HUMAN EVOLUTION AND ETHICS

The idea of evolution—that all organisms living and dead come by a naturalistic process of development from one or just a few forms—dates to the eighteenth century, but it was not until 1859 that Charles Darwin (in his Origin of Species) proposed the causal mechanism that today is generally thought the main force behind evolutionary change. Noting the potential population explosion existing among animals and plants, Darwin argued that there will be an inevitable struggle for existence and that this in turn leads to a natural selection of the ones with certain advantageous features. Adaptations like the eye and the hand are, therefore, the key mark of living beings.

The earliest of evolutionists all saw humans as being part of the process—usually the end point of a progressivist march upwards, from the primitive to the complex. Darwin initially said little about Homo sapiens, not because he did not want to include them in the evolutionary picture, but because he wanted first to establish the main outlines of the general case. In 1871 he did turn explicitly to humankind, and in the Descent of Man he argued that humans are completely and utterly part of the natural, living world. Drawing on a secondary mechanism, sexual selection, Darwin argued that the differences between men and women and between races are adaptive, although generally less for the immediate needs of survival and reproduction and more for the competition for mates between humans themselves.

Hominid History

It was around the time of the publication of the Origin of the Species that the first evidence of fossil humans were uncovered, remains of so-called Neanderthal Man, although it was not until the end of the nineteenth century that bones of the first unambiguous link between humans and their ancestors were discovered (Java Man, by the Dutch doctor Eugene Dubois). Since then a great deal of evidence has been unearthed about humans and their ancestors—the hominids. Most famously there is Lucy, Australopithecus afarensis, a being that lived in Africa about 4 million years ago, that walked upright and yet had an ape-size brain.

Modern thinking—based both on fossils and on molecular evidence—is that humans and the great apes (especially gorillas and chimpanzees) broke apart about 6 million years ago (Lewin). Most likely humans are more closely related to chimps than they are to gorillas. There was an upward growth of brain to the present size (about 1200 cubic centimeters), although there was a fair amount of diversification rather than one single line leading just to humans. Apparently all modern humans came from Africa about 150,000 years ago and are probably not related directly to the Neanderthals (who, incidentally, had slightly larger brains than present day humans). Sophisticated powers of speech are probably fairly recent (some argue that that was the key advantage of Homo sapiens over the Neanderthals), and full-blown culture and agriculture is very recent—only 10,000 years or more old.

Social Adaptations

As Darwin noted in the Descent of Man, apart from speech, one of the most distinctive aspects of humankind is that they are ethical beings. Humankind has a sense of right and wrong, and thus is led to act morally or ethically. Humans do things for others because they think them right rather than simply because they appeal to the self-interest of the doer. In fact sometimes people do things that are very much not in their own self-interest, like attempting to save a drowning child from a rapid river. If one takes a hard-line Darwinian position, arguing that adaptations are produced by selection to aid their possessors—I have eyes and hands because they help me—then the existence of the ethical sense is somewhat of a puzzle (Wright). Why do something for others when it puts the doer at risk? In the family situation, where the mother for instance aids her child, this is readily understandable. If the child does not survive then the mother does not reproduce. But what about the cases in which there is no relationship? One does not jump into the river only to save one's own children.

It has been stressed by students of animal behavior, especially by students of the behavior of higher organisms like the great apes, that there is no necessity to the appearance of an ethical sense and consequent behavior (Goodall, 1986). Ethical sense will not come into existence as a matter of course, even if the brain grows in size and power. There has to be a reason, and this reason most obviously is that this is an adaptation for social beings. There are great advantages to being social. Two or three can often do that which is impossible for one animal on its own—especially when the animals are foraging or hunting, practices that provide the high-protein supplies needed by organisms with high-maintenance adaptations like brains. At the same time, there are costs to being social, like the potential for spread of disease. Hence social animals tend to have (and need) special adaptations to exploit their sociality and to prevent the costs. Often, for instance, social animals have much better degrees of immunity against disease than do solitary animals.

Social animals—and humans are beyond all others, social animals—need abilities to help each other and at the same time to reduce intragroup strife. (It is for this reason that researchers often find that a better model for humans than close relatives like the orangutans—who are asocial—are less close relatives like the wolves—who are very social.) On the negative side, as one might say, humans are notable for not having very good physical methods of attack—their teeth, for instance, are puny besides those of chimpanzees. If one turns on a fellow human, the attacker is not very likely to rip the victim apart physically. Another important negative aspect of humans is the way in which the females do not come into heat or advertise their ovulation. There has been much discussion about the reason for this—sociobiologist Sarah Hrdy argues that a major reason for this behavior is that it keeps males guessing and hence in doubt about paternity, if they do not stay around and help with the family. Another reason obviously is that it keeps the group quieter and more stable—imagine trying to run complex social lives if women were often in heat.

On the positive side, a sense of morality is surely (in the opinion of Darwinian biologists) an adaptation for sociality. Organisms that take seriously their obligations to others are more stable and work together better than those that do not. Expectedly one finds what might at least be called protomorality—with senior group members enforcing behavior—in other social animals, especially (as emphasized by ethologist Frans de Waal) the chimpanzees.

What sort of morality might one expect an evolutionary process to produce? Will it decide, for instance, between utilitarians and Kantians? Probably not, for it will be too coarse grained for that—giving just basic directions that will then be fleshed out by culture. Significant is that both utilitarians (like Peter Singer) and Kantians (like John Rawls) have welcomed an evolutionary approach. Rawls particularly points out that it solves the big lacuna in any social contract approach to morality, namely how did the contract get put in place in the first place. It was not a group of old men around a fire but the genes. "The theory of evolution would suggest it is the outcome of natural selection; the capacity for a sense of justice and the moral feelings is an adaptation of mankind to its place in nature. As ethologists maintain, the behavior patterns of a species, and the psychological mechanisms of their acquisition, are just as much its characteristics as are the distinctive features of its bodily strictures; and these patterns of behavior have an evolution exactly as organs and bones do. It seems clear that for members of a species which lives in stable social groups, the ability to comply with fair cooperative arrangements and to develop the sentiments necessary to support them is highly advantageous, especially when individuals have a long life and are dependent on one another. These conditions guarantee innumerable occasions when mutual justice consistently adhered to is beneficial to all parties." (Rawls, p. 502–503).

Altruism

The technical biological term for organisms giving to others, at cost to themselves, is altruism (Wilson, 1975). It is important to note that this is a metaphor—it does not necessarily mean the altruism to which one refers when speaking of a good person, as in: Mother Teresa showed great altruism towards the poor of India. Ants helping others in the nest would be called altruistic, even though (as against the literal sense) there is clearly no implication that the ants consciously set out to do the right thing. Human altruism, or goodness as one might say, is therefore a sub-class of the general biological notion of altruism.

But why have humans developed so elaborate a method of interacting as a moral sense? Why, unlike the ants, are humans simply not hard-wired? There is a simple reason. Being hard-wired has virtues—there is no need for learning. The cost however is high. One cannot regroup and do something else if the situation changes. An ant will behave instinctively even though (because of changed circumstances) it may be doing itself or its nest a harm. Generally this does not matter, because ants are produced cheaply—a queen can afford the loss of a few thousand. Humans on the other hand are beings that require a great deal of care and only a few can be produced. (Technically humans are K-selected as opposed to ants that are r-selected.)

Humans need the ability to respond to change, especially to change brought on by fellow species members. A moral sense allows humans to do this. They can assess different or changing situations and act in the best interests of themselves and their brood. As philosopher Daniel Dennett has pointed out, this fact diffuses the oft-brought charge that any evolutionary approach to ethics must fail because it presupposed that humans have no real choices, they are genetically determined. It is true that humans are part of the causal chain, but they have a dimension of freedom not possessed by the ants. (In a sense humans are like the rockets that can adjust to moving targets, whereas ants are like cheap rockets that cannot change direction once fired.)

Selfish Genes

How does selection bring on altruism (using this now in the biological sense)? There is much debate. After Darwin most biologists assumed that selection could work for the group and that morality would emerge automatically—a species member that helped another was thereby helping the species. Famous was the notion of mutual aid, promoted by the Russian-born anarchist, Prince Petr Kropotkin. In the 1960s there was a sea change in opinion (going back in fact to the insights of Darwin himself). It was pointed out that group selection (selection for the benefit of the group over the individual) was too open to cheating. A selfish individual could take advantage of others (Williams). Hence came what Richard Dawkins has labeled the selfish gene view of the evolutionary process—in some sense, all adaptations (including social and behavioral adaptations) must be related back to self-interest. If they do not help the individual first and foremost, they will be wiped out.

The selfish-gene way of thinking was applied very fruitfully to the problem of altruism. William Hamilton (1964a, 1964b) introduced the idea of kin selection, arguing that altruistic behavior could be a very good strategy if one is helping others who share the same copies of genes as oneself—one is thereby reproducing by proxy as it were. Most dramatically Hamilton solved the question of why sterile workers (always female) in the hymenoptera (ants, bees, and wasps) devote their lives to their nest mates. In the hymenoptera only females have two parents, hence females are more closely related to sisters than to offspring and so it pays to raise fertile sisters rather than fertile daughters. More generally Hamilton showed that in any animal, if the conditions are right, then altruism will come into being.

Robert Trivers introduced a more general mechanism, that can function between non related organisms (even organisms of different species). Reciprocal altruism, so-called, suggests that if one gets a benefit by helping others, especially if others will thereby be more likely to help in response, then altruistic adaptations should come into play. Essentially, as Darwin himself realized, this is a case of: "If you scratch my back, then I will scratch your back." In complex, thinking animals like humans, one could expect this to be a powerful mechanism. There will be times—when one is young, old, or sick—when even the most powerful will appreciate aid. In conjunction with this will be memory, so that humans are able to enforce reciprocation, and learn quickly to exclude those who do not play the game. Those who receive and do not give will soon be excluded.

More generally the ideas and techniques of game theory have been applied profitably to questions of sociability generally and morality particularly (Maynard Smith 1982). Sophisticated models can now be built showing how and when particularly moral traits might be expected to emerge (Skyrms). At the same time, experimentation can show whether or not specific hypotheses are well-taken. There have, for instance, been serious studies on questions about when commitments are kept and when broken. Also on how people respond to fairness or the lack thereof.

Group Selection

Criticisms of this whole selfish-gene approach tend to be of two kinds. On the one hand, there are more philosophical objections. Mary Midgely objects that the whole point about morality is that it is not selfish, nor is it simply enlightened self-interest. Morality means giving without hope or expectation of reward. But this objection is to misunderstand both the theory and the metaphor. Selfish genes do not necessarily cash out as selfish people. In fact humans might operate more efficiently (in their biological interests) if what they do is done precisely because they do not think it self-centered. One must make a distinction between what Dawkins (1982) labels the replicators (the genes) and the vehicles (the whole organism). To speak of selfish genes is to say that selection makes characteristics that rebound ultimately on the actor. Genes themselves are neither selfish nor unselfish. They just are. Individuals (vehicles) might be selfish at times and (genuinely) altruistic at times. It just depends on the situation.

On the other hand, there are objections of a more biological nature. Every biologist recognizes that sometimes a group selective force might overcome the individual selective force. For instance in a constantly fragmenting and reuniting population (that is with many sub-populations forming and disappearing) and with strong pressure towards altruistic behavior, group attributes might emerge before they can be eliminated by individual forces—these attributes might persist by being merged into the whole group. It has been suggested that the maintenance of sexuality might result from such a group force (Maynard Smith, 1978). (Others however, including Hamilton, think that sexuality can be explained at the individual level [Hamilton et al.].)

In particular, with the human case, some think that a group selective force might be the key factor in altruism (human, literal altruism, that is). Biologist David Sloan Wilson and philosopher Elliott Sober argue this way. Illustrating their position with a short story by Stephen Crane, in which a group are caught in a life boat and can survive if and only if they all work together, Wilson and Sober conclude that only a group analysis will explain the successful outcome. Because of our ability to think and plan, humans can and do overcome the forces of individual selection and are shaped by group forces. "Behaving as part of a coordinated group is sometimes a life-or-death matter in which the slightest error—or the slightest reluctance to participate—can result in disaster for all. Situations of this sort—in which the members of a group are bound together by the prospect of a common fate—have been encountered throughout human evolution, with the important fitness consequences, so it is reasonable to expect that we are psychologically adapted to cope with them" (Sober and Wilson, p. 335–336). In 2002 Wilson extended his analysis to look at issues to do with the evolution of religion and its moral codes. He argues that something like the Calvinism of sixteenth century Geneva can be explained in terms of a kind of group selection, where adaptations appear for the benefit of the whole against the individual.

This is still very contentious. English sociobiologist John Maynard Smith argues that nothing here makes even probable the group selection hypothesis. He argues that even humans are unable to overcome the strong tug of the selfish gene. In the lifeboat case, there is no need to suppose other than that each individual saw that it was in his own interests to cooperate. As Ben Franklin said on signing the Declaration of Independence: "Gentlemen, we must all hang together or assuredly we shall all hang separately."

Conclusion

In conclusion therefore the best assessment is that evolutionary biology has brought many new insights to our thinking about human nature, including human moral nature. It would nevertheless be overly optimistic to think that we are even close to ending all debate or offering all the materials needed to solve all outstanding problems.

michael ruse

BIBLIOGRAPHY

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