“We are great apes. All the great apes that have ever lived, including ourselves, are linked to one another by an unbroken chain of parent-child bonds. Molecular evidence suggests that our common ancestor with chimpanzees lived, in Africa, between five and seven million years ago, say half a million generations ago. This is not long by evolutionary standards.” Richard Dawkins
Anyone desiring to know the nature and place of Homo sapiens in the natural world, of how our species fits into the wider web of biological history and relationships, can start by consulting the scientific tables. The formal identification, classification, and ordering of species into hierarchical arrangements is the task of taxonomy, and the first modern pioneer of the field was Carl Linnaeus (1707-1778).
Confronting a morass of unwieldy names and descriptions, Linnaeus set out to simplify and order biological classifications by arranging species in a hierarchy of relations based on shared physical characteristics. In 1735, he published the first edition of Systema naturae (System of Nature), which he constantly revised. His tenth and final edition (1758) became the standard reference for subsequent science. The “Linnaean taxonomy” organizes biodiversity into Kingdoms, which are then divided into increasingly specific groupings of Phyla, Classes, Orders, Families, Genera, and Species. Since Linnaeus, scientists have made numerous changes in his scheme, but his model remains the basis for efforts to formulate an international code of nomenclature that organizes species in a clear, relatively stable, and universal manner.
On the Linnaean model, moving from the general to the specific, human beings have been situated thus:
Kingdom: Animalia (animals)
Phylum: Chordata (post-anal tail, pharyngeal gill slits, notochord, and a hollow dorsal nerve cord)
Class: Mammalia (hair, warm-blooded, suckle their young)
Order: Primates (collar bone, grasping hands with opposable thumbs, incisors and molars, stereoscopic vision)
Family: Hominidae (bipedal)
Genus: Homo (large-brained, tool-using)
Species: Homo sapiens (language, rationality, and culture)
Linnaeus’ scheme, it should be emphasized, dramatically departed from, and was a clear advance over, the medieval “Great Chain of Being” model that ordered life in a hierarchy of complexity, intelligence, and perfection, with humans just below angels and God and other animals placed just above rocks and trees. Yet, despite the appearance of scientific objectivity and precision, taxonomies are not unbiased reflections of “natural” relationships captured by a disinterest, scribe-like mind recording reality as it really is; instead, they are social constructs and arbitrary arrangements conditioned by a host of assumptions and ideologies. Like the process of selecting and ordering “facts” in meaningful relations for a historical narrative, the construction of taxonomical hierarchies is shaped by a battery of theoretical and pre-theoretical biases. Thus, the category of “species” is subject to widely varying interpretations and perspectives, and is a social construct in the same manner as “race.”
Since the nineteenth century, scientists have advanced the category of “race” as objective and grounded in real biological differences among human beings. In truth, prevailing race theories were uninformed, hodge-podge attempts to homogenize vast populations into static, ideal types, whereas human groups are diverse, dynamic, and hybridized. Taxonomies also reflected racist biases (often not too subtle) that ranked the worlds’ cultures below “Caucasian” and “European.” Linnaeus himself smuggled racist and Eurocentric biases into his scheme with a concept of “race” that divided Homo sapiens into four categories: Americanus, Asiaticus, Africanus, and Europeans. He assigned “natural” characteristics to each type and constructed a hierarchy that positioned Europeans as superior and non-Europeans as inferior.
Thus, while seemingly as empirical as one can get, “race” is a social construction that has little to do with “objective” categorizing of “natural” differences, and much to do with politics and prejudice. “Race” is nothing but a phylogenic appearance adapted to a particular environment and is particularly meaningless in light of hybridized and multi-racial populations. Similarly, human “gender” differences are not “natural” relations,” but rather social constructions shaped by patriarchal biases. Throughout western culture, from Aristotle and the Bible to Rousseau, Freud, and beyond, male theorists have reflected the biological types of “male” and “female” through the social categories of “man” and “woman.” With alleged “natural” characteristics grounded in a dualistic and hierarchical logic, patriarchal ideology declares that men are “rational” and women are “emotional,” that men naturally command the public sphere and women necessarily belong to the private sphere of domestic life, and that men are the agents of history and women are the “second sex,” in Simone de Beauvoir’s phrase. Patriarchy defines men apart from and superior to women, and for the last ten thousand years this arbitrary hierarchical model has informed gender identities and social institutions and relations throughout western history, and other cultures as well.
“I am in favor of animal rights as well as human rights. That is the way … How smart does a chimp have to be before killing him constitutes murder?” Drs. Carl Sagan & Ann Druyan.
Similar to the constitution of race and gender in the ideologies of racism and sexism, there is a social construction of species in the form of speciesism. The arbitrary nature of taxonomy is evident in Linnaeus’ classifications. Initially, Linnaeus used the Aristotelian term of “quadruped” (itself not accurate in many ways) to define the Class Mammalia, but in the tenth edition of his book he introduced the term “mammalia” to characterize a diverse Class as comprised of species whose females have breast glands and suckle their young. His reasons had nothing to do with science and everything to do with politics, as Linnaeus had embarked on a campaign urging mothers to naturally breast-feed their babies, a project with which he identified enough to use it to essentialize a wide variety of animals as mammary-endowed “mammals.”
The term “Homo sapiens” itself is a biased and arbitrary classification that exaggerates differences between human and nonhuman primates. As members of Homo sapiens, we have an extensive evolutionary ancestry in the primate and mammalian worlds that shapes our emotions, desires, and actions, and thus humanity is a biological product. But, of course, we also have long social histories that also shaped us profoundly and in which the “natural” species “Homo sapiens” was transformed into the cultural construct of “human being.” Just as human males and females are socially reconstituted as “men” and “women” in ways that differ vastly from culture to culture, so members of Homo sapiens are constituted as “human beings” in richly diverse ways throughout history.
Different cultures construct vary species identities within which individuals understand (1) their commonality as a species (to they extent they in fact do recognize one another as “human” rather than as “savage,” “beastly,” “barbaric,” or “sub-human”), (2) their differences from (other) animals, and (3) their role in the cosmos as a whole. While species identity fluctuates throughout different cultures, in western societies and elsewhere, they draw from the same anthropocentric and speciesist logic that defines humans as separate from nature and animals, as superior to other species, and as the end to which the animals and the fruits of the earth are mere means.
Through the Looking Glass of Primates
“He who understands baboons would do more towards metaphysics than Locke.” Charles Darwin
A prolonged scientific debate and culture war continues to rage over the relation between humans and their closest relatives in the great apes; the controversy raises the question of whether the genetic, anatomical, and behavioral differences among humans and apes are significant enough to warrant classifying them in different Family and Genus groupings. The culture war over species identity predates Darwin and extends at least to Linnaeus himself who challenged speciesist assumptions.
Although a pious Lutheran, Linnaeus broke with scientific and religious convention by classifying humans and apes in the same primate Order. This provocation aroused the ire of a Lutheran Archbishop, who accused him of “impiety.” In response, Linnaeus wrote: “It is not pleasing that I must place humans among the primates…I desperately seek from you and from the whole world a general difference between men and simians from the principles of Natural History. I certainly know of none. If only someone might tell me one! If I called man a simian or vice versa I would bring together all the theologians against me. Perhaps I ought to, in accordance with the law of Natural History.”
Not only was Linnaeus’ scheme developed a century before Darwin’s theory of evolution, it took shape two centuries before the genetic revolution that shed a powerful new light on evolutionary history and biological relationships. Whereas earlier theories relied on overt, observable physical traits for taxonomical construction, the genetic revolution that began in the 1960s enabled scientists and anthropologists to classify species according to their genetic composition. While an important perspective, morphological similarities and differences are not always accurate scientific markers — although genetic techniques have their own types of imprecision.
Traditional schemes based on physical similarities such as bone structure postulated that chimpanzees and gorillas were biologically nearest to each other and closely related to orangutans, while having an indirect relation to humans. Common chimpanzees and pygmy chimpanzees (bonobos) were classified in their own Genus, Pan, while humans were placed in a separate Genus, Homo. The great apes were separated from humans at the Family level and cast into the Pongidae category apart from the Hominidae group that included only bipeds such as Homo sapiens. The breakthroughs of genetic science, however, have suggested a dramatically different arrangement.
Linnaeus, Darwin, and others recognized that humans have significant physical and structural similarities with chimpanzees and gorillas, and on morphological grounds belong in the same general grouping. DNA analysis established just how close we are to the great apes, showing that humans and chimpanzees shared a common ape ancestor, and diverged from one another along different evolution paths some five to eight million years ago. Through genetic science, scientists have established that humans share 95-98 percent of their genes with cimpanzees, such that chimpanzees are biologically closer to us than they are to orangutans and gorillas.
Yet, despite recent scientific evidence demonstrating the evolutionary closeness of humans and apes – not only genetically, but also behaviorally and psychologically — conventional taxonomies haven’t significantly changed over the last two centuries. As noted by biologist Morris Goodman, “Historically, the philosophy behind how we group organisms was flawed. Starting with Aristotle in ancient Greece, species have been grouped according to their `degree of perfection,’ with man as the pinnacle.” This metaphysical and anthropocentric view led to the “exaggeration of the differences between humans and their relatives” rather than to a more “objective view of man’s place in the kingdom of life.” As a key battle in the science wars that are inseparable from ongoing culture wars over values and politics, many theorists have urged redrawing the taxonomical map in a way that accurately reflects our true genetic and anatomical relationships with apes. Other researchers, however, have strenuously resisted making these changes, whether in the textbooks, teaching plans, or established frames of thought.
In an important 2003 study, scientists at Wayne State University provided new genetic evidence that humans and chimpanzees diverged so recently that chimps should be reclassified as Homo troglodytes. This change would make them full-fledged members of our Genus, Homo, such that they would reside with Homo erectus, Homo habilis, Neanderthals, and other “proto”-human types. To be consistent with other mammalian genera/species classifications, the Wayne State researchers argue that we need “to revise our definition of the human branch of the tree of life.” Their proposal is to establish three species under the genus Homo: Homo (Homo) sapiens, or humans; Homo (Pan) troglodytes, or common chimpanzees; and Homo (Pan) paniscus, or bonobo chimpanzees. Uniting great apes and humans in one Family grouping of Hominidae creates new subfamilies of Ponginae and Homininae. Using their model, we can chart the differences between the traditional and revised taxonomical schemes this way:
Common Homo sapiens
chimpanzee (Pan troglodytes)
Bonobo (Pan paniscus)
Homo (Pan) troglodytes
Homo (Pan) paniscus
Homo (Homo) sapiens
In similar fashion, geographer Jared Diamond categorizes humans as the “third chimpanzee,” along with common chimpanzees and bonobos. Humans do not constitute a distinct Family, or even a singular Genus, but rather belong in the same Genus as common and pygmy chimps. If we think without our speciesist blinders, Diamond suggests, we can recognize that there are today three – not one — existing Homo species (with two in imminent danger of extinction because of the actions of the third). Richard Dawkins is refreshingly clear and frank on our species status and place in nature: “The word ‘apes’ usually means chimpanzees, gorillas, orangutans, gibbons and slamangs. We admit that we are like apes, but we seldom realise that we are apes. Our common ancestor with the chimpanzees and gorillas is much more recent than their common ancestor with the Asian apes — the gibbons and orangutans. There is no natural category that includes chimpanzees, gorillas and orangutans but excludes humans… In truth, not only are we apes, we are African apes. The category ‘African apes,’ if you don’t arbitrarily exclude humans, is a natural one.”
Of course, for human supremacists this is a bitter pill to swallow, and many scientists resist the new taxonomy. Whereas some detractors rely on the weak argument that reclassification would be “confusing” (the terms do indeed get complicated), others raise more substantive objections. Anthropologist Bernard Wood states: “The argument is whether genetic relatedness is the only thing you should take into account… A genus should also be a group of very similar species that share attributes such as behavior and [mode of movement].”
It seems clear that many factors should be taken into account for sound taxonomical construction, including those visible and invisible to the naked eye; the macrocosmic and microcosmic; and morphological, genetic, and cultural criteria – the latter factor becoming increasingly interesting and important with ever more studies of the moral life of chimpanzees. But however the debates get resolved, we should not conclude that all scientists who seek to preserve the taxonomic status quo are motivated by reasons of “science” alone; rather, they are viewing the world through speciesist biases that condition how they select “facts,” respond to studies, and view humans in relation to their biological relatives. A new taxonomy that brought humans and primates together into the same Family threatens species identities, and may also provoke emotional discomfort with reminders of our animalic past and the deep evolutionary roots of rationality. In addition, the new outlook certainly threatens those who earn their salaries by experimenting on animals, the great apes above all.
The stakes here are not merely semantic, but also deeply philosophical, social, and ethical. As paleontologist Lee Berger observes, “The classification debate is not just a debate for the purist; it cuts to the very core of our understanding of humans’ place in nature and our evolutionary relationships with our closest living relatives.” Christopher Soligo, of the Human Origins research group in London, England, notes that the recent studies contributing to “blurring the boundaries between our species” have “political implications” because they challenge the speciesist dogma at the heart of science and social organization.” Morris Goodman points to one important possible consequence: “The loss of the [wild] chimp and gorilla seems imminent. Moving chimps into the human genus might help us to realize our very great likeness, and therefore treasure more and treat humanely our closest relative.”
If chimpanzees belong with us in the same Genus, if they too are a Homo species, this should make the arbitrary justifications used to perform cruel experiments on them even more frayed than they already are, and efforts to protect and grant them legal rights as “persons” all the more urgent.