humans and other animals

            I'll never
      Be such a gosling to obey instinct, but stand
      As if a man were author of himself
      And knew no other kin.

Corialanus' paean to human freedom would have been regarded, for most of the past 500 years, as unexceptional. It was taken for granted by most Western thinkers from the Renaissance onwards that human beings were exceptional creatures because of their possession of reason and consciousness, language and morality. Reason, as Descartes put it, 'is the noblest thing we can have because it makes us in a certain manner equal to God and exempts us from being his subjects'. This was the philosophy at the heart of both the scientific revolution and the Enlightenment.

Today, though, we no longer think in this way. The idea of humans as exceptional beings is seen as both scientifically false and politically dangerous. For most scientists, exceptionalism smacks of mysticism. Their Holy Grail is to understand humans in the same language as the rest of physical nature. And politically, there has developed an increasing tendency to see human hubris as the root of most of the ills of the world, from global warming to ethnic cleansing. 'We need protection from ourselves', the biologist Lynn Margulis has of the human species. This combination of scientific naturalism and political pessimism is helping transform our understanding of the human condition.

Historically, the question of what it is to be human - Who are we? Where did we come from? What defines our nature? - has been in the domain of poets and philosophers, theologians and novelists. In the Western tradition it was Aristotle and Aquinas, Dante and Descartes, Shakespeare and Schopenhauer to whom people turned for answers.

Then came the publication in 1859 of Charles Darwin's On The Origin of Species. Darwin's masterpiece transformed the debate not only by throwing new light on the relationship between humans and the rest of nature but also by holding out the hope that in understanding that relationship we might also begin to unravel the deepest mysteries of human existence. 'Origin of man now solved', Darwin wrote in his notebook in 1838. 'He who understands baboon will do more for metaphysics than Locke.'

Thirteen years after The Origin of the Species, Darwin published The Expressions of the Emotions in Man and the Animals, his most explicit attempt to demonstrate the animal roots of human nature. The emotional stuff of everyday life - love, joy, anger, sulkiness, guilt, disgust, horror, modesty - was, Darwin suggested, common both across all humans and between humans and other animals. This was a challenge both to the Creationist idea that emotions were specifically given to humans by God and to the racist view that every race had evolved separately. Darwin's argument that human emotions are universal, evolved and derived from those of animals was (and remains) deeply contentious.

The book was a sensational bestseller. Nine thousand copies sold within four months - an extraordinary figure for the time. (The Origin of Species had an initial print run of just 1250.) Yet after its second edition in 1889, the book remained largely forgotten for more than a century. Indeed, until a new edition appeared in 1998 to great acclaim, few would have even known that Darwin had written such a work.

Why did The Expressions of the Emotions collect dust for much of the twentieth century? Largely because in the decades that followed its publication, evolutionary theory was used to demonstrate, not the unity of humankind, but rather the idea that the struggle for existence had created unequal races, and that capitalist exploitation, colonial conquest and even genocide were simply the working out of the laws of natural selection.

As the racist consequences of social Darwinism became apparent, so psychologists and anthropologists increasingly shied away from any biological explanation of human behaviour. In the wake of Nazism and the Holocaust, the idea that human behaviour was entirely a cultural artefact came to dominate postwar thinking. The very idea of human nature became taboo. 'We knew how politically loaded discussions of inborn differences could become', the anthropologist Margaret Mead, one of the leading cultural anthropologists of the twentieth century, recalled in her autobiography Blackberry Winter. 'It seemed to us that further study of inborn similarities would have to wait upon less troubled times.'

The republication of The Expressions of the Emotions in 1998 reflected, however, another shift in perceptions of human nature. By the end of the twentieth century sociological explanations of human behaviour had increasingly fallen into disrepute, while evolutionary explanations had once more become fashionable. Not only are 'claims about human nature less dangerous than many people think', Steven Pinker argued in The Blank Slate, his full-frontal assault on cultural relativism, but 'the denial of human nature can be more dangerous than people think'.

It was in the 1970s that the debate about human nature was reignited by two books, neither which of which was, paradoxically, primarily about humans, but both of which have been hugely influential in shaping the debate about the nature of being human and both of which remain almost as controversial now as they were then: EO Wilson's Sociobiology (1975) and Richard Dawkins' The Selfish Gene (1976), two books whose very titles have helped sculpt the contemporary language of human nature.

'Skill in wielding metaphors and symbols', Richard Dawkins has written 'is one of the hallmarks of scientific genius'. Whether Dawkins himself qualifies as a scientific genius only history will record. But there have been few scientists - indeed, few writers in any genre - more skilled at metaphor-wielding. And there have been few more evocative metaphors in the modern age than that of 'the selfish gene', nor a scientific book with a greater impact on public consciousness than Dawkins' 1976 work that introduced both the phrase and the author to a startled non-scientific audience.

The Selfish Gene crystalised the 'gene-eyed view' of evolution developed through the 1960s and 1970s by a new generation of evolutionary thinkers, in particular William Hamilton and John Maynard Smith in England and the Americans George Williams and Robert Trivers. Evolution, Dawkins claimed, cares solely about the gene, not the individual. Individuals die at the end of their lifetimes, but a gene is potentially immortal. Genes are 'selfish' because their only function is to survive at the expense of their rivals. The body is simply a 'survival machine' built by genes to enable them to survive.

The publication of The Selfish Gene helped launch the so-called 'Darwin wars'. Critics such as Stephen Jay Gould and Richard Lewontin savaged what they called Dawkins' 'ultra-Darwinism', the belief that 'natural selection regulates everything of importance in evolution'. Much of Gould's criticism wer layed out in the columns he wrote for the magazine Natural History, many of which were collected in a series of books beginning with Ever Since Darwin.

Dawkins bit back and in a number of books - The Extended Phonotype, Climbing Mount Improbable, The Blind Watchmaker and River Out of Eden - refined and expanded his argument, challening both Creationists and his Darwinian critics. The fiercest defence of 'ultra-Darwinism' came not from Dawkins but from the philosopher Daniel Dennett whose 1995 book Darwin's Dangerous Idea, describes Darwinism as a 'universal acid' that eats through just about every traditional view and leaves in its wake a revolutionised world view.

The Selfish Gene, however, was not just a book about Darwinian theory but also, as the writer Andrew Brown puts it in The Darwin Wars, 'a book about genes read as a book about people'. The very idea of the selfish gene shocked many critics, seemingly attributing agency to genes and denying it to humans - though this is to be so dazzled by Dawkins' metaphoric skills as to miss his actual beliefs.

The controversy was fuelled by the fact that The Selfish Gene was published barely a year after the storm had broken over EO Wilson's Sociobiology. Wilson, a Harvard entomologist and world expert on ants, set out to synthesise all the known knowledge about social animals - from corals and jellyfish to ants and bees to birds and primates. But in the book's first and last chapters he also tried to show that the same principles of behaviour also applied to humans. 'Behaviour and social structure', Wilson believed, 'like all biological phenomena, can be studied as "organs", extensions of the genes that exist because of their superior adaptive value'.

Gould and Lewontin (Wilson's colleagues at Harvard) accused him of giving vent to theories that 'led to the establishment of gas chambers in Nazi chambers'. In her book Beast and Man, an attempt to restore biology to discussions of human nature, the philosopher Mary Midgely nevertheless denounced sociobiology as 'biological Thatcherism, romantic and egotistic, celebrating evolution as a ceaseless crescendo of competition between essentially "selfish" individual organisms'. In Not in our Genes, a book that Lewontin co-wrote with British biologist Stephen Rose and American psychologist Leon Kamin, Wilson is painted as a 'neoconservative libertarian' and sociobiology as 'yet another attempt to put a natural scientific foundation under Adam Smith'.

Once the hysteria of the initial response had died down the argument about the nature of sociobiology transmuted into the nature-nurture debate: is nature or nurture more important in shaping human psychology, behaviour and society? The debate generated considerable heat and invective, but beneath the caricatures thrown up by both sides there existed a surprising amount of commonality. 'No serious student of human behaviour has denied the potent effect of evolved biology on our cultural lives', Stephen Jay Gould wrote in An Urchin in the Storm. 'Our struggle is to figure out how biology affects us not whether it does.' The philosopher Janet Radcliffe Richards, a prominent supporter of evolutionary psychology, agreed. 'The disagreement between evolutionary psychologists and standard social science theorists', she wrote in Human Nature After Darwin, 'is not about whether the environment influences what we are but only about the extent to which an understanding of evolutionary origins can help show how and to what extent this happens.'

Meanwhile, sociobiology itself transmuted into evolutionary psychology, partly at least to avoid the political opprobrium attached to the label 'sociobiology'. In 1992 three academics, Leda Cosmides, John Tooby and Jerome Barkow edited a collection of papers under the title The Adapted Mind, which has come to be seen as a seminal work in laying the foundations of the new science of human nature.

Like Darwin in The Expressions of the Emotions, evolutionary psychologists sought both to ground human psychology in animal nature and to demonstrate the universality of human behaviours. The fieldwork of animal behaviourists has, in recent years, revealed the enormous complexity of the social life of animals, especially primates. Frans de Waal's fascinating study of chimpanzees at Arnhem zoo, for instance, popularised in books such as Good Natured and Chimpanzee Politics, often read like a cross between Dynasty and King Lear, an invitation into a world of generous friendships, treacherous alliances and bitter power struggles. The subtitles of his books - The Origins of Right and Wrong in Humans and Other Animals and Power and Sex Among Apes - tell their own story. For de Waal the lives of Great Apes open a window into the roots of human politics and morality. A stream of books by other primatologists - Andrew Whiten and Richard Byrne's Machiavellian Intelligence, David Premack's The Mind of an Ape, Richard Wrangham's Demonic Males, Robert Sapolsky's A Primate's Memoir, Marian Stamp Dawkins' Through Our Eyes Only? - have all tried to use the lives of primates to shine a light on the human condition.

If the study of animal lives has provided one source of data for the new science of human nature, another has come from the study of human lives across cultural divides. Even though human beings are 'morally free to make and remake themselves infinitely', Matt Ridley wrote in The Red Queen, 'we do not do so. We stick to the same monotonously human pattern of organising our affairs. If we were more adventurous, there would be societies without love, without ambition, without sexual desire, without marriage, without art, without grammar, without smiles.' There are not because all these are evolved traits, and hence common to all humans. Discover universal traits, the argument runs, and you are likely to have discovered evolved characteristics.

Darwin himself had enlisted the help of dozens of missionaries and colonial officers in writing The Expression of the Emotions, asking them to describe the way non-Europeans expressed certain emotions, to demonstrate that 'all the chief expressions exhibited by man are the same throughout the world'. In the 1960s, Paul Ekman updated Darwin's work by showing photographs of different facial expressions to people in 21 different cultures. Overwhelmingly Ekman's subjects, irrespective of culture, attributed the same emotions to each expression. Ekaman's studies, detailed in a series of books including The Face of Man and Emotions Revealed, have become classics in the field. More recently Marc Hauser has posed fiendish moral conundrums to people across different cultures. In his book Moral Minds Hauser argues that not only has 'nature designed a universal sense of wrong and right', but that humans are universally sensitive to the Kantian imperative that one should not treat people solely as means, but primarily as ends.

In the wake of 9/11 religion has become a key theme in the new science of human nature. The universality and persistence of religion has led many - such as Sam Harris in The End of Faith, Daniel Dennett in Breaking the Spell and Richard Dawkins in The God Delusion - to see it as an evolutionary hangover which has become maladpative. All three books draw heavily on the work of anthropologist Scott Atran who in his book In Gods We Trust explores humans in all cultures possess an evolved desire for supernatural explanations.

But the universal trait that lies at the heart of evolutionary psychology is the universality of the sex differences. As David Buss suggests in The Evolution of Desire: The Strategies of Human Mating, men and women can be viewed almost as distinct species. Men and women have different evolutionary strategies and therefore different evolved traits. 'Women's minds evolved to suit the demands of bearing and rearing children and of gathering plant food', Matt Ridley wrote in The Red Queen. 'Men's minds evolved to suit the demands of rising in a male hierarchy, fighting over women and providing meat for a family'. Men tend to be promiscuous, aggressive, risk-taking and spatially aware, women monogamous, cooperative, nurturing and linguistically advanced. For critics, such arguments only confirmed their suspicions of the ideological character of evolutionary psychology.

By the mid 1990s the map of human nature had been transformed. Where once the idea of human nature was treated with suspicion and ridicule, there was now barely a human activity for which someone did not have an evolutionary account. Human nature had been fully restored into discussions of human behaviour, political policy and social organisation. Darwinism, as former LSE director John Ashworth has put it, has become 'an "ism" for our times'.

But the restoration of human nature to public debate, and the increasing importance of science in defining the boundaries of that nature, has not made any easier the question of how we understand what it means to be human. Few people would deny that humans are animals, evolved beings with evolved bodies and evolved minds. Equally, few would deny that humans are in some fashion distinct from other animals. 'We are built as gene machines', Richard Dawkins wrote in The Selfish Gene, but we also possess 'the power to turn against our creators. We alone on earth can rebel against the tyranny of the selfish replicators.' According to Steven Pinker he is 'by Darwinian standards... a horrible mistake'. Why? Because he has chosen to remain childless. 'I am happy to be that way', he adds, 'and if my genes don't like it they can go and jump in the lake'.

But here is the rub. If we are built as gene machines how do we possess the power 'to turn against our creators', or to tell our genes to 'go jump in the lake'? If a horse or a chimp told its genes to go take a jump, it would not survive very long in evolutionary terms. So how is it possible for humans to act like this? Pinker explains it like this in How the Mind Works:

The mechanistic stance allows us to understand what makes us tick and how we fit into the physical universe. When those discussions wind down for the day, we go back to talking about each other as free and dignified human beings.

But freedom and dignity here have no relationship to the physical world, and hence to human nature. They seem to float free in a universe of their own. 'First we are told that our genes know what is best for us, that they control our lives , programming every little wheel in the human survival machine’, Frans de Waal observes in The Ape and The Sushi Master. 'But then the same authors let us know we have the option to rebel, that we are free to act differently... These authors want to have it both ways: human behaviour is an evolutionary product except when it is hard to explain.'

The real problem, as neurologist and writer Ray Tallis suggests in his wonderful book The Explicit Animal, is that we still lack an adequate framework in which to explore what it is to be human. Like every other organism, humans are shaped by both nature and nurture. But unlike any other organism, we are also defined by our ability to transcend both, by our capacity to overcome the constraints imposed both by our genetic and our cultural heritage. It is not that human beings have floated free of the laws of causation. It is rather that humans are not simply the passive end result of a chain of causes, whether natural or environmental. We have developed the capacity to intervene actively in both nature and culture, to shape both to our will. We are biological beings, and under the purview of biological and physical laws. But we are also conscious beings with purpose and agency, traits the possession of which allow us to design ways of breaking - or at least easing - the constraints of biological and physical laws. To misquote Corialanus, to be human, it seems, is both to be such a gosling to obey instinct and to stand as if a man were author of himself.