Spring 2003 Vol. 10, Issue 2
By David Sloan Wilson, PhD
Professor, Departments of Biology and Anthropology
Binghamton University, New York
Evolution and morality often seem to occupy opposite corners of human thought. After all, words such as 'bestial' refer to the very worst things that people do to each other. If we are mere beasts, what is to prevent us from behaving in a bestial fashion? So many people are reluctant to accept the theory of evolution, or to connect it to anything relevant to their own lives, for fear of the perceived dire moral implications if it were true.
The actual relationship between evolution and morality is more complex and interesting. Evolution can explain our capacity for moral behavior in addition to our capacity for immoral behavior, and understanding the biological basis of moral systems can make them stronger rather than weaker.
Every year I explain the biological basis of morality by asking my students to tell me what they associate with morality. One side of the blackboard becomes filled with their suggestions: charity, generosity, altruism, forgiveness, courage, honesty. There is very little disagreement about what constitutes goodness, at least on a broad scale. Then I ask for immoral traits and I can barely write fast enough to list their suggestions on the other side of the board: selfishness, deception, murder, cowardice, hypocrisy.
"What will happen if we place the epitome of a moral person and the epitome of an immoral person together on a desert island?" I ask my class. The answer is a nobrainer. The moral person will become shark food within days. Then I ask a second question: "What will happen if we put a group of moral people on one desert island and a group of immoral people on another desert island?" The answer to this question is also a nobrainer. The moral people will work together to escape the island or turn it into a little paradise, while the immoral people will turn their island into a living hell. Now my third and final question: "What will happen if we add a few immoral people to the moral island and a few moral people to the immoral island?" The answer to this question is not so easy, but is some messy combination of the decisive answers to the first two questions.
As simple as this class exercise might seem, it shows that there is nothing unbiological about the golden rule, the ten commandments, and all the other virtues preached by religious and ethical traditions around the world. Societies that adopt these virtues will survive and reproduce fabulously well and usually are encouraged to do just that by the injunction to be fruitful and multiply. The main problem with explaining morality as a biological adaptation 1 is its vulnerability to subversion from within. What we call immoral is parasitic and predatory on what we call moral. There's trouble in paradise as soon as the first immoral person paddles over to Virtue Island.
The formal version of my class exercise is called multilevel selection theory. Natural selection can operate among individuals within social groups (within group selection), but it can also take place among social groups within a larger population (among-group selection).
Within-group selection tends to favor the traits that we associate with immorality, that benefit the self at the expense of others and the group as a whole. Among-group selection tends to favor the traits that we associate with morality, which benefit others and the group as a whole, often at the expense of the self.
Species differ in the degree to which their properties have been molded by within- vs. among-group selection. Social insects (bees, wasps, ants and termites) are famous for their altruism and service to their colonies. What this means in evolutionary terms is that most traits in social insects evolved by increasing the fitness of the entire colony, relative to other colonies (among-group selection), rather than by increasing the fitness of the individual insect, relative to other insects within the same colony (within group selection). However, some traits in social insects have evolved by within group selection, such as workers laying their own eggs rather than participating in the economy of the hive. Other traits have evolved to prevent these "cheating" behaviors. Despite the many differences between social insect colonies and human social groups, the mix of cooperative, exploitative and policing activities in social insect colonies has an unmistakably human appearance.
Biological systems consist not merely of two tiers (individuals and groups) but many tiers. Individuals are themselves groups of lower-level units such as genes and cell lineages, and social groups are nested within larger groups and multispecies ecosystems. When multilevel selection theory is applied to the entire multitier hierarchy, striking discoveries result that cause our own moral systems to be seen as part of a much larger picture. For example, most genes and cell lineages evolve by increasing the fitness of the whole organism, relative to other organisms, but some evolve by spreading at the expense of other genes and cell lineages within the same organism. Just like cheating bees and individuals regarded as immoral in human groups, these "selfish" elements are favored by natural selection within their collectives but undermine the collective as an adaptive unit. We regard them as diseases but they are not foreign organisms that have invaded our bodies; instead they are a part of us that succeed at the expense of the rest of us, rather than by contributing to the communal effort! Examples include cancers and genes that subvert the usually fair process of meiosis. In the case of meiosis, division usually assures that all genes comprising an individual have the same chance of being represented in the gametes. The phenomenon of meiotic drive involves genes that "cheat" by subverting the "fair" rules of meiosis, getting into more than 50 percent of the gametes, but often decreasing the fitness of the individual as a result. Similarly, evolution in foreign disease organisms can favor traits that cause some strains to succeed at the expense of other strains within the same host, or by causing the entire disease population within the host to spread to new hosts. These examples of multilevel selection have important medical implications, in addition to their relevance to the study of morality.
Until very recently (by evolutionary standards) our ancestors lived in small groups who hunted and gathered for a living. Just as for bodies and beehives, traits could evolve by benefiting individuals at the expense of others within the same group, or by benefiting the whole group relative to other groups. Both levels of selection have been important in human evolution, which may well explain our morally ambivalent nature. We are capable of perceiving what is good for others and acting accordingly at least some of the time, but we are also sorely tempted to behave in ways that are regarded as immoral. We have a passion for evaluating the moral conduct of those around us and often judging them more harshly than we judge ourselves. Finally, even our limited capacity for morality has a disturbing way of stopping at the boundaries of our groups, giving way to behaviors such as genocide that are judged as the ultimate in immorality by the members of other groups.
Cultural evolution can be a multilevel process in addition to genetic evolution. A few years ago I encountered a religious passage written 350 years ago that stated "True love means growth for the whole organism, whose members are all interdependent and serve each other...We see the same thing among the bees, who all work with equal zeal gathering honey." This comparison between a body, a beehive and a religious community made me wonder if multilevel selection could make as much sense of religious groups as the other collective units of life. I believe that the answer is "yes." 2 In addition, the same evolutionary principles can explain other human social organizations - such as politically and ethnically defined groups - leading to a truly general theory of "unifying systems" in our own species and in life in general.
The possibility that human moral systems (religious and otherwise) can be explained as a product of evolution has only recently become an active field of inquiry and will surely be regarded as controversial against the background of previous intellectual traditions, religious and secular alike. In addition to challenging conventional views of religion, it also challenges major paradigms in the social sciences, such as individual selfinterest as a grand explanatory principle. However, far from threatening basic moral values, an evolutionary theory of "unifying systems" can strengthen them and lead to practical solutions to modern societal problems. After all, if morality is an adaptation that can evolve under appropriate social and environmental conditions, and if evolution can take place by fast-paced cultural processes in addition to slow-paced genetic processes, then by establishing the appropriate conditions we can influence the future course of moral evolution. 1
Footnotes
1 Moral behavior, such as members of a group altruistically helping each other, confers an evolutionary survival advantage. Moral systems have therefore evolved through natural selection and are deeply rooted in biology rather than simply in reason or religious revelation. 2
2 Wilson D S. >Darwin's Cathedral: Evolution, Religion, and the Nature of Society. Chicago, University of Chicago Press, 2002.
Suggested reading
Boehm C. Hierarchy in the Forest: Egalitarianism and the Evolution of Human Altruism. Cambridge, MA: Harvard University Press, 1999.
Smith M, Szathmary E, Szathmary J. The Origins of Life: From the Birth of Life to the Origin of Language. Oxford: Oxford University Press, 1999.
Seeley T. The Wisdom of the Hive. Cambridge, MA: Harvard University Press, 1995.
Sober E, Wilson D S. Unto Others: The Evolution and Psychology of Unselfish Behavior. Cambridge, MA: Harvard University Press, 1998.
in collaboration with
Dartmouth-Hitchcock Medical Center
The opinions expressed in the journal, Lahey Clinic Medical Ethics,
belong to the individual contributors and do not represent the institutional position
of Lahey Clinic on any subject matters discussed.
