The Evolution of Morals
The Evolution of Morals


The evolution of morals is explained in terms of (1) the evolution of innate human sociality and its bearing on morals, and (2) bridge theories which give usage descriptions of moral terms. From facts about innate sociality and language I shall derive “S believes A is wrong,” but not “A is wrong.” Social morality evolved as a combination of group egoism and impartial morality, each explainable causally in terms of evolved human sociality. Another bridge theory gives conditions under which revenge turns into retributive justice.

“Any animal with social instincts
would inevitably acquire a moral sense
as soon as its intellectual powers
became like those of humans.”
Charles Darwin, The Descent of Man, Ch. 4

Table of contents

We have ancestors, 100,000 years ago, I’ll guess, who had no morality–no moral concepts, moral beliefs or moral codes. We have more recent ancestors who did have moral beliefs and moral codes. What happened in between? By what describable changes did our earlier ancestors’ anger at theft become moral disapproval? There are two parts to my explanation of this change: an account of how most of the content of current morality resulted from the evolution of love and human sociality, and second, bridge theories, which are lists of word usage descriptions that tell us when a positive or negative feeling turns into a moral belief. From facts about innate sociality and language I shall derive “S believes A is wrong,” but not “A is wrong.” Moreover, unlike most definitions of “good” or “morally wrong,” a description of usage can convey the function of moral language without designating anything that is morally right or wrong.

The consensus of paleoethnologists is that humans evolved biologically to be social animals, which included the evolution of certain wants, fears and anxieties required for social living and which then were culturally reinforced. Even in pre-linguistic societies some behavior had to be taboo and deterred by fear of punishment or banishment.

Philosophers and scientists have long tried to explain altruistic motives, given that they appear to diminish likelihood of survival and therefore ought to be selected against in evolution (Hamilton, 1964). It is widely believed either that only perceived self interest can move us to act, or that both morality and self-interest are effective motives for action. Both alternatives depend on a false dichotomy that gets its plausibility from the distinction between particulars and kinds. The object of self-interest is a particular, not a kind of thing: my self-interest attends to me but even in the same circumstances not necessarily to my clone or identical twin. But morality, it is said, may judge a person only by qualities other people can have too such as cruelty, kindness or unfairness. No rule of social morality can refer to me and consequently moral terms designate qualities, not particulars.

However, group egoism generates moral judgments that combine descriptions and egocentric particulars: “Because it’s mine” is as fundamental as “because it’s me.” Group egoism explains a large part of social morality including obligations based on love and loyalty to my mate, my children, my clan or country. It can conflict with egoism as well as with impartial principles.

It will not do simply to say that if I may do something everyone may, for the natural response is, “Every what?” Every fellow club member, fellow American, fellow Christian, fellow human being, rational being, suffering being? These nested and overlapping domains of course make morals complicated. Social morality’s constraint within domains defined by group loyalties and social identities shows there is no sharp line between self-interest and altruism and that the possibility of altruism is not the fundamental question of moral psychology. The neo-Darwinian explanation of group loyalties as well as kin selection is that they are non-universalizable outside of a designated group because they fix on the physical coordinates of where one’s DNA type is likely to be located, or where protectors or caretakers of it such as one’s clan or country are located.

1. Kin selection, as developed by William D. Hamilton (Hamilton, 1964), is caring for relatives according to their degree of relatedness and it evolved independently of motives or understanding, as in the clear case of the social insects. Human parents value their child, who has one half of each parent’s DNA, more than their grandchild, who has one fourth, and their grandchildren more than mere friends.

2. Increasingly prolonged infancy and the dependence of young children were made safer by the evolution of parental love, loss of estrus and sexual romantic love. Each of these increased the likelihood that dependent young children would have both parents around long enough to survive on their own. Love, like loyalty, makes certain behavior feel necessary independently of considerations of self interest. It is our strongest passion, explains our strongest feelings of obligation because they most directly protect our DNA, and shape our world. Love is directed to a particular and not to a kind of thing because it evolved to protect one’s children, who have a particular location.

3. A number of mutually reinforcing things evolved to make us innately social, including kin selection, love, group loyalty, the felt need to belong, and fear of banishment. Feelings of security when living amongst familiar people with familiar social practices and in familiar spaces, fear of being outcast, and the world-wide development of ritual and ceremony, are all constitutive of human sociality.

Kin selection cannot explain altruism on the broader level of the clan. What was selected for was clan loyalty and other varieties of group egoism which do not depend at all on how close one is genetically to fellow clan members. Group loyalty was selected for because people in clans were safer than those who lived alone or just with immediate family.

Evolved emotional predispositions include our need to belong to groups and acquire social identities and loyalties, all of which makes the group fare better and thereby protect us better than if there were no group loyalties and social identities. Love, kin selection and innate sociality constitute the evolutionary basis of social morality and explain actions felt to be necessary independently of self interest. Arriving more recently than kin selection and love, loyalty made individuals emotionally dependent on clans and willing to sacrifice for them. This is in our DNA because those who clove to their clan were more likely to survive and pass on this disposition, whereas those who lacked such an attachment were more likely to wander off and starve, be killed by an enemy tribe or be dinner for a big cat. Another way to view a clan is as an advantageous environment to which individuals adapted.

What we now require is a bridge theory–something which, based on the preceding, says how ordinary likes and dislikes differ from moral beliefs. The bridge theory lists conditions I call marks of the moral. Satisfying the marks of the moral tells us that S believes or at least asserts that A is immoral, but it does not tell us that A is immoral. Our ancestors had moral beliefs and moral codes when their aversions, hates and likings came to satisfy the marks of the moral. If their beliefs only partly satisfied these conditions they would have had borderline cases of moral beliefs. We want to think a judgment is either moral or non moral, but in human affairs almost everything shades off into what it isn’t. A dislike or negative attitude toward something turns into a moral belief or moral judgment when enough of the following features characterize it:

  • 1. It concerns benefit and harm to humans and the higher animals.
  • 2. It is communicated by special words.
  • 3. It appeals to reasons that have a general appeal in the community.
  • 4. It is universalizable, that is, a person is willing to judge similar cases similarly, even when one of these cases concerns oneself.
  • 5. It can require actions contrary to self-interest.
  • 6. It is taught to the young.
  • 7. It is all things considered, that is, it judges an action in the light of self-interest, effects on others, and anything else thought relevant.
  • 8. It often is promulgated ritually and ceremonially, as a way of indicating that the community and not just an individual is speaking.
  • 9. It expresses a positive or negative attitude toward the object of the judgment.
  • 10. It is urged upon the listener and rejection of what is urged is answered with anger or argument.
  • 11. It is preached in formal religious and political settings.

If a clan spoke, reasoned and acted in ways 1-11 they had morals, but if in not enough of these ways they did not. The list aims to describe the contexts and conditions under which reasonably educated English speakers use “morally wrong,” etc., and is what I suggest should replace definitions of moral words. This is in the spirit of Ludwig Wittgenstein’s admonition, in Philosophical Investigations, to consult the use, not the meaning. These eleven conditions, singly or together, carry neither moral realist nor emotivist theoretical implications.

Before they had language our ancestors had to be social. The emotional predispositions for sociality had to evolve before the evolution of language, the latter requiring the evolution of the brain’s speech center, the voice box, infant babbling and, of course, people to talk to. Could they have moral beliefs? My suggestion is they could not if they couldn’t talk, and therefore couldn’t give reasons and argue. The evolutionary sequence had to be sociality first, then language, and finally morals.

We can conjecture how particular moral ideas arose. For example, sense of unfairness, a moral idea, very likely can be deconstructed into clan rejection anxiety. The mechanics of unfairness is relatively straightforward; it is being denied benefits others receive in similar circumstances. A clue to understanding this is the outrage and anger perceived unfairness elicits, typically more than from equally harmful illnesses, accidents or combat. Unfairness has little to do with degree of perceived harm and everything to do with actual or symbolic exclusion, with being treated as an outsider or non-member when one is not an outsider.

When young people are not shamed or blamed for behavior for which others are shamed and blamed, they are being treated like outsiders or non-members, that is, like invading Huns or wild animals. The result is alienation, a loss of sense of belonging and hence loss of one’s social identity. Given that these young people evolved to be innately social animals like the rest of us, they seek substitute social identities in gangs or counter-culture groups. Alienation kills sense of belonging, and hence pride and shame on which traditional social control largely depends.

Another bridge theory provides an explanation of retributive justice. It is often said that retribution is revenge and therefore has no moral status. Retributivists explain retribution in terms of desert, reciprocity, or making things even again, so as to distinguish the moral idea of retributive justice from the non-moral (or immoral) idea of revenge. I accept that retribution is a moral idea and revenge is not. However, explaining retributive justice without incorporating revenge is hopeless. Revenge turns into retributive justice when the desire to harm wrongdoers is constrained by the following empirical conditions (or by an improved version of them):

  • 1. Those who decide how, if at all, to punish A are neither A’s relatives or friends nor stand to gain or lose from the decision.
  • 2. Similar punishments are given for similar offenses.
  • 3. The punishment is decreed in a setting of formality and ritual, which conveys the idea that the community and not just an individual is speaking.
  • 4. Punishments are not secret but are codified and promulgated by an appropriate official body.
  • 5. Criminals must be believed to have actually done the deed for which they are being punished.

Retributive justice thus is sanitized revenge. Vengeance, the idea of a person being owed something bad, is fundamental to humans, showing itself not just in criminal justice but also in countless informal interactions such as ignoring or snubbing someone, cursing them, ignoring them, refusing to invite or to help someone, assaulting them and so on. Personal accountability is a primary way societies distinguish members from non-members. The anthropologist Christoph von Furer-Haimendorf (Furer-Haimendorf, 1971) explained criminal justice as the institutionalization and ritualization of retaliation as societies became sufficiently secure and complex.

But are moral judgments true or false, do they assert moral facts? These moral realist claims are logically compatible with the explanation of morality I have laid out. But must genuine moral judgments assert moral facts or be literally true or false? Many people, philosophers as well as non-philosophers, believe this is part of what moral words mean and they would feel that morality is an illusion or a fraud if moral judgments were never true or factual.

Suppose there is an antiquated community where shepherds tell time, direction and the seasons by watching the stars and planets. When asked what stars are they say the stars are gods. One of them is persuaded, with the aid of telescopes and a little schooling, that the stars are not gods. He might respond, “Rats, stars don’t exist” and stop looking at them, on the ground that part of what he means by “stars” is “gods.” Or he might be persuaded that what he called stars are still useful for telling time, etc., and that he might as well keep calling them stars. If he does, we need not conclude that “gods” isn’t part of what he meant by “stars.” Rather, he was persuaded to give up part of what he meant by “star” in the light of plausible empirical claims. We chiseled off part of what he meant by “star” but the ways he used the stars were not affected. So too, even if part of what people meant by “morally right” and “morally wrong” were moral facts, and moral facts do not exist, might we not chisel that off without their needing to conclude that nothing is right or wrong?

The salient truths are the empirical ones: Our society and our security depend on honesty, fairness, and keeping unwanted hands off other people’s bodies and property. The differences between our morals and premoral clans that just yelled and banished people for violating taboos are smaller and more enlightening than some people might think.


  1. Boyd, Robert, 2006, “The Puzzle of Human Sociality,” Science, December 8
  2. von Fuerer-Haimendorf, Christoph, 1964, Morals And Merit, Chicago, University of Chicago Press
  3. Hamilton, William D., 1964, “The Genetical Evolution of Social Behavior, I,” Journal of Theoretical Biology,
  4. Oldenquist, Andrew, 1984, “Loyalties,” Journal of Philosophy;
  5. Oldenquist, Andrew, 1988, “An Explanation of Retribution,” Journal of Philosophy
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