Thursday, October 25, 2018

Elite Body Armor in the Evolution of Archaic States

Ancient Greek, Roman, Samurai, and Aztec Body Armor

The Earliest Pictorial of Armored, Helmeted Warriors in Phalanx Formation on the Sumerian Stele of Vultures (2525 BC)

The Stele of Vultures is a stone slab erected by King Eannatum of Lagash to commemorate his defeat of the king of Umma in one of the many wars fought by states in ancient Mesopotamia--what is now southern Iraq.  It is called the Stele of Vultures because it depicted vultures tearing at the corpses of the defeated soldiers.  In the picture sketched above, it depicts armored and helmeted soldiers in a phalanx formation, armed with spears, trampling their opponents.  Since fighting in a phalanx requires special training and discipline, these are probably professional soldiers; and so this could be the first evidence in history of a standing professional army.  Prior to this, Neolithic armies were composed of men brought together to fight in some temporary crisis, and then they disbanded once the fighting was over.  We also know from other cuneiform tablets that some of the kings of the Mesopotamian city-states paid to maintain 600-700 full-time soldiers.  This state-supported military maintenance included expensive helmets, armor, weapons, and chariots.  The helmets were made of copper with a leather liner underneath.  The chariot was a Sumerian invention that became a major part of the military technology of Eurasian archaic states.  (See Richard A. Gabriel and Karen S. Metz, A Short History of War: The Evolution of Warfare and Weapons [Carlisle Barracks, PA: Strategic Studies Institute, Army War College, 1992], which is available online.)

Prior to this, for hundreds of thousands of years of human evolution, human beings lived in stateless societies that were roughly egalitarian and democratic, in that most of the adult males had equal access to coercive power, because throwing stones, spear-throwers, and bows and arrows were easily available; and so the great majority of individuals could use their coercive threat to prevent exploitative rule by an elite few.  In the Neolithic Chiefdoms, there was some status ranking, and prominent men might lead a society in war, but leaders who sought tyrannical dominance could be checked by the coercive power of the multitude of individuals resisting exploitation.

Beginning around 5,200 BC, there is evidence in Mesopotamia for villages and small towns of sedentary foragers, farmers, and pastoralists who managed their collective affairs and trade with the outside world.  So even after the development of agriculture, with the farming of domesticated plants and the herding of domesticated animals, human beings still lived in societies without bureaucratic states.

The first state in Mesopotamia--showing a state apparatus with walls, tax collectors, bureaucratic officials, and a priestly establishments--was probably Uruk.  A city wall was first built at Uruk around 3,200 BC.  By then Uruk was probably the largest city in the world, with a population between 25,000 and 50,000.

Following the model of Uruk, roughly twenty other city-states arose in the Mesopotamian alluvium.  Now it seemed that the liberty and equality of the state of nature had been lost as many people found themselves in organized state societies oppressed by slavery, forced labor, military conscription, and exploitative taxes.

According to Paul Bingham, the one primary cause for this move from egalitarian and democratic stateless societies to elite ruled archaic states is the new military technology of elite body armor.  Unlike stones, spear-throwers, and bows, specialized body armor is expensive and thus controlled by small groups of elite individuals.  Bingham's evidence for this is that in every archaic state--ancient Mesopotamian states, ancient Rome, ancient Inca state, ancient Mayans, ancient Aztecs, Imperial Japan, the Hawaiian states--coercive power is concentrated in elite armored warriors who are less than 10% of the male population.  Some evidence does not seem to conform to this pattern, however. Ancient Egypt was one of the earliest archaic states, and yet there is little evidence that Egyptian soldiers were heavily armored.  (See John Coleman Darnell and Colleen Manassa, Tutankhamun's Armies: Battle and Conquest During Ancient Egypt's Late Eighteenth Dynasty [Hoboken, NJ: John Wiley, 2007], pp. 81-83.)

Archaic states have hierarchical societies in which a small elite at the top rule for their self-interest in exploiting the majority of the people through enslavement, forced labor, conscription, and oppressive taxation.  Nevertheless, when these archaic states became too tyrannical, the state subjects could flee or rebel and thus bring the disintegration of the state, which confirms Locke's account of how people through resistance and rebellion against governmental tyranny reclaim their natural freedom.

I have written about the evidence for this in ancient Mesopotamia here and here.  This explains why Pierre Goodrich chose the Sumerian word amagi--the first word in the oldest written language for "liberty"--as the logo for the Liberty Fund.  The greatest threat to human liberty--the emergence of the archaic state in Mesopotamia--elicits the natural human resistance to tyranny that manifests the natural human longing for liberty that was shaped in the evolutionary state of nature.

Tuesday, October 23, 2018

Stephen Hawking's Unscientific Atheism and the Dubious Idea of Nothingness

When the theoretical physicist Stephen Hawking died last March at the age of 76, he was the most famous scientist in the world.  He was the Lucasian Professor of Mathematics at the University of Cambridge, which was the position once held by Isaac Newton.  The picture of Hawking in his wheelchair--a brilliant mind in a body almost completely paralyzed by motor neuron disease--had become an iconic image of the scientist, comparable to Albert Einstein's face.  Hawking's ashes were buried in Westminster Abbey between Newton and Charles Darwin.

In 1988, Hawking's first book--A Brief History of Time--became an international best-seller.  When he died, he was working on his last book, which has just been published--Brief Answers to the Big Questions (Bantam Books, 2018).  In such books, written for a popular audience, we can see Hawking trying to shape popular culture to conform to his understanding of modern science.

Crucial to that project is his answer to the first Big Question in his new book--Is there a God?  His answer is No.

Hawking's atheism was troubling for his first wife--Jane--because she was a devout Christian.  (Charles and Emma Darwin faced a similar struggle, which I have written about here and here.) This and other problems in their marriage are thoughtfully depicted in Jane's published memoir of their life and in the movie based on her writing--The Theory of Everything.  The actor playing the part of Stephen--Eddie Redmayne--received the Academy Award for Best Actor, and he writes the Foreword to Brief Answers.  The movie is well worth watching.  I watched it for the first time a few months ago while flying across the Pacific from Australia to the U.S.  Here's the trailer:

Although Hawking insists that his atheism is dictated by science, his atheism is actually unscientific, because his reasoning is fallacious and unsupported by empirical evidence.  He fails to see that modern science can neither prove nor disprove the existence of God, because there is no scientific way to resolve the Reason-Revelation debate.  And so he also fails to see that a modern liberal regime shaped by the Scientific Enlightenment must foster the intellectual freedom of thought about the Reason-Revelation debate, while also fostering the practical freedom of association in forming religious communities.

Consider this first paragraph in his first chapter of Brief Answers:
"Science is increasingly answering questions that used to be the province of religion.  Religion was an early attempt to answer the questions we all ask: why are we here, where did we come from?  Long ago, the answer was almost always the same: gods made everything.  The world was a scary place, so even people as tough as the Vikings believed in supernatural beings to make sense of natural phenomena like lightning, storms, or eclipses.  Nowadays, science provides better and more consistent answers, but people will always cling to religion, because it gives comfort, and they do not trust or understand science" (25).
The claim that people "cling to religion" only because they "do not trust or understand science" is false.  Lots of prominent scientists--from Newton to Francis Collins--have been religious believers.  Newton thought that his Principia Mathematica supported the design argument for the existence of God.  In his "General Scholium" to the Principia, he declared: "This most beautiful system of the Sun, Planets, and Comets, could only proceed from the counsel and dominion of an intelligent and powerful being. . . . This Being governs all things, not as the soul of the world, but as Lord over all: And on account of his dominion he is wont to be called Lord God Pantokrator, or Universal Ruler."  Biologists like Francis Collins and astrophysicists like Owen Gingerich have affirmed theistic evolution in arguing that God can act through the natural causality of Darwinian evolution.  Darwin himself recognized this position (taken by people like Asa Gray) as intellectually defensible.  Darwin was an agnostic, but he was not an atheist, because he could not see how science could completely refute theism.  I have written about theistic evolution (here  and here) and Darwin's agnosticism (here).  Hawking is silent about all of this, and so he does not explain what is wrong with scientific theism.

Some scientific theists have argued that the scientific idea of the Big Bang--the idea that the whole universe arose from nothing about 14 billion years ago--points to God, because only God could have created everything out of nothing.  On the contrary, Hawking argues, science can explain how the universe arose from nothing without any need for God as the Creator.  Here's Hawking's reasoning in Brief Answers:
". . . What could cause the spontaneous appearance of a universe?  At first, it seems a baffling problem--after all, in our daily lives things don't just materialize out of the blue.  You can't just click your fingers and summon up a cup of coffee when you feel like one.  You have to make it out of other stuff like coffee beans, water and perhaps some milk and sugar.  But travel down into this coffee cup--through the milk particles, down to the atomic level and right down to the sub-atomic level, and you enter a world where conjuring something out of nothing is possible.  At least, for a short while.  That's because, at this scale, particle such as protons behave according to the laws of nature we call quantum mechanics.  And they really can appear at random, stick around for a while and then vanish again, to reappear somewhere else."
"Since we know the universe itself was once very small--perhaps smaller than a proton--this means something quite remarkable.  It means the universe itself, in all its mind-boggling vastness and complexity, could simply have popped into existence without violating the known laws of nature.  From that moment on, vast amounts of energy were released as space itself expanded--a place to store all the negative needed to balance the books.  But of course the critical question is raised again: did God create the quantum laws that allowed the Big Bang to occur?  In a nutshell, do we need a God to set it up so that the Big Bang could bang?  I have no desire to offend anyone of faith, but I think science has a more compelling explanation than a divine creator."
"Our everyday experience makes us think that everything that happens must be caused by something that occurred earlier in time, so it's natural for us to think that something--maybe God--must have caused the universe to come into existence.  But when we're talking about the universe as a whole, that isn't necessarily so.  Let me explain.  Imagine a river flowing down a mountainside.  What caused the river?  Well, perhaps the rain that fell earlier in the mountains.  But then, what caused the rain?  A good answer would be the Sun, that shone down on the ocean and lifted water vapor up into the sky and made clouds.  Okay, so what caused the Sun to shine?  Well, if we look inside we see the process known as fusion, which hydrogen atoms join to form helium, releasing vast quantities of energy in the process.  So far so good.  Where does the hydrogen come from?  Answer: the Big Bang.  But here's the crucial bit.  The laws of nature itself tell us that not only could the universe have popped into existence without any assistance, like a proton, and have required nothing in terms of energy, but also that it is possible that nothing caused the Big Bang.  Nothing" (33-35).
 Notice the incoherence in Hawking's reasoning here.  He claims to explain the origin of the universe from nothing, but his explanation actually assumes that the universe originated from something!  On the one hand, he says that "nothing caused the Big Band."  But on the other hand, he must appeal to "the quantum laws that allowed the Big Bang to occur."  He must assume at the origin of the universe the reality of the laws of quantum mechanics and of quantum vacuum states.  That's not nothing! That's something!

Hawking falsely assumes the possibility of absolute nothingness.  Since human beings have no experience of absolute nothingness, whereas all of our experience confirms the being of things, there is no empirical evidence for absolute nothingness.  Even the very idea of nothingness as a product of the theological imagination pondering the doctrine of creation ex nihilo is dubious, because in the absence of any empirical evidence, I doubt that people even understand what they are saying when they ask why the world arose out of nothing.

Hawking might have responded to this objection by asserting that the scientific theory of the Big Bang shows that we have scientific evidence of absolute nothingness, because the theory tells us that before the Big Bang about 14 billion years ago, the universe did not exist.

But there are lots of problems with this interpretation of the Big Bang theory.  First, there is disagreement among cosmologists as to whether the Big Bang was a "singularity"--a sudden appearance of space/time and physical laws from nothingness.  Some believe the Big Bang was a lawful emergence of the present universe from a previous one, although then we confront the problem that the theory of multiple universes is not open to empirical observation and testing.

The second problem is that if we see the Big Bang as a singularity, then there was no time prior to the Big Bang, and therefore there were no earlier moments of time in which nothing existed.

The third problem is that if we use the principles of quantum mechanics to infer that the universe arose from nothing as a quantum fluctuation, then we assume (as Hawking does) the existence of quantum mechanics, which is not absolute nothingness.

Finally, any interpretation of the Big Bang as something coming from nothing can only be a work of wildly speculative imagination without any basis for empirical testing.  Notice that in offering his theory of how the universe arose from nothing without God, Hawking does not propose any way to empirically test his theory, because in principle it is not testable.  If science requires testing theories against empirical data, then Hawking's theory is not science.

The failure of Hawking and others to offer a scientific explanation of how the universe arose from nothing without any need for God's creative activity has been interpreted by some Christian apologists (like William Lane Craig) as indicating that the Big Bang actually proves scientifically the existence of God.  But that is not true, because the Christian doctrine of creation ex nihilo is not a scientific idea at all since it is not open to empirical testing.

This was understood by the first cosmologist to propose a Big Bang theory of the universe--the Jesuit priest Georges Lemaitre.  When Pope Pius XIII in 1951 pointed to Lemaitre's Big Bang theory as scientific evidence for divine creation of the universe from nothing, Lemaitre criticized the Pope for failing to see how his scientific theory had nothing to do with the Christian doctrine of creation.  Lemaitre explained that the theory of the Big Bang is not a theory of how the universe could arise "from nothing," but rather it is a theory of how the universe could have arisen from what Lemaitre called a "primeval atom," or from a hyper-dense sphere of cold matter, disintegrating through radioactivity into an expanding universe, or from what some people called "the cosmic egg."

Lemaitre thus separated the scientific theory of the universe's origin from something and the religious doctrine of the universe's creation from nothing.  Here Lemaitre was in agreement with Thomas Aquinas, who declared that "It is by faith alone do we hold and not be any demonstration that can be proved, that the world did not always exist. . . . that the world began to exist is an object of faith, but not of demonstration or science" (Summa Theologica, I, q. 46, a. 2).

I have elaborated some of these points in previous posts herehere, and here.

Saturday, October 20, 2018

How the Bow and Arrow Caused the Neolithic and Agricultural Revolutions

        A Reconstruction of Cahokia Mounds
Cahokia Mounds Today in Illinois near St. Louis

The Chaco Canyon Great Houses of the Anasazi People in New Mexico

A Prehistoric Cave Picture of Hunters with Bow and Arrow

If the scale of human non-kin social cooperation depends on the range and effectiveness of the weapons for law enforcement, then we can predict that the invention of the bow and arrow expanded social cooperation beyond what was possible with the atlatl.  This can be seen in the archaeological record of prehistoric North America, where the introduction of the bow (AD 300-700) was followed by a great increase in the size and complexity of Native American societies, which is called the North American Neolithic transition.  The introduction of the bow also preceded the much earlier Neolithic transition to sedentary villages in Eurasia around 11,000 BCE in the Natufian culture in the Levant of the southeastern Mediterranean basin (Bingham and Souza 2009; Bar-Yosef 1998).

Bows are more accurate than atlatls, and it is easier to learn to shoot arrows consistently than to throw atlatls consistently (Bettinger 2013; Cattelain 1997; Whittaker 2013).  You can see this by watching some of the videos of people demonstrating the throwing of atlatls, and they show that it's much harder to control the trajectory of an atlatl than to control the flight of an arrow shot from a bow. It is also easier to repeatedly shoot a volley of arrows at a target than to repeatedly throw atlatls.

When our prehistoric ancestors shifted from using atlatls to using bows, they probably doubled or even tripled their success in using their weapons to hunt animals or kill other humans.  Locke's "executive power of the law of nature"--the natural right to punish those who violate the customary norms of social cooperation--became more effective with the bow as a weapon of enforcement.  According to the "social coercion theory" of Paul Bingham and Joanne Souza (2009, 2013), we should see archaeological evidence for increasing scale and complexity of social cooperation after the introduction of the bow, because this weapon improves the credible treat of violent coercion to punish cheaters, free-riders, or social parasites, thus suppressing conflicts of interest to sustain cooperation.

The bow appears for the first time in Southwest Eurasia about 14 thousand years ago (kya), in Europe and in far northern North America about 12 kya.  In North America, the bow spread slowly from north to south.  It did not appear in the southern regions of North America (what is now the United States) until about 200 to 700 AD (Blitz 1988; Maschner and Mason 2013).  This global pattern in the spread of the bow constitutes a natural laboratory experiment.  In principle, we should be able to test the prediction of social coercion theory that the introduction of the bow will be followed by increased social complexity and scale as people settle into villages, engage in complex market exchange, begin domesticating plants and animals, and then later practice extensive field agriculture.

An alternative to the social coercion theory is the warfare theory, which says that the introduction of the bow led to increased warfare between groups, and then there was increased social complexity and economic intensification as a response to the demands of increased warfare.  According to social coercion theory, increased warfare is an effect rather than a cause of the increased social and economic complexity that is caused by the increased effectiveness of the bow as weaponry for enforcing intense social cooperation within a group.  We should be able to see whether the introduction of the bow leads first to increased social and economic complexity followed by increased warfare, which is the prediction of social coercion theory.

The problem, however, is that the archaeological record for dating the appearance of the bow and arrow is often unclear.  Wooden bows and arrows are likely to decay over thousands of years.  Often the stone points are the only surviving evidence.  But then it can be hard to distinguish arrowheads from atlatl dart tips.

The solution to this problem is to measure the length, width, thickness, and weight of the stone points, and then develop standards for distinguishing atlatl dart tips from arrowheads based on these quantitative measurements.  Arrowheads tend to be smaller, thinner, and lighter than atlatl dart points. 

Projectile Points from Prehistoric Mississippi and Alabama: a. Late Arrow Points (Hamilton/Madison Type); b. Early Arrow Points (Baker's Creek Type); c. Dart Points (Copena Type) (Blitz and Porth 2013)

The best way to see the evolution of these artifacts over thousands of years of prehistoric North America is to look at Noel Justice's three books on stone age spear and arrow points in the United States, which describe, date, and categorize the prehistoric stone points, along with beautiful photographs (Justice 1988, 2002a, 2002b).

In 2012, there was a widely publicized report in Nature about the discovery of stone tools dating to 71,000 years ago at the Pinnacle Point prehistoric site in South Africa.  Some of these microliths appeared to be projectile points.  One commentator said that this showed that the bow and arrow was used by people in Africa as early as 71,000 years ago (McBrearty 2012).  But the authors of the report said that these stone points could have been used to tip atlatl darts rather than arrows (Brown et al. 2012, p. 592).  So, as far as I know, there is no clear evidence for arrowheads older than about 14,000 years ago.  (I would be happy to hear from anyone who knows about evidence for an older date.)

I have written (here) about the earliest Neolithic Transitions in ancient Mesopotamia, in which sedentary hamlets become larger villages that domesticated plants and animals for farming, which was followed by fixed field agriculture and then archaic states centered in the first cities (such as Uruk).  I said nothing there about the possible importance of the bow in those transitions.

The archaeological records of the Neolithic revolutions in Eurasia are difficult to study, because they are eight to eleven thousand years old, and over time the records decay or even totally disappear.  By contrast, the archaeological records of the Native Americans of North America provide an almost perfect natural laboratory.  The bow was introduced into this region relatively recently--between 100 and 700 AD in the continental United States.  The archaeological studies of this region are well-developed.  And it is such a large and ecologically diverse region that one can study adaptations for variable environmental settings.  

Bingham and Souza argue that this prehistoric North American record supports their social coercion theory in showing how the introduction of the bow caused an increase in social complexity that sparked the Neolithic revolutions in North America (Bingham and Souza 2009, 360-399; Bingham, Souza, and Blitz 2013; Bingham and Souza 2013).

Consider the consequences of the introduction of the bow into the ancient American Southwest (Bingham and Souza 2009, 376-78; Bingham and Souza 2013; Reed and Geib 2013; VanPool and O'Brien 2013). Four thousands of years, Native Americans in the Southwest lived as nomadic foragers hunting with atlatls and horticulturists who cultivated maize.  Then, the earliest evidence for the use of bows appeared from 100 AD to 400 AD.  From 400 AD to 525 AD, they began to show the Anasazi culture: they lived a more sedentary life in villages, they expanded their use of pottery, and they brought large areas of land under agricultural cultivation.  By 600 AD, they were accumulating enough stored grain to feed themselves for two to four years, and they thus generated a surplus to support extensive trade. By 900 AD, they were living in large blocks of apartment-like structures, showing a new scale of social complexity and economic intensification.  The famous Pueblo Bonito massive buildings in Chaco Canyon (in Northwest New Mexico) were built.  Eventually, thousands of people were living here, with hundreds of acres of land for the cultivation of maize watered by a complex system of irrigation.  This is what happens, Bingham and Souza argue, when a new weapon like the bow extends the range of law enforcement and thus expands social cooperation.

A similar historical pattern appeared in the mid-continental United States where the introduction of the bow around 600 AD preceded the emergence of the Mississippian cultures beginning around 800 AD (Bingham and Souza 2009, 378-79; 2013; Blitz and Porth 2013)  The Mississippian culture was a mound-building civilization that began in the Mississippi River Valley and then spread across the Midwest and the Upland South.  It prevailed across a series of urban settlements and villages linked together by trading networks extending as far west as the Rockies.  The largest city was Cahokia, located east of what is now East St. Louis, Illinois.  Cahokia was probably the largest urban settlement in North America north of Mexico.  The second largest urban settlement was in Moundsville, near what is today Tuscaloosa, Alabama.  The most prominent archaeological record of the Mississippian culture is in the huge earthern pyramid mounds that seem to have been sites for temples and religious ceremonies as well as houses and burial buildings.  The Mississippians practiced large-scale and intensive maize agriculture that sustained their large populations and complex economies of exchange and specialization.

The one driving cause for this increase in social and economic complexity in the Mississippian culture, Bingham argues, was the development of the bow as a weapon that could enforce expanded social cooperation.  Even if we see some evidence that the bow was one cause for this, however, we might object that surely there were other causes as well, and so Bingham's theory suffers from being too simplistic.

For example, the prominence of the Mississippian mounds as structures built for religious rituals points to the importance of religious belief as a primary factor in supporting the evolution of social cooperation among tens of thousands of people who were not kin and who were largely anonymous to one another.  Shared religious beliefs and rituals seemed to have been crucial for binding these people together in moral communities.  Some anthropologists have claimed that the Neolithic transition to agricultural civilization required changes in religious beliefs that would hold people together in large religious communities (Cauvin and Watkins 2000).

Some evolutionary anthropologists have argued that the cultural evolution of prosocial religions was one of the major causes for the cultural evolution of large agrarian states.  The beliefs and practices of these religions promoted social cooperation in large communities based on the shared belief in a morality enforced by an all-powerful and moralistic God.  Like Darwin, they see this cultural evolution as driven by group selection in war:  groups with prosocial religions were stronger than groups without such religions.  I have written about this in a previous post (here).

But to say that religious belief was a primary cause for the Neolithic transitions, Bingham complains, is to confuse effect for cause or proximate for ultimate causation.  From the point of view of Darwinian evolutionary science, beliefs are merely the proximate tools for carrying out evolved behavioral strategies for individual self-interest.  The social cooperation of non-kin requires social coercion through the credible threat of violence against cheaters and free-riders.  A new weapon like the bow and arrow allows this social coercion to expand to the scale of large Neolithic communities.  Religious belief can then become a mere means in human proximate psychology for motivating the cooperative behavior demanded by social coercion.

Through out most of our evolutionary history, our ancestors lived in small foraging bands where everyone knew everyone else.  They shared information about the world, including their social world, which held them together as a mutually informed social group. They monitored one another's conduct.  They were vigilant in punishing misbehavior and thus enforcing a shared belief system that included the social contract--the customary norms for conduct.

But then as social groups grew in size during the Neolithic transition, people were connected to too many people to know them all well; and so they could not monitor what everyone was doing and thinking.  They could not sustain their social identity as a mutually informed social group through the face-to-face interactions of people personally known to one another.

The solution to this problem was to bring together large collections of people to engage in ritual celebrations--perhaps at a temple complex on top of a sacred mound--where people would be required to profess their loyalty to a communal belief system.  Anyone suggesting any doubt in this belief system would be ostracized.  Affirming this belief system simultaneously bound the members of the community into a social unit and cut them off from members of any competing communities.

Such a belief system, Bingham observes, would include three kinds of beliefs.  There would be pragmatic beliefs about the material world pertinent to adaptive activities--such as foraging, hunting, farming, and so on.  There would be social contract beliefs about the customary norms of social conduct for the community--such as not stealing property or not murdering other members of the community.  And there would be identifier beliefs that distinguish the members of one community from those of other communities.

The first two kinds of belief--pragmatic and social contract beliefs--can be empirically verifiable by reference to our experience of the material and social worlds.  But the identifier beliefs may be so obscure and esoteric that they have no verifiable reference to the ordinary world of human experience.  This includes beliefs about the gods and spirits--about a world of invisible powers beyond the visible world.  These beliefs are purely self-referential, with no reference to the real world, because their purpose is not to help us navigate our way in the material and social world but to identify us as set apart from and against them.  (Today, we see such xenophobic identifier beliefs expressed in fascist and populist political movements.)

Bingham identifies his own identifier beliefs as those of the scientific atheists, who believe that the belief system predominant in a modern liberal democratic society should be secular scientific materialism, which allows people to doubt or deny religious beliefs without fear of punishment, and which requires that the political order of a modern society should promote and respect the scientific pursuit of truth based on reason rather than revelation.

We might wonder, however, whether a predominantly secular civilization is possible?  Or does the social prevalence of scientific atheism subvert the moral order of human life by denying its grounding in religious belief?  Is a society of atheists impossible?  Is atheism contrary to our evolved human nature?

We can think about such questions by considering the implications of the scientific atheism proclaimed by celebrated scientists like Stephen Hawking.  My next post will be on Hawking's posthumously published book--Brief Answers to the Big Questions. 


Bar-Yosef, Ofer. 1998. "The Natufian Culture in the Levant, Threshold to the Origins of Agriculture." Evolutionary Anthropology 6: 159-177.

Bettinger, Robert L. 2013. "Effects of the Bow on Social Organization in Western North America." Evolutionary Anthropology 22: 118-123.

Bingham, Paul, and Joanne Souza. 2009. Death from a Distance and the Birth of a Humane Universe. Charleston, SC: BookSurge.

Bingham, Paul, and Joanne Souza. 2013. "Theory Testing in Prehistoric North America: Fruits of One of the World's Great Archeological Natural Laboratories." Evolutionary Anthropology 22: 145-153.

Bingham, Paul, Joanne Souza, and John H. Blitz. 2013. "Social Complexity and the Bow in the Prehistoric North American Record." Evolutionary Anthropology 22: 81-88.

Blitz, John H. 1988. "Adoption of the Bow in Prehistoric North America." North American Archaeologist 9: 123-145.

Blitz, John H., and Erik S. Porth. 2013. "Social Complexity and the Bow in the Eastern Woodlands." Evolutionary Anthropology 22: 89-96.

Brown, Kyle S., et al. 2012. "An Early and Enduring Advanced Technology Originating 71,000 Years Ago in South Africa." Nature 491: 590-593.

Cattelain, Pierre. 1997. "Hunting During the Upper Paleolithic: Bow, Spearthrower, or Both?" In Heidi Knecht, ed., Projectile Technology, 213-240. New York: Plenum Press.

Cauvin, J., and T. Watkins. 2000. The Birth of the Gods and the Origins of Agriculture.  Cambridge: Cambridge University Press.

Justice, Noel. 1988. Stone Age Spear and Arrow Points of the Midcontinental and Eastern United States. Bloomington: Indiana University Press.

Justice, Noel. 2002a. Stone Age Spear and Arrow Points of California and the Great Basin. Bloomington: Indiana University Press.

Justice, Noel. 2002b. Stone Age Spear and Arrow Points of the Southwestern United States. Bloomington: Indiana University Press.

McBrearty, Sally. 2012. "Sharpening the Mind." Nature 491: 531-532.

Maschner, Herbert, and Owen K. Mason. 2013. "The Bow and Arrow in Northern North America." Evolutionary Anthropology 22: 133-138.

Reed, Paul F., and Phil R. Geib. 2012. "Sedentism, Social Change, Warfare, and the Bow in the Ancient Pueblo Southwest." Evolutionary Anthropology 22: 103-110.

VanPool, Todd L., and Michael J. O'Brien. 2013. "Sociopolitical Complexity and the Bow and Arrow in the American Southwest." Evolutionary Anthropology 22: 111-117.

Whittaker, John C. 2013. "Comparing Atlatls and Bows: Accuracy and Learning Curve." Ethnoarchaeology 5: 100-111.

Tuesday, October 09, 2018

The Atlatl (Spear Thrower) in the Cultural Evolution of Lockean Liberalism

                                                 Weapon Masters Videos on the Atlatl

A Fragment of an Atlatl Dated between 15.2-15.9 Thousand Years Ago Made of Engraved Antler with the Hook Still Intact, from El Miron Cave, Cantabria, Spain (Morales and Straus 2008)

Beginning about 1.8 million years ago, our human ancestors could enforce social cooperation by threatening cheaters and free riders with killing from a distance through throwing rocks or javelins.  The effective lethal range of these weapons is about fifteen meters.  Paul Bingham estimates that with such weapons up to about ninety people could encircle a small group of free riders or cheaters while remaining in range.  In this way, Locke's executive power of the law of nature could coercively enforce social cooperation among no more than ninety individuals.  And so, for about 1.7 million years, that was the limit for human non-kin social cooperation, because the scale of their cooperation was limited by the range of their weapons for remote killing.

Then about 50,000 to 30,000 years ago, something happened to produce what paleoanthropologists call "behaviorally modern humans" (Bar-Yosef 2002; Hill et al. 2009; Klein 2009).  Their anatomy was the same as earlier humans, but their behavior showed a stunning increase in their mental complexity and abstraction.  They were able to migrate out of Africa, and by about 20,000 years ago, they had migrated throughout Eurasia, Australia, North America, and South America.  This began the human dominance of the whole planet. Their tools become more complex and sophisticated.  Their ornaments became more abstract and esthetically evocative.  Their art showed a distinctly human sense of beauty, as in this cave art:

There was also an expansion in the scale of social cooperation, as indicated by large "public works" such as huge earthen mounds and by evidence for long-distance trade networks.  If the scale of social cooperation depends on the range of weaponry for remote killing, then there must have been some new weapon with a range greater than that for thrown rocks or javelins.  And, indeed, there is evidence for the first appearance of atlatls (the Aztec word for spear throwers).

An atlatl amplifies the human throwing motion so that the bolt (or dart) is launched to greater distances, higher velocities, and more penetrating power than thrown stones or hand thrown spears.  Originally, the atlatl was invented by humans to be a weapon for hunting wild game, but then it could be used as a weapon against other humans in war or to punish cheaters and free riders, and thus to coercively enforce a larger scale of cooperation.  Bingham estimates that while thrown stones and javelins could enforce cooperation among up to 90 individuals, atlatls could expand this tenfold up to 900 individuals.

Bingham argues that this expanded the range of cooperation because this new weapon allowed law enforcement to encompass a larger group of people, which then increased the scale of information sharing.  This increase in cultural information sharing could then cause all of the other increases in inventiveness and complexity that characterize the behaviorally human revolution--including more complex tools, abstract art, and more intricate human artifacts.

Bingham's theory makes falsifiable predictions that can be tested against the archaeological evidence.  For example, it predicts that the appearance of atlatls in the archaeological record precedes the appearance of the many traits of behavioral modernity.

The throwing stick and the bolt shaft of the atlatl are normally made mostly of wood and therefore likely to perish over thousands of years.  But some apparently atlatl fragments made of bone, antler, or ivory have been dated to around 16-17 thousand years ago--such as the fragment from El Miron Cave pictured above (O'Driscoll and Thompson 2018; Morales and Straus 2008).

The oldest indirect evidence of atlatls come from the sharp stone points that have the shape and size that identify them as atlatl bolt points rather than thrusting spear points or arrow points.  Thrusting spear points are larger and heavier than bolt points, which are larger than arrow points.  Some of the oldest bolt points have been dated at 50 to 40 thousand years ago (O'Driscoll and Thompson 2018; Shea 2006; Shea and Sisk 2010).

John Shea--Bingham's colleague at Stony Brook University--sees some evidence of bolt points in sub-Saharan Africa as early as 100,000 years ago, although they become more common after 50,000 years ago.  Shea admits, however, that he is baffled by the fact that historic hunter-gatherers in Africa have not used the atlatl.  It's perplexing if atlatls were used in prehistoric Africa but not later.

Shea thinks Bingham has part of the puzzle for human evolution, but not all.  Shea thinks the technology of the atlatl is not enough to explain human complexity, and that spoken language is a crucial factor.  By contrast, Bingham thinks the evolution of human non-kin cooperation supported by coercive weaponry to manage the problem of conflicts of interest created the conditions for the evolution of language: non-kin cooperation was the cause, language was the effect (Bingham and Souza 2009, 240-76).  I am inclined to agree with Shea that while the technology of projectile weapons is one critical factor in shaping human evolution--for the reasons indicated by Bingham--it cannot be the only prime cause.

Here's a video of John Shea showing how ancient atlatls were made and used:

One of the most conspicuous signs of behaviorally modern humans is the construction of huge earthen mounds that apparently were used for local gatherings, perhaps seasonally.  Here is one of the Hopewell mounds in Ohio:

As many as one thousand people could have gathered on this mound.  Although archaeologists continue to debate the functions of these mounds, they seem to be designed for local gatherings.  And since Hopewell societies were connected by extensive trading networks, people were probably meeting at these spots for trade--looking for mates, goods, services, and information.  Such centers of commercial activity would have needed law enforcement to sustain peaceful exchange by punishing thieves and cheaters.  The Hopewell culture flourished from 100 BCE to 500 CE, prior to the arrival of the bow and arrow, so their best weapon for law enforcement would have been the atlatl, and the range of the atlatl was great enough to sustain a scale of cooperation up to one thousand people.

Hopewell burial mounds often have symbolic artifacts.

Hopewell Art

These symbolic artifacts were clearly traded over vast distances, and so they probably functioned as currency for exchange.  Symbolic objects can serve as a form of money because they are precious and difficult to counterfeit.  They can also be worn as ornaments or be signs of status, just as gold, silver, and diamonds can be both currency and valuable ornaments in our culture.

The economic trade in such valuable objects would have been impossible without some coercive law enforcement with weapons like the atlatl to punish thieves and cheaters and thus securing the rights of property and contract.

The evidence for such trade over 100,000 years or more refutes Friedrich Hayek's claim that market exchange is a recent invention in human history.  On the contrary, we might conclude that Adam Smith was right in seeing that human beings are economic animals who naturally strive to "truck, barter, and exchange."

Some of my posts responding to Hayek and defending the idea that the extended order of liberal capitalism appeals to our evolved human nature can be found herehere, and here.


Bar-Yosef, Ofer. 2002. "The Upper Paleolithic Revolution." Annual Review of Anthropology 31: 363-93.

Bingham, Paul, and Joanne Souza. 2009. Death from a Distance and the Birth of a Humane Universe. Charleston, SC: BookSurge.

Hill, Kim, Michael Barton, and A. Magdalena Hurtado. 2009. "The Emergence of Human Uniqueness: Characters Underlying Behavioral Modernity." Evolutionary Anthropology 18: 187-200.

Klein, Richard G. 2009. The Human Career: Human Biological and Cultural Origins. 3rd ed. Chicago: University of Chicago Press.

Morales, Manuel R. Gonzalez, and Lawrence Guy Strauss. 2009. "Extraordinary Early Magdalenian Finds from El Miron Cave, Cantabria (Spain)." Antiquity 83: 267-81.

O'Driscoll, Corey A., and Jessica C. Thompson. 2018. "The Origins and Early Elaboration of Projectile Technology." Evolutionary Anthropology 27: 30-45.

Shea, John J. 2006. "The Origins of Lithic Projectile Point Technology: Evidence from Africa, the Levant, and Europe." Journal of Archaeological Science 33: 823-46.

Shea, John J., and Matthew L. Sisk. 2010. "Complex Projectile Technology and Homo sapiens Dispersal into Western Eurasia." PaleoAnthropology 2010: 100-22.

Monday, October 08, 2018

Friedrich Nietzsche and Lou Salome: The Movie

"Lou Andreas Salome: The Audacity To Be Free" is a good movie about the life of Lou Salome (1861-1937)--the Russian philosopher, novelist, essayist, and psychoanalyst, who became a seductive muse for Friedrich Nietzsche, Paul Ree, Rainer Rilke, and Sigmund Freud.  This is a German movie released in Germany in 2016 and then released this year in North America with English subtitles.  It can now be found at Amazon.

Cordula Kablitz-Post is the director of the movie and the co-author of the screenplay.  The movie shows her intelligent study of Lou's life and writings.  Four different actresses play Lou at four periods of her life.

Here is the trailer.

I have written about Nietzsche being "under Lou Salome's whip" (here and here).  She wrote the first--and perhaps most insightful--book on Nietzsche.  She saw that Nietzsche's early and late writings show his struggle with his religious longings, which he overcame only for a time in his middle writings (such as Human, All Too Human), where he showed his devotion to a philosophic and Darwinian science.  Like me, Lou thought that Nietzsche's middle writings were his best.

Nietzsche's struggle with God and with the possible consequences of the death of God is suggested in one scene (about 58 minutes into the movie), where Salome and Nietzsche are playfully swimming in a river.  As they joke about death and drowning, Lou speaks about her loss of faith in God as a young girl. Then Nietzsche says: "Living without faith takes a lot of energy. Perhaps it's even impossible. And it will be our undoing someday."

The meaning of "our undoing" from our loss of faith is suggested by the coming of Nazism to Germany in 1933.  Lou is in poor health in that year in Germany--she will die in 1937--and she is dictating her memoir to a young admirer--Ernst Pfeiffer, who will edit her memoir for publication in 1951.

We see how Nietzsche's sister--Elisabeth Forster-Nietzsche--helped to break up Lou's friendship with Nietzsche.  We also hear about Elisabeth's management of the Nietzsche Archives to turn Nietzsche into the Nazi Philosopher and her scorn for Lou, who fears Nazi persecution.

In this way, the movie intimates the question of whether Nietzsche's death of God and Lou's philosophic freedom from faith lead somehow to the Nazi catastrophe.

I have written about the "Nazi philosophers" here, here., and here.

I haven't yet figured out how all of this is related to another theme of the film: the complexity of human eroticism at many levels--sexual, intellectual, and religious.  I might need to study some of Lou's other writing, such as the first two chapters of her memoir--entitled "The God Experience" and "The Experience of Love."

Wednesday, October 03, 2018

Throwing Stones to Kill from a Distance: The Evolutionary Origin of Lockean Liberalism?

We humans are unique among all animals in our ability to throw projectiles at high speeds and with amazing accuracy.  We must wonder how this is possible and why this has evolved as a trait of our human nature.

This image shows the differences in the position of the shoulder between chimpanzees (left) and humans (right).  These differences can be seen in both the muscular anatomy and in the bony anatomy of the scapula (shoulder blade).

This allows humans to store elastic energy (like a slingshot) in the tendons, ligaments, and muscles crossing the shoulder.  This energy is then used to catapult the arm forward in a fast motion, which allows very rapid throws.  This was made possible by changes in the upper body that appeared first almost 2 million years ago in the species Homo erectus.  This allows humans to throw projectile missiles (such as rocks and spears) with deadly speed and accuracy (Roach et al. 2013).  Today, we see that most clearly in professional baseball pitchers who can throw baseballs at 90 to 100 miles an hour, again and again.  By contrast, chimpanzees trained to throw can throw a ball only about 20 miles per hour, even though adult chimpanzees are physically stronger in some ways that adult humans. 

This helped our hominin ancestors to kill from a distance in hunting dangerous animals.  The archeological evidence for intensified hunting behavior among our hominin ancestors supports this conclusion.

This capacity for killing at a distance also helped our human ancestors to punish other humans in exercising what John Locke called "the executive power of the law of nature."  Locke recognized that punishment could be costly for the punisher, because "such resistance many times makes the punishment dangerous, and frequently destructive, to those who attempt it" (ST, sec. 126).  The costs of punishment come mostly from provoking violent attacks from those who are being punished.  So the power to punish could never be effectively executed until the risky costs of punishment could somehow be reduced, so that the immediate costs of coercive punishment could be less than its immediate benefits in enforcing social cooperation.

Locke never explains how this could have happened. One likely explanation is that human beings became the first animals capable of killing at a distance by throwing rocks at their victims.  Once this developed as a technique for hunting large animals, it could then be used to kill or threaten other humans who deserved punishment.  Many people could throw stones at a misbehaving individual, and the punishers could do this with little risk to themselves. Thus the evolved human power to punish violators of the law of nature through killing at a distance could be a crucial evolutionary adaptation for Lockean liberalism.  The expansion of social cooperation enforced by cheap punishment of cheaters has evolved from the expanding range of the weapons for remote killing--from rocks to bow-and-arrow to guns to nuclear bombs.

Anthropologists studying nomadic hunter-gatherers have recognized their remarkable egalitarianism--that all adult individuals are equally free in their autonomy and freedom from domination by others.  This looks like Locke's state of nature.  Anthropologists have seen that this egalitarianism requires "leveling mechanisms"--means by which individuals can prevent bullies from dominating them.

One of the critical leveling mechanisms is the equal access to weapons for remote killing.  Anthropologist James Woodburn (1982) noted that in hunter-gatherer bands, all males have equal access to weapons.  "Hunting weapons are lethal not just for game animals but also for people.  There are serious dangers in antagonizing someone: he might choose simply to move away, but if he feels a strong sense of grievance that his rights have been encroached upon he could respond with violence" (436).  Some men will try to dominate others by giving orders or by stealing wives and property, but this is punished by violent retaliation.  Woodburn observes:  "In normal circumstances, the possession by all men, however physically weak, cowardly, unskilled or social inept, of the means to kill secretly anyone perceived as a threat to their own well-being not only limits predation and exploitation; it also acts directly as a powerful levelling mechanism."  For Thomas Hobbes, this was the ground for equality in the state of nature: despite all the inequality in human traits, no one was so superior as to be free from the threat of being killed by those he might try to dominate.

Biologist Paul Bingham has developed this idea into a general theory of human social evolution (Bingham 1999, 2000; Bingham and Souza 2009; Okada and Bingham 2008).  Humans are unique because they are the first animals to be able to kill adult members of their species remotely.  Every other unique feature of humans--such as language, abstract reasoning, morality, and so on--is simply an effect of that one cause.

Bingham argues that the uniquely human capacity for killing at a distance explains the uniquely human capacity for kinship-independent social cooperation.  The evolution of all organisms creates the problem of conflicts of interest that impede social cooperation, because all organisms must compete for the resources necessary for survival and reproduction.  A common way to manage those conflicts of interest is to cooperate with close kin, because kinship creates overlapping interests.  So animals cooperate with close kin, and cooperation with non-kin is typically very limited.  So, for example, among mammals, mothers commonly care for their offspring.  Some animals--such as social insects--cooperate in huge colonies, but this depends on kinship: in ant and bee colonies, most of the (female) members of the colony work to rear their sisters (and a few brothers).

Like other animals, humans cooperate with their kin, but they also cooperate with non-kin much more expansively than is the case for other animals.  To do this, they must manage the problem of conflicts of interest.  And they do that by employing the cheap punishment made possible by remote killing to enforce cooperation: cheaters and free-riders are deterred from their misbehavior by the costs of punishment.

There is a lot of archaeological, anatomical, and ethnographic evidence to support this theory that the uniquely human capacity for throwing stones to kill from a distance initiated the uniquely human evolution of kin-independent social cooperation in a manner that sustains Lockean liberalism (Bingham and Souza 2009, 147-204; Isaac 1987; Marzke et al. 1988; Aiello and Dean 1990; Roach et al. 2013).

Beginning around 2.3 to 2.5 million years ago, there are archaeological deposits in East Africa of stone flakes and fossil prey bones indicating the evolution of hominid scavenging and hunting.  There is also evidence of the evolution of elite human throwing associated with this early scavenging/hunting.  There are piles of stones that archaeologists call "manuports" because the archaeological context suggests that they were moved across the landscape.  Some of these manuports are of the size and shape that would make them good ammunition for throwing at prey animals or at other humans.

There is also skeletal evidence that the first fully human ancestors emerging about 2 million years ago had evolved the anatomical traits--in the hands, arms, torso, pelvis, and feet--that make humans uniquely good throwers.  The hands and arms of our primate ancestors are adapted more for climbing than for throwing, because they were adapted for an arboreal life.

Darwin noticed how skillful hunter-gatherers in Tierra del Fuego were in throwing stones forcefully and accurately.  By contrast, he saw that monkeys and apes were clumsy throwers.  He thought this was one uniquely human trait arising from bipedality and the design of the human hand and arm, which might help to explain human dominance over the Earth (Darwin 2004, 68-72).

Other European explorers of the New World and the South Pacific discovered how deadly this rock throwing could be, because aboriginal people could attack European intruders with a bombardment of stones (Isaac 1987).

If Bingham is right, that evolved uniquely human capacity for elite throwing was the cause for the evolution of the big human brain that arises from a uniquely human life history that depends upon human kin-independent social breeding (Bingham and Souza 2009, 120-146).  "It takes a village to raise a human child," and unlike the social breeding of other animals, the human village that helps in the rearing of offspring includes many adults of both sexes who are not close kin.  It also includes many adult members who are armed for the projection of coercive threat that enforces the village's non-kin cooperation.

A newborn chimp has a very big and heavy brain.  But a newborn human has an even bigger and heavier brain.  Moreover, the human infant's brain will grow much faster and longer.  This growth will extend even into young adulthood.  And while a chimp mother can provide enough food and care for her offspring by herself, a human mother must provide so much more food and better food and so much more care for her offspring that she cannot do this without help from others.  A human mother needs to be a member of a large society--at least as large as a foraging band--that will help in the rearing and protection of her child.  And this society will extend beyond her kin to include unrelated adults.  That's why "it takes a village to raise a human child."

But then we might wonder why the help of her husband would not be enough for her.  Maybe, "it takes a couple to raise a child!"  That's Locke's solution to the mother's problem.  He argues that like many birds, human beings are pair-bonding animals because mothers need the help of fathers in providing food, rearing, and protection for the children, when mothers alone cannot do this.  Human beings are naturally cooperative breeders in families of mothers, fathers, and children (FT, secs. 86-89; ST, secs. 77-84).  Some evolutionary anthropologists today support this idea--that pair-bonding is the crucial evolutionary adaptation in human evolution.

But this doesn't explain why other pair-bonding animals like birds didn't follow the human evolutionary path towards large communities of non-kin members.  And it doesn't explain why human pair-bonded families depend on the support of that large community of both kin and non-kin members.

The proper explanation, Bingham suggests, is that humans are unique in their capacity for non-kin social cooperation, which supports the uniquely human life history for sustaining the growth and rearing of that big human brain.  Non-kin cooperation is impossible without some way to manage the conflicts of interest that necessarily arise among individuals who are unrelated to one another.  Humans are unique because they stumbled into a clever trick for managing such conflicts of interest by the low-cost punishment of cheaters and free-riders through killing or threatening to kill them from a distance.

In foraging bands, most or even all adult individuals have access to such coercive threat, which has a levelling effect in securing each individual's autonomy and freedom from domination.  Consequently, power is democratized in foraging societies, and social norms are formulated and enforced through a broad consensus.

But then, Bingham argues, with the emergence of archaic states, coercive power was concentrated in ruling elites that could enforce their will on the great multitude.  To restore or at least approximate the equal liberty of the hunter-gatherer society--what Locke called the state of nature--access to the weapons of coercive threat would have to be once again equalized.

Here Bingham has rediscovered an insight of some political philosophers--that the structure of political order depends on whether the access to weapons of coercive power is confined to a few or open to many.  In the Politics, Aristotle writes:
"Since there are four parts of the multitude, the farming, the working, the merchant, and the laboring elements, and four parts of the city are useful with a view to war, the horse-rearing, the heavy-armed, the light-armed, and the seafaring elements, wherever it happens that the country is suitable for horses, conditions are naturally apt for instituting a strong oligarchy (for the preservation of the inhabitants derives from a force of this sort, and horse-rearing is done by those possessing larger properties); where it is suitable for heavy arms, the next sort of oligarchy (for the heavy-armed element is made up of the well off more than the poor).  Light-armed and naval forces, on the other hand, are wholly popular.  At present, therefore, wherever this sort of multitude is numerous, and there is a factional split, the oligarchs often get the worst of the contest. . . . This is the way the people prevail over the well off in factional splits: being light-armed, they can easily contend against a force of cavalry and heavy-armed troops" (1321a5-21).


Aiello, L., and C. Dean. 1990. An Introduction to Human Evolutionary Anatomy. San Diego: Academic Press.

Bingham, Paul. 1999. "Human Uniqueness: A General Theory." Quarterly Review of Biology 74: 133-69.

Bingham, Paul. 2000. "Human Evolution and Human History: A Complete Theory." Evolutionary Anthropology 9: 248-57.

Bingham, Paul, and Joanne Souza. 2009. Death from a Distance and the Birth of a Humane Universe. Charleston, SC: BookSurge Publishing.

Darwin, Charles. 2004. The Descent of Man. 2nd edition. London: Penguin Books.

Isaac, Barbara. 1987. :"Throwing and Human Evolution." The African Archaeological Review 5: 3-17.

Marzke, M. W., et al. 1988. "Gluteus Maximus Muscle Function and the Origin of Hominid Bipedality." American Journal of Physical Anthropology 77: 519.

Okada, D., and Paul Bingham. 2008. "Human Uniqueness--Self-Interest and Social Cooperation." Journal of Theoretical Biology 253: 261.

Roach, Neil T., et al. 2013. "Elastic Energy Storage in the Shoulder and the Evolution of High-Speed Throwing in Homo." Nature 498: 483-86.

Woodburn, James. 1982. "Egalitarian Societies." Man 17: 431-51.