The Cultural Tradition of Nut-Cracking with Tools Among Chimpanzees

Using stone and wooden tools as anvils and hammers to open nuts is a cultural tradition among some chimpanzees.  A series of YouTube videos of this behavior can be found here. 

Chimpanzees use hammers of stone or wood to crack various species of nuts on anvils of stone or root (McGrew 2004, 119-120).  Soft-shelled nuts can be cracked with wood.  Hard-shelled nuts can be cracked only with stone.  The best stone hammers are carried from one worksite to another.  Nut-cracking is a skilled activity, because the chimp  must apply just the right force in the right way to crack the nuts open.

Using tools for cracking nuts is one of the many behavioral traits that show a cultural diversity among chimpanzees that is comparable to the cultural diversity of humans (Boesch 2012, 219-225; McGrew 2004, 126-128).  Comparing the wild chimpanzee communities across Africa shows that each community has its own distinctive repertoire of behavioral traditions that indicates the cultural history of each community.  Hammer and anvil use is one example of variation in material culture.  Nut-cracking is found only in west Africa, and not at all in central or east Africa.  Most of the nut-cracking is found near the convergence of the borders of eastern Liberia, western Ivory Coast, and southeastern Guinea, which suggests that this cultural tradition was invented in this area and then diffused outward.  Remarkably, the chimpanzees that have been studied for the longest time--those in Gombe and Mahale in east Africa--have never shown a single case of cracking nuts with tools, although the nuts are there, and although the local people use stones to crack nuts.

As McGrew (2004, 126) has suggested this resembles the striking differences in cultural traditions often found among human beings, as in the contrast between the foraging Tasmanians and the aboriginal foragers of the Australian mainland.  The Tasmanians did not have hafted stone tools, bone tools, nets, fish hooks, shields, spear throwers, boomerangs, canoes, or fire-making, although all of this was part of the culture of the Australian foragers.

Some people have argued that the behavioral diversity among the chimpanzee communities in Africa could be a product of differences in the ecological environments or genetic differences between the communities.  But a study of three neighboring communities of chimpanzees in the Tai National Park in the Ivory Coast showed cultural differences in nut-cracking that could not be explained by ecological or genetic differences (Luncz, Mundry, and Boesch 2012).  These three groups live in the same forest environment.  And since females frequently migrate out of their natal groups at maturity to join another group, great genetic differences between the communities are unlikely.  All three communities use hammers to crack nuts, but they differ in their selection of hammer material and hammer size.  During the nut season, the nuts are harder early in the season and softer later in the season.  Harder nuts require stone hammers to open them.  Softer nuts can be opened with wooden hammers, which are more plentiful.  Two of the communities tended to switch from stone hammers to wooden hammers during the season.  But one community tended to stay with stone hammers the entire season, which suggested a distinct cultural tradition of hammer selection.

Human cultural traditions often have a long history, and human tool use can even be traced back into the prehistoric Stone Age.  The same is true for the chimpanzee cultural tradition of tool-use in cracking nuts.  In 1843, there was a report of chimpanzees in west Africa using tools to crack nuts, and this was cited by Darwin in The Descent of Man as evidence for cultural traditions of tool-use among apes (2004, 102-103).  In the 16th and 17th centuries, some Portuguese people reported seeing this in Sierra Leone (Sept and Brooks 1994).  This would suggest that this cultural tradition has been in west Africa for at least 400 years.

Recently, scientists have reported archaeological evidence for chimpanzee sites for cracking nuts with tools that can be dated as at least 4,300 yeas old (Mercader 2007).  The ancient tools at these sites show use-wear patterns and microscopic organic residues that identify them as chimpanzee tools rather than human tools.  This shows how the methods of archaeology used to study the prehistoric human Stone Age can be used to study the prehistoric chimpanzee Stone Age, and from this has emerged a new discipline--"primate archaeology" (Haslam et al. 2009).

The opponents of biopolitical science often argue that the study of primate behavior has no application to human behavior, because only human beings are cultural animals.  Even many of the proponents of biopolitical studies--like John Hibbing and his colleagues--concede that while biology can illuminate the genetic bases of politics, biology has nothing to say about cultural history. 

This research on chimpanzee culture refutes this stance by showing that nonhuman animals do have culture and cultural traditions, and that these cultural traditions are historically contingent.  The study of cultural history is thus as much a part of biology as is genetics.

It is true, however, as I have indicated in various posts, that symbolic evolution is uniquely human, and therefore human culture shows a capacity for symbolic niche construction that chimpanzees and other animals do not have.  I have written about the history of Lockean liberalism as symbolic niche construction. 

A biopolitical science would study political life at four levels: genetic evolution, behavioral cultural evolution, symbolic cultural evolution, and individual political judgment.

REFERENCES

Boesch, Christophe. 2012. Wild Cultures: A Comparison Between Chimpanzee and Human Cultures. Cambridge: Cambridge University Press.

Darwin, Charles. 2004. The Descent of Man. 2nd edition. New York: Penguin Classics.

Haslam, Michael, Adriana Hernandez-Aguilar, Victoria Ling, Susana Carvalho, Ignacio de la Torre, April DeStefano, Andrew Du, Bruce Hardy, Jack Harris, Linda Marchant, Tetsuro Matsuzawa, William McGrew, Julio Mercader, Rafael Mora, Michael Petraglia, Helene Roche, Elisabetta Visalberghi, and Rebecca Warren. 2009. "Primate Archaeology." Nature 460:339-344.

Luncz, Lydia, Roger Mundry, and Christophe Boesch. 2012. "Evidence for Cultural Differnces Between Neighboring Chimpanzee Communities." Current Biology 22:922-926.

McGrew, William. 2004. The Cultured Chimpanzee: Reflections on Cultural Primatology. Cambridge: Cambridge University Press.

Mercader, Julio, Huw Barton, Jason Gillespie, Jack Harris, Steven Kuhn, Robert Tyler, and Christope Boesch. 2007. "4,300-Year-Old Chimpanzee Sites and the Origins of Percussive Stone Technology." Proceedings of the National Academy of Science 404:3043-3048.

Sept, Jeanne M., and George E. Brooks. 1994.  "Reports of Chimpanzee Natural History, Including Tool Use, in 16th- and 17th-Century Sierra Leone." International Journal of Primatology 15:867-878.

Political Assassinations Among Chimpanzees?

On January 7, 1974, six adult chimpanzee males of the Kasakela community in Gombe National Park, Tanzania, attacked as a gang against a lone male from the neighboring Kahama community.  Although the victim was still alive when his attackers left, he was never seen again, and so he was presumed to have died.  One month later, another gang of six Kasakela males brutally attacked another lone male from the Kahama community, who also disappeared and was presumed dead.  Over a period of three years, such attacks led to the extinction of the Kahama community, and the Kasakela community took over the territory of the Kahama community.

When Jane Goodall first reported this violent warfare between two chimpanzee communities, it shocked the world, because Goodall had previously reported that chimpanzees were peaceful--indeed, much more peaceful than human beings.  After years of studying this intercommunity warfare at Gombe, Goodall concluded that this was evidence for an instinctive propensity to warfare in the primate species that is the closest living evolutionary relative of human beings, and thus suggests the possibility that such warfare is an inherited propensity for human beings.  Richard Wrangham, Michael Wilson, and others have elaborated this "chimpanzee model" for explaining the evolution of warfare among human ancestors.

Goodall's observations of chimpanzee intercommunity violence have now been confirmed by similar observations from many chimpanzee communities across Africa.  What is most surprising about this is that lethal violence within chimpanzee communities is extremely rare (Newton-Fisher and Emery Thompson 2012).  Chimpanzees often become aggressive in conflicts with one another, but they usually resolve their conflicts without physical contact; and even if there is some physical violence, it is almost never lethal, even though chimpanzee canines are powerful weapons for wounding and killing victims.  Most aggression between adult males consists of bluffing attacks without physical contact--threatening gestures and vocalizations and charging displays.  (This is also true for human beings, who often engage in bluffing displays of aggression, but for whom homicide is rare, despite the publicity given to homicidal violence.)

After decades of observations of chimpanzee communities across Africa, there have been only four documented cases of lethal violence between adult males of the same community, in which a coalitional gang of adult males killed a lone victim.  Kaburu et al. (2013) point out that the individuals killed in these cases were either low-ranking males or they were previously deposed alpha males.

In the revised edition of his Chimpanzee Politics, Frans de Waal reported that in the summer of 1980, Luit--the alpha male of the chimpanzee community in the Arnhem Zoo in the Netherlands--was attacked brutally and killed by Nikkie and Yeroen, who had previously been alpha males (de Waal 1998, 211-214).  De Waal describes the bloody scene: "Apart from bitting off fingers and toes and causing deep gashes everywhere, the two aggressors removed Luit's testicles, which were found on the cage floor."  This looks like a political assassination.  But it's hard to know whether this case of lethal violence among captive chimpanzees is an abnormal consequence of their captive conditions.  The killing of Luit occurred at night, when the chimps were confined in their night cages.

Kaburu et al. claim to report the first case of lethal violence among wild chimpanzees in which the victim was the incumbent alpha male.  PM was the alpha male of the M-group of chimpanzees in the Malale Mountains National Park in Tanzania when he was killed on October 2, 2011.  He had been the alpha male since 2007.  After a bloody fight between PM and PR, the beta male, PR left.  A weakened PM  was then attacked brutally by a coalition of four other adult males, including two former alpha males (AL and DE).  AL was the alpha male overthrown by PM in 2007.  After the killing, there was a period of social instability.  AL became the alpha male for a short time.  But by November, PR had become the alpha male and is now the alpha male of the M-group.

Kaburu et al. explain this as an opportunistic attempt by AL (the third ranking of 10 adult males) to seize the alpha position once he saw that PM was weakened by the fight with PR, although AL was unable to hold his alpha position for long against the challenge of PR.

When I asked Michael Wilson (a primatologist at the University of Minnesota) about whether there were any other cases of alpha males being killed, he mentioned two cases at Gombe.  Vincent was the alpha male of the Mitumba community at Gombe.  He fell from a tree and severely injured himself.  He lived for another three months before two adult males attacked and killed him.  Michael says he has not yet written a report of this case.

The second case was that of Goblin, another alpha male at Gombe.  He was severely attacked and would have died if a vet had not treated his wounds.  Kaburu et al. mention this case, but they claim that Goblin had been deposed from his alpha position before the attack.

I would like to know more about how common the killing of alpha males might be for chimpanzees and how this compares with the history of political assassinations among human beings.

REFERENCES

de Waal, Frans. 1998. Chiampanzee Politics. Revised edition. Baltimore: Johns Hopkins University Press.

Kaburu, Stefano S. K., Sana Inoue, and Nicholas E. Newton-Fisher. 2013. "Death of the Alpha: Within-Community Lethal Violence Among Chimpanzees of the Mahale Mountains National Park." American Journal of Primatology 75:789-797.

Newton-Fisher, Nicholas e. and Melissa Emery Thompson. 2012. "Comparative Evolutionary Perspectives on Violence." In The Oxford Handbook of Evolutionary Perspectives on Violence, Homicide, and War, 41-60. Eds.Todd K. Shackelford and Viviana A. Weekes-Shackelford. Oxford: Oxford University Press.

Some of my posts on chimpanzee politics can be found here, here, here, here, here, and here.

The Biopolitical Science of Locke's State of Nature: An APSA Convention Paper

I have written a paper for the 2015 convention of the American Political Science Association in San Francisco, September 3-6.

The paper is "The Biopolitical Science of Locke's State of Nature."  Here's the abstract:

As part of the project for developing a biopolitical science, a biological science of human nature and human history can be used to clarify and perhaps even resolve some of the fundamental debates in the history of political philosophy.  For example, applying biological science to the debate between Hobbes, Locke, and Rousseau over the state of nature can show that Hobbes was partly right, Rousseau was mostly wrong, and Locke was mostly right.  In support of this conclusion, this paper shows how biological science sustains Locke’s account of eight features of the state of nature: human self-ownership, divine ownership, familial society, the law of reputation, egalitarian hierarchy, war and peace, consent to government, and resistance to tyranny. This shows how, as part of a biopolitical science, we can develop a biopolitical philosophy.

My panel will meet on Friday, September 4, 11:30 am to 1:00 pm, at the Hilton San Francisco Union Square, in the room Union Square 21.

The Neurobiology of Self-Ownership: The Self-Awareness of One's Body, One's Agency, and the Social Emotions of Justice

                                                             The Right Insular Cortex


Normally, we are aware that our arms and legs belong to us and not to someone else.  When we move our limbs, we are aware that our limbs are moving, and when we are resting, we are aware that our limbs are not moving.  This self-awareness or self-ownership of our bodies and our agency allows us to distinguish our bodies from the bodies of other people and to identify our actions as different from the actions of others.

It seems strange, therefore, when Rene Descartes says that he could doubt the existence of his body, and therefore the reality of his body as his was not part of his self-evident sense of his own existence as a thinking being without a body.  But, amazingly, there really are people who are not self-aware of their arms and legs or of the movement of their limbs as belonging to them.  They look at one of their arms or legs, and they think this is someone else's limb (Karnath and Baier 2010a, 2010b). 

Oliver Sacks tells the story of a man who woke up in a hospital bed, and when he moved, he felt someone's leg in his bed.  He thought the nurses were playing a cruel joke on him by putting a severed leg in his bed while he slept.  He threw the leg out of the bed.  But when he did this, he somehow came after it.  Falling on the floor, he was shocked to discover that the leg was attached to his body.  He began punching the leg and trying to tear it from his body.  When Sacks arrived, he told the man he shouldn't be punching the leg like that.  "And why not?" the man exclaimed.  "Because it's your leg," Sacks answered.  "Don't you know your own leg?" The man insisted that this was not his leg.  Sacks then asked him, "If this is not your left leg, then where is your own left leg?" The man turned pale.  "I don't know," he said.  "I have no idea.  It's disappeared.  It's gone.  It's nowhere to be found . . ." (Sacks 1985, 53-55).

One possible explanation for this man's condition is that he had suffered damage to the right insular cortex of his brain, causing weakness or paralysis on the left side of his body (hemiparesis or hemiplegia), and that he had lost his self-awareness of his left leg as belonging to him (Ibanez et al., 2010; Karnath and Baier 2010a, 2010b).

The insular cortex is a crucial part of the neural network of the brain that supports self-awareness and self-ownership of one's body and the social emotions in which concern for oneself is extended to concern for others.  In understanding this, social neuroscience provides the evolved biological ground in the brain for what John Locke identified as human self-ownership or self-concern that is extended to concern for others in mammalian animals like humans.

Locke asserts: "Though the Earth, and all inferior Creatures be common to all Men, yet every Man has a Property in his own Person.  This no Body has any Right to but himself" (ST, sec. 27).  "From all which is evident, that though the things of Nature are given in common, yet Man (by being Master of himself, and Proprietor of his own Person, and the Actions or Labour of it) had still in himself the great foundation of Property" (ST, sec. 44).

In his Essay Concerning Human Understanding, Locke identifies a "person" or "self" as "a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places."  All the parts of a human body are vitally united to this thinking self, "so that we feel when they are touched, and are affected by, and conscious of good or harm that happens to them, are a part of ourselves; i.e. of our thinking conscious self."  Consequently, "the limbs of his body are to every one a part of himself; he sympathizes and is concerned for them."  "Self is that conscious thinking thing . . . which is sensible or conscious of pleasure and pain, capable of happiness or misery, and so is concerned for itself, as far as that consciousness extends.  Thus every one finds that, whilst comprehended under that consciousness, the little finger is as much a part of himself as what is most so" (Locke 1959, II.xxvii.9, 11, 17).

Human beings have natural rights to life, liberty, and property, therefore, because they own themselves and thus rightly claim autonomous control of their lives.  And yet, as social mammals who naturally come together in families for sexual mating, conjugal bonding, and parental care of offspring, human beings are naturally inclined to extend their care for themselves to care for others to whom they are attached (FT, secs. 86-89; ST, secs. 54-56, 77-84).

A. D. (Bud) Craig has traced out the fundamental neuroanatomical basis for all human emotions, and he has argued that this shows how the neural substrates for human self-awareness or consciousness are based on the neural representation of the physiological state (the homeostasis) of one's body. This manifests the embodiment of emotional self-consciousness. In particular, he argues that there is a phylogenetically novel sensory pathway in primates, most fully developed in human beings, that provides for a self-conscious integration of the physiological condition of the body (the material "self") with one's sensory environment, with one's motivational condition, and with one's social situation in the anterior insular cortex (AIC) (Craig 2002; 2003; 2008; 2009; 2010a; 2010b).

The evolution of mammalian social behavior depends on the evolution of pain or "negative affect," which includes pain, fear, panic, and anxiety. In all vertebrates, fear and pain are represented in the brainstem and hypothalamus as signals to elicit self-preserving behavior. In mammalian evolution, these neural mechanisms are modified so that animals care for their offspring as well as themselves. This includes modifying the cortex of the mammalian brain to elaborate the representation of pain to include anxiety tied to separation from or threat to loved ones.

Craig's research clarifies this neural evolution of pain by classifying pain as a homeostatic emotion rather than as a sensation of touch. Pain belongs to "interoception"--the sense of the physiological condition of the body--and it is therefore part of the evolved mechanisms for self-preservation.

The insular cortex receives signals from all the tissues of the body, and these signals are integrated with physical and social stimuli from outside the body and with the memory of past experiences as well as imaginative projections of future experiences. This supports a general awareness of the body's condition in space and time. The anterior cingulate cortex (ACC) can then be activated to motivate behavior to correct whatever is wrong. This neural processing mechanism seems to be unique to primates, but it's more highly developed in human beings.

Both the insular cortex and the ACC respond not only to physical pain from bodily injury but also social pain from social injury. It seems that in mammalian evolution, the neural circuitry for physical pain was appropriated for registering social pain in animals adapted for social attachment. Mammals must care for the survival and well-being not only of themselves but of others to whom they are attached. Extending the neural mechanisms originally evolved for individual self-preservation to include the welfare of offspring and social partners secures mammalian social order. The uniquely human evolution of the neocortex elaborates this mammalian development to sustain human love and concern for others.

When we use the language of physical pain to describe our social pain ("a broken heart"), we recognize the embodiment of our natural social consciousness, in which our mind, our brain, our body, and our social life are inseparably intertwined.

The anterior insular cortex (AIC) is involved not only in interoceptive self-awareness but also in the social emotions that support cooperation and fairness (Lamm and Singer 2010).  Observing pain in others activates parts of the neural network that are also activated when we experience pain in ourselves.  Empathy for the pain of others activates the most anterior parts of the AIC, which overlaps with activation related to pain experienced in oneself.  But the activation associated with the experience of pain in oneself encompasses a much larger portion of the insula (including the middle and posterior insular cortex).  To some degree, then, the neural activity for self-concern is extended to concern for others.  But still our self-concern is distinguished from our concern for others.

Brain imaging studies of people playing the Ultimatum Game suggest that a sense of fairness is supported by the AIC and other parts of the brain associated with social emotions, because these neural networks are activated when players decide to defect against unfair but not fair players (Sanfey et al. 2003).  This does not happen when the unfair players are computers, because the human players don't see the computers as intentional agents who can be rightly blamed and punished for their unfairness. 

And thus the AIC is part of a neural network supporting feelings of care and concern for oneself and for others and their welfare that sustains the sense of justice that Locke identifies as "the law of nature" enforced by "the natural executive power of the state of nature" for punishing those who violate that natural law.

REFERENCES

A. D. (Bud) Craig. 2002.  "How Do You Feel? Interoception: The Sense of the Physiological Condition of the Body," Nature Reviews Neuroscience 3: 655-666

Craig.  2003. "A New View of Pain as a Homeostatic Emotion," Trends in Neurosciences 26: 303-307

Craig, 2008. "Interoception and Emotion: A Neuroanatomical Perspective," In Handbook of Emotions, 3rd ed., edited by Michael Lewis, Jeannette Haviland-Jones, and Lisa Barrett, 272-288. New York: Guilford.

Craig. 2009. "How Do You Feel--Now? The Anterior Insula and Human Awareness," Nature Reviews Neuroscience 10: 59-70.

Craig. 2010a. "The Sentient Self." Brain Structure and Function 214: 563-577.

Craig. 2010b. "The Insular Cortex and Subjective Awareness." In George Prigatano, ed., Advances in the Study of Anosognosia, 63-87. New York: Oxford University Press.

Ibanez, Agustin, Ezequiel Gleichgerricht, and Facundo Manes. 2010. "Clinical Effects of Insular Damage in Humans." Brain Structure and Function 214:397-410.

Karnath, Hans-Otto, and Bernard Baier. 2010a. “Right Insula for Our Sense of Limb Ownership and Self-Awareness of Actions.” Brain Structure and Function 214:411-417

Karnath, Hans-Otto, and Bernard Baier. 2010b. “Anosognosia for Hemiparesis and Hemiplegia: Disturbed Sense of Agency and Body Ownership.” In George P. Prigatano, ed., Advances in the Study of Anosognosia, 39-62. New York: Oxford University Press.

Lamm, Claus, and Tania Singer. 2010. "The Role of Anterior Insular Cortex in Social Emotions." Brain Structure and Function 214:579-591.

Sacks, Oliver. 1985. The Man Who Mistook His Wife for a Hat, and Other Clinical Tales. New York: Summit Books.

Sanfey, A.G., Rilling, J.K., Aronson, J.A., Nystrom, L.E., and Cohen, J.D. 2003. "The Neural Basis of Economic Decision-Making in the Ultimatum Game." Science 300: 1755-1758.


Other posts on these themes can be found here, here, here., here., here, and here.

The Evolution of Violent and Nonviolent Resistance to Tyranny: From Foraging Society to the Present

In John Locke's state of nature, all individuals are free and equal because they can punish anyone who tries to bully or tyrannize over them, which Locke calls the "executive power of the law of nature."  For the worst offenders--such as murderers--the natural punishment is death.

Although the threat of such punishment can enforce the social norms of cooperation that constitute the law of nature and that can make the state of nature a state of peace, this state of society without government tends to become a state of war, because, in the absence of formal institutions for establishing, judging, and enforcing laws, people lack any impartial system for the rule of law, and their natural propensity to partiality in judging their own cases leads to violent feuding.  To secure the peace of society, governments are established by the consent of individuals to provide known, settled laws established by formal lawmakers, interpreted by impartial judges, and executed by those entrusted with the natural executive power of the whole society. 

When these powers of government are abused, in being used by the rulers to exploit the ruled contrary to the common good of all, then the people, according to Locke, have the natural right to reclaim the natural executive power for punishing tyrants through overthrowing government and consenting to a new government that is more likely to secure their natural rights.  In their resistance to tyrannical government, people have a natural right to meet force with force, even to the point of killing their rulers.

There are two lines of historical evidence for judging whether Locke is correct about this.  The first is the evidence about the history of human foragers.  The second is the evidence of the history of resistance to tyrannical government.

As I have indicated in previous posts, anthropological studies of the foraging bands that are most likely to resemble our late Pleistocene ancestors indicate that Locke is largely correct in his account of the state of nature as a customary social order in which all individuals had the right to punish deviants.  Punishment included killing, although this was not common, and it was mostly directed against murderers.  The more common forms of punishment were gossip, ridicule, shunning, and physical forms of punishment short of lethal violence.  As Christopher Boehm has shown, foragers enforce their moral norms mostly through what Locke calls the "law of reputation," or what evolutionary theorists call "indirect reciprocity."

The history of political violence and rivalry over governmental rule also shows that people are inclined to exercise their natural right to punish rulers who abuse their powers in tyrannical ways.  In recent years, there have been some rigorously quantitative studies of this history that show a historical pattern of declining political violence and increasing nonviolent resistance to tyranny.

In the first systematic and quantitative study of regicide in Europe, Manuel Eisner (2011) has collected data on the frequency of violent death and regicide among 1,513 monarchs in Europe between AD 600 and 1800.  He has distinguished four categories of violent death: accident, battle death, murder, and legal execution.  He found that in the seventh century, the frequency of regicide was 2,500 murders per 100,000 years in office.  There was a long decline in regicide.  So that by the eighteenth century, the frequency of regicide was about 200 per 100,000 years in office.  By comparison, the homicide rate in Western Europe today is around 0.6-1.5 per 100,000 person-years.  Clearly, then, European kingship before the Industrial Revolution was one of the most dangerous occupations in the world, comparable to that of soldiers in combat.

Eisner found that for most of this history, regicide was carried out within the noble elite in the competition for political rule.  But, then, by the seventeenth century, regicide became increasingly a matter of legal execution--such as the execution of Charles I in 1649 and the execution of Louis XVI in 1793.  In the Glorious Revolution of 1688, James II was deposed without being executed.

The decline in regicide seems to be part of the general historical decline in homicide (Eisner 2003; Pinker 2011).  This general pattern of declining violence seems to be associated with a Hobbesian pacification process, in which the state claims a monopoly on the legitimate use of violence, and with a Lockean liberal culture of bourgeois virtues that arise in modern commercial societies, in which people learn to control their violent impulses for the sake of peaceful economic and social exchange.

While a Hobbesian state can bring peace, it can also bring tyrannical coercion that provokes violent resistance.  And yet, there is some evidence that resistance to Hobbesian tyranny has become more nonviolent.

Erica Chenoweth and Maria Stephan (2008, 2011) entered into a data base all forms of both violent and nonviolent revolutions and reforms since 1900.  Analyzing that data, they found that nonviolent resistance campaigns were more than twice as likely to succeed as violent resistance movements.  Violent resistance is largely limited to young, strong, and violent males.  But the methods of nonviolent resistance--such as strikes, boycotts, and symbolic protests--can recruit a broad array of people. 

And, indeed, as Locke indicated, successful revolutions depend on "people power."  Chenoweth and Stephan were even able to specify that every campaign that achieved the active and sustained participation of just 3.5 percent of the population was successful, and that many succeeded with even less participation.  Every campaign that did surpass the 3.5 percent threshold was nonviolent.

This provides quantitative evidence for Locke's account of government by consent of the governed.  Tyrants cannot rule by themselves.  They need supporters--or what Bruce Bueno de Mesquita and Alastair Smith (2011) call a "minimum winning coalition."  Of course, in a dictatorship, that winning coalition can be a very small elite group of people who receive special benefits from the dictator's rule.  But as Chenoweth and Stephan show, that small group of people supporting the dictator can be persuaded by a small nonviolent resistance movement to turn against the dictator.  Dictators cannot rule without at least the passive acquiescence of the great body of the people, and thus they can be overthrown by the active resistance of 3.5 percent or less of the people, even when that resistance is nonviolent.

So while the exercise of the natural executive power to punish tyrants has often been violent, it can also succeed when it's nonviolent.

REFERENCES

Bueno de Mesquita, Bruce, and Alastair Smith. 2011. The Dictator's Handbook: Why Bad Behavior Is Almost Always Good Politics. New York: Public Affairs.

Chenoweth, Erica, and Maria Stephan. 2008. "Why Civil Resistance Works: The Strategic Logic of Nonviolent Conflict." International Security 33: 7-44.

________. 2011. Why Civil Resistance Works: The Strategic Logic of Nonviolent Conflict. New York: Columbia University Press.

Eisner, Manuel. 2003. "Long-Term Historical Trends in Violent Crime." Crime and Justice 30: 83-142.

________. 2011. "Killing Kings: Patterns of Regicide in Europe, AD 600-1800." British Journal of Criminology 51: 556-577.

Pinker, Stephen. 2011. The Better Angels of Our Nature: Why Violence Has Declined.  New York: Viking.


Chenoweth has summarized her research in a TED talk. and a lecture at Dartmouth College.

Does Biblical Liberalism Support LGBT Rights?

Ten years from now, I predict, the movement for LGBT (lesbian, gay, bisexual, transgender) rights will be largely successful, and Biblical religious believers will claim that this success was due to the cultural influence of Biblical religion.  Just as it is commonly argued today that the abolition of slavery and the general idea of universal human rights manifest the influence of the Biblical teaching that all human beings have equal dignity as created in the image of God, so too it will be argued that equal rights for LGBT people shows the influence of the same Biblical teaching.  What this shows is how easily the Bible--or at least the New Testament--can be interpreted as supporting classical liberal thought, as early modern classical liberals like Locke and Spinoza saw.

Right now, the debate over LGBT rights is commonly said to be a debate between secularist libertarians and religious believers.  But one can see the beginnings of the shift among Biblical religious believers towards recognizing LGBT rights.  What's most interesting about this is that the shift is beginning to occur even among some leading evangelical theologians who embrace the idea that the Bible is the divinely inspired and inerrant word of God, and who therefore must question the traditional interpretation of the Bible as condemning LGBT people.

This development has recently been covered in an article in The New York Times.  One of the leaders in this movement is the Rev. David P. Gushee, an evangelical theologian at Mercer University.  He has explained his position in a recent lecture.

Gushee draws an analogy between Christian anti-Semitism and the Christian persecution of LGBT people.  In both cases, there have been thousands of years of Christian tradition interpreting the Bible as condemning these two groups of people.  But, then, sometime around 1965, there was a shift against the tradition of Christian anti-Semitism and towards the view that the Christian teaching of universal love or the Golden Rule applies to Jews, and that the interpretation of the Bible as identifying Jews as Satanic Christ-killers is mistaken.

Now, a similar shift is beginning to emerge in the Christian view of LGBT people.  The Biblical verses that appear to condemn LGBT people are being reexamined in the light of the Christian teaching of universal love or the Golden Rule, so that Biblical believers can see that these verses have been misinterpreted, and that the Bible actually requires Christians to love LGBT people as having the same human dignity as all human beings created in God's image.

In his gay marriage decision, Justice Anthony Kennedy emphasized the word "dignity."  Rev. Gushee has said: "Dignity language is a widely used cognate for the idea that every person is made in God's image and is sacred for that reason.  So what I think Judge Kennedy did was reach to one of the core concepts of our civilization."  So for Gushee, the argument for LGBT people having equal human "dignity" that must be recognized by law rests on a secularization of a Biblical religious teaching.

My prediction is that within ten years almost all Christians will be saying this, and they will be puzzled as to why it took 2,000 years for Christians to see that this is the correct reading of the Bible's teaching.

Many Christians today cannot accept this, because they think it's obvious that giving equal rights to LGBT people violates the sexual ethics of Christianity.  But Gushee argues that LGBT people can be held to the same standard of sexual ethics that applies to all Christians--"celibacy outside of lifetime covenantal marriage, monogamous fidelity within lifetime covenantal marriage."  The Christian opponents of LGBT rights will have to dispute this.

Some of my posts on the classical liberalism inherent in the Bible can be found here, here, here, here, and here.

The Evolution of Indirect Reciprocity in Locke's Law of Reputation

In his Essay Concerning Human Understanding, John Locke argued that our ideas of moral good and evil were derived mostly from "the law of opinion or reputation," because most human beings identified virtue as whatever was praised in their society and vice as whatever was blamed, and most human beings want to gain the reward of having a good reputation and avoid the punishment of having a bad reputation (II.28.5-12).  This has been one of the most controversial teachings in the Essay, because Locke's critics have identified it as endorsing a crude cultural relativism that denies that there is any natural or rational standard of moral good and evil.

The modern evolutionary account of morality supports this Lockean law of reputation understood as "indirect reciprocity," in which people are motivated to do good deeds for others as long as these good deeds win them a good reputation.  Some evolutionary anthropologists have shown that the sort of hunter-gatherer bands in which human beings have lived for most of their evolutionary history most likely developed a moral order based primarily on such reputational selection favoring conformity to the customary moral rules of society.

Good and evil are nothing but pleasure and pain, Locke believes.  Moral good and evil can then be understood as "the conformity or disagreement of our voluntary actions to some law, whereby good or evil is drawn upon us, from the will and power of the lawmaker" (II.28.5). 

There are three kinds of laws corresponding to three kinds of lawmakers with different kinds of rewards and punishments for enforcing their laws.  Divine law is God's law enforced with His eternal rewards and punishments.  Civil law is the law made by human legislators exercising the force of government to enforce their laws.  The law of opinion or reputation is the law established through social praise and blame in which people in every social group by a "tacit consent" determine what is virtue and vice, rewarding the praiseworthy with a good reputation and punishing the blameworthy with a  bad reputation.

Locke also calls the law of reputation the philosophical law, not because philosophers make it, but because this is the law most studied by pagan philosophers when they inquire into the character of virtue and vice, because they generally assume that virtue is what is thought praiseworthy.

Locke believes that studying the "history of mankind," which includes the anthropological history of societies around the world and the American Indians, will show that most human beings have been governed mostly, if not entirely, by the law of reputation, because while people might think they can evade the laws of God or the government, they can rarely escape the punishment of censure when they offend those with whom they associate.

When Locke was accused of moral relativism, because he seemed to say that virtue and vice had no fixed meaning in being determined by the arbitrary movements of social praise and blame, he responded in two ways.  First, he said that he was reporting as a matter of fact how most human beings determine virtue and vice as what is generally praised or blamed by those around them, and surely one could hardly deny this as a factual truth.

His second response was to point out that he had indicated that despite the variability and fallibility of social praise and blame as a standard of moral goodness, what people generally regard as praiseworthy or blameworthy are "as to the main" the same everywhere, and "in a great measure," they correspond to "the unchangeable rule of right and wrong," and they do not stray very far from "the Law of Nature," which is "that standing and unalterable rule by which they ought to judge of the moral rectitude and gravity of their actions" (p. 19, II.28.11).

This might seem to contradict what Locke says in denying that there are any innate practical principles, and in citing as evidence for this that some societies have practiced moral outrages like infanticide, patricide, and cannibalism.  Locke observes:

"He that will carefully peruse the history of mankind, and look abroad into the several tribes of men, and with indifferency survey their actions, will be able to satisfy himself, that there is scarce that principle of morality to be named, or rule of virtue to be thought on, (those only excepted that are absolutely necessary to hold society together, which commonly too are neglected betwixt distinct societies,) which is not, somewhere or other, slighted and condemned by the general fashion of whole societies of men, governed by practical opinions and rules of living quite opposite to others" (I.2.10).

Notice, however, the parenthetical remark--there are some rules that are absolutely necessary for the social order of any group, and so these rules are likely to be universally recognized, although even these rules might not be observed in conflicts with outside groups.  In fact, Locke notes, there is a connection between virtue and "public happiness," in that some virtues are necessary for preserving society, and consequently most people will see that it's in their self-interest to promote those social virtues (I.2.6).

"Justice and truth are the common ties of society; and therefore even outlaws and robbers, who break with all the world besides, must keep faith and rules of equity amongst themselves; or else they cannot hold together" (I.2.2).  Indeed, as Peter Leeson (The Invisible Hook, 2009) has shown in his history of pirate societies, pirate crews had to consent to the captain's code of good behavior before sailing.  They were obliged to swear upon a hatchet (rather than a Bible) that they would obey the captain's articles of agreement, which had arisen as a spontaneous self-organized order to prevent these societies of outlaws from collapsing into disorder.  So there really is honor among thieves.

Locke's law of reputation was reaffirmed by David Hume and Adam Smith, who stressed the extent to which morality was rooted in the natural human concern for how one appears to others and the desire, as Smith put it, for a mutual sympathy of sentiments.  Charles Darwin thought this human moral sensitivity to social approbation and disapprobation could have evolved by natural and cultural selection.

In 1987, in The Biology of Moral Systems, Richard Alexander brought this line of reasoning under the term "indirect reciprocity."  Kin selection theory could explain the evolution of morality among genetic kin.  But it was hard to see how this could be extended to non-kin.  Robert Trivers argued that the theory of reciprocal altruism could explain the moral cooperation of genetically unrelated individuals engaged in reciprocal relationships based on the idea that "I'll scratch your back if you scratch mine."  Beyond such direct reciprocity, Alexander saw the possibility of indirect reciprocity--"I'll scratch your back if you have the reputation for scratching the backs of others."

This evolved morality as based on kin selection and reciprocity (both direct and indirect) does not require a morality of self-sacrifice, Alexander argues.  This morality requires a conscience that can  be described as "the still, small voice that tells us how far we can go without incurring intolerable risks or costs to our own interests" (107).

There are various ways in which a natural concern for one's reputation could evolve as serving one's reproductive interests.  Those with good reputations might be identified as the best sexual mates, and they might elicit cooperation and generosity from others in one's society.  Those with bad reputations could expect social punishments that could lessen their reproductive fitness.

Studies of foraging societies have provided some evidence that this is true.  Foraging bands tend to have around 25-30 members.  Of these, only about 10% to 20% are genetically related.  About half are affinal relatives (in-laws).  The rest are not related at all.  So kin selection cannot fully explain their social cooperation (Hill et al. 2011).  Direct reciprocity might explain some cooperation where two partners are directly benefiting one another.  But much of the cooperation seems to depend on indirect reciprocity, where people cooperate or not based on good or bad reputation.

Christopher Boehm (2012) has gathered clear evidence for this evolution of morality through the effects of reputation.  He has studied the ethnographic records for 339 hunter-gatherer societies.  He has eliminated those groups with characteristics that would not have been typical for foragers in the Late Pleistocene.  For example, he eliminated those groups that were dependent on missions, those that traded food with horticulturalists, those involved in the European fur trade, and those who were sedentary and began to store food.   This left him with 150 groups that he could identify as "Late Pleistocene appropriate" (LPA).  He then developed a system for coding the data with 232 social coding categories--such as "sharing with kin" and "aid to nonrelatives favored."  So far, he has fully coded 50 out of the 150.

From that data, he can see that the most common forms of social deviance that are punished in all or almost all foraging societies are murder, sorcery or witchcraft, stealing, beating of someone, failing to share, bullying, and lying.  The most common forms of punishment are gossip, ridicule, direct criticism, social distancing, group ostracism, nonlethal physical punishment, and temporary expulsion from the group.  The most severe forms of punishment (particularly for murder) are the entire group killing the culprit, a group member selected to kill the culprit, and permanent expulsion from the group.  When a murderer kills one person, it's assumed that someone in the victim's family will take vengeance against the murderer.  When a murderer kills two or more people, he is punished by the whole group.  Often the group will ask one of the murderer's relatives to kill him.  And in most cases, it is a "him," because most of the deviant violence is perpetrated by men.

These groups have no formal legal systems or governments, and so these social rules are all customary norms.  The enforcement of these norms through punishment is through what Locke calls "the executive power of the state of nature," or the natural right of all individuals to punish those who attack them, steal from them, cheat them, bully them, or otherwise disrupt the customary social order.

Reputation is crucial in all of this, because those reputed to be social deviants are punished, and those reputed to be cooperative and generous are rewarded.  As Locke indicated, the group recognizes as virtuous those traits that conform to the customary norms of the group and as vicious those traits that violate those norms.

Boehm argues that since punishment for violating these norms lessens the reproductive fitness of the violator, then we can imagine that evolution would favor the emergence of a moral capacity for conscience, so that people would develop the ability to suppress their antisocial tendencies and to feel guilt and shame when they express those tendencies.  We can confirm this by considering the evidence from neuroscience that the human brain is wired for moral judgment and moral emotions, and those few who lack this wiring (psychopaths) do not have the moral sense typical of normal people.

REFERENCES

Alexander, Richard. 1987. The Biology of Moral Systems.  New York: Aldine de Gruyter.

Boehm, Christopher. 2012. Moral Origins: The Evolution of Virtue, Altruism, and Shame. New York: Basic Books.

Hill, Kim R., et al. 2011. "Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure." Science 331: 1286-1289.

Leeson, Peter. 2009. The Invisible Hook: The Hidden Economics of Pirates. Princeton, NJ: Princeton University Press.

Locke, John. 1959. An Essay Concerning Human Understanding. 2 vols. New York: Dover Books.

Monogamous Pair-Bonding in the Lockean State of Nature

Unlike Jean-Jacques Rousseau, John Locke believed that our human ancestors in the state of nature were social animals, because the "first society" was the conjugal society of husband and wife and the familial society of parents and children.  Modern evolutionary anthropology supports Locke over Rousseau by providing evidence that the evolution of monogamous pair-bonding among our prehistoric foraging ancestors gave birth to the unique structure of human society.

In the Two Treatises, Locke gives both religious and natural explanations for human familial bonding.  It shows the "wisdom of the great Creator" that He has created human beings with inclinations for monogamous marrying and for mothers and fathers caring jointly for their children (FT, 86-89; ST, 77-80).  This can also be explained through the natural history of animal reproduction.  For some animals, whose offspring can survive on their own without much parental care shortly after birth, Locke explains, mothers care for the offspring with no need for fathers to provide any care, and consequently there is no need for any enduring bond between the sexual mates.  But for those animals whose offspring cannot survive without extensive and prolonged care from both parents, there is a natural need for an enduring pair-bonding of the sexual mates to provide biparental care.  If mothers cannot feed themselves and their offspring without the help of males, because they need the meat provided by male hunting, or if birth-spacing is so short that mothers can often have multiple dependent offspring requiring prolonged care from both parents, then these animals will have a more enduring conjugal bond; and this is true for human beings.  As compared with other animals, human offspring are dependent on adult care for a long period during which the offspring must not only be nourished but also educated, because complex human social life requires a prolonged period of social learning.

In contrast to Locke, Rousseau argued that human beings in the "pure state of nature" were asocial and almost completely solitary animals.  Men and women encountered one another by accident and engaged in sexual intercourse whenever the desire moved them, but they immediately left each other and felt no tie to one another.  Mothers nursed their children for a short period.  But as soon as the children could feed themselves, they left their mother, and they soon would no longer recognize one another.  So while the maternal attachment to children was the one social bond in the state of nature, it was only a momentary bond that created no enduring social recognition (SD, 108, 112, 120-21, 130-31, 137, 142, 147, 216, 219).

In one of the longest notes in the Second Discourse (213-20)--note l--Rousseau quotes the entirety of sections 79-80 of Locke's Second Treatise, where Locke lays out his reasoning for monogamous pair-bonding and biparental care in the state of nature.  Rousseau denies the factual truth of Locke's claims about animal reproduction and parental care, and accuses him of making the same mistake that Hobbes made in projecting what we see in human beings today back into the state of nature.  Today, human beings develop romantic attachments so that they prefer one sexual mate over another, and this can develop into a conjugal bond.  When children are conceived, parents become attached to them and care for them.  But there is no reason to believe that people in the state of nature felt this, Rousseau insists.  In the state of nature, once a man and a woman had satisfied their sexual appetite, they would have separated, with no enduring passion of love.  If the woman conceived a child, there would be no reason for the father to see this as his child.  Thus, in the state of nature, sexual mating was so indiscriminately promiscuous that fathers never recognized their children, and mothers recognized their children only for a short time.  Marriage and family life did not appear until the second stage of human evolution, which Rousseau calls the "nascent society" of the "sociable savage" (SD, 146-52).

Claiming that savage human beings began with "purely animal functions," Rousseau adds a note (note j)--the longest note in the Second Discourse--on the reports of European travelers about the strange variety in the animals and human beings that they have seen around the world (115, 203-13).  They have seen "anthropomorphic animals" that are called orangutans, pongos, or mandrills.  Although these animals have many human traits, most travelers identify them as beasts, but Rousseau suspects that more precise research might conclude that they are remnants of the earliest savage humans.  He thus implies the idea of human evolution from nonhuman animals.  He was the first thinker in the eighteenth century to suggest that humans evolved from apes, and thus he anticipating modern evolutionary theory (Wokler 1976, 1978; Frayling and Wokler 1982).

Travelers have described the characters and customs of the foreign peoples they have seen, but Rousseau suspects that they have not accurately reported how different these foreign cultures are from European culture.  Rousseau complains that these travel reports are coming mostly from sailors, soldiers, merchants, and missionaries, who are not motivated by the intellectual curiosity that would produce precise studies of these foreign animals and human beings.  Rousseau hopes that soon some rich philanthropists will provide the money to support some philosophic scientists who could devote at least ten years of their lives to voyaging around the world and studying the animals and humans they find, and then they could return to write "the natural, moral, and political history" of the animal and human world.

Beginning in the first half of the nineteenth century, scientific travelers like Alexander von Humboldt, Alfred Russel Wallace, and Charles Darwin began the world-wide scientific research that Rousseau had hoped to see (Carroll 2009).  Now, after two centuries of anthropological research and almost a century of primatological research, we now have, for the first time, the scientific knowledge required for clarifying and perhaps resolving the debate between Hobbes, Locke, and Rousseau over what human ancestors looked like in the state of nature.  Through the comparative study of behavioral primatology and social anthropology grounded in evolutionary biology, we can reconstruct the natural evolutionary history of human social life from our nonhuman primate ancestors to our prehistoric hunter-gatherer ancestors.

The conclusion that emerges from that study, I argue, is that in their accounts of the state of nature, Locke was mostly right, Rousseau was mostly wrong, and Hobbes was partly right and partly wrong.

Here I will concentrate on the question of whether and how monogamous pair-bonding evolved in the human state of nature as the fundamental element in the universal deep structure of human sociality.  The best single survey of the evidence and argumentation for answering this question is in the work of Bernard Chapais (2008, 2011a, 2011b, 2013), who has shown how the primate evolution of reciprocal exogamy--the exchange of women for marriage between kin groups--made human societies unique among primate societies by integrating local groups through bonds of biological kinship and affinal kinship (the kinship of in-laws).

Despite the diversity of marital arrangements in different human cultures, there is an underlying unity in that all types of marital unions are cultural offshoots of the same biologically natural stem pattern--enduring pair-bonds.  Monogamous, polygynous, polyandrous, and even homosexual marriages are all based on enduring pair-bonds.  In a polygynous marriage, a single man maintains pair-bonds with two or more women.  In a polyandrous marriage, a single woman maintains pair-bonds with two or more men.  Homosexual marriage is same-sex pair-bonding.  In most human societies (over 80%), polygynous marriage has been permitted, although most marriages (over 90%) are monogamous even in societies that permit polygyny.  Thus, most human marriages have been monogamous.

Of course, sexual promiscuity and adultery has been common in all human societies.  But in no human society has promiscuity been the only or the main form of sexual mating.  This separates us from the primate species most closely related to us by evolutionary descent--chimpanzees and bonobos--because they are totally promiscuous, with no enduring pair-bonding.  Other primate species do show enduring pair-bonding--in single monogamous pairs, single polygynous units, single polyandrous units, or multiharem groups of several polygynous units assembled together.  But human pair-bonding mating systems are unique in their bilateral kin recognition (recognizing kin on both the mother's and the father's side) and bilateral affinity (both spouses recognizing their respective in-laws).

Rousseau was wrong in asserting that in the state of nature, savage human beings were solitary animals who mated promiscuously with no enduring social bonds.  Locke was right in recognizing that the earliest human beings were hunter-gatherers who lived in bands of families based on pair-bonded  monogamous or polygynous mating and extensive parental care of children by both mothers and fathers.

Archaeologist anthropologists Kent Flannery and Joyce Marcus argue that the evidence generally supports Rousseau's history of human social evolution.  But in making this argument, they silently throw out Rousseau's first stage of human evolution--living as solitary animals--because they begin with what Rousseau saw as the second stage that arose with the establishment of families (Flannery and Marcus 2012, 19-39).

One defense of Rousseau would be to point to his intimation that the savages in the "pure state of nature" were actually orangutans or chimpanzees, from which human hunter-gatherers evolved.  The hunter-gatherer bands studied by anthropologists are organized around families with conjugal love and parental love, but these belong to the second phase of human evolution, according to Rousseau, which he calls "nascent society" (SD, 146-52).

And yet, Rousseau's account of the original state of nature is not even true for chimpanzees or orangutans.  These primates are sexually promiscuous, with no enduring pair-bonding of sexual mates.  But they are not solitary animals, because they show enduring mother-child bonding and other social bonds.  Rousseau is wrong in claiming that when offspring leave their mothers, they no longer recognize one another.  Maternal care and bonding extends beyond weaning.  In most primate species, females stay in their natal group, and males migrate to another group when they reach puberty.  In these species, mother-daughter bonds can extend throughout the lifespan.  With chimpanzees and bonobos, most females leave their natal group at puberty, and males stay.  Here the bond between mothers and their resident sons extend for long periods beyond weaning.

Of all the apes, orangutans are the most solitary, in the sense that most individuals spend most of their time alone.  So they might be the one primate species that most resembles the solitary savage of Rousseau's pure state of nature.  But even they show a social organization.  Mothers care for their offspring, even after weaning.  Orangutans live in loose communities organized around a dominant male.  Mature females tend to settle close to their mothers and sisters.  This social life allows for social learning, which creates cultural traditions that distinguish one orangutan community from another.  Various skills (such as tool use and nest building) and communication signals seem to be passed from generation to generation through social learning.

But while apes are social animals, they do not show the complexity and flexibility of human social structure because they lack the enduring pair-bonding that makes human society possible.  Locke rightly saw the importance of pair-bonding in human hunter-gatherer societies, and he also rightly saw that a major adaptive function of human pair-bonding is the collaboration of mothers and fathers in the parental care of children.  Among hunter-gatherers, pair-bonds are parental partnerships.

Locke recognized the high costs of maternity--in pregnancy, lactation, post-weaning care, and the short birth intervals that make it necessary for mothers to feed more than one child at a time--and that these costs were higher for human beings than other species.  He also recognized that fathers could reduce these costs by helping mothers in caring for their children, particularly through male hunting and sharing of meat with mothers.  Modern anthropological studies of hunter-gatherer bands have confirmed the importance of parental cooperation, which suggests that this was the original evolutionary function of human pair-bonding, as it evolved in the earliest hominid ancestors, such as Australopithecus afarensis (Fisher 1992, 2006; Lovejoy 1981).  High sexual dimorphism (males being much larger than females) is correlated with polygynous mating systems in which males fight with other males in the attempt to monopolize access to females.  Low sexual dimorphism, as is shown by human beings,  is correlated with monogamous mating.  Some paleoanthropologists see evidence that the fossil skeletons of Australopithecus afarensis show low sexual dimorphism comparable to that of human beings, which they interpret as evidence that the earliest hominid ancestors of human beings had turned to monogamous pair-bonding and parental care (Reno et al. 2003; Reno et al. 2010).  This would support Locke's claim that humans in the original state of nature were organized in families of pair-bonded mates cooperating in caring for their children.

Other anthropologists, however, offer a different evolutionary scenario.  They argue that there is growing evidence and argumentation for an evolutionary history of pair-bonding in which stable breeding bonds did not originally evolve for parental care, although that is their present-day adaptive function (Chapais 2008, 157-84).  They assume that our earliest common ancestor with chimpanzees had a chimpanzee-like social structure--the promiscuous multimale-multifemale group.  The question then is what were the evolutionary steps required to reach the present human social structure--the multifamily human group in which most families are monogamous, and a few are polygynous.  Comparison with primate species suggests that there must have been an intermediate stage--the multiharem group in which all families are polygynous, and some males have no mates, which is the social structure of hamadryas and gelada baboons.  This evolutionary history requires two steps.  The first step is from sexual promiscuity to the multiharem group.  The second step is from the multiharem group to the multimonogamous family group (Chapais 2008, 171-84).

The general consensus among paleoanthropologists is that the fossil evidence of Australopithecus afarensis shows high sexual dimorphism, which suggests a polygynous mating system like that of hamadryas and gelada baboons (Gordon et al. 2008; Lockwood et al. 1996; Plavcan et al. 2005).  But in polygynous primate systems, fathers do not help the mothers care for their children.  For males, the benefit of polygynous mating is in guarding their mates from other males.  In fact, for most mammals and primates, both monogamous and polygynous, pair-bonding is primarily a mating arrangement rather than a parental partnership.  In most monogamous species that show cooperative parenting, paternal care has evolved after monogamy was already established (Brotherton and Komers 2003).  Among monogamous primate species, some show direct paternal care (in callitrichids, siamangs, and titi monkeys); but paternal care is not shown in other species (such as gibbons, tarsiers, and lemurs) (van Schaik and Kappeler 2003).

If our hominid ancestors lived in multiharem societies like hamadryas baboons, then we would have to wonder why and how our ancestors eventually moved to the mating system of human hunter-gatherers, with mostly monogamous mating and cooperative parenting.  Chapais points out that hamadryas males differ in their competitive abilities, so that some have big harems, others have smaller harems, and many have none.  If they had roughly the same fighting abilities, fighting would be so costly for them that they would have to give up their harem system.  Chapais (2008, 176-79) suggests that that is what happened when hominid males began to make tools that could be used as weapons.  If all males can use weapons, and perhaps form coalitions, for fighting, this would have a leveling effect that would favor the egalitarianism of monogamy.  This would not completely eliminate polygynous inclinations, but it would constrain those inclinations.  And, indeed, that is what we see in human mating systems.  Many men will seek polygynous mating when they have the power and resources to do this successfully, but most men will have to settle for monogamy.

But why should these hominid males care for their children?  Chapais's answer is that pair-bonding was a preadaptation for the evolution of paternal care.  Once males were monogamously pair-bonded with their mates, then they would probably share food with the family; and as the feeding and caring for the children exceeded the abilities of the mothers, fathers could specialize in hunting large animals, while mothers could gather plants and small animals.

As a consequence of that deep evolutionary history, we can now see the biochemistry of monogamy and parental cooperation in the human brain and endocrine system (Fisher 2006; Brizendine 2006, 2010).

If the human state of nature is identified as the life of the earliest members of Homo sapiens, then all of this research in evolutionary anthropology confirms Locke's account of humans in the state of nature as egalitarian hunter-gatherers living in pair-bonded monogamous families where mothers and fathers cooperated in caring for their children.  But if the human state of nature is identified as the life of  hominids who evolved prior to the emergence of Homo sapiens, then there is disagreement about whether the human pattern of pair-bonded families with parental cooperation can be found in those earliest hominid species.  The crucial debate over whether the hominid fossil record shows a human-like pattern of sexual dimorphism in hominid species, which would suggest monogamous pair-bonding and parental cooperation, cannot be resolved because the fossil record is too fragmentary and sparse.  Another problem is that the causes and functions of sexual dimorphism are so complex that they are hard to interpret.  For example, sexual dimorphism depends on both male traits and female traits, and so it's hard to know whether dimorphism has arisen from male traits, from female traits, or from both (Plavcan 2011, 2012).

REFERENCES

Brizendine, Louann. 2006. The Female Brain. New York: Morgan Road Books.

Brizendine, Louann. 2010. The Male Brain. New York: Harmony Books.

Brotherton, Peter, and Komers, Petr. 2003. "Mate Guarding and the Evolution of Social Monogamy in Mammals," in Ulrich Reichard and Christophe Boesch, eds., Monogamy: Mating Strategies and Partnerships in Birds, Humans, and Other Mammals (Cambridge: Cambridge University Press), 42-58.

Carroll, Sean B. 2009. Remarkable Creatures: Epic Adventures in the Search for the Origins of Species (Boston: Houghten Mifflin Harcourt).

Chapais, Bernard. 2008. Primeval Kinship: How Pair-Bonding Gave Birth to Human Society (Cambridge, MA: Harvard University Press.

Chapais, Bernard. 2011a. "Understanding Dimorphism as a Function of Changes in Male and Female Traits," Evolutionary Anthropology 20: 143-55.

Chapais, Bernard. 2011b. "The Deep Social Structure of Humankind." Science 331: 1276-1277.

Chapais, Bernard 2012. "Sexual Size Dimorphism, Canine Dimorphism, and Male-Male Competition in Primates: Where Do Humans Fit In?" Human Nature 23: 45-67.

Fisher, Helen. 1992. Anatomy of Love: The Natural History of Monogamy, Adultery, and Divorce. New York: Norton.

Fisher, Helen. 2006. Why We Love: The Nature and Chemistry of Romantic Love. New York: Henry Holt.

Flannery, Kent, and Marcus, Joyce. 2012. The Creation of Inequality: How Our Prehistoric Ancestors Set the Stage for Monarchy, Slavery, and Empire (Cambridge, MA: Harvard University Press).

Frayling, Christopher, and Wokler, Robert. 1982. "From the Orangutan to the Vampire: Towards an Anthropology of Rousseau," in R. A. Leigh, ed., Rousseau After 200 Years (Cambridge: Cambridge University Press), 109-29.

Gordon, A. D., Green, D. J., and Richmond, B. G. 2008. "Strong Postcranial Size Dimorphism in Australopithecus afarensis: Results from Two New Resampling Methods for Multivariate Data Sets with Missing Data." American Journal of Physical Anthropology 135: 311-28.

Lockwood, C. A., Richmond, B. G., Jungers, W. L., and Kimbel, W. H. 1996. "Randomization Procedures and Sexual Dimorphism in Australopithecus afarensis." Journal of Human Evolution 31: 537-48.

Lovejoy, C. O. 1981. "The Origin of Man." Science 211: 341-50.

Plavcan, J. Michael. 2011. "Understanding Dimorphism as a Function of Changes in Male and Female Traits." Evolutionary Anthropology 20: 143-55.

Plavcan, J. Michael. 2012. "Sexual Size Dimorphism, Canine Dimorphism, and Male-Male Competition in Primates: Where Do Humans Fit In?" Human Nature 23: 45-67.

Plavcan, J. Michael, Lockwood, C. A., Kimbel, W. H., Lague, M. R., and Harmon, E. H. 2005. "Sexual Dimorphism in Australopithecus afarensis Revisited: How Strong is the Case for a Human-Like Pattern of Dimorphism?" Journal of Human Evolution 48: 313-20.

Reno, P. L., Meindl, R. S., McCollum, M. A., and Lovejoy, C. O. 2003. "Sexual Dimorphism in Australopithecus afarensis Was Similar to that of Modern Humans." Proceedings of the National Academy of Sciences USA, 100: 9404-9409.

Reno, P. L., McCollum, M. A., Meindl, R. S., and Lovejoy, C. O. 2010. "An Enlarged Postcranial Sample Confirms Australopithecus afarensis Dimorphism Was Similar to Modern Humans." Philosophical Transactions of the Royal Society B. 365: 3355-3363.

van Schaik, Carel P, and Kappeler, Peter M. 2003. "The Evolution of Social Monogamy in Primates." In Ulrich H. Reichard and Christophe Boesch, eds., Monogamy: Mating Strategies and Partnerships in Birds, Humans, and Other Mammals, 59-80. Cambridge: Cambridge University Press.

Wokler, Robert. 1976. "Tyson and Buffon on the Orangutan."  Studies on Voltaire and the Eighteenth Century 155: 2301-2319.

Wokler, Robert. 1978. "Perfectible Apes in Decadent Cultures: Rousseau's Anthropology Revisited." Daedalus 107: 111-17.


Some of these points have been developed in other posts here, here, here, here, and here.

Did Leo Strauss Think that Liberalism's Success Denied the Need for Esoteric Writing?

I have written a series of posts--here, here, and here-- about Arthur Melzer's book Philosophy Between the Lines: The Lost History of Esoteric Writing.  Some of the writing in those posts is included in an article--"Does Modern Liberalism's Success Deny the Need for Esoteric Writing and Thus Refute Strauss?"--that has just been published in Perspectives on Political Science (July/September, 2015). 

This entire issue of PPS is devoted to a symposium of essays on Melzer's book edited by Peter Minowitz.  The other authors are Francis Fukuyama, Norma Thompson, Catherine Zuckert, Michael Zuckert, Michael Frazer, Adrian Blau, Douglas Burnham, Miguel Vatter, Roslyn Weiss, Grant Havers, and Peter Augustine Lawler.  The next issue of PPS will have four or five new articles on the book and Melzer's response to the entire symposium.  (If you have access to any good academic library, you should be able to download PPS.)

My main idea is that Melzer's book points to a contradiction in Leo Strauss's account of esoteric writing.  On the one hand, Strauss seems to agree with the pre-modern view that esoteric writing is necessary and desirable because of the natural conflict between the philosophic life of the few and the moral, religious, or political life of the many.  On the other hand, Strauss seems to agree with the modern view that in a liberal or open society, there is no natural conflict between the philosophic life and the practical life, and therefore esoteric writing is unnecessary and undesirable.

None of the other authors in the PPS symposium explicitly recognize this contradiction.  But some of them do implicitly point to it.  Some of them say that Strauss  agrees with the pre-modern view of the philosophic life as the only naturally good life, as a life for a few human beings that must conflict with the practical life of the many, and therefore esoteric writing is necessary and desirable to keep these opposing lives from harming one another.  And yet some of these authors also say that Strauss endorses modern liberal democracy in establishing open societies in which esoteric writing is no longer necessary or desirable, because complete freedom of thought and speech does not weaken the social order of a liberal society.

So far, I have not seen anyone who can clear up this apparent contradiction in Strauss's writing.  Nor have I seen anyone who can plausibly deny that modern liberalism really has succeeded in creating a largely open society with no need for esoteric writing.  In such a society, the philosophic life is not the only naturally good life restricted to a few, but it is rather one of the natural goods of life that is open to all human beings.  On this point, I agree with Lawler, who writes:

"As St. Augustine says, action and contemplation are for all of us.  Even Socrates should have practiced the virtues of generosity and charity and parental responsibility, and all of us should have some time--because we're all given the inward inclination--to contemplate the truth about who each of us is and what we're born to do.  This line of thinking is the way both to restore the dignity of liberal education and to recover the truthful foundation of the rights we all cherish.  The bottom line: I don't think we should practice esoteric writing, and I don't think it ever faithfully or unambiguously served the truth.  Truths that Melzer presents as once esoteric and now inauthentic commonplaces among sophisticates (e.g., that love is an illusion and suffering is meaningless) turn out not to be true, deep down, after all" (203).

Lawler has responded to this post on his "Postmodern Conservative" blog.

The Evolution of Adam

Can a Christian be a Darwinian?

Yes, I think so, but it all depends on how one interprets Christianity and how one interprets Darwinism.  If you think Christianity requires that one reads the Bible as literally true in everything it says, or if you think that Darwinian science denies the existence of God as the Creator of nature, then you must think that a Christian cannot be a Darwinian.

But I don't think that Christians have to read the Bible as literally true in all that it says.  In fact, no reasonable Christian can do this, because the Bible makes some claims that are contradictory, some claims that are clearly poetic imagery rather than literal assertions, and some claims that are clearly false if interpreted literally.

And I don't think that Darwinian science necessarily denies the existence of the Creator.  It is possible to be a theistic evolutionist.  Darwin left that open as a possibility by embracing the idea of dual causality--the idea that natural science studies the secondary causes that govern the natural universe, but not the primary causes that originate from the Creator.  So while Darwin rejected what he called "the theory of special creation"--the theory that the Creator had to miraculously intervene into nature to create every form of life--Darwin accepted the possibility that the Creator was the First Cause of the laws of nature through which every form of life evolved.

Catholic Christians generally and many Protestant Christians have had no difficulty in embracing theistic evolutionism.  But most fundamentalist or evangelical Protestants have rejected this position because they assume that the Bible must be read as literally true, and that Darwinian science must deny this literal truth of the Bible in its claims about the natural history of the universe and humanity.

I am pleased to see, however, that some evangelical Christians are beginning to accept theistic evolution.  One can see this, for example, in the debate over whether Christians must believe that Adam and Eve were real human beings--the first human beings created by God, who sinned in disobeying God, and who passed on their original sin as an inheritance of all human beings who are descended from them.  The various positions in this debate are well represented in a symposium on the "historical Adam" at the website of Books and Culture, a journal sponsored by Christianity Today, the leading evangelical magazine.

Hans Madueme and William Vandoodewaard speak for the Calvinist Reformed tradition in asserting that orthodox Christianity requires a belief in the literal historical reality of Adam and of original sin as the product of Adam's disobedience, which means that Christians cannot accept Darwinian evolution as a true account of human origins.

The other commentators argue the other side--that no reasonable Christian can believe in the historical reality of Adam.  There are two reasons for this.  First, a reading of the first few chapters of Genesis as compared with other ancient creation stories make it clear that these stories were mythic accounts of the origins of the universe and human beings that are not believable today.  So, for example, the Genesis story assumes a three-tiered vision of the universe with a solid firmament (containing the Sun, the Moon, and the stars) separating Heaven and the waters above from the waters below and the Earth below, and with an underworld under the surface of the Earth.  No reasonable person today believes this to be accurate.  And yet a Christian can affirm the truth of Christian theology without having to affirm the truth of this ancient view of the universe.

Second, evolutionary science shows that human beings evolved from primate ancestors over millions of years, and therefore the belief in the historical Adam as created in the Garden of Eden must be rejected.  The truths of modern natural science can be embraced by Christians as manifestations of God's general revelation through nature as distinguished from His special revelation through the Bible.  Galileo defended this "two books" approach--the book of God's Word and the book of God's works--to show that Christians could affirm the Copernican view of the solar system as superior to the geocentric view of the Bible.

Madueme does make a good point, however, that once we deny the historical truth of Adam, it's hard to see why we shouldn't deny the historical truth of everything else in the Bible, including the historical truth of Jesus and his resurrection.  "We're told that we can't affirm a historical Adam because it's scientifically unbelievable, but why then trust Paul on the resurrection when that, too, is scientifically unbelievable? Or, to flip the script, if we believe the resurrection, then a historical Adam is no biggie."

But surely Madueme would not say that if we believe the resurrection, then a geocentric universe is no biggie.

Other posts on these issues can be found here, here, here, here, here, and here.

The Empirical Falsifiability of Kennedy's Natural Law Reasoning for Gay Marriage

Natural law reasoning is an empirical science insofar as it makes falsifiable predictions about the failure of laws that deny human nature.  So, for example, if one agrees with Robert George and others that the monogamous marriage of a man and a woman is the only kind of marriage that can secure the two natural ends of marriage--conjugal bonding and parental care of children--and that same-sex marriage is not real marriage because it cannot secure these two natural ends, then one can predict that legalizing gay marriage will fail because it cannot satisfy the natural human desires for marital bonding and parental care.  Justice Kennedy agrees that marital arrangements are to be judged by whether they can achieve these two natural ends, but he argues that same-sex marriages can be as successful as opposite-sex marriages in securing these two ends.

Now that Obergefell v. Hodges has established gay marriage as a national constitutional right, we can begin to accumulate the evidence for deciding between these two falsifiable predictions--George's prediction that gay marriage will fail and Kennedy's prediction that it will succeed.  But in the responses to the Obergefell decision that I have seen, I have not seen many people making this point.

Consider the symposium on Kennedy's opinion at the First Things website, which shows the wide range of responses from conservative Christians and Jews.  Many of the writers here insist that they are defending truth against the lie of the LBGT agenda.  The lie, according to Patrick Deneen is "that the conjugal view of marriage has as little basis in reason or nature as denial of basic rights to people based upon the color of their skin.  The analogy's success has relied upon the loud and insistent demand that we not notice, nor regard as relevant or germane, the fact that men and women are different, and most importantly, that their sexual union is oriented toward reproduction."

Here Dineen rightly points to the central constitutional argument in Kennedy's decision.  In Loving v. Virginia (1967), state laws prohibiting biracial marriage were struck down as violating the 14th Amendment's protection of liberty and equality.  It was declared that marriage was "one of the vital personal rights essential to the orderly pursuit of happiness by free men," and that this included the right to marry someone of a different race.  When some homosexuals argued that excluding same-sex couples from marriage was unconstitutional for the same reason that excluding biracial couples from marriage was unconstitutional, the Court rejected this reasoning in Baker v. Nelson (1972).  Kennedy's decision overturns Baker v. Nelson in declaring that same-sex couples have the same right to marry as biracial couples.

The debate over biracial marriage was part of the debate over slavery prior to the Civil War.  Abraham Lincoln's critics argued that his appeal to equality of rights in condemning slavery as morally wrong would dictate an equal right to biracial marriage.  Lincoln responded, particularly in the Lincoln-Douglas debates of 1858, by insisting that he had never argued for the equal right of white men to marry black women.  This is often cited as showing Lincoln's racism, but the careful way in which he spoke suggests that he could not endorse biracial marriage in 1858, because of the racial bigotry of his times, although future changes in cultural attitudes might eventually make it possible to have something like the Loving decision.  This is the sort of moral and constitutional progress over time that Kennedy relies on.

But while conservative Christians today accept the legalization of biracial marriages as moral and constitutional progress, they reject the reasoning by analogy that would extend this to gay marriages, because legalizing biracial marriages in Loving still adhered to the traditional definition of marriage as between a man and a woman.

Now, at least, we can clarify if not resolve this debate by looking at the evidence.  Now we can look at our experience with one-race heterosexual marriages, two-race heterosexual marriages, and same-sex marriages to see how well they achieve the natural ends of marriage--conjugal bonding and parental care.

My prediction is that same-sex marriages can at least approximate opposite-sex marriages in securing these natural ends.  In the First Things symposium, Wesley Hill points to this idea.  He refers to a book by the gay journalist Jonathan Rauch--Denial: My Twenty-Five Years Without a Soul.  Rauch says that his life as a solitary homosexual was empty until he decided that he had a right to marry.  "They and he have found, at last, a name for his soul.  It is not monster or eunuch.  Nor indeed homosexual.  It is: husband."

Hill says that that last sentence of Rauch's book "left a lump in my throat."  "His portrayal of marriage as the main place to find dignity, belonging, and the end of loneliness sounds eerily similar to the view of marriage promoted in otherwise orthodox, traditional Christian churches.  In countless sermons, songs, Bible studies, and informal pew-side conversations, I heard that message like the peal of a gong: singleness equals alienation, marriage means home."

So is gay marriage "eerily similar" to heterosexual marriage in the natural needs that it satisfies? 

If the writers for this First Things symposium are right, the constitutional right to same-sex marriage will not end Rauch's loneliness and lead him home, because it's impossible for same-sex marriage to fulfill the natural desire for conjugal bonding.  Nor will same-sex marriage fulfill the natural desire for parental care, because it's impossible for a same-sex couple to provide properly for the well-being of children.

And yet, of the 23 writers in this symposium, Mark Regnerus is the only one to explicitly state a falsifiable prediction of gay marriage's failure: "marriage is a conservative institution and ultimately indestructible.  Hence an attempted alteration of the sort we are witnessing won't work."  He predicts that while the rate of gay marriage will rise over the next few years, the rate will decline dramatically over the next 15 years as gays discover that gay marriage doesn't work.

Regnerus is an interesting case, because he's a sociologist at the University of Texas who has published a study claiming to show that young adults reared by gay parents are not as well off as those reared by heterosexual parents. He found those raised by gay parents were more likely to have problems — welfare dependence, less education, marijuana use — than young adults from stable families led by heterosexuals. But he later acknowledged that his study didn't include children raised by same-sex couples in a stable relationship, and that provoked criticisms from people who claimed that this was a flawed and biased study.  He was one of the people offering expert testimony in the Michigan case that was appealed to the Supreme Court and became part of the Obergefell decision.  In his testimony, Regnerus said that there is not enough rigorous research to justify any firm conclusions about the effects of gay parenting on children.  In any case, this points to the possibility that empirical research could settle some of the debate over gay marriage.

Here is his original article.  Here is his response to his critics.  And here is a piece in Slate on the debate over his research.

There is another falsifiable prediction here.  Robert George and others predict that when the governmental licensing of marriage is not restricted to the "real marriage" of a man and a woman open to reproduction and caring for children, this will destroy the traditional institution of marriage.  Oddly, this contradicts George's argument that marriage is created not by government but by nature.