A final thought
The tendency has always been strong to believe that whatever received a name must be an entity or being, having an independent existence of its own. And if no real entity answering to the name could be found, men did not for that reason suppose that none existed, but imagined that it was something peculiarly abstruse and mysterious.
JOHN STUART MILL
SEVEN
A Positive Conclusion
WALT WHITMAN, that great man of little brain (see p.124), advised us to “make much of negatives,” and this book has heeded his words, some might say with a vengeance. While most of us can appreciate a cleansing broom, such an object rarely elicits much affection; it certainly produces no integration. But I do not regard this book as a negative exercise in debunking, offering nothing in return once the errors of biological determinism are exposed as social prejudice. I believe that we have much to learn about ourselves from the undeniable fact that we are evolved animals. This understanding cannot permeate through entrenched habits of thought that lead us to reify and rank—habits that arise within social contexts and support them in return. My message, as I hope to convey it at least, is strongly positive for three major reasons.
Debunking as positive science
The popular impression that disproof represents a negative side of science arises from a common, but erroneous, view of history. The idea of unilinear progress not only lies behind the racial rankings that I have criticized as social prejudice throughout this book; it also suggests a false concept of how science develops. In this view, any science begins in the nothingness of ignorance and moves toward truth by gathering more and more information, constructing theories as facts accumulate. In such a world, debunking would be primarily negative, for it would only shuck some rotten apples from the barrel of accumulating knowledge. But the barrel of theory is always full; sciences work with elaborated contexts for explaining facts from the very outset. Creationist biology was dead wrong about the origin of species, but Cuvier’s brand of creationism was not an emptier or less-developed world view than Darwin’s. Science advances primarily by replacement, not by addition. If the barrel is always full, then the rotten applies must be discarded before better ones can be added.
Scientists do not debunk only to cleanse and purge. They refute older ideas in the light of a different view about the nature of things.
Learning by debunking
If it is to have any enduring value, sound debunking must do more than replace one social prejudice with another. It must use more adequate biology to drive out fallacious ideas. (Social prejudices themselves may be refractory, but particular biological supports for them can be dislodged.)
We have rejected many specific theories of biological determinism because our knowledge about human biology, evolution, and genetics has increased. For example, Morton’s egregious errors could not be repeated in so bald a way by modern scientists constrained to follow canons of statistical procedure. The antidote to Goddard’s claim that a single gene causes feeble-mindedness was not primarily a shift in social preferences, but an important advance in genetical theory—the idea of polygenic inheritance. Absurd as it seems today, the early Mendelians did try to attribute even the most subtle and complex traits (of apolitical anatomy as well as character) to the action of single genes. Polygenic inheritance affirms the participation of many genes—and a host of environmental and interactive effects—in such characters as human skin color.
More importantly, and as a plea for the necessity of biological knowledge, the remarkable lack of genetic differentiation among human groups—a major biological basis for debunking determinism—is a contingent fact of evolutionary history, not an a priori or necessary truth. The world might have been ordered differently. Suppose, for example, that one or several species of our ancestral genus Australopithecus had survived—a perfectly reasonable scenario in theory, since new species arise by splitting off from old ones (with ancestors usually surviving, at least for a time), not by the wholesale transformation of ancestors to descendants. We—that is, Homo sapiens—would then have faced all the moral dilemmas involved in treating a human species of distinctly inferior mental capacity. What would we have done with them—slavery? extirpation? coexistence? menial labor? reservations? zoos?
Similarly, our own species, Homo sapiens, might have included a set of subspecies (races) with meaningfully different genetic capacities. If our species were millions of years old (many are), and if its races had been geographically separated for most of this time without significant genetic interchange, then large genetic differences might have slowly accumulated between groups. But Homo sapiens is, at most, a few hundred thousand years old, and all modern human races probably split from a common ancestral stock only about a hundred thousand years ago. A few outstanding traits of external appearance lead to our subjective judgment of important differences. But biologists have recently affirmed—as long suspected—that the overall genetic differences among human races are astonishingly small. Although frequencies for different states of a gene differ among races, we have found no “race genes”—that is, states fixed in certain races and absent from all others. Lewontin (1972) studied variation in seventeen genes coding for differences in blood and found that only 6.3 percent of the variation can be attributed to racial membership. Fully 85.4 percent of the variation occurred within local populations (the remaining 8.3 percent records differences among local populations within a race). As Lewontin remarked (personal communication): if the holocaust comes and a small tribe deep in the New Guinea forests are the only survivors, almost all the genetic variation now expressed among the innumerable groups of our five billion people will be preserved.
This information about limited genetic differences among human groups is useful as well as interesting, often in the deepest sense—for saving lives. When American eugenicists attributed diseases of poverty to the inferior genetic construction of poor people, they could propose no systematic remedy other than sterilization. When Joseph Goldberger proved that pellagra was not a genetic disorder, but a result of vitamin deficiency among the poor, he could cure it.
Biology and human nature
If people are so similar genetically, and if previous claims for a direct biological mapping of human affairs have recorded cultural prejudice and not nature, then does biology come up empty as a guide in our search to know ourselves? Are we after all, at birth, the tabula rasa, or blank slate, imagined by some eighteenth-century empiricist philosophers? As an evolutionary biologist, I cannot adopt such a nihilistic position without denying the fundamental insight of my profession. The evolutionary unity of humans with all other organisms is the cardinal message of Darwin’s revolution for nature’s most arrogant species.
We are inextricably part of nature, but human uniqueness is not negated thereby. “Nothing but” an animal is as fallacious a statement as “created in God’s own image.” It is not mere hubris to argue that Homo sapiens is special in some sense—for each species is unique in its own way; shall we judge among the dance of the bees, the song of the humpback whale, and human intelligence?
The impact of human uniqueness upon the world has been enormous because it has established a new kind of evolution to support the transmission across generations of learned knowledge and behavior. Human uniqueness resides primarily in our brains. It is expressed in the culture built upon our intelligence and the power it gives us to manipulate the world. Human societies change by cultural evolution, not as a result of biological alteration. We have no evidence for biological change in brain size or structure since Homo sapiens appeared in the fossil record some fifty thousand years ago. (Broca was right in stating that the cranial capacity of Cro Magnon skulls was equal if not superior to ours.) All that we have done since then—the greatest transformation in the shortest time that our planet has experienced since its crust solidified nearly four billion years ago—is the product of cultural evolution. Biological (Darwinian) evolution continues in ou
r species, but its rate, compared with cultural evolution, is so incomparably slow that its impact upon the history of Homo sapiens has been small. While the gene for sickle-cell anemia declines in frequency among black Americans, we have invented the railroad, the automobile, radio and television, the atom bomb, the computer, the airplane and spaceship.
Cultural evolution can proceed so quickly because it operates, as biological evolution does not, in the “Lamarckian” mode—by the inheritance of acquired characters. Whatever one generation learns, it can pass to the next by writing, instruction, inculcation, ritual, tradition, and a host of methods that humans have developed to assure continuity in culture. Darwinian evolution, on the other hand, is an indirect process: genetic variation must first be available to construct an advantageous feature, and natural selection must then preserve it. Since genetic variation arises at random, not preferentially directed toward advantageous features, the Darwinian process works slowly. Cultural evolution is not only rapid; it is also readily reversible because its products are not coded in our genes.
The classical arguments of biological determinism fail because the features they invoke to make distinctions among groups are usually the products of cultural evolution. Determinists did seek evidence in anatomical traits built by biological, not cultural, evolution. But, in so doing, they tried to use anatomy for making inferences about capacities and behaviors that they linked to anatomy and we regard as engendered by culture. Cranial capacity per se held as little interest for Morton and Broca as variation in third-toe length; they cared only about the mental characteristics supposedly associated with differences in average brain size among groups. We now believe that different attitudes and styles of thought among human groups are usually the nongenetic products of cultural evolution. In short, the biological basis of human uniqueness leads us to reject biological determinism. Our large brain is the biological foundation of intelligence; intelligence is the ground of culture; and cultural transmission builds a new mode of evolution more effective than Darwinian processes in its limited realm—the “inheritance” and modification of learned behavior. As philosopher Stephen Toulmin stated (1977, p. 4): “Culture has the power to impose itself on nature from within.”
Yet, if human biology engenders culture, it is also true that culture, once developed, evolved with little or no reference to genetic variation among human groups. Does biology, then, play no other valid role in the analysis of human behavior? Is it only a foundation without any insight to offer beyond the unenlightening recognition that complex culture requires a certain level of intelligence?
Most biologists would follow my argument in denying a genetic basis for most behavioral differences between groups and for change in the complexity of human societies through the recent history of our species. But what about the supposed constancies of personality and behavior, the traits of mind that humans share in all cultures? What, in short, about a general “human nature”? Some biologists would grant Darwinian processes a substantial role not only in establishing long ago, but also in actively maintaining now, a set of specific adaptive behaviors forming a biologically conditioned “human nature.” I believe that this old tradition of argument—which has found its most recent expression as “human sociobiology”—is invalid not because biology is irrelevant and human behavior only reflects a disembodied culture, but because human biology suggests a different and less constraining role for genetics in the analysis of human nature.
Sociobiology begins with a modern reading of what natural selection is all about—differential reproductive success of individuals. According to the Darwinian imperative, individuals are selected to maximize the contribution of their own genes to future generations, and that is all. (Darwinism is not a theory of progress, increasing complexity, or evolved harmony for the good of species or ecosystems.) Paradoxically (as it seems to many), altruism as well as selfishness can be selected under this criterion—acts of kindness may benefit individuals either because they establish bonds of reciprocal obligation, or because they aid kin who carry copies of the altruist’s genes.
Human sociobiologists then survey our behaviors with this criterion in mind. When they identify a behavior that seems to be adaptive in helping an individual’s genes along, they develop a story for its origin by natural selection operating upon genetic variation influencing the specific act itself. (These stories are rarely backed by any evidence beyond the inference of adaptation.) Human sociobiology is a theory for the origin and maintenance of specific, adaptive behaviors by natural selection*; these behaviors must therefore have a genetic basis, since natural selection cannot operate in the absence of genetic variation. Sociobiologists have tried, for example, to identify an adaptive and genetic foundation for aggression, spite, xenophobia, conformity, homosexuality,* and perhaps upward mobility as well (Wilson, 1975).
I believe that modern biology provides a model standing between the despairing claim that biology has nothing to teach us about human behavior and the deterministic theory that specific items of behavior are genetically programed by the action of natural selection. I see two major areas for biological insight:
1. Fruitful analogies. Much of human behavior is surely adaptive; if it weren’t, we wouldn’t be around any more. But adaptation, in humans, is neither an adequate, nor even a good argument for genetic influence. For in humans, as I argued above (p. 324), adaptation may arise by the alternate route of nongenetic, cultural evolution. Since cultural evolution is so much more rapid than Darwinian evolution, its influence should prevail in the behavioral diversity displayed by human groups. But even when an adaptive behavior is nongenetic, biological analogy may be useful in interpreting its meaning. Adaptive constraints are often strong, and some functions may have to proceed in a certain way whether their underlying impetus be learning or genetic programing.
For example, ecologists have developed a powerful quantitative theory, called optimal foraging strategy, for studying patterns of exploitation in nature (herbivores by carnivores, plants by herbivores). Cornell University anthropologist Bruce Winterhalder has shown that a community of Cree-speaking peoples in northern Ontario follow some predictions of the theory in their hunting and trapping behavior. Although Winterhalder used a biological theory to understand some aspects of human hunting, he does not believe that the people he studied were genetically selected to hunt as ecological theory predicts they should. He writes (personal communication, July 1978):
It should go without saying … that the causes of human variability of hunting and gathering behavior lie in the socio-cultural realm. For that reason, the models that I used were adapted, not adopted, and then applied to a very circumscribed realm of analysis.… For instance, the models assist in analyzing what species a hunter will seek from those available once a decision has been made to go hunting [his italics]. They are, however, useless for analyzing why the Cree still hunt (they don’t need to), how they decide on a particular day whether to hunt or join a construction crew, the meaning of hunting to a Cree, or any of a plethora of important questions.
In this area, sociobiologists have often fallen into one of the most common errors of reasoning: discovering an analogy and inferring a genetic similarity (literally, in this case!). Analogies are useful but limited; they may reflect common constraints, but not common causes.
2. Biological potentiality vs. biological determinism. Humans are animals, and everything we do is constrained, in some sense, by our biology. Some constraints are so integral to our being that we rarely even recognize them, for we never imagine that life might proceed in another way. Consider our narrow range of average adult size and the consequences of living in the gravitational world of large organisms, not the world of surface forces inhabited by insects (Went, 1968; Gould, 1977). Or the fact that we are born helpless (many animals are not), that we mature slowly, that we must sleep for a large part of the day, that we do not photosynthesize, that we can digest both meat and plants, that we age and die. These are all
results of our genetic construction, and all are important influences upon human nature and society.
These biological boundaries are so evident that they have never engendered controversy. The contentious subjects are specific behaviors that distress us and that we struggle with difficulty to change (or enjoy and fear to abandon): aggression, xenophobia, male dominance, for example. Sociobiologists are not genetic determinists in the old eugenical sense of postulating single genes for such complex behaviors. All biologists know that there is no gene “for” aggression, any more than for your lower-left wisdom tooth. We all recognize that genetic influence can be spread diffusely among many genes and that genes set limits to ranges; they do not provide blueprints for exact replicas. In one sense, the debate between sociobiologists and their critics is an argument about the breadth of ranges. For sociobiologists, ranges are narrow enough to program a specific behavior as the predictable result of possessing certain genes. Critics argue that the ranges permitted by these genetic factors are wide enough to include all behaviors that sociobiologists atomize into distinct traits coded by separate genes.
But in another sense, my dispute with human sociobiology is not just a quantitative debate about the extent of ranges. It will not be settled amicably at some golden midpoint, with critics admitting more constraint, sociobiologists more slop. Advocates of narrow and broad ranges do not simply occupy different positions on a smooth continuum; they hold two qualitatively different theories about the biological nature of human behavior. If ranges are narrow, then genes do code for specific traits and natural selection can create and maintain individual items of behavior separately. If ranges are characteristically broad, then selection may set some deeply recessed generating rules; but specific behaviors are epiphenomena of the rules, not objects of Darwinian attention in their own right.
The Mismeasure of Man Page 38