Volume 9, NO. 8 - November 1999
More in this Issue...

As the featured speaker at the twentieth annual Darwin festival at Salem State College in Salem, Massachusetts, Harvard professor Stephen Jay Gould is lecturing to a packed auditorium--not only professional biologists and students but also retirees and blue-collar workers. It is the birthday of both Abraham Lincoln and Charles Darwin (who happened to be born in the same year as well as on the same day), and Gould is talking about American history. Stocky and clean shaven, with a plump baby face and thick graying hair, he wears a tie in honor of the occasion but no jacket. He is unfolding bit by bit what he calls his Back to the Future theory of history, his belief that hundreds of chance occurrences got us where we are today. If Robert E. Lee's second in command hadn't misunderstood his orders, Gould suggests, the South might have won the Battle of Gettysburg, and then the war, and we might still be a divided country. He's building up to his central theme: that history is unpredictable and serendipitous, that human existence arose by chance, and that life, intelligent or otherwise, is devoid of any special significance in the larger scheme of things.

Toward the end of his rhythmic, free-form lecture, Gould pauses in mid-sentence. He has noticed that one person in the crowd of nearly a thousand is quietly leaving through a back exit. "Don't you want to hear the last ten minutes?" he cries out in obvious distress. "I don't mean to be arrogant about my status, but most of these folks you have all the time. Me you only got for a little while."

Such pugnacity is hardly surprising to Gould's numerous admirers and critics. For years, he has been an aggressive voice of reason in the argument against creationism and other varieties of pseudoscience. But Gould, who seems to thrive on controversy, is also entangled in a battle with a school of fierce anti-creationists called evolutionary psychologists, who believe that human nature is largely mapped out in our genes. Most recently, the Massachusetts Institute of Technology psychology professor Steven Pinker has been responsible for generating public interest in evolutionary psychology (EP). Not only does Pinker have a gift for the clear expression of complicated ideas, but, with his good looks and stylish clothes, he knows how to get media attention. His first book, The Language Instinct(1995), was an engaging discussion of the nature of language and its evolution. In 1997, Pinker's How the Mind Works appeared to great fanfare and quickly became a national best-seller.

The disagreement between Pinker and Gould is the latest variation on the old nature-versus-nurture debate that has been raging for centuries. The most recent skirmishes date back to the 1970s, when sociobiology, a new discipline dedicated to explaining social behavior in biological terms, was catapulted into the limelight. Gould became a leading early critic of sociobiology, penning eloquent disquisitions on the ability of humans--not their genes--to determine their own fate. But in the 1980s, molecular biologists began identifying more and more genes involved in human diseases and behavior. Sociobiology once again gripped the public imagination, but this time under the name of evolutionary psychology--sociobiology with a relentless focus on human psychology.

The argument between evolutionary psychologists and their critics centers on elemental mysteries of human nature. It is about the sort of tough questions that kids ask--Why are some people bad? Why do some breeds of dogs kill squirrels, and can they be taught not to?--as well as some more adult concerns: Are older men genetically programmed to abandon their longtime wives and take up with younger women? To what extent is intelligence, sexual preference, or the capacity to nurture mapped out in our genes? How deeply entrenched is the hatred and distrust of warring ethnic groups throughout the world?

There is a certain poetry in the fact that Gould's office is located in Harvard's venerable Museum of Comparative Zoology, founded in 1859 by Louis Agassiz, its first director and Harvard's last creationist. The walls of Gould's office bear the names of the animal classes, the letters visible in faded black paint dating from the days when the room was still an exhibition hall. The office itself is the size of a basketball court, filled with crowded bookshelves and tables piled high with the great diversity of the world Gould celebrates in his writing. This is the perfect Gould habitat, sprawling and packed with stuff.

A brilliant essayist and lecturer, Gould is the most popular science writer in America, which is remarkable because he engages serious ideas and draws from a rich store of knowledge of literature and history. In addition to half a dozen books, Gould has published nine collections of the essays he's been writing for Natural History over the last twenty-five years. He thinks of himself as a scientist in the tradition of Galileo, who was unusual in his time for writing in Italian, the language of the people, rather than Latin, which was then the norm for serious scientific discourse. He is still troubled by the fact that his friend the late astronomer Carl Sagan was denied entrance to the National Academy of Sciences. "Scientists will say, 'he was a popular writer but also a good scientist,'" Gould complains. "The but has to be changed to an and."

Gould himself has been the object of a fair amount of sniping over the quality of his science. His theory of punctuated equilibrium--the idea that sudden rapid changes in evolutionary history are followed by long periods of relative stability--has a limited following among his colleagues. Gould proposed his theory--sometimes called jerky evolution--as an alternative to the classical theory of slow, continuous evolution. A Gould antagonist, Richard Dawkins, the English evolutionary biologist responsible for the term "selfish gene," has been known to refer to the theory of punctuated evolution as "evolution by jerks." In his most recent book, Unweaving the Rainbow(1998), Dawkins characterizes Gould as a guy who's been "seduced by bad poetry."

Whereas Gould prefers to see human behavior as a complex and unpredictable interaction of culture, and a highly pliable set of genetic potentials, EPists have little patience with such a wishy-washy notion. They prefer to break down human psychology into a set of "complex adaptations," specific traits exquisitely suited to perform their functions, in the often repeated mantra. To EPists, it is a given that everything complicated and interesting about animals, and humans in particular--ranging from the way we find mates, to the working of the eye, to the ability to detect cheaters in social interactions--is the result of the long, slow, incremental process of Darwinian natural selection.

"You can't have a parent without an eye and an offspring with one," Pinker explains to me. "It's all gradual and Darwinian." We are sitting at the dining room table in his newly renovated condo a few blocks north of Harvard Square. The apartment, like Pinker's understated dark dress shirt and black jeans, is up-to-the-minute and impeccable. Every counter and surface is shiny and clear; there's not a stray magazine or envelope in sight. It's the kind of home that makes you suspect that there must be a back room where all the mess is stored.

The eye is the classic example of a complex adaptation. As Pinker explains it, an animal picks up a random mutation for a clearer lens, which makes it better able to avoid predators and find mates than animals with less clear lenses. This individual will give rise to offspring with better eyes, and over the course of generations, animals with clearer lenses will take over the population. At some point down the line, one of these animals may acquire another random mutation, this time for a rounder eyeball, which enables the eye better to focus images. In this way, mutation by mutation, over hundreds of generations, the multiple components of a complex function are acquired.

For Gould, it is Pinker's insistence on natural selection as the only valid scientific explanation for the origin of complex animal behaviors that is so galling. Although Gould acknowledges the importance of natural selection, he believes that the EPists have failed to appreciate other principles of evolutionary change such as random genetic drift, catastrophic events, and the constraints of basic laws of form. Furthermore, he contends, by identifying a genetic origin for many complex human behaviors, the EPists would have us believe that human behaviors are far more entrenched and immutable than they really are. Whereas Pinker argues that all of our complex mental functioning has been crafted over thousands of generations by natural selection to achieve a particular end, Gould believes that human attributes as basic as language may be accidental.

It was a British graduate student named Bill Hamilton who in the early 1960s had the insight that leads directly to Pinker's view of the human mind. Believing he'd forfeited his chance for a Ph.D. from London University by pursuing his heretical approach to the study of altruism, Hamilton sat for hours in train stations and public gardens to relieve the loneliness of his student rooms. While he sat, he mulled over a startling new idea, which he later named the theory of inclusive fitness.

Today, Hamilton is a tall, white-haired man of sixty-three, a Royal Society professor at Oxford widely considered the most influential evolutionary thinker since Darwin. "I had the feeling that I might be a crank," recalls Hamilton of his student days. He describes three experiences that influenced his thinking. As a schoolboy, he recognized that he felt a greater sense of obligation to his brothers and sister than to his school friends. Also, his mother kept bees, and he'd seen how the sister worker bees often sacrificed their lives for the good of the colony. Lastly, he had been deeply dissatisfied with the lectures on evolution he received as an undergraduate at Cambridge University, where it seemed to him that his professors did not give Darwin's mechanism of natural selection its proper due.

Hamilton realized he could explain the puzzling phenomenon of sister bees sacrificing themselves for the good of the hive by shifting the perspective from the survival of an animal's offspring to the dissemination of its genes. Thanks to a peculiar system of sex assignment, a female bee shares more genes with her sisters than with her direct descendants. If the goal is to make the greatest number of copies of her genes, a female bee is better off helping her mother make more sisters than she is producing her own offspring. In 1964, Hamilton pointed this out in a seminal two-part paper titled "The Genetical Evolution of Social Behavior." More generally, his gene's-eye point of view made it clear that the traditional Darwinian concern with an organism's investment in its children was too limited. Post-Hamilton, sacrifice for siblings and more distant relatives as well as one's own children made sense. In 1976, Dawkins popularized this idea in an enormously influential book, The Selfish Gene.

To the consternation of his critics, Gould believes that human attributes as basic as language may be accidental.

But if it hadn't been for the Harvard entomologist E.O. Wilson, Hamilton's theory would very likely never have come to Dawkins's attention. Wilson seized on the idea and prodded his reluctant peers to recognize its significance. At sixty-nine, Wilson still has the lean, angular build of a marathon runner. Though he has an almost courtly conversational style and retains the aura of a southern gentleman, he has a relentlessly driven, competitive nature that has resulted in an extraordinarily productive career. There are many folktales surrounding Wilson that illustrate one or another of the qualities that have made him successful, including the story of his reaction to Hamilton's 1964 paper. In one widely circulated version, Wilson is sent a copy of the paper to review, skims it, and, believing it to be the ravings of another manic graduate student, tosses it in the trash. Hours later, in the middle of the night, he realizes he's made a terrible mistake, bolts out of bed, and rushes back to the lab to retrieve the paper before the janitors empty the trash.

"That's a great story," Wilson laughs, "but it's not true." The truth, he insists, is that he read the paper on a long train ride from Boston to Miami (he's a reluctant flier). Hamilton's idea struck him as improbable and too simple, and it didn't seem to lend itself to broad applications. But when Wilson couldn't find a logical flaw in the paper, he grew angry. He, not Hamilton, was the world authority on social insects, and certainly no one else was going to explain the behavior of insect societies. Yet the more he thought about it, the more he became convinced that the theory was fundamentally correct. By the time he reached Miami, he was a convert. "I would never throw out an article like that," he explains. "At the very worst, I'd file it for future reference."

With Hamilton's ideas in mind, Wilson went on to formulate the basic tenets of sociobiology. In 1975, he published a beautifully illustrated overview of his theory titled Sociobiology: The New Synthesis. If he had confined himself to animals other than ourselves, as he'd originally intended, his life would have been more peaceful. But in a characteristically ambitious finale, he tacked on a chapter extending his theory to humans. Our species is genetically programmed to be warlike and territorial, he wrote, and males will typically dominate females in human social hierarchies. He hypothesized the existence of genes for spitefulness and homosexuality, genes for conformity that make humans easy to indoctrinate, and genes that make us favor kin and be wary of strangers. In a section on hunter-gatherer societies, Wilson cataloged the behavior patterns of various members. He found that, just as in ant colonies, different members of the groups played different roles. There were individuals of higher status, leaders and outstanding specialists, for example, who generally established themselves by their mid-thirties. These elites, he wrote, do more than their share of work and dominate the group's sluggish, unproductive members.

Inside the academic anthill, there was no doubt as to which kind of ant Wilson was. Already, as a graduate student, he'd sensed he had a special destiny, as another Wilson tale suggests: He and a fellow graduate student are driving back to Harvard after attending a meeting at which all the greatest minds in evolutionary biology had gathered. Wilson's friend is awestruck at having been in the presence of such greatness. After driving along in silence for a while, Wilson turns to him and says, "It shouldn't be very hard to get to the top of that heap."

In Cambridge, the reaction to Wilson's book was intensely negative. Fifteen local scientists, including Gould and Richard Lewontin, a universally admired population geneticist, formed the Sociobiology Study Group. Together, Lewontin, who had been brought up by a French nanny on Manhattan's Upper East Side, and Gould, the Queens-born son of a Marxist court stenographer, led the opposition. With his ease with mathematics and a powerful analytic mind, Lewontin brought rigor and salience to the critique of sociobiology. For months, the small group of allies plotted against sociobiology in Lewontin's office. At his own desk one floor above, Wilson had no idea what was brewing just below his feet. In November 1975, the Sociobiology Study Group published a letter in The New York Review of Books(NYRB).

The letter, signed by all fifteen members of the study group, stated its objections in no uncertain terms. Sociobiology, it asserted, is part of a tradition of biological determinism that has "provided an important basis for the enactment of sterilization laws and restrictive immigration laws by the United States...and also for the eugenics policies which led to the establishment of gas chambers in Nazi Germany." The invocation of Nazism was clearly intended to cause alarm. Less widely appreciated, however, was that there had been a pseudoscientific crusade in the early part of this century to improve the American gene pool. Laws passed in more than thirty states led to the sterilization of tens of thousands of people judged mentally feeble or morally inferior, and immigration from nations deemed of inferior genetic stock was restricted. Gould and Lewontin's letter sounded a warning bell: Supposedly objective science had been used--and could be again--to justify dubious politics and prejudices.

Wilson was not one to take the Sociobiology Study Group attack lying down. After licking his wounds for several weeks, he began a counteroffensive. Since both Lewontin and Gould were widely known for their radical politics, he devoted himself to the study of Marxist economic theory so as better to understand the "enemy in the field." In December 1975, his rebuttal appeared as a letter in the NYRB. In it, he accused the authors of intentionally distorting his meanings in order to make a case against him. In March of the following year, Wilson wrote a more detailed reply to his detractors in BioScience, a professional journal. In that article, he refers to a statement by a Harvard professor characterizing Wilson as a "privileged member of Western industrial society whose book attempts to preserve the status quo." Wilson points out that, as a Harvard professor, the author of the statement enjoyed identical privileges.

Today, Wilson recalls those days with a wry chuckle. "Gould and Lewontin going on in Marxist tones--we're talking about a bygone era, in an intellectual as well as a political sense. Sometimes we wondered, 'Who did Lewontin think he was, writing those letters from his Vermont dacha?'" The Vermont dacha is a reference to Lewontin's cabin in southern Vermont, where he has long spent as much time as possible, talking crops and weather with local farmers and acting the part of crusty old New England codger.

In 1978, Wilson was a featured speaker at the symposium on sociobiology held by the American Association for the Advancement of Science (AAAS) in Washington, D.C. Gould was scheduled to speak at the same session. Wilson, who had fractured his ankle jogging, had decided to deliver his speech from his seat onstage rather than make his way to the lectern. A few minutes after he had begun to talk, a group of protesters from the International Committee Against Racism (INCAR) stormed the stage. One dumped a pitcher of water over his head while the others chanted, "Wilson, you're all wet!" A few minutes later, the protesters withdrew, and the audience broke out in a spontaneous standing ovation for the injured, dripping Wilson. Gould took the microphone and quoted Lenin on the inappropriate use of violence. Later he explained that the attack on Wilson had been an "infantile disorder" of socialism.

Did Gould and Lewontin's attacks push Wilson further down the path toward human sociobiology? "Their attacks and other criticisms coming particularly from the New Left saying that this was bad science, and that I was racist and capitalist, were one of the major stimuli for me to move ahead," Wilson says. "Otherwise I might have delayed a considerable period of time before I wrote a book aimed at a broad audience." In 1978, he brought out On Human Nature, a broad defense of sociobiological theory. "Not just to answer them," he says, "but perhaps in part to respond to what I considered scurrilous and unfounded criticism." A few years later, Wilson began to move in new directions, becoming a tireless and influential crusader for the cause of biodiversity, the movement devoted to the preservation of the diversity of animal and plant species.

The tension was nearly unbearable as the elevator inched its way to the third floor. As the doors opened, Lewontin turned to Wilson and said, "I'm glad that you're doing real science again."

An inconspicuous directory in the dim lobby of the Museum of Comparative Zoology Laboratories informs you that Lewontin's office is on the third floor and Wilson's is on the fourth. It's a long, slow elevator ride up. A veteran of the sociobiology wars recalls unwittingly stepping into the elevator with Wilson and Lewontin in the late 1970s, shortly after Wilson had published a new monograph on ants. The tension was nearly unbearable as the elevator inched its way to the third floor. No one uttered a word. As the doors opened and Lewontin got out, he turned to Wilson and said, "I'm glad that you're doing real science again."

A central hall with laboratories on either side leads from the elevator to the Lewontin lab common room. In it, there's a vast rectangular wooden table covered with old copies of the NYRB and scientific journals. Mounted to the wall, a magnificent moose head has watched over generations of students. A minute after the appointed hour, Lewontin appears and ushers me into his office. Lean and fit, with a round face and a full head of dark hair, one would never guess that he's seventy. Though he's one of Harvard's most eminent faculty members, there's no sign of his special status--no couches, Oriental rugs, honorary degrees, or art--not a luxury or frill of any kind.

Why is it, I ask, that he objects to the Wilson-Pinker view of major human behaviors as adaptations crafted by natural selection? "Instead of talking about adaptations," Lewontin replies, "we should say organisms do the things they can do: Fish gotta swim and birds gotta fly.

"We'd be better off flying," he continues, though he, like Wilson, is afraid of flying in airplanes. "It would increase our fitness, we'd be better able to flee from predators. But if we flap our arms, we don't get any lift." He stands up and starts flapping his arms to illustrate. "Even if I picked up a pair of Ping-Pong paddles, it wouldn't help." He's walking around the room now, madly flapping his arms and still not getting any lift. "Until you're doing something, you're not doing it," Lewontin says by way of summary, "and natural selection can't help. What natural selection does is to make more efficient what the organism is already doing."

Lewontin's argument is that natural selection alone can't explain the origin of flight or of any complicated new function. Unless a little bit of change gives an animal a little bit of an advantage, the change won't be selected for, and obviously a little bit of a wing doesn't do any good. Darwin was well aware of the problem and devoted considerable thought to it. "An organ originally constructed for one purpose...may be converted to one for a wholly different purpose," he wrote in The Origin of Species(1859). This principle of functional shift makes it impossible to presume that any complex adaptation was crafted by natural selection, argue Gould and Lewontin. In particular, it doesn't make sense to say that a specific human behavior was selected for its current function when its original function may have been entirely different. Gould later proposed the term "exaptation" (to be distinguished from "adaptation") for features arising along these circuitous pathways. This is the first line of defense against Wilson-Pinker sociobiological thinking.

But Gould and Lewontin went further. In 1979, they wrote a paper for a British conference on adaptation and natural selection titled "The Spandrels of San Marco," in which they argued that many aspects of the design of animals are purely accidental. The paper has acquired legendary status. There even exists a collection of essays using the techniques of postmodern literary criticism to analyze the spandrels paper as scientific rhetoric.

Gould and Lewontin cleverly chose an example from the history of architecture to illustrate their point. Spandrels are unintended by-products of an architectural design. At the medieval cathedral of San Marco in Venice, the spandrels are four triangular spaces inadvertently created when the church's dome was mounted on four rounded arches. In the case of the cathedral, Lewontin and Gould argued, it would be easy to infer that the lavishly decorated spandrel is the heart of the architect's design. By analogy, "adaptationists," as Lewontin and Gould dub sociobiologically inclined biologists, mistake a by-product of an adaptation for a genuine adaptation. The origin of a complex adaptation is impossible to know, and any such attempt to invent hypotheses is, according to Lewontin and Gould, unscientific speculation. Critics of sociobiology label these hypothetical scenarios "Just So Stories," after Rudyard Kipling's children's book in which fanciful explanations are offered for adaptations such as the elephant's trunk.

Lewontin added another important piece to the case in his 1984 book, Not In Our Genes. Even if it were possible to understand an individual in terms of his genes and environment, he argued, we still would not understand group behavior. The whole could not, even in principle, be reduced to the sum of its parts.

For a period in the early 1980s, it seemed Gould and Lewontin's views had gained the upper hand. But it was precisely at this time that the revolution in molecular biology spun into high gear. With the development of new techniques for the sequencing and manipulation of DNA, it became easier and easier to identify and clone genes. Suddenly genes were being identified for just about everything. In Drosophila melanogaster, the common fruit fly and beloved laboratory organism of generations of geneticists, genes were found that affected sexual behavior, the pace of the internal clock, learning, and memory. Not only that, but many virtually identical genes were found in humans, whose evolutionary line diverged from insects more than half a billion years ago. Simultaneously, molecular biologists started identifying the genes that play roles in human disorders, such as Alzheimer's, Huntington's, and Parkinson's diseases. As the decade progressed, the flood of DNA information led to the formation of a generously funded human genome project to sequence the entire three billion base pairs of human chromosomal DNA.

Now Gould and Lewontin were on the defensive. They had always argued that it was bad science to break up an animal into individual traits or behaviors in order to claim that they are determined by particular, selectable genes. In the early days, the Sociobiology Study Group had criticized the idea that there were genes for specific and variable forms of human behavior, including spite, aggression, xenophobia, conformity, and homosexuality. Later, Gould expanded the argument to include even body parts. "Hundreds of genes contribute to the building of most body parts and their action is channeled through a kaleidoscopic series of environmental influences," he wrote in a Natural History essay.

Yet by the early 1990s, gene-based explanations for human behavior were on the rise. The stage was set for the reemergence of sociobiology under the new name of evolutionary psychology. In 1992, the husband-wife psychologist-anthropologist team of Leda Cosmides and John Tooby laid down the manifesto for the new discipline of EP in their introduction to an edited volume of original papers titled The Adapted Mind. EP was essentially an extension of Wilson's program applied exclusively to humans, with a few amendments to quell the leftist critique. Proponents of EP are quick to emphasize that human nature was crafted by natural selection to solve the problems of life on the African savanna 1.8 million years ago and that traits that may have been advantageous then, like xenophobia and aggression, may not confer a selective advantage in the modern world. Hoping to avoid the criticisms that were leveled against the first sociobiologists, the new generation insists it is most interested in understanding the evolution of universal features of the human species, not in the particular genes that make one person different from another, such as genes for IQ or homosexuality.

In 1997, an especially acrimonious debate over EP broke out when Gould took on the new school of sociobiologists in a long two-part article in the NYRB. Describing his foes as "Darwinian fundamentalists," he addressed himself to what he saw as the essential weakness of the adaptationist approach: "The human brain must be bursting with spandrels that are essential to human nature and vital to our self-understanding but that arose as nonadaptations, and are therefore outside the compass of evolutionary psychology, or any other ultra-Darwinian theory."

No wallflower when it comes to protecting his turf, Steven Pinker leaped to defend his science. "The ideas of EP are not as stupid as Gould makes them out to be," he wrote in a letter to the NYRB published later that year. "Indeed, they are nothing like what Gould makes them out to be." It doesn't matter, Pinker argued, whether a complex adaptation originated as an exaptation or a spandrel; if it later serves a useful function for the organism, it must have been acted on by natural selection to serve that function. "That there is a particular school of adaptationism is a rhetorical device," Pinker told me. "The school is just about everybody," he asserted, referring to the legions of scientists who study animal behavior using the sociobiological paradigm. "Gould and Lewontin have influence over social scientists and literary types who read The New York Review of Books and Natural History; they didn't like the direction sociobiology was going. Marxists don't want there to be an innate human nature, particularly not one that smacks of selfishness, greed, and aggression. They always say that a person's science can't be divorced from his politics, but they never apply this argument to themselves."

In the case of Lewontin, at any rate, this charge is often made. "There's almost no scientific subject on which he's positive," says Bill Hamilton. "I can't understand how such a good mind can be so negative about science per se. The politics always comes first. He doesn't admit it, but that's the case." Writing in his autobiography, Naturalist(1994), Wilson says that Lewontin "was stage-cast for the role of contrarian. He possessed a deep ambivalence that kept both friend and foe off balance." Before publication, Wilson sent Lewontin a copy of the manuscript asking for his comments. After a long period of silence, Wilson had his assistant hunt Lewontin down. A few days later, the manuscript was returned unopened with a letter attached to it. "Dear Ed," Lewontin wrote, "Given that our disagreements are so fundamental and broad and given the wide-spread misapprehension that they are personal rather than scientific, you can always say with complete honesty that you gave me the opportunity to comment on your manuscript and I declined. Autobiography is not a genre I am tempted either to read or to write. In order to get through life we all create elaborate fictions about ourselves, but I have always felt that these were better left to the hours between waking and sleeping."

"It's only an illusion that there's a president in the oval office of the brain who oversees the activity of everything," says Pinker.

Gould, who has always been somewhat more interested than Lewontin in finding common ground with his opponents, has recently shown some openness to EP ideas about the differences between the sexual attitudes of males and females. In the EP view, males are likely to be promiscuous because it is advantageous to spread their sperm far and wide. Females, on the other hand, are programmed to be more selective: Their eggs are more precious than male sperm, and they are strapped into months of gestation and suckling after conception. In his NYRB attack on EP, Gould goes so far as to call this line of reasoning the "most promising" EP has to offer, and he admits that it "probably does underlie some different and broadly general emotional propensities of human males and females." However, he cautions the EPists against pushing this theory too far and suffering the fate of Freudians, who "elevated a limited guide into a rigid creed that became more of an untestable and unchangeable religion than a science."

Lewontin, who married his high school sweetheart and can to this day be seen walking hand in hand across Harvard Yard with her, takes a much harder line. "I'm a man, and I don't go around screwing young girls," he says. "I'm human, and so I have to be explained."

One can almost see Lewontin hiking through the Vermont woods shaking his head in despair at the loss of Comrade Gould. There had been no more articulate spokesman in the battle against bourgeois decadence.

Meanwhile, Pinker, busy promoting his latest book, Words and Rules: The Ingredients of Language(Norton), marches forward. In a recent appearance in London, Pinker and Dawkins held a public forum titled "Is Science Killing the Soul?" which was attended by 2300 people and sold out weeks in advance. Pinker spoke of the fiction of the unified self. "It's only an illusion that there's a president in the Oval Office of the brain who oversees the activity of everything," he said, in what undoubtedly struck many as a particularly apt metaphor.

The notion that there is no unified self is fundamental to EP. If the brain is a collection of computers, each one of which performs a highly specialized function, then it makes sense to invoke natural selection acting over millions of years to account for the existence of those computers.

This view of the mind broken up into an array of independently evolved modules is disquieting to many. As the Rutgers philosopher Jerry Fodor, the author of a forthcoming book titled The Mind Doesn't Work That Way(MIT), puts it, "If there is a community of computers in my head, there had also better be somebody who is in charge, and, by God, it had better be me." If one does not believe that human intelligence is the sum of an array of computers, then one must postulate the existence of some more general cognitive ability that gives us the capacity for complex thought. And this general ability, Fodor believes, may be the result of a small but crucial evolutionary shift that distinguished our brains from the brains of other primates.

Like Fodor, Lewontin and Gould argue that the EPists have it wrong: Language, consciousness, and most of our distinctively human mental capacities are side effects of the fact that our brain grew big for other reasons. Furthermore, they caution, these reasons cannot be reconstructed. Our extraordinary human abilities are epiphenomena of "all those loose connections with nothing to do," explains Lewontin. As an example of a nonadaptive trait, he offers the uniquely human ability to use recursion in language, that is, to make sentences of the form: "I say that Noam Chomsky says, when people say..." Though chimps can be taught to compose simple sentences of the form "I want" or "I see" on a computer, they cannot be taught to use recursion.

Does Lewontin have a theory about the origin of this unique linguistic ability of humans? "You could invent a story," he explains with distaste. "You could say it was an advantage to early human beings in being able to say, 'I saw Joe doing that,' but that's just yak!"

Pinker insists that our ability to use language has evolved because language offered a selective advantage. "Being articulate is highly valued in all cultures," he says. "Tribal chiefs are high in verbal skills and have more offspring."

It is symbolically fitting that Gould and Lewontin were teaching their undergraduate course on evolution for the last time this spring while a few hundred yards down the road Pinker and a recently tenured Harvard animal behaviorist named Mark Hauser were giving a popular graduate seminar on evolutionary psychology.

"If there is a community of computers in my head, there had also better be somebody who is in charge, and, by God, it had better be me," says Fodor.

The point of Pinker and Hauser's course is to trace the origins of human thought. There is no doubt that we can learn a lot about human language from studying apes and birds, Hauser told me after the seminar one afternoon. The way birds learn their songs is strikingly similar to the way humans learn language.

In his characteristically acerbic way, Lewontin dismisses this idea. It is simply impossible to say how novel abilities like human language arose. He jibes: "One way to get around the problem that language is a novelty is to define it in such a way that doesn't make it a novelty. You'll say bird twitter is language." In a 1998 article titled "The Evolution of Cognition: Questions We Will Never Answer," Lewontin wrote, "It might be interesting to know how cognition (whatever that is) arose and spread and changed, but we cannot know. Tough luck." This spring, Lewontin will publish a collection of his essays with the appropriately contrarian title It Ain't Necessarily So.

Even if God were to descend on Cambridge and part the waters of the Charles River at Lewontin's feet, it would still be unthinkable to imagine the skeptical biologist embracing religion. Gould, on the other hand, has recently been evincing a new sympathy for the realm of the unscientific. In his most recent book, Rocks of Ages: Science and Religion in the Fullness of Life(1999), he not only sets out terms for a peaceful coexistence with the obdurate religious believers among us but seems to offer another defense against the sociobiological threat. His thesis is that it makes perfect sense to see science and religion as distinct and complementary forms of human endeavor: Science addresses the "factual character of the natural world"; religion is concerned with spiritual meaning and morality.

This dualism stands in stark contrast to the views of Wilson, Dawkins, and Pinker, who categorically deny the existence of a soul or spirit. Indeed, from the outset, it was Wilson's goal to deny the existence of an independent moral realm. In On Human Nature, he says, "Human behavior...is the circuitous technique by which human genetic material has and will be kept intact. Morality has no other demonstrable ultimate function." Consilience(1998), Wilson's latest and most ambitious statement to date, takes an even more radical position, arguing that "there is intrinsically only one class of explanation." He goes on to make the bold assertion that "all tangible phenomena, from the birth of stars to the workings of social institutions, are based on material processes that are ultimately reducible, however long and tortuous the sequences, to the laws of physics."

Gould insists that it is not possible to reduce ethics to sociobiology or to unify knowledge by subsuming one theory in another. Even if human traits like xenophobia and aggression, for example, were in the end shown to be the result of adaptations in the Pleistocene era, Gould contends, science alone will not suffice as an explanatory system. The man who largely made his name insisting on the purposelessness of life has found a place in his heart for religion. But that's not to say Gould has turned into any kind of crypto-creationist. No matter who turns out to be right in the end, he and his adaptationist foes can at least agree with Darwin that "whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."

James Schwartz is a writer who lives in Brookline, Massachusetts.