Doris Schroeder discusses Evolutionary Ethics in the Internet Encyclopedia of Philosophy.
Evolutionary ethics tries to bridge the gap between philosophy and the natural sciences by arguing that natural selection has instilled human beings with a moral sense, a disposition to be good.
It implicitly acknowledges only humans have morality:
If this were true, morality could be understood as a phenomenon that arises automatically during the evolution of sociable, intelligent beings
Charles Darwin was the first to tackle evolutionary ethics:
The biologization of ethics started with the publication of The Descent of Man by Charles Darwin (1809-1882) in 1871. In this follow-up to On the Origin of Species, Darwin applied his ideas about evolutionary development to human beings.
But on what basis would evolution lead to morality?
Darwin would say that humans are biologically inclined to be sympathetic, altruistic, and moral as this proved to be an advantage in the struggle for existence.
Are any organisms moral agents? No. So evolution for billions of years has not acted on moral principles. Why should it suddenly be different for humans?
Spencer is more in line with the principles of evolution where whatever causes an individual to survive over another is the driving force of evolution:
Spencer elevated alleged biological facts (struggle for existence, natural selection, survival of the fittest) to prescriptions for moral conduct.
But what we find is the basic principle of evolution is opposite to the principle of morality:
his account of Social Darwinism is contentious to date because it is mostly understood as “an apology for some of the most vile social systems that humankind has ever known,” for instance German Nazism
So, both Darwin and Spencer failed to answer how biological evolution accounts for morality:
Moral good was previously identified with universal human pleasure and happiness by Spencer. If the evolutionary process directs us towards this universal pleasure, we have an egoistic reason for being moral, namely that we want universal happiness. However, to equate development with moral progress for the better was a major value judgement which cannot be held without further evidence, and most evolutionary theorists have given up on the claim (Ruse, 1995: 233; Woolcock, 1999: 299). It also is subject to more conceptual objections, namely deriving “ought” from “is,” and committing the naturalistic fallacy.
The fundamental issue of objective morality is the “ought” problem. Why ought humans behave in a particular way, regardless of how they actually behave?
It is this unexplained, imperceptible change from “is” to “ought” which Hume deplores in moral systems. To say what is the case and to say what ought to be the case are two unrelated matters, according to him. On the one hand, empirical facts do not contain normative statements, otherwise they would not be purely empirical. On the other hand, if there are no normative elements in the facts, they cannot suddenly surface in the conclusions because a conclusion is only deductively valid if all necessary information is present in the premises.
Thomas Huxley argues morality cannot be accounted for by biological evolution:
The thief and the murderer follow nature just as much as the philantropist. 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.
The article discusses what is the naturalistic fallacy:
“Good,” according to Moore, is a simple property which cannot be described using more basic properties. Committing the naturalistic fallacy is attempting to define “good” with reference to other natural, i.e. empirically verifiable, properties. This understanding of “good” creates serious problems for both Darwin and Spencer. Following Bentham and Mill, both identify moral goodness with “pleasure.” This means they commit the naturalistic fallacy as good and pleasant are not identical. In addition, Spencer identifies goodness with “highly evolved,” committing the naturalistic fallacy again. (Both Moore’s claim in itself as well as his criticism of evolutionary ethics can be attacked, but this would fall outside the scope of this entry.)
Evolutionists have abandoned using biological evolution to explain morality, but moved to sociobiology:
Despite the continuing challenge of the naturalistic fallacy, evolutionary ethics has moved on with the advent of sociobiology.
Ethics, following this understanding, evolved under the pressure of natural selection. Sociability, altruism, cooperation, mutual aid, etc. are all explicable in terms of the biological roots of human social behavior.
Morality requires defining what is good. But sociobiology does not offer this.
Wilson avoids the naturalistic fallacy in Sociobiology by not equating goodness with another natural property such as pleasantness, as Darwin did. This means that he does not give an answer to our first essential question in ethics. What is good?
Does it answer why we should be good?
However, like Darwin he gives an answer to question two. Why should we be moral? Because we are genetically inclined to be moral. It is a heritage of earlier times when less morally inclined and more morally inclined species came under pressure from natural selection.
This is simply an assertion without justification. No other animals are morally inclined. And if we are genetically inclined, that only answers the “is” rather than the “ought”.
Hence, we do not need divine revelation or strong will to be good; we are simply genetically wired to be good. The emphasis in this answer is not on the should, as it is not our free will which makes us decide to be good but our genetic heritage.
If it is simply genetics and we are hard-wired to be good, then it is not a moral issue. Judgment is required for a moral action. Someone has to choose between doing something good or evil. If it’s prewired, there is no moral judgment.
The article defines the fields of ethics:
For philosophy students, ethics is usually divided into three areas: metaethics, normative ethical theory, and applied ethics. Metaethics looks for possible foundations of ethics. Are there any moral facts out there from which we can deduce our moral theories? Normative ethical theories suggest principles or sets of principles to distinguish morally good from morally bad actions. Applied ethics looks at particular moral issues, such as euthanasia or bribery.
It closes with the unresolved issues of evolutionary ethics:
* How can a trait that was developed under the pressure of natural selection explain moral actions that go far beyond reciprocal altruism or enlightened self-interest? How can, for instance, the action of Maximilian Kolbe be explained from a biological point of view? (Kolbe was a Polish priest who starved himself to death in a concentration camp to rescue a fellow prisoner.)
* Could not human beings have moved beyond their biological roots and transcended their evolutionary origins, in which case they would be able to formulate goals in the pursuit of goodness, beauty, and truth that “have nothing to do directly with survival, and which may at times militate against survival?” (O’Hear, 1997: 203).
* Morality is universal, whereas biologically useful altruism is particular favoring the family or the group over others. “Do not kill” does not only refer to one’s own son, but also to the son of strangers. How can evolutionary ethics cope with universality?
* Normative ethics aims to be action-guiding. How could humans ever judge an action to be ensuring long-term survival? (This is a practical rather than conceptual problem for evolutionary ethics.)
* Hume’s “is-ought” problem still remains a challenge for evolutionary ethics. How can one move from “is” (findings from the natural sciences, including biology and sociobiology) to “ought”?
* Similarly, despite the length of time that has passed since the publication of Principia Ethica, the challenge of the “naturalistic fallacy” remains.
As the article admits, “evolutionary ethics still has a long way to go.”