Evolutionary ethics

Evolutionary ethics concerns approaches to ethics (morality) based on the role of evolution in shaping human psychology and behavior. Such approaches may be based in scientific fields such as evolutionary psychology or sociobiology, with a focus on understanding and explaining observed ethical preferences and choices. Alternatively and to a large extent separately, theories or ideas about evolution may be used to justify and advance particular ethical systems and particular morals (i.e. what is right and wrong). A real life example of this would be the Diana monkey which warns other monkeys that predators are approaching by yelling, at the cost of it’s own life (as by warning the other monkeys- the monkey reveals itself to predators). This moral behavior can save countless other monkeys, at the cost of only one. More monkeys survive to reproduce- and the species live on.

Evolutionary psychology
Evolutionary psychology attempts to explain major features of psychology in terms of species-wide evolved (via natural selection) predispositions. Ethical topics addressed include altruistic behaviors, deceptive or harmful behaviors, an innate sense of fairness or unfairness, feelings of kindness or love, self-sacrifice, feelings related to competitiveness and moral punishment or retribution, moral "cheating" or hypocrisy, and inclinations for a wide variety of actions judged morally good or bad by (at least some within) a given society.

An historically key challenge to evolutionary psychology has been how altruistic feelings and behaviors could have evolved when the process of natural selection is based on competition between different genes. Theories addressing this have included kin selection and reciprocal altruism (both direct and indirect, and on a society-wide scale). Group selection theories have also, more controversially, been advanced.

Analytic philosophy
In 1986, Michael Ruse summarized the role of evolution as the source of ethical feelings: Our moral sense, our altruistic nature, is an adaptation—a feature helping us in the struggle for existence and reproduction—no less than hands and eyes, teeth and feet. It is a cost-effective way of getting us to cooperate, which avoids both the pitfalls of blind action and the expense of a superbrain of pure rationality.

In applying science to metaethics, Ruse writes: In a sense … the evolutionist's case is that ethics is a collective illusion of the human race, fashioned and maintained by natural selection in order to promote individual reproduction. … ethics is illusory inasmuch as it persuades us that it has an objective reference. This is the crux of the biological position.

History
In his 1893 book Evolutionary Ethics, Thomas Huxley allows that ethical sentiments have evolved but denies that this provides a basis for morality: The propounders of what are called the "ethics of evolution," when the "evolution of ethics" would usually better express the object of their speculations, adduce a number of more or less interesting facts and more or less sound arguments, in favour of the origin of the moral sentiments, in the same way as other natural phenomena, by a process of evolution. I have little doubt, for my part, that they are on the right track; but as the immoral sentiments have no less been evolved, there is, so far, as much natural sanction for the one as the other. The thief and the murderer follow nature just as much as the philanthropist. Cosmic evolution may teach us how the good and the evil tendencies of man may have come about; but, in itself, it is incompetent to furnish any better reason why what we call good is preferable to what we call evil than we had before. Huxley's criticism alluded to the is-ought problem developed earlier by David Hume and the related naturalistic fallacy developed later by G. E. Moore.