Marx was a materialist. In 1837, during his second year at the University of Berlin, he wrote to his father mentioning his struggle to understand Hegel’s system of philosophy and, more importantly, describing his efforts to bring together art and science, which were divorced from one another in the university (Marx 1837/1975:
18). While many writers have focused on Marx’s intellectual debt to Hegel, fewer have examined his connections with traditions of materialist thought. His attempt to bring the arts and sciences together in a single system involved studies in natural science, history, and the romantic philosophy of Friedrich Schelling (1755–1854) who sought the common basis of nature and self. Two years later, Marx (1839/1975) took extensive notes on the non-deterministic materialism of Epicurus (341–271 BC) and the school he established. Briefly, the Epicureans believed that life rose up from the earth rather than descending from the heavens; claimed that there were more worlds than this one and that the present one will change; noted the emergence and finite duration of living forms; denied the influence of distant, divine powers; stressed the importance of contingency or chance as opposed to necessity or teleology; argued that mind and body were united; and emphasized that men and women were active agents in the acquisition of knowledge and that they were capable of forging their own happiness (Foster 2000: 21–65). Marx’s doctoral dissertation, which he completed in 1841, dealt with the differences between ancient Greek philosophies of nature (Marx 1840–1/1975). In his view, the Epicureans who had influenced early Enlightenment writers—like Francis Bacon, Thomas Hobbes, and Isaac Newton—were also the key that would unlock understanding of the present.
Marx thought of Epicurus as “the greatest representative of Greek Enlightenment”
(Marx 1840–1/1975: 73).
As we saw in the last chapter, Marx was concerned with questions about the emergence and development of human natural beings, their creation of human and natural history, and their metabolism with nature. These were important issues in his materialist account of history. He framed his argument in terms of changes in human corporeal organization, ensembles of social relations, and activities and practices that varied because of the different metabolisms that existed between human social individuals and the particular natural and social worlds (environments) in which they lived. He saw these changes in non-teleological, historical terms. Parts of his theoretical perspective were already supported by empirical evidence while other parts were suppositions based on the limited evidence available. This combination included (1) the anatomical similarities of human beings and chimpanzees recognized by Edward Tyson in 1699; (2) the close taxonomic and presumably historical relationship of human beings and non-human primates postulated by Carolus Linnaeus in the 1735 and subsequent editions of his Systema Naturae; (3) the diverse arguments proposed from 1750 onward by the Comte de Buffon, James Hutton, Charles Lyell, and Abraham Gottlob Werner that the earth was significantly older than commonly believed; and (4) the view expounded by Georges Cuvier in 1812 that there was, in fact, a succession of past worlds on earth. Thus, as Valentino Gerratana (1973: 64) put it, “Marx was already not only taking for granted the principle of the historical evolution of animal species and of nature in general, which found little favour in the sciences of the time, but [he was] also tending to exclude from that evolution any finalist [teleological] assumption.”
From the late 1830s onward, when Marx was formulating his materialist conception of history, his slightly older contemporary—a young Englishman named Charles Darwin (1809–82)—was also working out his own materialist views about the historical evolution of plants and animals (Ospovat 1981). Perhaps Marx’s (1857–8/1973: 105) most directly germane comment about human evolution before the appearance of Darwin’s The Origin of Species in 1859 was that “human anatomy contains a key to the anatomy of the ape. The intimations of higher development among the subordinate animal species, however, can be understood only after the higher development is already known.” His later remark—“since Darwin demonstrated that we are all descended from apes, there is scarcely any shock whatever that could shake ‘our ancestral pride’”—suggests that, while Marx (1864/1985) was amused at the public outcry over the implications of Darwin’s ideas (i.e., human beings and apes shared a common ancestor, and there was a transition from ape to human), he was definitely not bothered by them. As we shall see, while Marx, in fact, had the highest regard for Darwin’s insights, he was also critical of the way in which Darwin and others naturalized explanations of social inequality and other culturally constructed categories.
Thus, this chapter has four goals. The first is to review the bases for Marx’s agreement and positive valuation of Darwin’s arguments in The Origin of Species and to survey subsequent developments of evolutionary theory. The second is to use the lens provided by Engels’s (1876/1972) “The Part Played by Labor in the Transition from Ape to Man” and by Marx’s own theoretical framework to examine relevant data derived from paleoanthropology and the natural sciences in order to discern the interplay of the changing dispositions and anatomical structures of human beings and their primate relatives as well as the emergence of practices such as tool-making and language. The third is to consider the implications of this biocultural nature for population structures. The fourth is to examine briefly Marx’s and Engels’s critique of the naturalization of explanations of the social relations of capitalist society and how this critique played out in the historical development of anthropology both here and abroad.
Marx (1860/1985) first read The Origin of Species in 1860. He immediately recognized its significance, and, except for a minor complaint about the style of the argument, he had nothing but praise for the volume. Marx commented explicitly about certain points of agreement or conclusions he drew from Darwin’s arguments. Moreover, there must have been other points of agreement between Marx and Darwin because of the materialist perspective they shared; these can be inferred either from Marx’s other writings or from the implications of his materialist theoretical perspective.
The former include: (1) a short quote from Darwin’s chapter on variation describing how natural selection acts on variations of form under different conditions (Marx 1861–3/1991: 387–8; 1863–7/1977: 461); (2) the notion that evolution is a gradual, ongoing process (Marx 1867/1987: 494, 1868/1987a: 558–9); (3) evolution involves both the continued preservation of what has been inherited and the assimilation of new traits (Marx 1861–3/1989: 427–8); (4) acknowledgement of Darwin’s “history of natural technology, the formation of the organs of plants and animals, which serve as the instruments of production for sustaining their life” (Marx 1863–7/1977: 493); (5) a refutation of Malthus in Darwin’s discussion of the extinction of animal species (Marx 1861–3/1989: 350–1); (6) human natural beings are descended from apes and, hence, are also a unity with nature (Marx 1864/1985: 581; Marx and Engels 1845–6/1976: 39–41); (7) Darwin’s “struggle for existence” in natural history is analogous to class struggle in human history (Marx 1860/1985: 232); and (8) a rejection of teleological arguments in natural science and, by extension, the adoption of a notion of historically contingent change (Marx 1861/1985: 246–7). In the latter category of inferences that may be drawn from Marx’s other writings or from his materialist perspective, we should include at least: (9) a notion of internal motors of formation and change as opposed to external engines of development, and (10) non-reductive forms of argumentation. In my view, one thing that emerges from Marx’s comments is that he saw Darwin, like himself, as more concerned with explaining processes of change rather than origins or events.
Darwin’s Metaphors and Theory of Evolution by Natural Selection
The idea of evolution was “in the air” by the beginning of the nineteenth century. The universe had evolved according to Kant, the earth had evolved gradually according to Hutton, life on earth had evolved according to Lamarck and Geoffrey St. Hilaire, and even human beings had evolved according to Buffon and Rousseau—from apes no less. Nevertheless, there was a good deal of resistance to the idea of evolution.
Part of it arose from the fact that none of Darwin’s predecessors had satisfactorily explained how one species actually evolved into another. The other source of discontent among the public and a few natural historians was that it threatened their beliefs, religious and otherwise, about the world and man’s place in it (Desmond 1989). The publication of Charles Darwin’s The Origin of Species in 1859 fuelled the discontent. At the same time, it marked a radical departure from the teleological worldviews of his predecessors, who saw “the real objects of the world as imperfect reflections of underlying ideals or essences” and “that the real variations between real objects only confuse us in our attempts to see the essential nature of the universe” (Lewontin 1974: 168). Instead of sweeping away the real variations among individuals of the same species in order to focus on the type, Darwin focused his attention on that variation and made it the object of his study. His singularly stunning insight, as Richard Lewontin put it, was that
individual variation and the differences between species were causally related. Darwin’s revolutionary theory was that the differences between organisms within a species are converted to the differences between species in space and time. Thus, the differences between species are already latent within them, and all that is required is a motive force for the conversion of variation. That force is natural selection. (1974: 170; emphasis in the original)
Darwin, like Marx, initially framed his ideas in terms of already existing metaphors, analogies, and analytical categories. He built on the language and imagery of German romanticism, political economy, animal breeding, and natural science as he struggled to explain his new understandings of the natural world and the evolution of species (e.g. Kohn 1996; Richards 1992; Schweber 1980, 1985).
Anyone who has ever written even a term paper will understand and hopefully be sympathetic with the notion that the language and imagery in which arguments are initially conceived are often quite different from those that clearly explain ideas and their implications. In a more self-reflexive moment, perhaps, this might account for Marx’s two comments in letters about Darwin’s “clumsy English style of argumentation” as well as his own, at times, fumbling and often opaque attempts to say what he actually meant.
Darwin used four powerful metaphors in The Origin of Species to frame and express his new ideas about nature, variation, and the motor force driving evolution.
They are “an entangled bank,” “the struggle for existence,” “natural selection,” and “wedging.” His metaphors were used singularly or more frequently in combination to produce powerful, evocative images rich in meaning. He employed the phrase “an entangled bank” to express the complexity of organization of nature. The dual sources of inspiration were the engravings, paintings, and poems he was familiar with before his journey on the Beagle, on the one hand, and the luxuriant, Amazonian rainforests of Brazil, on the other (Kohn 1996). In The Origin, Darwin described the interrelatedness of all nature in the following way:
It is interesting to contemplate the entangled bank, clothed with many plants of many kinds with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. (1859/1964: 489; emphasis added)
Darwin’s second metaphor was “the struggle for existence.” It too was not a new idea. Herder, for example, had remarked on crowding as well as the struggle between individuals and between species for survival; however, there was no sense of the potential for transformation in his view (Lovejoy 1959b: 211–2). Darwin, in contrast, used the metaphor to mean interdependence, chance, as well as contest, endurance, or persistence. He wrote that:
I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including dependence of one being on another, and including (which is more important) not only the life of the individual but success in leaving progeny. Two canine animals in a time of dearth, may be truly said to struggle with each other over which shall get food and live. But a plant on the edge of the desert is said to struggle for life against the drought, though more properly it should be said to be dependent on moisture.
A plant which annually produces a thousand seeds, of which on average only one comes to maturity, may be said be more or less truly said to struggle with plants of the same and other kinds which already clothe the ground. The mistletoe is dependent on the apple and a few other trees, but can only in a far-fetched way be said to struggle with these trees, for if too many of these parasites grow on the same tree, it will languish and die.
But several seedling mistletoes, growing close together on the same branch, may more truly be said to struggle with each other. As the mistletoe is disseminated by birds, its existence depends on birds; and it may metaphorically be said to struggle with other fruit-bearing plants, in order to tempt birds to devour and thus disseminate its seeds rather than those of other plants. In these several senses which pass into each other, I use for convenience the general term of struggle for existence. (Darwin (1859/1964: 62–3; emphasis added)
Darwin’s third metaphor, “natural selection,” was used to describe both how variation is maintained and how descent with modification occurs. He relates it to his second metaphor, the struggle for existence:
Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring. The offspring, also, will thus have a better chance of surviving, for, of the many individuals of any species which are born, but a small number can survive. I have called this principle, by which each slight variation, if useful, is preserved by the term Natural Selection, in order to mark its relation to man’s power of selection. (Darwin 1859/1964: 61; emphasis added)
Darwin used his fourth metaphor, “wedging,” to represent in mechanical terms how natural selection actually operates on the hereditary variation that exists between individuals and between species. The imagery refers specifically to the activities of quarrymen and the implement they used at the Salisbury Craigs in Scotland to cut stone from the cliff faces, and, in the process, how they transformed a beautiful natural landscape into an ugly monument (Kohn 1996: 36).
The fact of nature may be compared to a yielding surface, with ten thousand sharp wedges packed close together and driven by incessant blow, sometimes one wedge being struck, and then another with greater force. (Darwin 1859/1964: 67)
Let us describe Darwin’s theory of evolution by natural selection in slightly different terms. It is based on a series of observations he made about differences between individuals and on breeding experiments that he and other breeders conducted. First, hereditary variation exists between individuals of the same species and between different species. Second, the number of eggs, sperm, or seeds produced by an individual vastly exceeds the number of individuals born. This, in turn, exceeds the number that survive to the reproductive stage and that can potentially contribute hereditary material to the next generation; in one of Darwin’s plant breeding experiments only about one seed of a thousand actually germinated. Third, some individuals have a greater likelihood of becoming adults and reproducing than others, because the hereditary material they possess is advantageous for some reason in the environments in which they live. Fourth, as a result of differential survival, this advantageous material has a greater likelihood of being passed on to succeeding generations. Thus, Darwin could explain how both descent with modification and the formation of new species (speciation) occurred. He could account for the way these happened. He could assert with certainty that the kinds of plants and animals that exist today are the modified descendents of different kinds of organisms that lived in the past. He could declare with equal certainty that whatever happened in the future would be based on the organisms and conditions of the present.
Darwin’s great insights were the principles of variation, heredity, and selection.
What he could not explain, however, was the connection between individual variation, on the one hand, and the inheritance (heritability) of characteristics from one generation to the next, on the other. An Augustinian monk—Gregor Mendel (1822–84), a contemporary of both Marx and Darwin—would provide answers to these questions. While Mendel published the results of his experiments with plant hybrids in 1866, Marx was completely unaware of his work and Darwin, if he were aware of it, did not understand its importance. Although Mendel’s work was finally recognized in the early 1900s, its significance was still being hotly debated into the 1930s (Allen 1978).
The Problems of Variation and Inheritance
If Darwin made variation the proper study of biology, then Mendel was responsible for clarifying the mechanisms by which hereditary variation is created and transmitted. As Richard Lewontin (1974: 173–8) notes, Darwin and the other plant and animal breeders of his day were aware that offspring tend to resemble their parents (like produces like) but yet are different from them and that these differences are also inherited to some extent. They attempted to cross organisms from different varieties, and even species, and saw that, if any of the hybrids produced were fertile, they tended to revert to one or the other of the original parental type over a number of generations. Because the breeders focused on the differences rather than on the similarities, they viewed variation and inheritance as ontologically distinct categories. The effects of this were: (1) they saw the variation existing between individuals within the same species as different from the variation that exists between species; and (2) they focused their attention on the group or variety rather than on the individual. What Mendel did that was different from his contemporaries was that he focused on individuals, their ancestors, and their progeny. In other words, he distinguished between the individual and the group. Let us consider briefly what Mendel did in his experiments and what he actually showed.
Mendel bred varieties of garden peas that differed from one another in a few traits—that is, when tall plants were bred with tall plants, their offspring were also tall. Mendel then bred a tall plant with a short one and noted that each of the hybrid offspring was tall and, in this trait, they resembled one of their parents. However, when he bred the hybrids of the first generation with one another, he noted that their offspring resembled one or the other of the original parental types—roughly three-quarters were tall and one quarter was short. On the basis of this experiment, he concluded, with regard to the characteristic being studied (1) that the hybrid individuals inherited a discrete particle (gene) from each of the parents; (2) that the expression of the gene for tallness was dominant over the other; and (3) that these particles re-assorted themselves in the offspring of the first-generation hybrids in such a way that there were both tall and short individuals in the second generation.
When he bred individuals that were hybrids for two traits—such as tall vs. short plants and smooth vs. wrinkled pods—he observed that the gene pairs associated with different physical characteristics—let us say height and seed color—were inherited independently from one another. In other words, the significance of Mendel’s work was, to paraphrase Lewontin (1974: 177–8), that it showed that variation and inheritance were manifestations of the same underlying phenomena but that they required two different kinds of causal explanation.
Mendel’s studies buttressed a later flurry of activity from the 1920s onward that was concerned with the genetic variation of populations and with how genetics related to the process of selection. This involved conceptualizing a local population of individuals, all of whose genes constitute the gene pool of the population, its reservoir of hereditary material that is passed from one generation to the next. Many individuals or only a few may contribute to and share in the gene pool. The pool may be stable through time or change from one generation to the next depending on the particular conditions that prevail or appear. These investigations had three important consequences. First, they made it clear that no two individuals in a population have exactly the same combination of genes—including identical siblings who were born with the identical genetic systems but were subjected to different environmental and historical circumstances so that different genes mutated. Second, they clarified the nature of the genetic variation that exists within a population, identifying recombination, gene flow, and mutation as important sources. Recombination is what occurs when two individuals mate and their offspring receive half of their genetic complement from each parent. If the organism has about 30,000 gene pairs, as each human being seems to have, then the continual reshuffling from one generation to the next becomes a major source of the genetic variation that occurs in a population.
Gene flow occurs when an individual from outside the population breeds with an individual from the population, and new genetic material is potentially introduced into the gene pool. The other source of variation is mutation. While many but not all of the mutations that appear in the gene pool of a population are variants that are already known and that already exist in the population, some are not. As a result, mutation is the ultimate source of new genetic material in a population. Third, these researchers began to examine how selection, as well as mutation and migration, alter frequencies of particular genes in a population They also suggested that genes acted in ways that controlled the metabolism of cells which in turn controlled the expression of particular characteristics; unfortunately, given the technology of the time, they had no way to prove it (Allen 1978: 126–40, 198).
The first generation of population geneticists—Ronald A. Fisher (1890–1962), John B. S. Haldane (1892–1964), and Sewall Wright (1889–1988)—recognized that Mendel’s principles operated in all organisms; that small-scale, continuous variability in characteristics, like height, also had a genetic basis; and that even small selection pressures acting on minor genetic differences can result in evolutionary change (Gould 2002: 504). In a phrase, they integrated and synthesized the views of Mendel and Darwin. They established the foundations for linking the traditional subfields of biology—genetics, paleontology, ecology, systematics, or developmental physiology, to name only a few—into a more holistic biology, that would come to be called the Modern Synthesis or the New Synthesis in the 1940s. This fusion was launched with the publication of Theodosius Dobzhansky’s (1900–75) Genetics and the Origin of Species in 1937.
The Modern Synthesis and Beyond
The heyday of the Modern Synthesis may have been in 1959 at the time of various centennial celebrations of the publication of The Origin of Species. Gould (2002:
503–84) described the Modern Synthesis as “a limited consensus,” that had “hardened” in the 1940s and 1950s in time for those celebrations. By the early 1960s, however, the three central tenets of the synthesis—adaptation, the individual organism as the unit of selection, and the sufficiency of microevolutionary theory to explain change as it is refracted in the fossil record—began to be challenged.
One manifestation of the hardening, as Gould describes it, was an increased emphasis on adaptation: Every gene or gene complex was somehow adaptive.
Adaptations, as you recall, are the products of natural selection modifying the gene pool of population in such a way that it increases the harmony between the population and its environment. Any hereditary characteristic that increases this congruity and promotes survival is an adaptation; adaptations take many different forms and may involve morphological, physiological, or behavioral features that enable individuals to survive and produce offspring. However, evidence was beginning to accumulate which indicated that some genes may be neutral—that is, they have no selective significance with regard to increasing or decreasing the fitness of individuals living in a particular environment, and, hence, they are neither advantageous nor deleterious. The second manifestation of the hardening and the challenge revolved around the question: At what level or levels does selection operate—the gene, the individual, the population, or the species? Advocates of the new synthesis argued that, while selection operates at the level of the individual, the adaptations that result might be beneficial to the group as well. The challengers disagreed. The arguments they raised in the 1960s and 1970s continue to the present.
The third tenet is that the explanation used to account for small changes in the gene pool of a contemporary population is merely writ large, but identical, to the one that is refracted in the paleontological record. That is, change is steady and slow.
Gould (2002: 558) called this the “principle of extrapolation.” One challenge to the uniformitarianism embodied in this tenet has been over the issue of whether the evolutionary process is always gradual, or whether it proceeds by fits and starts with moments of rapid change preceded or followed by periods of relative stasis (punctuated equilibrium). Gould concludes his discussion of the Modern Synthesis by noting how well it has endured, in spite of the challenges.
Molecular biology has been a major growth field in the United States, England, and France since 1945 (Allen 1978: 187–228; Appel 2000). This development was accompanied by number of new technologies and techniques—computers, X-ray crystallography, DNA sequencers, powerful mathematical and statistical methods, and so forth—that afforded opportunities to examine for the first time the molecular structure of cell nuclei, the three-dimensional arrays of DNA molecules on chromosomes, the structure of genes, the regulation and development of genes, the sequence of DNA molecules on chromosomes, and the entire genomes of a number of species, including even that of human beings. We now know, for instance, that the genomes of human beings and chimpanzees are virtually identical (99 percent); that the rates of change in the proteins produced by the DNA code vary little from species to species; that human beings and chimpanzees had a common ancestor 5 to 7 million years ago; that the 6 billion or so human beings in the world today fundamentally have, with few exceptions, the same genotype; or that there is more variation within human populations—let us say from Africa, Scandinavia, or Japan—than there is between them (Lewontin 1995; Marks 2002).
There seem to be two counter-tendencies in biology today. The research of many biologists is reductionist in the sense that they are concerned with breaking down their objects of inquiry—the cell, the gene, the organism, or the environment—into their constituent parts. Another group—notably Richard Lewontin (1929–), Richard Levins (1935–), and their associates—views nature as a totality, a historically contingent and ever-changing structure. Nature is, in their perspective, a multi-leveled whole, a unity of contradictions, characterized by spontaneous activity, positive and negative feedback, the interpenetration and interaction of categories from different levels of the whole, and the coexistence of opposing principles that shape interaction.
The various elements of the whole—the parts and the levels—as well as the whole itself are continually changing, though at different rates; consequently, at any given moment, one element might appear to be fixed in relation to another (Levins and Lewontin 1985: 133–42, 272–85). The importance of this dialectical world is that it helps us think of genes, organisms, and environments as interacting parts of a whole rather than distinct entities with their own roles to play. Lewontin (2000: jacket), for example, rejects the idea that genes determine the organism, which then adapts to its environment. He argues instead that the individual organism is a unique consequence of the interaction of genes and the environment, and that individual organisms, “influenced in their development by their circumstances, in turn create, modify, and choose the environments in which they live.” Marx would have appreciated how Lewontin and Levins have conceptualized and framed issues concerned with human natural beings and how we came to be the way we are, because of the non-reductive and dialectically interactive aspects of their argument.
The title of this section derives from David McNally’s (2001) insightful essay, “Bodies that Talk: Sex, Tools, Language, and Human Culture,” in his Bodies of Meaning. We saw in the preceding chapters the three distinctive markers Enlightenment writers used to characterize human beings: they reasoned, they made tools, and they talked.
The anatomists and physicians of that era had a fourth characteristic: they walked upright. These are legacies from the Enlightenment. They were part of Marx’s intellectual inheritance as well. However, as we saw in the last chapter, he did not frame his answer to the question of what human beings are precisely in these terms. He emphasized instead that human beings were sensuous, active creatures; that there was a dialectical interplay between their corporeal organization and the ensembles of social relations that shaped their activities; that their bodily organs were transformed into instruments of labor and production; that they objectified the world and the resources it provides to satisfy established needs and to create new ones; and that their conscious life activity in contrast to that of animals was increasingly determined by social relations and culture.
As Raymond Corbey (2005: 93) correctly observes, scientific definitions of the genus Homo (that is, modern human beings and their ancestors) established in the late 1940s and early 1950s—e.g. erect bipedalism, a well-developed thumb, or rapid expansion of cranial capacity associated with craniofacial remodeling and reduction in jaw size—often incorporate or imply philosophical understandings of humanness, such as upright gait, tool-making, large brains, language, and culture. In the 1950s, it was possible to believe that these traits appeared roughly at the same time. We now know that they did not appear simultaneously, but rather sequentially over a period of time that spanned 5–7 million years for some scholars or 2–3 million years for others. The result of this is that the biological definition of Homo clashes with popular and philosophical views of what it means to be human. Consequently, some paleoanthropologists have argued that the genus contains both “animal” hominids and “human” hominids, and that the transition from ape to human occurred some time since the late Tertiary. This refracts in some complex way the criterion or criteria that particular individuals select to define “human.” Another potential complicating factor results from the fact that geneticists have found that chimpanzees and, to a lesser extent, gorillas are the closest living animal relatives of human beings.
The primatologists who study these apes often stress their similarities with human beings rather than their differences. Thus, they portray the apes as conscious, active, and social creatures who vocalize, communicate, occasionally use tools, and have distinctive personalities; when they talk about ape language and culture, the discussion becomes murkier and the audience more skeptical.
For our purposes here, the question is not whether the answers provided by present-day scientists are fundamentally different from and thus incommensurate with those of Marx, but rather how do or might Marx’s views articulate with contemporary perspectives and practices. A relatively unknown essay by Frederick Engels, Marx’s friend and collaborator for more than forty years, provides additional clues for contemplating the linkages.
Engels’s “The Part Played by Labor in the Transition from Ape to Man”
The publication of Darwin’s The Descent of Man in 1871 was the impetus for Engels (1876/1972) to set down his own views on the transition from non-human primate to human natural being. It is useful to keep in mind a few facts about the context in which Engels wrote his essay, “The Part Played by Labor in the Transition from Ape to Man.” While the first remains of “Neanderthal man” had been found in 1856, their significance was neither recognized nor appreciated until the early years of the twentieth century (Delisle 2007: 70–124). While writers speculated about whether human beings had lived at the same time as extinct animals, the first incontrovertible evidence was only uncovered in 1859; it consisted of stone tools and fossil animal bones sealed beneath an unbroken stalagmitic deposit in Brixham Cave in southern England. As a result, Engels’s argument was a deductive one, as were those of his contemporaries (Trigger 1967/2003).
Engels argued that the ancestors of human beings were social, arboreal apes who lived in the Old World tropics toward the end of the Tertiary period, which we now know occurred between about 2 and 23 million years ago. He was clear that both human and non-human primates were behaviorally highly complex, and structurally integrated organisms. Even though he had no conception of the microevolutionary processes described above, he was also clear that a change in one behavior would ultimately be linked with changes in other organs (sensory and anatomical structures) and behaviors. Through reading and possibly even trips to the zoo, he argued that the arboreal primates of the present day used their forelimbs and hindlimbs differently when they climb. On this basis, he suggested that the decisive first step in the transition from ape to human involved upright walking, an erect gait. This change in the locomotor behavior and structures was accompanied by other changes, most notably in the hand. These changes involved the development of greater dexterity and of a precision grip involving an opposable thumb long before the first flints were fashioned into knives and these early humans began to manufacture tools.
The development of the hand and all that this entailed were linked, in turn, with the development of the brain and other sensory organs, with new relations to the objects of nature, with increased dependence on others and the formation of new ensembles of social relations, and importantly with the development of language. The latter was facilitated by changes in the hand, speech organs, and brain—a combination that enabled these early humans to undertake more complex activities and to change the environments in which they lived in planned, conscious ways.
Marx and Engels often forged and refined ideas in their letters. However, in none of these, to my knowledge, did they discuss Engels’s essay about the transition from ape to human, even though they may have done so in conversation. Moreover, there is no evidence that Marx disagreed in any way whatsoever with Engels’s conclusions in this regard. While parts of Engels’s argument could be stated with more precision today in light of the vast quantities of information that have been gathered, especially since the late 1950s, the basic timeline—erect posture, tool-making, and language— is still correct. In fact, it was adopted by paleoanthropologists, most prominently Sherwood Washburn (1911–2002) in the late 1950s (e.g. Washburn 1960; Washburn and Howell 1963; Woolfson 1982). The issues debated today are not whether the steps outlined by Engels occurred, but rather where and when they took place.
Fossils and Proteins
In Marx’s day, the empirical evidence for the evolution of human beings was provided by the comparative anatomy of living species. Today, that evidence is provided by fossilized bones and their associated environments, by the similarities and differences of DNA or protein sequences that exist among different species, and by the molecular clock that the various sequences provide (Marks 2002: 7–31). The issues that paleoanthropologists explore and resolve are still upright walking, tool-making, language, and culture; however, the terrain of the debates has shifted in the last fifty or so years because of the vast quantities of new information.
According to molecular anthropologists, the last common ancestor shared by modern human beings and chimpanzees, our closest relative in the animal kingdom, lived 10 to 5 million years ago, and gorillas diverged from that group around 11 to 9 million years ago (Patterson, Richter, Gnerre, Lander, and Reich 2006). Together with earlier discoveries of fossil hominids in South Africa, this finding helped to focus attention since the 1960s on the tropical regions of Africa, especially those east of the Rift Valley in Ethiopia, Kenya, and Tanzania. Here, there were fossil-bearing deposits that dated to the end of the Tertiary—that is, the Pliocene Era, which occurred roughly 5 to 2 million years ago. In the mid 1990s, paleoanthropologists began to look for ancestral chimpanzees and gorillas on the west side of the Rift Valley, where the extant species live today. In Chad, they found a number of fossil hominids in late Miocene and early Pliocene deposits that ranged in age from about 7 to 3.5 million years ago. No one questions that the various early hominid species on both sides of the Rift Valley were bipedal walkers, keeping in mind that anatomical clues for this form of locomotion are scattered over the body: toes, ankles, knees, hips, shoulders, neck, and hands, to name only a few. Thus, at the present time, it seems that human natural beings appeared first in the tropics, perhaps in the triangle formed by Chad, Ethiopia, and South Africa. The fossil evidence has raised a number of questions: Did all of them share the same locomotor pattern? Were they bipedal all of the time or only part of the time? Are some individuals ancestral chimpanzees instead of precursors to the genus Homo? Did some of the earlier individuals belong to one of the later ancestral species shared by chimpanzees and early hominids? Did any of these individuals belong to species that stand in the direct ancestral line of modern human beings (Delisle 2007: 326–8; Gibbons 2006)?
Besides the fact that ancestral ape and hominid species resided in tropical Africa 5 to 10 million years ago, what were the circumstances in which quadrupedal, tree-climbing primates became bipedal? Paleoanthropologists have described a number of potential advantages of upright walking that might have served them well: visual surveillance against predators, hunting, carrying food and other objects, feeding on low branches, and reducing the energy costs of traveling long distances because of scarcity of resources, and even display (Delisle 2007: 327). Marx would have been fascinated, I suspect, by the changing circumstances in which this fundamental change occurred.
Let us look briefly at two recent works. First, Pierre Sepulchre and his associates (2006) argued that the 6000-km-long escarpment created 12 to 10 million years ago by tectonic uplift associated with the formation of the Rift Valley in East Africa altered the prevailing patterns of atmospheric circulation, which brought moisture and precipitation to the interiors of Kenya and Ethiopia. The reorganized atmospheric circulations brought less moisture to the region, and, by 8 to 6 million years ago, the environmental conditions were beginning to shift from woodland to savanna grassland habitats and species; this transition occurred between 5 and 3.7 million years ago. A second argument, made by Geoffrey King and Geoff Bailey (2006), is that the ancestral apes and hominids of tropical Africa lived in the broken, hilly country created by the formation of the Rift Valley. Moreover, these complex, environmental mosaics with their diverse and variable resources were the primary habitats of the early hominids rather than the emerging savannas that were inhabited by new kinds of ungulates and a rapidly expanding diversity of terrestrial monkeys—the ancestors of modern baboons and macaques. This broken, hill country, they argue, continued to be the preferred habitat for human beings along their entire dispersal route of dispersal as they then began to move into the Eurasian landmass about 2 million years ago. The relation of these changes to the evolution of human beings will become apparent in the next few pages.
Engels’s second inferred step in the gradual appearance of human natural beings involved changes in the anatomy and manual dexterity of the hand. This was closely associated with upright posture and gait. While all primates manipulate objects to varying degrees with their hands (as do raccoons and squirrels), the hands of modern human beings are quite distinctive in several respects—e.g. they can open a jar lid or thread a needle. Chimpanzees and other apes cannot do either easily, if at all.
Modern human beings have power and precision grips and a much greater range of motion and rotation in their fingers, wrists, forearms, and shoulders than do nonhuman primates. These capacities are reflected in both anatomical structures and the ranges of motion they exhibit; they include long, opposable thumbs relative to the length of the other digits and the ability to rotate the index finger toward the thumb.
These features contrast with those of modern chimpanzees, which have a restricted range of motion of the thumb; curved digits that are relatively long with respect to the length of the thumb; and powerful grasping muscles in both their hands and wrists (Trinkhaus 1992).
The manufacture and use of stone tools has been taken as an indication of manual dexterity, a sign that “man the tool-maker” has arrived on the scene. The earliest stone tools now known are chipped cobbles and flakes from 2.5-million-year-old deposits in Ethiopia. These are probably not the oldest tools in the world; right now, however, they are the oldest ones we know about. We know that modern chimpanzees will break off twigs and use them to fish for termites, and we can safely presume, I believe, that at least some hominids used sticks or rocks, for example, earlier than 2.5 million years ago. What we do not know about the tools from Ethiopia is who made them. There were two genera of early hominids in Ethiopia between about 2.5
and 1.0 million years ago: Australopithecus and Homo. We suspect that the latter made the tools, because the configuration of the fingers, hand, wrists, and forearms more closely resemble those of modern human beings. The australopithecines had hands with long curved fingers, thumbs and little fingers with a restricted range of rotation, and heavily muscled fingers and wrists adapted for grasping. Some paleoanthropologists argue that both genera manufactured and used stone tools; others suggest that only some australopithecines had the manual dexterity to make tools; a third group claims that stone tool-making was restricted to the genus Homo.
Tool-making, of course, is a marker for something else. In this instance, as Engels indicated, it is linked with the development of the brain. All of the early hominids that lived before 2.5 million years ago had brain volumes that resembled those of chimpanzees. A significant increase in brain volume began to appear about 2.0
million years ago in the genus Homo and continued until about 100,000 years ago.
The brain volumes of modern human beings are roughly three times larger than those of their Plio-Pleistocene ancestors. Paleoanthropologists have suggested a number of reasons for the expansion of brain size: the need for increased brain power to facilitate complex manipulative tasks like making stone tools; increased hunting; social cooperation; food sharing; language; and heat stress. Two issues emerge. First, what is the relationship between increased brain size and the structural organization of the brain itself? Second, was this increase in brain size gradual and continuous, or was it punctuated with episodes of growth followed by periods of relative stasis (Delisle 2007: 328–30)?
The development of the brain was, of course, Engels’s third step in the evolution of human corporeal organization (Schoenemann 2006). There are three facts about the brain that it is useful to keep in mind. The convolutions on the brain’s surface leave their imprint on the interior surface of the skull; consequently, by examining the endocasts of the imprints left on the skulls, it is possible to learn about the surface organization of the brain. The second fact is that the endocasts of human and nonhuman primates—that is, chimpanzees and modern human beings—are different from one another. The third is that brains consume enormous amounts of energy; human adults, for example, use about 20 percent of the metabolic energy they have to regulate the temperature of their brains. Heat regulation is accomplished by the circulation of blood through a complex network of arteries and veins that crisscross their brains. Dean Falk (2004: 161) has suggested that the vascular system of the hominid brain was reorganized to deal simultaneously with “the changed hydrostatic pressures associated with erect posture” and with the changes mentioned earlier in this section that were taking place in the habitats of the African tropics in general and, more specifically, in the habitats in which the early hominids lived 7 to 2 million years ago.
Examining the endocasts of apes, the large and small species of australopithecines, and early members of the genus Homo, Falk learned (1) that the surface organization of the brains of large australopithecines resembled those of modern chimpanzees, and (2) that they were different from those of the later, small australopithecines and early species of Homo, both of which had features resembling the brain surfaces of modern human beings. In her view, the dentition of the large australopithecines, as well as associated paleoenvironmental evidence, indicated that they continued to live in wooded habitats. In contrast, the teeth and paleoenvironmental data indicated that the small australopithecines and early species of Homo moved into more open country, possibly savannas, but as likely the environmental mosaics described earlier in which patches of trees, grasslands, and water dotted the landscape. The heat stress induced by spending more time in open country created another set of selection pressures along with gravity and the changes in hydrostatic pressures that accompanied bipedal locomotion. More important, until the vascular system of the brain was able to regulate temperature more efficiently in those hominids that had moved into more open habitats, brain volumes remained low—that is, roughly similar to those of apes. Once the vascular system of the brain became more efficient, brain volumes increased. This process became apparent in the remains of H. habilis about 2.5 million years ago. It seems to have been a fairly continuous process until about 100,000 years ago, when the growth curve flattened out (Lee and Wolpoff 2003).
The vascular system is not the only organ of the human body involved in heat regulation; others include sweat glands, the distribution of hair, and skin. Two of the truly distinctive features of modern human beings are that they have about 2 million more eccrine sweat glands than non-human primates, and that these glands are distributed over the entire surface of their bodies. What makes sweating an effective evaporative, cooling mechanism is that human beings are relatively hairless in comparison to the living apes, even though they have about the same number of hair follicles as chimpanzees. The reason for their appearance is that their hair shafts are much smaller than those of apes; hence they appear hairless except for the tops of the heads. In this regard, Adrienne Zihlman and B. A. Cohn (1988: 404) note that “hair retention on the head is probably important in protecting the scalp from the sun’s ultraviolet rays and may assist in stabilizing the temperature of the brain.” One inference that might be drawn from this extended argument is that even the earliest of our big-brained ancestors probably appeared relatively hairless in comparison to their primate contemporaries.
This inference has some additional implications. As you will recall, hominid populations began to move out of the African tropics and onto the Eurasian landmass about 2 million years ago. Their remains have been found at deposits that are about 1.8 million years old at Dmanisi, which is located north of the Caspian Sea, where winter temperatures occasionally plunge below 0 °F (–17.8 °C). So, what does this imply for a relatively hairless hominid? Brian Fagan suggests an answer:
For Homo erectus to be able to adapt to the more temperate climates of Europe and Asia, it was necessary not only to tame fire but to have both effective shelter and clothing to protect against heat loss. Homo erectus probably survived the winters by maintaining permanent fires, and by storing dried meat and other foods for use in the lean months. (Fagan 1990: 76)
Thus, the elaboration of culture, Engels’s fourth step in the transition from ape to human being, is not unrelated to the development of the brain and other sensory organs. It also involved extending the body’s instruments of production and objectifying the world around them in new ways as they appropriated new kinds of external objects to satisfy new needs that were essential for their survival and reproduction in their new circumstances.
The final step mentioned by Engels was the development of language. Both modern human beings and non-human primates, especially chimpanzees, are quite vocal. Both use vocalizations and gestures to communicate information, which suggest that our common ancestors 10–5 million years ago probably did the same.
Nevertheless, the vocalizations and gestures of non-human primates are not the same as language, which is unique to the human species. Language, as you know, has three central features: (1) basic sound units produced in the oral cavity, which lack innate or intrinsic meaning; (2) rules for combining and recombining these sounds into larger units, like words (morphology) and sentences (syntax), have the capacity to communicate enormous ranges of information and meaning (semantics); and (3) symbolic reference involves both the arbitrariness of the utterance with regard to what is being represented and the ability to refer to things that are not immediately present or exist only in some abstract sense (Deacon 1992a). These features distinguish human language from other forms or systems of communication—such as the dances of honeybees, seasonal whale songs, or the calls of monkeys—which, respectively, are referential but not symbolic, involve mimicry, and express ranges of immediate feelings like fear, anger, or pleasure.
There are important neuroanatomical differences between the vocalizations of non-human primates and the speech of modern human beings. Terrence Deacon describes them in the following manner:
[Non-human] primate calls are controlled by neural circuits in the forebrain and midbrain that are also responsible for emotion and physiological arousal, but not the motor cortex, even though this area can control the muscles of the larynx and mouth. Stimulation of the vocalization areas in a monkey brain often produce other signs of arousal—such as hair standing on end, display postures, facial gestures and even ejaculation.
Human speech uses a very different set of neural circuits. It depends on the region of the motor cortex that controls the mouth, tongue and larynx and the areas that are in front of it. Repeated efforts to train primates to mimic even simple speech sounds have had little success. The unique skill in learning to speak suggests that this facility may reflect some critical neurological difference. The ability to combine a larger number of component sounds to form larger units, words and phrases, makes possible to syntactic complexity of speech. Common brain areas may be involved in speech production and grammatical processes because defects in grammar and speech production caused by brain damage often occur together. (Deacon 1992b: 119)
Two regions of the human brain involved in speech production are Broca’s area and Wernicke’s area. The former is a motor speech area associated not only with sensorimotor control of the structures of the oral cavity, the varied positions of the tongue, and their coordination with movements of the respiratory system, but also with manipulative and gestural abilities; it is typically located on the left hemisphere of the cortex and also seems to be associated with right-handedness—the tendency shared by about 90 percent of the human population today (non-human primates typically do not show a preference for left- or right-handedness). The latter, Wernicke’s area, which controls understanding and formulating coherent speech, is located on the cortex amid areas that are associated with seeing, hearing, and feeling (Gibson and Jessee 1999: 205; Tobias 1998: 72).
All normally developed human brains have Broca’s and Wernicke’s areas. Since they are located on the surface of the brain, they leave imprints on the interior surface of the skull and thus appear on endocasts. While there are no endocasts currently available for hominids that lived before about 3 million years ago, both appear on endocasts of H. habilis (c.2.5 million years ago). An endocast from a late, small australopithecine, A. africanus (c.3.1 to 2.6 million years ago), has an ape-like pattern but shows evidence of Broca’s area. Thus, the earliest representatives of the genus Homo seem to have had the neural capacity for spoken language. The configurations of their brain surfaces resembled those of modern human beings rather than apes. This development coincided in time with the initial expansion of brain volume, the appearance of stone tool making (culture in the broadest sense), and preceded by a half million or so years the initial movements of hominids out of the African tropics (Tobias 1998).
Between 7 million and 2 million years ago, a set of complex, interrelated changes occurred in the heads of our human and pre-human ancestors. A few of these were: the brain was reorganized as both the vascular and neural systems evolved; the surface topography of the cerebral cortex became more folded and complex; asymmetric hemispherical specialization of the brain appeared; the anatomy of the craniofacial region was significantly shortened, and, toward the end of that period, the volume of the brain itself expanded, particularly in the frontal area. In other words, the brains of our ancestors who lived 2 million years ago were quite different from the brains of their ancestors who lived 5 million years earlier. With regard to the evolution of language, the faculty seems to have been an emergent phenomenon that was a byproduct of other developments, rather than one that was built on a pre-existing structure or structures shared with other primates. That is to say, there is not a single structure that is concerned exclusively with language and speech production; instead there seem to be several areas—one associated with emotions, another with sensation and motor control—that have become, in the course of the last 5 million or so years, interconnected by neural circuitry that was evolving simultaneously in response to selection pressures that had nothing to do with the development of language and only a little to do with other systems of communication more broadly defined.
The interconnections between the faculties of language and tool use in human natural beings were confirmed more than seventy years ago. Lev Vygotsky and Alexander Luria (1930/1994) assessed studies that compared the development of speech and practical intelligence in individuals, both apes and human children; these studies showed (1) that the practical behavior of apes is independent of any speech-symbolic activity, and (2) that tool-use by apes was analogous to that of human beings who were either pre-verbal children or deprived of the ability to speak (aphasics).
While the tool-using abilities of apes remained essentially unchanged throughout their lives, those that children manifested at different stages of psychological development changed dramatically, especially after they began to talk, first to themselves and then increasingly to others when they were confronted with a problem to solve.
While practical intelligence (tool-use) operates independently of speech in young children, practical activity and speech are increasingly interconnected as the child matures. The egocentric, inner speech of four-year-olds becomes increasingly communicative as they turn to peers and adults for information and insight about the issues they confront. As the human child matures, speech increasingly moves from solving the problems that are immediately at hand to a planning function that precedes their actions; that is, speech and interpersonal relations begin to guide and dominate what they will do in future. In a phrase, practical activity (tool-use in this case) and language began to be linked increasingly in the development of human natural beings, not only in their evolution over the past 7 million years but also in the maturation process of the each individual human being. It is part of the complex process by which natural beings became human natural beings.
As we have just seen, there are significant differences in the growth and development patterns of non-human primates and human beings. For example, ape neonatal infants have about 50 percent of the brain volume of adults of the same species, and their brains typically grow to roughly the same size as the adults by the end of their first year of life. In contrast, human infants are born with brain volumes that are about 25 percent of the size of those of adults; their brains double in size during the first six months, are about 75 percent the size of adults by two and a half, 90 percent by age five, and 95 percent in their tenth year. This protracted process of growth and development of humans has a number of implications: (1) brain development occurs much more rapidly in apes and through a seemingly smaller number of developmental stages; (2) the growth rate in brain volume extends beyond well beyond the first year of life in human beings; (3) human infants are relatively helpless in comparison to ape infants during the first years of life; (4) this prolonged period of maturation coincides with growth and developmental stages that witness not only the formation of new neural connections but also the related elaboration of practical activity and speech; and (5) the changes in the neural circuitry of human infants and children are, in fact, associated with the elaboration of practical activity and speech.
Paleoanthropologists have discerned the ape and human patterns of brain growth and development in the fossil remains of early hominids, provided that cranial and pelvic bones are present in their sample. An important limiting factor with regard to brain volume at the time of birth is the cross-section of the mother’s birth canal.
The size and shape of the neonate’s head cannot be greater than the width and height of the birth canal. For example, an early hominid—H. rudolfensis that lived about 2.5 million years ago—had a brain volume of 800–900 cc but a birth canal that was only able of passing a fetal head with brain size of about 200 cc (Stanley 1998: 160–3). Thus, they infer that the human rather than the ape pattern of growth and development was already in existence at that time. This implied that the infants also exhibited the same pattern of prolonged maturation and dependence that exist in modern human beings. These traits coincided in time with the appearance of tool-making and language; they also coincided with the expansion of those stages of brain growth and psychological development when new neural connections are being formed as tool-use and speech become increasingly social activities embedded in ensembles of social relations.
With more than 130 years of hindsight, it appears that “Engels got it right!”
The broad outlines of his argument have stood the test of time. Nonetheless, the accumulation of diverse sorts of empirical evidence during that period has added unimaginable detail and enriched our understanding of the process. On the one hand, neither Marx nor Engels ever questioned that human natural beings were also social beings. As Engels (1876/1972: 251) put it, our primate ancestors “lived in bands.”
On the other hand, they never considered in any extended manner the implications that the life histories, fertility, and mortality patterns of the early hominids might have on the demography and population structures of those groups.
Demography and Population Structure
Neither Marx nor Engels ever wrote systematically about the relation between population and political economy (Seccombe 1983). Marx (1863–7/1977: 784) suggested that “every particular historical mode of production has its own special laws of population, which are historically valid only within that particular sphere. An abstract law of population exists only for plants and animals, and even then only in the absence of any historical intervention by man.” He refused to abstract population from historically specific social structures or ensembles of social relations. His comment is part of a larger discussion about the relation between the capitalist mode of production and the formation of a reserve army of labor. Marx was certainly aware of differences in mortality and fertility, the effects of the movement of workers from the countryside to industrial cities; and the deleterious effects of industries, like pottery-making, on the health and life expectancies of the individuals engaged in those activities. Marx (1863–7/1977: 471) certainly recognized that age and sex were important factors structuring the division of labor in capitalism, and that they were potentially implicated in structuring discontinuities from one mode of production to another. He also implied that the determination of population dynamics is situated in the inner workings of particular modes of production, and that “population forces will periodically come into contradiction with themselves and with other elements of any given socio-economic system, and will tend to make their own contribution of time to the developmental propulsion of particular modes through time and space”
(Seccombe 1983: 33).
As you will recall from earlier discussions in the last chapter and this one, labor and thus the division of labor were characteristics that, in Marx’s view, distinguished human natural beings from natural beings. Biodeterminists, drawing on liberal social theory (notably John Locke), rooted the division of labor and the nuclear family in biology; in their view, sharing or exchange occurred because of the biological differences between males and females, which resulted in different dispositions and activity patterns. Females, whose mobility was periodically constrained by infant care, remained in close proximity to home bases and foraged for vegetable foods, while larger, more aggressive males hunted for meat, which was essential for survival, and shared this prize both with their offspring and with the mothers of those offspring (e.g. Washburn and Lancaster 1968). However, there are three problems with this perspective: (1) most non-human primates, including chimpanzees, forage individually most of the time; (2) the perspective does not explain how individuals of both sexes transformed themselves from self-feeders to producers; and (3) Engels (1884/1972) argued that families, as we construe them today, developed out of “bands.” Marx and Engels never doubted that our primate ancestors were social beings. Not surprisingly, they did not speculate about the demographic aspects of the transition from social natural beings to human natural beings, nor did they ever comment on the potential implications of mortality, fertility, and age structure in that transition; however, other writers have thought about these issues.
The early hominids were sexually dimorphic—that is, adult males were larger than adult females—but these differences were not as great as the sexual dimorphism found in non-human primates, such as chimpanzees or gorillas. The males and females of sexually dimorphic primates have roughly the same growth rates until puberty; the males continue to grow for several years after reaching this stage, while the females stop. Lila Leibowitz (1985, 1986) argued that the larger body size of adult males was not related to dominance and sex roles, but rather to reproductive and foraging advantages; it was correlated with either solitary existence (orangutans) or transient group membership (chimpanzees and gorillas). The larger body size of adult males gave them a greater chance for survival outside a social group; it also meant that both males and females engaged in the same foraging activities but in different places.
There is a great deal of variability not only in male and female roles but also in the relations between the sexes with groups of non-human primates (Leibowitz 1985, 1986). There is even variation between social groups of the same species—e.g.
baboon troops in which food resources and concentrated vs. those where resources are dispersed. Chimpanzees probably show the greatest flexibility and diversity of relations. The core members of chimpanzee social groups are adult females and their juvenile and infant offspring. Adult males join these core groups temporarily for greater or lesser periods of time, before wandering off to forage in other localities, either alone or in all-male groups. Thus, self-feeding is the rule in the core and all-male groups, except at those rare times when a small animal is killed and the meat is shared with individuals foraging nearby.
As we have seen, the maturation pattern of our primate ancestors who lived 3 million years ago was essentially the same as that of modern human beings. They reached reproductive age at about the same rate as we do. Paleodemographic studies indicate that infant and juvenile mortality was high, that about half of the individuals died or were killed before they reached reproductive age, and that the average life span of the survivors was about twenty years. Assuming that females had their first infants shortly after reaching puberty, when they were twelve or thirteen years old, and that they did not ovulate for the three or so years when they were lactating and nursing, their second infant would have been born when they were fifteen or sixteen years old, and their third when they were eighteen or nineteen.
Such a demographic profile has several implications. First, few, if any, females were alive when their offspring reached puberty. Second, most of the members of a social group were prepubescent individuals who had not reached reproductive age.
Third, many of the juveniles were orphans who had to fend for themselves in order to survive. Fourth, they were exposed to prolonged learning in a social group that was composed largely of other prepubescent individuals. The conclusion that Leibowitz drew from this evidence is that age or stage of maturation may have been more important than sex in structuring the social relations of early human populations.
Her observations and arguments suggest a model of early hominid society. The social groups were small and composed mainly of individuals who had not yet reached reproductive age. Within these groups, prepubescent males and females of the same age were roughly similar in size; they foraged for themselves from a young age and shared food with other individuals, when there was more than any one of them could consume. In the process of growing up in a small group, they learned to use and make simple wooden and stone tools from their peers. They shared information about the world around them through language. Their understanding of their world was gained through practical activities and experiences, the successes and failures of everyday life. Food sharing involves a degree of cooperation that does not exist in contemporary non-human primates and presumably did not exist among their ancestors, except on the most limited bases. It is an attribute that involves cooperation among individuals as well as new levels of understanding, trust, and confidence in the motivations of others. However, cultural understandings and ways of doing things changed slowly. There were so few individuals in these early groups that new ways of seeing and understanding the world or making new tools were often not validated because of the absence of an appreciative audience.
It appears that H. erectus populations living between 2 million and 500,000 years ago may have exhibited less sexual dimorphism than their immediate ancestors.
This evidence, coupled with their movement into new landscapes in Eurasia and the changes that had already been taking place and that were continuing to occur in Africa, suggest that diminished sexual dimorphism was likely associated with new forms of social organization. Leibowitz suggests that adult males may have been integrated into the juvenile, adult female, and infant groups on a full-time basis.
Their integration coincided with two other changes that facilitated both new forms of cooperation and further development of human natural beings themselves: (1) systematic hunting and hence the increased consumption of meat (a high energy, protein-rich food source); and (2) appearance of spatially organized, hunting and hearth-centered activities that were carried out more or less simultaneously in different places. If this change refracts new relations based in some complicated manner on sex differences, then shifts in the ensembles of social relations refracting changes in the age structure of human populations occurred much more recently.
Rachel Caspari and Sang-Hee Lee (2006) have argued that significant changes in the numbers of individuals surviving to adulthood—i.e., the ratio of older to younger individuals in a population—did not occur until the last 50,000 years or so. This change, they argued, was not a biological one but rather one rooted in culture and social relations. In practical terms, it means that there were then grandmothers and grandfathers, repositories of practical knowledge, who could share that information with the younger generations of the social groups.
Compare the following statements made by Marx about Darwin’s The Origin of Species. The first was made less than a month after its publication. The second was made two and a half years later.
Darwin, by the way, whom I’m reading just now, is absolutely splendid. There was one aspect of teleology that had yet to be demolished, and that has been done. Never before has so grandiose an attempt been made to demonstrate historical evolution in Nature, and certainly never to such good effect. One does, of course, have to put up with the crude English method. (Marx 1859/1983: 551)
I’m amused that Darwin, whom I’ve been taking another look, should say that he also applies the “Malthusian” theory to plants and animals, as though in Mr. Malthus’s case, the whole thing didn’t lie in its not being applied to plants and animals, but—only with its geometric progression—to humans as against plants and animals. It is remarkable how Darwin rediscovers, among the beasts and plants, the society of England with its division of labour, competition, opening up of new markets, “inventions” and Malthusian “struggle for existence.” It is Hobbes’ bellum omnium contra omnes [i.e., war of all against all] and is reminiscent of Hegel’s Phenomenology in which civil society figures as an “intellectual animal kingdom,” whereas, in Darwin, the animal kingdom figures as civil society. (Marx 1862/1985: 381)
What stands out in both quotations is Marx’s critique of the naturalization of social inequalities, the transposition of capitalist social relations to nature, and their reappropriation into capitalist society as “natural” relations. One target was Thomas Hobbes (1588–1679), the seventeenth-century materialist and political theorist who had argued that human individuals always act out of self-interest to satisfy their appetites and avoid their aversions, and that, in order to avoid being thrust back into a state of nature during the time of the English Civil War, they should submit their own individual wills to, or at least not resist, that of the sovereign in exchange for self-preservation and avoiding death (Wood and Wood 1997: 94–111). A second target was Thomas Malthus (1766–1834) who also assumed that self-interest and competition were the foundations of modern society, that poverty was a natural outcome of social relations, and that the tendency to over-reproduce far outstripped the capacity of society to produce food, which led to a limited food supply and a “struggle for existence” among its members. It is important to note here that Marx believed that “human nature” was not fixed but varied from one historical epoch to another, and that his concept of class struggle was different from those of Darwin who viewed struggle between different individuals of the same species in terms of differential reproduction and survival, Alfred Russel Wallace (1823–1913), and Malthus who viewed struggle in terms of limitations imposed on society as a whole by its environment (Bowler 1976: 639, 647–50).
In 1875, Frederick Engels made a similar point with regard to “bourgeois Darwinians” who saw only struggle for existence in nature where only a few years earlier they “laid emphasis on co-operation”:1
All that the Darwinian theory of the struggle for existence boils down to is an extrapolation from society to animate nature of Hobbes’ theory of the bellum omnium contra omnes and of bourgeois-economic theory together with the Malthusian theory of population. Having accomplished this feat . . . these people proceed to re-extrapolate the same theories from organic nature to history, and then claim to have proved their validity as eternal laws of human society. (Engels 1875/1991: 107–8)
The questions are: What happened in the thirteen years that intervened between Marx’s letter and that of Engels? What were the relationships of the liberals and socialists that Engels called bourgeois Darwinians to the development of anthropology?
When Darwin was composing The Origin of Species in the 1840s and 1850s, many of the concepts (e.g. evolution) and metaphors (e.g. “struggle for existence”
or “survival of the fittest”) that he would eventually use had already been employed by others. In a real sense, they had entered into the public domain and were being deployed by naturalists, political economists, and social commentators at a time when the popularity of reductive materialist arguments was on the rise in some circles and challenged in others, especially in those with strong religious convictions. The advocates of this reductionist standpoint were attempting to explain the development of human society as well as human psychology and social organization in terms of natural laws that were derived from biology or even physics; their perspective frequently emphasized the naturalness of hierarchy, gradualism, or equilibrium.
What many but not all of the advocates of this standpoint attempted to do was replace the notion of divine intervention with the “laws of nature.” Moreover, their efforts were facilitated by the fact that they also used the same conceptual frameworks and drew on the same analogies and metaphors to describe the human and natural realms. As a result, it was not uncommon by the 1850s for writers to slip between claims that human beings had a nature, and that nature had a moral economy (Jones 1980: 1–9). These tendencies became increasingly common in many countries after the publication of The Origin of Species in 1859 (e.g. Glick 1988). Twelve years later, Darwin (1874/1998) published his views about the human species and the development of the intellectual and moral faculties of primitive and civilized peoples in The Descent of Man. Darwinism and evolutionism were concerned with the individual, with the evolution of the human psyche and intelligence, and with the evolution of human social and social organization. While they were liberal reactions against entrenched aristocratic and conservative understandings of the world, they also became part of emerging discourses about individualism, meritocracy, the struggle for existence, and scientific racism that came to be called Social Darwinism after 1879; however, many features and metaphors, like “the struggle for existence”
or “nature red in tooth and claw,” associated with Social Darwinism were in use before Darwin wrote either The Origin of Species or The Descent of Man. While it is possible to argue that Darwin was a Social Darwinist, it is also clear that some of his followers were socialists and others were not.
Anthropology—an emerging discipline concerned with human variation, the evolution of human societies, and the cultural practices and beliefs of marginal peoples—also began to coalesce rapidly in the 1860s and 1870s (e.g. Hammond 1980; Harvey 1983; Kelly 1981; Stocking 1987; Weikart 1999; Weindling 1989:
11–59). Its early practitioners often had the same understandings of human beings, human diversity, and societal evolution and made use of the same analogies and metaphors as Darwin and his followers. However, anthropology was never a politically homogeneous discipline even at its inception. Some early figures in the history of anthropology—like Franz Boas (1858–1942) or Robert H. Lowie (1883–1957) in the United States—were socialists who rejected the positivism of the social evolutionary perspectives and replaced them instead with empiricist-inspired and grounded studies of the cultural practices of particular communities, populations rather than types of individuals, the weaknesses of scientific racist arguments, or the politics of science (Pittenger 1993). For example, Lowie was highly critical of Lewis Henry Morgan’s Ancient Society and of Ernst Haeckel (1834–1919), who was one of the leading exponents of Darwin’s thought in Germany; at the same time, he praised the writings of Russian anarchist Peter Kropotkin (1842–1921), especially his Mutual Aid: A Factor of Evolution (Kropotkin 1904/1989) and of the socialist Alfred Russel Wallace.
For our purposes in this book, it is worth noting that discourses which naturalize social hierarchy and power relations have been and continue to be pervasive and influential in anthropological practice and theory and their appropriations by states including socialist ones (e.g. Patterson and Spencer 1995; Ssorin-Chaikov 2003; Yanagisako and Delaney 1995). It is also clear, as the letters quoted above indicate, that Marx and Engels were early opponents of the naturalization of cultural categories.
In this chapter, we examined how Marx’s materialism was an outcome of his efforts as a student to bring together the arts and sciences and then, a few years later, to address questions concerned with the emergence and development of human natural beings and their relationship with the worlds in which they lived. For Marx, the attraction of Darwin’s theory of evolution by natural selection was precisely its materialist foundations. One can only presume that Marx would have applauded subsequent clarifications of the underlying mechanisms of descent with modification and speciation as well as of the historically contingent and ever-changing structure of the world in which these mechanisms operate. We then moved to an examination of Engels’s essay on the role of labor in the transition from non-human primate to human natural being and suggested that Marx agreed with the views of his longtime friend. We also saw that the broad outlines of Engels’s argument have stood the test of time, although the kinds of detailed information available today are infinitely richer than when he wrote. Engels linked the emergence of human natural beings with a series of interconnected changes in the corporeal organization of our ancestors that involved bipedalism, changes in the anatomy and dexterity of the hand, expansion and reorganization of the brain, tool-making, language, and the elaboration of culture. We then examined data clarifying these developments; some of the data derived from the investigations of neuroanatomists, while others came from paleoanthropological inquiries in African and Eurasia. Finally, we raised questions about the kinds of social relations that might have existed in these early communities, and how issues of mortality, fertility, life expectancy, and life history might have effected and produced diverse social structures.
There is, however, another set of linkages between Marx, Darwin, and their successors that we explored: the naturalization of social inequalities through the use of folk categories that are understood as the biological categories of Western modernity.