse, M. Taking Darwin Seriously. Oxford, 1986.

Ruse, M., and E. O. Wilson. "Moral Philosophy as Applied Science." Philosophy, Vol. 61 (1986), 173192.

Skyrms, B. Evolution of the Social Contract. Cambridge, 1996.

Spencer, H. The Principles of Ethics. 2 vols. London, 1892.

Wilson, E. O. On Human Nature. Cambridge, MA, 1978.

Wright, R. The Moral Animal. New York, 1994.

Michael Ruse (1996, 2005)

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Evolutionary Ethics

Evolutionary Ethics

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 selectionthe evolution of ethics. Second is the issue of how the process of evolution appears to exacerbate the problem of natural evil and theodicythe 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 biologyethics from evolution.

Evolution of ethics

Charles Darwin (18091882) 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 (18251895) 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 (18201903) evolutionary ethics, and the debates continue to this day.

See also Ecology, Ethics of; Evolution, Biocultural; Evolutionary Epistemology; Nature; Nature versus Nurture; Sociobiology


alexander, richard d. the biology of moral systems. new york: de gruyter, 1987.

arnhart, larry. darwinian natural right: the biological ethics of human nature. albany: state university of new york press, 1998.

boehm, christopher. "how, when, and why did the unique aspects of human morality arise?" in evolutionary origins of morality: cross-disciplinary perspectives, ed. leonard d. katz. bowling green, ind.: imprint academic, 2000.

dawkins, richard. the selfish gene (1976), rev. edition. oxford: oxford university press, 1989.

huxley, thomas h. evolution and ethics and other essays. new york: appleton, 1894.

murphy, nancy, and ellis, george. on the moral nature of the universe: theology, cosmology, and ethics. minneapolis, minn.: fortress press, 1996.

nitecki, matthew h., and nitecki, doris v. evolutionary ethics. albany: state university of new york press, 1993.

ruse, michael. "evolutionary theory and christian ethics: are they in harmony?" zygon 29, no. 1 (1994): 524.

sober, elliott, and wilson, david sloan. unto others: the evolution and psychology of unselfish behavior. london and cambridge, mass.: harvard university press, 1998.

williams, george c. "huxley's evolution and ethics in sociobiological perspective." zygon 23, no. 4 (1988): 383407.

jeffrey p. schloss

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