After World War II, the question of how to define a universal human nature took on new urgency. Creatures of Cain charts the rise and precipitous fall in Cold War America of a theory that attributed man’s evolutionary success to his unique capacity for murder.
Drawing on a wealth of archival materials and in-depth interviews, Erika Lorraine Milam reveals how the scientists who advanced this “killer ape” theory capitalized on an expanding postwar market in intellectual paperbacks and widespread faith in the power of science to solve humanity’s problems, even to answer the most fundamental questions of human identity. The killer ape theory spread quickly from colloquial science publications to late-night television, classrooms, political debates, and Hollywood films. Behind the scenes, however, scientists were sharply divided, their disagreements centering squarely on questions of race and gender. Then, in the 1970s, the theory unraveled altogether when primatologists discovered that chimpanzees also kill members of their own species. While the discovery brought an end to definitions of human exceptionalism delineated by violence, Milam shows how some evolutionists began to argue for a shared chimpanzee-human history of aggression even as other scientists discredited such theories as sloppy popularizations.
A wide-ranging account of a compelling episode in American science, Creatures of Cain argues that the legacy of the killer ape persists today in the conviction that science can resolve the essential dilemmas of human nature.
|Publisher:||Princeton University Press|
|Product dimensions:||6.20(w) x 9.40(h) x 1.50(d)|
About the Author
Erika Lorraine Milam is professor of history at Princeton University. She is the author of Looking for a Few Good Males: Female Choice in Evolutionary Biology.
Read an Excerpt
Humanity in Hindsight
IN 1859 CHARLES DARWIN published On the Origin of Species at the age of fifty. Centennial celebrations of Origin thus doubled as the sesquicentennial of his birth. Historical retrospectives published for the centenary provided a welcome opportunity for postwar anthropologists, biologists, and paleontologists to signal their conviction in the progress of science and trust that evolutionary theory provided key insights into human nature. Contested news of fossil discoveries and archeology were favorite subjects of journalists covering anthropological research — then as now. Postwar evolutionists used discussions of these fossils in the context of the Darwin centennial to craft a vision of a united humanity, a historical past shared by all living humans before our species had been riven by cultural and political identities. Looking back at the previous century also gave paleoanthropologists a boost of confidence. Whereas Darwin had built his theory of human descent on comparative anatomy and logic, they had access to recent studies in blood typing, genetics, and a wide array of hominid fossils.
Publications began to appear in 1958 honoring the occasion on which Charles Lyell and Joseph Hooker presented to the Linnaean Society a "brief sketch" from Darwin and a short essay by Alfred Russel Wallace, each outlining a "natural means of selection" that explained how, over the course of the history of life on Earth, new organic species had emerged and been transformed. Origin followed seventeen months later, summarizing the voluminous evidence and keen argumentation Darwin had been accumulating and honing for years. In the 1950s, scientists looked back, both acknowledging Origin as Darwin's "great contribution to biology" and pointing to how much more they now knew about genetics, paleontology, and zoology. According to Margaret Mead, the celebrations of Darwin's publication of On the Origin of Species had refocused anthropologists' collective attention on evolution as a potential framework for thinking about human nature. In measuring Darwin's successes and failures, anthropologists used their historical reflections to highlight what they identified as the most promising components of evolutionary thought and evidence from recent decades and the evidentiary holes that remained to be filled when describing the emergence of humanity in the geological past.
Darwin's dark jacket and white-bearded face — for he was almost always depicted as an elder sage — stood for a generation of Victorian gentlemen already out of place in the modern scientific world they helped create. Depending on the perspective of recent historians, Darwin has been a warrior in the heroic battle against the backward forces of slavery, a villainous instigator of secular fervor that resulted in dehumanization and genocide, and just about everything in between. In the 1950s, though, Darwin's legacy was far less contested. Retrospective appraisals of (to invoke its full title) On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life both celebrated Darwin's achievements and noted how much science had advanced in the intervening years.
Loren Eiseley's Darwin's Century was one of the first and best-selling forays into the centenary genre, and he fared well in the growing market for "intellectual" paperbacks. His version of Darwin's intellectual development and legacy began the way many classes on the history of modern biology still begin: by emphasizing early-modern scientific empiricism and the desire of Enlightenment natural historians to catalog and classify all living species according to a great scale of nature. Against this background, Eiseley posited, evolutionary thinking — the idea that species have not been static in time, but some have gone extinct and others slowly evolved into new forms — emerged in France, rising from the secularized ashes of the revolutionary republic. Eiseley made clear that Darwin's legacy therefore rested on his innovative mechanism explaining the transformation of species. Like Eiseley, the retrospective essays and books published in the years around the centenary pointed to Darwin's theory of natural selection as his "most important generalization." University presses ensured that a variety of editions were produced for academic consumption, from facsimile reprints of Origin's first edition to a variorum comparison of all editions published during Darwin's life.
Natural selection is an elegant, simple idea. If species are composed of many individuals that compete for access to limited resources, then those individuals who are better able to marshal the resources around them will survive and raise a greater number of offspring than their neighbors. As a result, the next generation of that species will look slightly different, because the traits that helped the previous generation succeed will be more commonly represented. Over the eons, as the physical landscapes of Earth inexorably changed, so too did species adapt to the new conditions in which they lived. Most dramatically for the British public, the sandstones of southern England and around Paris had once accumulated at the bottom of a warm freshwater sea, fossilizing now-extinct shells and the skeletons of ichthyosaurs in layers of sediment. Documenting evidence that natural selection was the best explanation for these changes in the living world required far more work.
Darwin had been developing his "big book" about species transformation since the 1840s and was induced to publish it earlier than planned by a letter from Wallace, who had written from the island of Ternate — one of the Maluku Islands that now comprise northeastern Indonesia. Despite their differences in social class, Darwin and Wallace's friendship was cemented in their correspondence, where they "met on the equal ground of pen and paper." Wallace wrote to Darwin about his idea of explaining how one species could come to be replaced with a superior, "more perfectly adapted and more highly organized form" as a result of environmental pressures differentially killing some individuals and not others. Darwin was surprised to find the essential features of his theory of natural selection in the words of Wallace's letter, perhaps because of his relative isolation from the avant-garde chatter of his friends. In 1842 Darwin had moved from London to Down (then a rural parish in Kent) and convinced himself despite Lyell's warning that other researchers were not wrestling with issues of species, varieties, transformation, and adaptation. After Darwin and Wallace's brief contributions were read to the Linnaean Society in 1858, Darwin compressed his ideas and wrote what he viewed as an "abstract" of his longer manuscript — On the Origin of Species.
A century later, the developmental biologist Conrad Hal Waddington wrote that despite Darwin's brilliance in describing speciation, he had never fully understood the problem of variation, which left a large conceptual gap in natural selection. Natural selection only works if the traits that help some individuals survive and reproduce more than other members of the species are passed along to their offspring, who in turn exhibit the same traits — but in the late nineteenth century, the mechanisms of heredity had yet to be worked out. Darwin remained unaware of Gregor Mendel's careful breeding of peas. (Long after Darwin died, Mendel's research would be rediscovered in 1900 by a growing community of researchers exploring the physical basis of heredity, a field that came to be called genetics.) In Waddington's judgment, without a mechanism for heredity, natural selection as a theory failed to measure up to Isaac Newton's far more "complete and self-sufficient" contribution to science: universal gravitation. For Waddington, biologists were able to complete the conceptual work Darwin began in the nineteenth century only when they finally dismissed the possibility that characteristics acquired over the lifespan of an individual could be biologically inherited by their offspring. Also a geneticist by training, Dobzhansky was more generous, noting that first Mendelian genetics and then molecular genetics had "borne out Darwin's conclusions" and "opened to view the causal processes that bring about evolution." Dobzhansky claimed Darwin had instigated "one of the greatest revolutions in the history of human thought" by demonstrating that "man is a part of nature and kin to all life." This idea was not new with Darwin, Dobzhansky quickly added — other natural historians had made similar arguments at least two generations earlier, including Darwin's paternal grandfather, Erasmus, who had died several years before Charles's birth — but he had made the concept of humanity's long evolutionary history convincing.
The physical anthropologist and paleontologist Wilfrid Le Gros Clark praised Darwin's Descent of Man and Selection in Relation to Sex, published twelve years after Origin, as "an act of great moral courage" for championing the antiquity of man with almost no direct fossil evidence to back his claims. For Darwin, as for his contemporaries, primates had played a key role in scientific reconstructions of humanity's past. Lacking access to paleontological specimens, Darwin had based his own thoughts on primate and human evolution almost entirely on species still alive today. In Descent of Man, Darwin had further suggested that humanity's intellectual development made possible all other specializations that make us human, from our capacity to manufacture and use tools, to our conceptual appreciation that the past and future may differ from the present. Le Gros Clark commented that "since Darwin's day ... the evidence relating to human evolution has grown to vast proportions," placing paleoanthropology on more solid scientific ground. Instead of one so-called missing link, anthropologists had several, allowing tentative reconstructions of humanity's successive adaptations. Paleoanthropologists routinely inferred a fossil ancestor's relative intelligence from the size of its brain case and, therefrom, the size of the brain those bones had protected in life. Based on this accumulated evidence, Le Gros Clark argued that the era of extrapolating the history of humanity's evolution by indirectly comparing ourselves to modern apes had finally come to an end — he contended the analysis of bones and fossils were the only sure way to understand the evolutionary past of humanity. Le Gros Clark noted, too, that paleoanthropologists studying human origins still required a healthy dose of courage because their necessarily speculative conclusions were likely to be disproven tomorrow.
Fearful that his colleagues were lionizing Darwin, the zoologist S. Anthony Barnett warned against lapsing into an absurd "cult of the individual." Historians had long noted Darwin's indebtedness to economic theories of competition, paleontologists' fossil evidence documenting species extinction, and geologists' reconstructions of changes in the physical characteristics of landscapes over the course of millennia past. Therefore, Barnett suggested, Darwin alone could not be credited with sparking all the subsequent transformations in biology, since his work and ideas had materially depended on the intellectual climate in which he worked and wrote.
Loren Eiseley agreed with Barnett, and in his own retelling of the mental evolution of humanity, Wallace emerged as a hero equal to Darwin. Wallace's experience in tropical archipelagos had led him to conclude that the "natives" were mentally only a "little inferior" to the average European. This position had presented Wallace with a dilemma, Eiseley suggested. Natural selection could not explain a mental capacity "far in excess" of that required by the environment, nor could natural selection explain the artistic, mathematical, or musical abilities of humanity. Wallace had inferred that a spiritual source unknown to science must have been involved in the development of the human brain. Upon reading Wallace's views, Darwin had written to him expressing his disappointment. Eiseley paraphrased Darwin's reaction: "If you had not told me you had made these remarks, I should have thought they had been added by someone else. I differ grievously from you and am very sorry for it." (Darwin also filled his letter to Wallace with excitement over their mutual interests and the tone of the entirety was much less sharp than Eiseley's brief excerpt implied.)
The significant differences between the brains of all humans and those of animals continued to gnaw at Eiseley. He posited that an Ice Age hunter from twenty thousand years ago who painted mammoths on the cave walls of Lascaux shared "precisely the same brain" as a modern aeronautics engineer. The hunter and the engineer differed merely in the cumulative knowledge and ideas humanity had used to shape the natural world generation after generation. According to Eiseley, it was ultimately culture rather than mental endowment that defined their relative intellectual capacities. Eiseley grieved that Darwin never changed his mind and scientists forgot Wallace's challenge. "It isn't precisely that nature tricks us," Eiseley wrote. "We trick ourselves with our own ingenuity. I don't believe in simplicity."
Trickery, indeed, had played a role in the history of paleoanthropology, a fact of which Eiseley was well aware. Quarrymen in the mid-nineteenth century working in the Neander Valley outside of Düsseldorf had found an unusually shaped skull and associated bones. Hermann Schaaffhausen, the comparative anatomist who first described the bones, hailed them as an anatomically distinct "primitive" human ancestor, but the pathologist Rudolf Virchow and the retired physiologist August Franz Mayer dismissed them as the relics of a diseased Russian horseman who had died as his army traversed Germany on the way to assail France earlier in the century. In the following decades, however, more and more specimens were identified that shared the same peculiar morphologies, providing firm evidence of prehistoric humanity. Neanderthals (Homo neanderthalensis), as these individuals became known, generated considerable popular and scientific interest. By the 1950s, archeologists' excavations of numerous ancient sites demonstrated that Neanderthals hunted prey with spears and other weapons, controlled fire, buried their dead, and left traces that many archeologists interpreted as signs of religious practice.
Eiseley focused particular attention on an insidious case, known as Piltdown Man, that he believed had led scientists to misunderstand the role of the brain in the physical development of humanity. Discovered in 1912 in gravel beds near the village of Piltdown, south of London, the Piltdown fossils appeared to confirm that human ancestors much older than Neanderthals had lived in Europe. They also reinforced what Darwin had suggested in Descent of Man — that prehuman brains had enlarged early in the divergence of humans from other apes, making possible tool use and manufacture, bipedalism, language, and ultimately culture. A controversial find from the beginning, in the early 1950s scientists finally confirmed the Piltdown fossils were frauds. Whoever perpetrated the deception (theories abounded) had combined the cranium of a small adult human with the lower jaw of an orangutan, replaced the canines in the upper jaw with their orangutan equivalents but filed them down to make them look more like ape-human intermediates, and then stained everything to resemble the quarry rocks. Based on differing levels of fluorine in the teeth, as well as dental wear patterns, paleoanthropologists determined that the canine and mandible were definitely modern and deliberately faked. They concluded the bones represented "a most elaborate and carefully prepared hoax."
The removal of Piltdown Man as a viable "missing link" left a gap of several million years between a putative common ancestor belonging to both human and chimpanzee lineages, and the remains of individuals who closely resembled modern humans, like Neanderthals. Paleontologists suggested that a few skull fragments found in India, dubbed Ramapithecus, might have come from an ancient ancestor shared by both humans and chimpanzees. Yet Ramapithecus remained a highly controversial designation until postcranial specimens could be found. In the 1950s and 1960s, without linked evidence of a pelvis or scapula and arm bones, scientists could only speculate as to whether the species was bipedal or arboreal. Eiseley therefore concluded that Darwin had been wrong when he suggested that the expansion of the brain in our ancestors preceded the origin of other characteristics scientists identified as uniquely human. Instead, Eiseley argued that brain development in humans must have evolved after bipedalism, possibly even after our capacity to manufacture and use tools. This, he suggested, was "the real secret of Piltdown"— a conclusion for which he felt "roundly castigated" by his colleagues. Eiseley took care to reassure his readers that despite their protests he was, deeply, an evolutionist and a scientist. His case was helped by the fact that without Piltdown, the sequence of fossils looked cleaner and more linear (Figure 2).(Continues…)
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Table of Contents
Part I The Ascent Of Man 17
1 Humanity in Hindsight 27
2 Battle for the Stone Age 41
3 Building Citizens 60
Part II Naturalizing Violence 79
4 Cain's Children 89
5 The Human Animal 102
6 Man and Beast 113
Part III Unmaking Man 125
7 Woman the Gatherer 133
8 The Academic Jungle 143
9 The Edge of Respectability 153
Part IV Political Animals 169
10 The White Problem in America 177
11 A Dangerous Medium 190
12 Moral Lessons 205
Part V Death Of The Killer Ape 225
13 The New Synthesis 235
14 The Old Determinism 246
15 Human Nature 261