The Embodied Capital Theory of Life History Supports Locke on Parental Care in the State of Nature

Leo Strauss taught his students at the University of Chicago that any serious student of the history of political philosophy must assume the possibility that what the great philosophers have taught might be true.  Writers of the textbooks on the history of political philosophy--like that of George Sabine--had assumed the truth of "historicism"--that all the great philosophers have been so imprisoned by the cultural prejudices of their time and place that they could not see the truths about political life that contemporary readers can see today.  But Strauss argued that historicism is itself the great cultural prejudice of our time that cannot be affirmed as true without contradicting itself, and therefore serious thinkers must consider the possibility that the human mind can free itself of common opinions and apprehend what is simply true, and thus that the great philosophers--from Plato and Aristotle to Rousseau and Nietzsche--might help us to see some truths about human nature and human history that go beyond the largely unexamined opinions of our day.

Roger Masters was one of the students at Chicago who was persuaded by Strauss's argument, and Masters devoted himself to the careful study and translation of the writings of Jean-Jacques Rousseau, with the thought that Rousseau was one of those great philosophers who might teach something about the truth of human nature and politics.  Masters became one of the leading translators and scholars of Rousseau in the 1960s.  He was particularly interested in Rousseau's account of the state of nature and social contract reasoning as compared with Thomas Hobbes and John Locke.

Then, in the 1970s and 1980s, Masters began to study evolutionary science and Darwinian anthropology, with the thought that this science of human evolution might illuminate the debate between Hobbes, Locke, and Rousseau over the state of nature.  Masters thus became one of the first political scientists to apply Darwinian science to the study of political philosophy.

According to Rousseau, neither Hobbes nor Locke recognized that in the state of nature human beings were so completely solitary that they would have lived in a state of peace and equality without any dependence on other human beings.  Masters wrote this as his English translation of one of Rousseau's passages in the Discourse on the Origin of Inequality:

"Alone, idle, and always near danger, savage man must like to sleep, and be a light sleeper like animals which, thinking little, sleep so to speak all the time they do not think.  His self-preservation being almost his only care, his best-trained faculties must be those having as principal object attack and defense, either to subjugate his prey or to save himself from being the prey of another animal." (Rousseau 1964, 112)

This was published in 1964 in Masters' edition of The First and Second Discourses.  Then, in 1982, when Masters read Frans de Waal's Chimpanzee Politics, which describes the complex political lives of chimpanzees competing for power and alpha male dominance in small groups, Masters saw that this implied that the earliest evolutionary ancestors shared with chimpanzees and human beings were probably highly political animals.  He also saw that anthropologists studying the societies of human hunter-gatherers had shown the complex social order of these primitive human groups. Consequently, it seemed that biologists and anthropologists had shown that human beings in a state of nature could not have been utterly solitary, as Rousseau claimed. 

And if Strauss was right about taking seriously the possibility that the teaching of a great philosopher like Rousseau could be true, this must include the possibility that the teaching could be false.  Philosophers make empirical claims about human nature and human history that could be either confirmed or denied by scientific research.  So, Masters had to admit that Rousseau's teaching about the state of nature had been refuted by Darwinian science.  "Like chimps," Masters concluded, "humans are by nature social animals with innate political behaviors of a sort ignored by Rousseau in the passage I'd translated" (Masters 2013, 227).

I agree with Masters about this, because in a series of posts, I have argued that the evidence from evolutionary science and political anthropology allows us to judge the philosophic debate over the state of nature and to conclude that while Rousseau was mostly wrong, Hobbes was partly right, and Locke was mostly right.  This illustrates how the study of the history of political philosophy can become a biopolitical science.

Consider, for example, how Locke's account of the human family as the "first society" in the state of nature is confirmed by the "embodied capital theory" of the evolution of human life history, which is supported by lots of evidence gathered by Darwinian primatologists and anthropologists.

In the Two Treatises, Locke gives both religious and natural explanations for human familial bonding in the state of nature.  It shows the "wisdom of the great Creator" that He has created human beings with desires for monogamous marrying and for mothers and fathers jointly caring for their children (1970a, 86-89; 1970b, 77-80).  This can also be explained through the natural history of animal reproduction as adapted to the feeding niche for each species.  For some frugivorous animals who feed on grass and plants, whose offspring can survive shortly after birth without much parental care, Locke explains, mothers care for the offspring with no need for fathers to provide any parental care, and consequently there is no need for any enduring bond between the sexual mates.  But for those carnivorous animals who feed on meat from hunting, 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 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 of childhood, in which children cannot produce enough food to feed themselves.  During this period of dependence, offspring must be not only nourished but also educated, because complex human social life requires a prolonged period of social learning in which children learn the skills they will need to become productive adults.

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, and then they immediately left each other and felt no tie to one another.  Mothers nursed their children for a short time.  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 between parents and children and no support for the mother and child from the father (Rousseau 1964, 108, 112, 120-21, 130-31, 137, 142, 147, 216, 219).

In one of the longest notes in the Second Discourse (1964, 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. 

Against Locke, Rousseau insists that primitive human beings were totally frugivorous in their feeding and not at all carnivorous.  Mothers and children who feed on grass and plants can easily feed themselves without any need for meat from male hunters.  Furthermore, Rousseau argues that fact that human females have only two teats indicates that they rarely have more than one child at a time that needs care, and thus mothers and children have no need for help from the men.

Over the past 100 years, studies of human hunting-gathering societies and comparative studies of other primate and mammalian societies have provided evidence that Rousseau was mostly wrong, and Locke was mostly right.  This evidence shows that as compared with other mammals and primates, human beings show at least five distinctive traits (Balshine 2012).  The first four pertain to human life history.  Human beings have an unusually long lifespan.  They have also have an unusually long period of juvenile dependence on adults.  They show an unusual pattern of support for reproduction from older post-reproductive adults.  And they show male support of reproduction through the provisioning of females and their offspring.  The fifth distinctively human trait is unusually large brains that bring increased capacities for social learning, teaching, and thinking about cognitively challenging problems.  Human hunter-gatherers, who live in what the early modern philosophers called the state of nature, show all of these traits.

One persuasive evolutionary theory that fits all of this evidence for these distinctively human traits is the embodied capital theory developed by Hillard Kaplan and his colleagues (Kaplan et al. 2000).  The main idea is that the human species show an evolutionary adaptation for a feeding niche based on high-quality, nutrient-dense, and difficult-to-acquire foods, which is a skill-intensive niche that requires extended learning through big brains.

Chimpanzees and other nonhuman primates feed mostly on leaves, small, unripe fruit, and large, ripe fruit, which constitutes over 90% of their diet.  Gathering this food requires so little skill and effort that young chimpanzees after they have been weaned can gather enough to feed themselves.  Chimpanzees do extract some food from nuts and insects in ways that require some skill that has to be learned.  And the males do engage in some hunting that requires some skill.  But the extracted food and the hunted meat is a very small portion of their diet, and the skills required for acquiring this food are not very complicated.

By contrast with chimpanzees, over 75% of the diet of human foragers is meat from hunting, which requires great skill that comes only from adult males who have learned those skills over a period of 30 years or more.  In contrast to leaves and fruit, meat is higher quality food, rich in protein, and highly concentrated, but it is also more difficult to acquire.  Hunted meat provides the nutrition necessary for the growth and maintenance of big brains that consume high levels of metabolic energy.  And it is these big brains that are necessary for learning the skills necessary for successful hunting.

Unlike chimpanzees, adult male human foragers must produce food for the feeding of women and children.  Human children consume more food than they produce until about age 20.  Human females consume more food than they produce throughout their childhood and their years of reproductive fertility.  Human females produce slightly more than they consume only after menopause and before old age.  Human females can have shorter birth intervals than apes do, because human females get food subsidies from adult male hunters, so that mothers can care for two or more children at a time.  Most of the production of food comes from adult males (ages 25-55) through hunting, who share their food with women and children.

Tracking and killing wild game of many different species is an intellectually challenging problem that takes many years of social learning with a large brain that requires many years of growth.  Consequently, both mothers and fathers must make many years of resource investments in the rearing and educating of their children before they can become productive contributors to reproductive fitness.

If this is the scientific description of the state of nature--of the original life of our earliest human ancestors--then Locke was mostly right, and Rousseau was mostly wrong.  This would then be an example of how Darwinian science can contribute to the study of the history of political philosophy by helping us to judge the claims that the philosophers have made as being true or false.

REFERENCES

Balshine, Sigal. 2012. "Patterns of Parental Care in Vertebrates." In Nick J. Royle, Per T. Smiseth, and Mathias Kolliker, eds., The Evolution of Parental Care, 62-80. Oxford: Oxford University Press.

Kaplan, Hillard, Kim Hill, Jane Lancaster, A Magdalena Hurtado. 2000. "A Theory of Human Life History Evolution: Diet, Intelligence, and Longevity." Evolutionary Anthropology, 9:156-185.

Masters, Roger. 2013. "On the Relationship between Liberalism and Darwinism," in Stephen Dilley, ed., Darwinian Evolution and Classical Liberalism: Theories in Tension, 217-236. Lanham, MD: Lexington Books.

Locke, John. 1979. Two Treatises of Government. Edited by Peter Laslett. Cambridge, UK: Cambridge University Press.

Rousseau, Jean-Jacques. 1964. The First and Second Discourses. Translated by Roger D. and Judith R. Masters.  New York: St. Martin's Press.