Descriptive evolutionary ethics consists of biological approaches to morality based on the alleged role of evolution in shaping human psychology and behavior.
For example, the nearly universal belief that incest is morally wrong might be explained as an evolutionary adaptation that furthered human survival.
In Chapters IV and V of that work Darwin set out to explain the origin of human morality in order to show that there was no absolute gap between man and animals.
[2] Critics such as Thomas Henry Huxley, G. E. Moore, William James, Charles Sanders Peirce,[3] and John Dewey roundly criticized such attempts to draw ethical and political lessons from Darwinism, and by the early decades of the twentieth century Social Darwinism was widely viewed as discredited.
More recently, a number of evolutionary biologists, including Richard Alexander, Robert Trivers, and George Williams, have argued for a different relation between ethics and evolution.
In Alexander's words: “Ethical questions, and the study of morality or concepts of justice and right and wrong, derive solely from the existence of conflicts of interest.” [5] The latter, in turn, are inevitable consequences of genetic individuality.
"[6] Rather, he argued, The two major contributions that evolutionary biology may be able to make to this problem are, first, to justify and promote the conscious realization that it is conflicts of interest concentrated at the individual level which lead to ethical questions, and, second, to help identify the nature and intensity of the conflicts of interest involved in specific cases.
[5] This view runs contrary to that of the majority of philosophers who work on evolutionary ethics, since it denies the existence of an innate “moral sense” in humans.
Descriptive evolutionary ethics seeks to explain various kinds of moral phenomena wholly or partly in genetic terms.
Ethical topics addressed include altruistic behaviors, conservation ethics, an innate sense of fairness, a capacity for normative guidance, feelings of kindness or love, self-sacrifice, incest-avoidance, parental care, in-group loyalty, monogamy, feelings related to competitiveness and retribution, moral "cheating," and hypocrisy.
A key issue in evolutionary psychology has been how altruistic feelings and behaviors could have evolved, in both humans and nonhumans, when the process of natural selection is based on the multiplication over time only of those genes that adapt better to changes in the environment of the species.
According to David Copp, for example, evolution would favor moral responses that promote social peace, harmony, and cooperation.
If we can fully explain, for example, why parents naturally love and care for their children in purely evolutionary terms, there is no need to invoke any "spooky" realist moral truths to do any explanatory work.
[19] Scrutinizing similar situations, the developing mind pondered idealized models subject to definite laws.
[20] This behavioral pattern is not conventional (metaphysically constructive) but represents an objective relation similar to that of force or momentum equilibrium in mechanics.