No event did more to establish the fame and prestige of the Museum of Natural History than the Gobi Desert expeditions of the 1920s. The discoveries, including the first dinosaur egg, were exciting and abundant, and fit the sheer romance of Hollywood’s most heroic mold. It is still hard to find a better adventure story than Roy Chapman Andrew’s book (with its chauvinistic title:) The New Conquest of Central Asia. Nonetheless, the expeditions utterly failed to achieve their stated purpose: to find in Central Asia the ancestors of man. And they failed for the most elementary of reasons—we evolved in Africa, as Charles Darwin surmised fifty years earlier.

Our African ancestors (or at least our nearest cousins) were discovered in cave deposits during the 1920s. But these australopithecines failed to fit preconceived notions of what a “missing link” should look like, and many scientists refused to accept them as bonafide members of our lineage. Most anthropologists had imagined a fairly harmonious transformation from ape to human, propelled by increasing intelligence. A missing link should be intermediate in both body and brain—Alley Oop or the old (and false) representations of stoop-shouldered Neanderthals. But the australopithecines refused to conform. To be sure, their brains were bigger than those of any ape with comparable body size, but not much bigger. Most of our evolutionary increase in brain size occurred after we reached the australopithecine level. Yet these small-brained australopithecines walked as erect as you or I. How could this be? If our evolution was propelled by an enlarging brain, how could upright posture—another “hallmark of hominization,” not just an incidental feature—originate first? In a 1963 essay, George Gaylord Simpson used this dilemma to illustrate

“the sometimes spectacular failure to predict discoveries even when there is a sound basis for such prediction. An evolutionary example is the failure to predict discovery of a ‘missing link’, now known [Australopithecus], that was upright and tool-making but had the physiognomy and cranial capacity of an ape.”

We must ascribe this “spectacular failure” primarily to a subtle prejudice that led to the following invalid extrapolation: We dominate other animals by brainpower (and little else); therefore, an increasing brain must have propelled our own evolution at all stages. The tradition for subordinating the upright posture to an enlarging brain can be traced throughout the history of anthropology. Karl Ernst von Baer, the greatest embryologist of the nineteenth century (and second only to Darwin in my personal pantheon of scientific heroes) wrote in 1828: “Upright posture is only the consequence of the higher development of the brain . . . all differences between men and other animals depend upon construction of the brain.” One hundred years later, the English anthropologist G.E. Smith wrote: “It was not the adoption of the erect attitude or the invention of articulate language that made man from ape, but the gradual perfecting of the brain and the slow building of the mental structure, of which erectness of carriage and speech are some of the incidental manifestations.”

Against this chorus of emphasis on the brain, a very few scientists upheld the primacy of upright posture. Sigmund Freud based much of his highly idiosyncratic theory of the origin of civilisation upon it. Beginning in his letters to Wilhelm Fliess in the 1890s and culminating in his 1930 essay on Civilization and Its Discontents, Freud argued that our assumption of upright posture has reoriented our primary sensation from smell to vision. This devaluation of the olfaction shifted the object of sexual stimulation in males from the cyclic odors of estrus to the continual visibility of female genitalia. Continual desire in males leads to continual receptivity in females. Most mammals copulate only around periods of ovulation; humans are sexually active at all times (a favorite theme of writers on sexuality). Continual sexuality has centered the human family and made civilisation possible; animals with strongly cyclic copulation have no impetus for stable family structure. “The fateful process of civilisation,” Freud concludes, “would have set in with man’s adoption of an erect posture.”

Although Freud’s ideas gained no following among anthropologists, another minor tradition did arise to stress the primacy of upright posture. (It is, by the way, the argument we tend to accept today in explaining the morphology of australopithecines and the path of human evolution.) The brain cannot begin to increase in a vacuum. A primary impetus must be provided by an altered mode of life that would place a strong, selective premium upon intelligence. Upright posture frees the hands from locomotion and for manipulation (literally, from manus = “hands”). For the first time, tools and weapons can be fashioned and used with ease. Increased intelligence is largely a response to the enormous potential in free hands for manufacture—again, literally. (Needless to say, no anthropologist has ever been so naive to argue that the brain and posture are completely independent in evolution, that one reached its full human status before the other began to change at all. We are dealing with interaction and mutual reinforcement. Nevertheless, our early evolution did involve a more rapid change in posture than in brain size; complete freeing of our hands for using tools preceded most of the evolutionary enlargement of our brain.)

In another proof that sobriety does not make right, von Baer’s mystical and oracular colleague Lorenz Oken hit upon the “correct” argument in 1809, while von Baer was led astray a few years later. “Man by the upright walk obtains his character,” writes Oken, “the hands become free and can achieve all other offices. . . . With the freedom of the body has been granted also the freedom of the mind.” But the champion of the upright posture during the nineteenth century was Darwin’s German bulldog Ernst Haeckel. Without a scrap of direct evidence, Haeckel reconstructed our ancestor and even gave it a scientific name. (Pithecanthropus, by the way, is probably the only scientific name given to an animal before it was discovered. When Eugène Dubois discovered Java-man in the 1890s, he adopted Haeckel’s generic name but he gave it the new specific designation Pithecanthropus erectus. We now usually include this creature in our own genus as Homo erectus.)

But why, despite Haeckel’s demurral, did the idea of cerebral primacy become so strongly entrenched? One thing is sure; it had nothing to do with direct evidence—for there was none for any position. With the exception of Neanderthal (a geographic variant of our own species, according to most anthropologists), no human fossils were discovered until the closing years of the nineteenth century, long after the dogma of cerebral primacy was established. But the debates based on no evidence are among the most revealing in the history of science, for in the absence of factual constraints, the cultural biases that affect all thought (and which scientists try so assiduously to deny) lie nakedly exposed.

Indeed, the nineteenth century produced a brilliant expose from a source that will no doubt surprise most readers—Frederick Engels. (A bit of reflection should diminish surprise. Engels had a keen interest in the natural sciences and sought to base his general philosophy of the dialectic of materialism upon a “positive” foundation. He did not live to complete his Dialectic of Nature, but he included long commentaries on science in such treatises as the Anti-Duhring.) In 1876, Engels wrote an essay entitled, “The Part Played by Labor in the Transition from Ape to Man.” It was published posthumously in 1896 and, unfortunately, had no visible impact upon Western science.

Engels considers three essential features of human evolution: speech, a large brain, and upright posture. He argues that the first step must have been descent from the trees, with subsequent evolution to upright posture by our ground-dwelling ancestors. “These apes when moving on level ground began to drop the habit of using their hands and to adopt a more and more erect gait. This was a decisive step in the transition from ape to man.” Upright posture freed the hand for using tools (labor, in Engels’s terminology); increased intelligence and speech came later: “Thus the hand is not only the organ of labor, it is also the product of labor. Only by labor, by adaptation to ever new operations . . . by the ever-renewed employment of these inherited improvements in new, more and more complicated operations, has the human hand attained the high degree of perfection that has enabled it to conjure into being the pictures of Raphael, the statues of Thorwaldsen, the music of Paganini.”

Engels presents his conclusions as though they followed deductively from the premise of his materialist philosophy, but I am confident that he cribbed them from Haeckel. The two formulations are almost identical, and Engels cites the relevant pages of Haeckel’s work for other purposes in an earlier essay written in 1874. But no matter. The importance of Engels’s essay lies not in its substantive conclusions, but in its trenchant political analysis of why Western science was so hung up on the a priori assertion of cerebral primacy.

As humans learned to master their material surroundings, Engels argues, other skills were added to primitive hunting—agriculture, spinning, pottery, navigation, arts and sciences, law and politics, and finally, “the fantastic reflection of human things in the human mind: religion.” As wealth accumulated, small groups of men seized power and forced others to work for them. Labor, the source of all wealth and the primary impetus for human evolution, assumed the same low status of those who labored for the rulers.* Since rulers governed by their will (that is, by feats of mind), actions of the brain appeared to have a motive power of their own. The profession of philosophy followed no unsullied ideal of truth. Philosophers relied on state religious patronage. Even if Plato did not consciously conspire to bolster the privileges of rulers with a supposed abstract philosophy, his own class encouraged an emphasis on thought as primary, dominating, and all together more important than the labor it supervised This idealistic tradition dominated philosophy right down through Darwin’s day. Its influence was so subtle and pervasive that even scientific but apolitical materialists like Darwin fell under its sway. A bias must be recognised before it is challenged. Cerebral primacy seemed so obvious and natural that it was accepted as given, rather than recognised as a deep-seated social prejudice related to the class position of the professional thinkers and their patrons. Engels writes:

“All merit for the swift advance of civilisation was ascribed to the mind, the development and activity of the brain. Men became accustomed to explain their actions from their thoughts, instead of from their need. . . . And so there arose in the course of time that idealistic outlook on the world which, especially since the downfall of the ancient world, has dominated men’s minds. It still rules them to such a degree that even the most materialistic natural scientists of the Darwinian school are still unable to form any clear idea of the origin of man, because under that ideological influence they do not recognise the part that is played therein by labor.”

The importance of Engels’s essay does not lie in the happy result that Australopithecus confirmed a specific theory posed by him—via Haeckel—but rather in his perceptive analysis of the political role of science and of the social biases that must affect all thought.

Indeed, Engels’s theme of separation of the head and hand has done much to set and limit the course of science throughout history. Academic science, in particular, has been constrained by an idea of “pure” research, which in former days barred a scientist from extensive experimentation and empirical testing. Ancient Greek science labored under the restriction that patrician thinkers could not perform the manual work of plebeian artists. Medieval barber-surgeons who had to deal with battlefield casualties did more to advance the practice of medicine than academic physicians who rarely examined patients and who based their treatment on a knowledge of Galen and other learned texts. Even today, “pure” researchers tend to disparage the practical, and terms such as “aggie school” and “cow college” are heard with distressing frequency in academic circles. If we took Engels’s message to heart and recognised our belief in the inherent superiority of pure research for what it is—namely a social prejudice—then we might forge among scientists the union between theory and practice that a world teetering dangerously near the brink so desperately needs.

Note

* Editor’s note: Marx and Engels did not propose that labor was the source of all wealth, as Gould suggests here. Instead, as Marx wrote in Critique of the Gotha Program: “Labour is not the source of all wealth. Nature is just as much the source of use values (and it is surely of such that material wealth consists!) as labour, which itself is only the manifestation of a force of nature , human labour power”.