Is the threat of capital punishment really the foundation of good behavior?

Richard Wrangham embraces controversy, and appears to enjoy munching apples from carts he upsets himself. While his new book seems to be the history of an amalgam of moral and political virtues and vices, its thesis is actually the large claim that these have evolved; and he has no compunction about writing that the foundation stone of good behavior is the possibility of capital punishment (against it though he is in today’s world).

It’s not just that the logic of his argument requires this hypothesis; he has found examples of premeditated (‘proactive’), co-operative (‘coalitionary’) killing in the Pleistocene record, providing an empirical basis for his claims about our evolution. Chimpanzees have (reactive) murderous rages. There are also many attested examples of male chimpanzees bullying their most frequent sex partner, and of them committing infanticide, enough to cause us to look for the adaptive value of such behavior (in both cases such proactive aggression increases the male’s chances of perpetuating his own genes). Proactive aggression, Wrangham argues, provides a necessary evolutionary curb on the reactive sort.

Wrangham is British, and holds the chair of biological anthropology in the newish department of human evolutionary biology at Harvard. Like his fellow anthropologist, the late Sidney Mintz (also Richard Dawkins, Steven Pinker and Matthieu Ricard), Wrangham’s academic work changes our ideas about everyday life. In Catching Fire: How Cooking Made Us Human (2009), he made the once startling, now easy-to-accept, claim that the mastery of fire allowed our ancestors to evolve bigger brains by reducing the larger digestive apparatus needed to extract nutrition from raw food — that learning to cook (meat and grains) was essential to the evolution of our hunter-gatherer species. (What would be the consequences for the future development of H. sapiens of adopting a vegan diet?)

The Goodness Paradox takes the further step of looking at matters that are normally the province of philosophers — ethics and politics — from the viewpoint of evolutionary biology. That is, Wrangham is asking questions about how we behave to each other, in pairs, families, tribes, states and even larger groups, not from the ethicist’s perspective of how we ought to behave, or what some political philosophers see as their task of justifying how we do behave. He is attempting to determine how the way we in fact do behave had adaptive value for our species in the course of our ‘descent’ (as Darwin dubbed it) from primate ancestors. Although John Rawls, another great Harvard thinker, who dealt with moral and political philosophy, doesn’t even get an entry in the 38-page bibliography or the 12-page index, Wrangham seems to accept parts of Rawls’s argument invoking the ‘original position’ — presumably when our African ancestors acquired language 250,000 years ago.

Though it would enhance the value of this magisterial work if he had engaged more directly with contemporary philosophy, Wrangham’s goodness paradox boils down to the conflict between the positions of two philosophers. He characterizes the followers of Rousseau as saying, ‘We are a naturally peaceful species corrupted by society’, whereas ‘Hobbesians see us as a naturally violent species civilized by society’.

He regards H. sapiens as a chimera — the mythological beast with the body of a goat and head of a lion. His view is that,with respect to our tendency for aggression, a human being is both a goat and a lion. We have a low propensity for reactive aggression, and a high propensity for proactive aggression. The subject of this book is: ‘Why did this unusual combination evolve?’ How, in the course of evolution, were genes selected for which gave their bearers an advantage from being a reflective antagonist rather than an impulsive, easily provoked destroyer?

‘Reactive aggression’ leads individual humans to murder, and to lesser crimes, some categorized as manslaughter. Reactive killing of their own kind is common in chimpanzees, but less so in bonobos. The key to its opposite, proactive aggression, is premeditation. Obviously, there are some solo proactive aggressions, such as violent acts of revenge, or sadistic sexual fantasy. (I imagine this would include the duel, as honor killings pose no problem for Wrangham’s argument.) Note that ‘successful aggressors initiate action only when they perceive they are likely to achieve their goals at appropriately low cost’ — emphasizing that repeated aggressive behavior must have some adaptive value. Humans are capable of proactive aggression in groups; as families, clans, tribes, mafias, gangs or nation states, we can plan the killing of single individuals, wars, or wiping out entire other groups, genocide. Other primates cannot do this because they lack what we developed a quarter of a million years ago, language, which allows us to plot and conspire.

What restrains us? Wrangham’s answer: the same thing that prevents your pet dog from using your house as her lavatory — domestication. Domestication confers evident evolutionary advantages: unlike wolves, Lassie and her descendants have evolved a genetic make-up that enables them to cater to our ideas of hygiene, and in exchange we feed, house and cuddle them. Learning to avoid reactive aggression is a major aspect of domestication. Homosexuality is the welcome by-product of domestication — in bonobo society it promotes stability (and the claim about prenatal exposure to testosterone affecting the ratio of ring finger to index finger is true). If we domesticated our pets and farmyard animals, who domesticated us?

Wrangham insists that we did it ourselves; we are self-domesticated. Currently, human beings who allow themselves to be provoked into reactive aggression often wind up in the criminal courts. Our language-evolving ancestors in the Pleistocene needed an era or two to develop legal codes, so how did they discourage unhelpful behavior? Wrangham’s solution to this puzzle is, at first, alarming. As soon as there was language, there was the possibility of people agreeing to join together to punish reactive aggressors; but, of course, the only sanction that always worked was to kill the malefactor — socially approved homicide. ‘Capital punishment has been the ultimate source of law and order.’

Wrangham writes in the penultimate paragraph of this extraordinarily detailed, cogently argued, hugely important book:

I hope that, very soon, every country will abolish capital punishment, just as most countries have abolished other ancestral behaviors such as cannibalism, slavery and marital rape. Whether something is natural says nothing about whether we should give it a place in our lives today.

One finding is relevant to Brexit. ‘At the end of the Pleistocene, just before the beginning of agriculture,’ Wrangham writes, there might have been as many as ‘36,000 different societies, each with sovereignty over its home area’. Today’s figure is 195, and ‘as the number of independent societies has declined, so has the frequency of wars’. ‘In the distant future,’ he concludes, ‘humanity could become a single nation: extrapolations from past trends suggest a date between 2300 CE and 3500 CE for a World State to be established.’ Though this would minimize deaths from anarchic violence, ‘the possibilities of tyranny could enable other kinds to flourish’. Science fiction, or social science?

This article was originally published in The Spectator magazine.