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The Great Debate at Newcastle Science Festival 2004

Of Blank Slates and Zombies
Notes from a day school held as part of Newcastle Science Festival 2004
Caspar J M Hewett

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Human Nature: The Story So Far

From Copernicus to Darwin

Our tale begins in the fifteenth century with the work of Nicolaus Copernicus (1473-1543) which began a revolution in the way we see ourselves the repercussions of which are still felt today. He recognised in the motions of the heavenly bodies a pattern which undermined the ancient view of nature and as a consequence he placed the sun, not the Earth, at the centre of the universe. The importance of this cannot be understated for humanity itself was displaced by this heliocentric view of the universe - if we were not at the centre of the universe then we were more peripheral and insignificant. Galileo Galilei (1564-1642), who further developed the work of Copernicus, argued against the imposition of authority on the study of natural phenomena and for freedom of inquiry and expression - and suffered the consequences at the hands of the Roman Inquisition.

Before Copernicus and Galileo nature was viewed in functional terms; a teleological view derived primarily from the work of Aristotle in which an object could be understood only in terms of its purpose or function. In the work of Copernicus and Galileo we see the seed of an entirely new vision of nature as autonomous and proceeding according to its own laws - a vision which ultimately led to the scientific revolution. As this notion of a natural order developed humanity was placed further within it and this eventually led to the concept of natural law as the basis of human nature. Although the new ideas placed humanity within the natural order the thinkers of the period celebrated human reason as the instrument through which nature could be explored. For Galileo’s contemporary Francis Bacon (1561-1626) the ambition was to provide a new foundation for human knowledge based on a systematic scientific methodology - knowledge was ‘the restitution and reinvesting (in great part) of man to the sovereignty and power . . . which he had in his first state of creation.’

Thus these great thinkers provide the start point for the many questions about what we are and our place in the universe that are the subject of this discussion.

The Enlightenment

The Enlightenment is the term used to describe the intellectual movement that began in the 17th Century in England with John Locke (1632-1704) and the deists and developed in the 18th Century in France with Enlightenment philosophes such as Pierre Bayle (1647-1706), Francois-Marie Arouet de Voltaire (1694-1778) and Denis Diderot (1713-84) and in Germany with thinkers such as Christian Wolff (1679-1750), Moses Mendelssohn (1729-86) and Gotthold Ephraim Lessing (1729-81). This period is often described as the Age of Reason or Age of Enlightenment in contrast to the superstition and irrationality characteristic of the Middle Ages.

Immanuel Kant (1724-1804) described the Enlightenment as

the emergence of man from his self-imposed infancy. Infancy is the inability to use one’s reason without the guidance of another. It is self-imposed when it depends on a deficiency, not of reason, but of the resolve and courage to use it without external guidance. Thus the watchword of the Enlightenment is: Sapere aude! Have the courage to use one’s own reason!

Broadly the Enlightenment can be characterised by a number of doctrines related to a belief in progress, human perfectibility and a questioning of authority and tradition. Enlightenment thinkers saw reason as humanity’s central capacity and argued that beliefs should be accepted only on the basis of reason - not on the authority of tradition or religious doctrine. They believed that human beings are by nature rational and good, that both the individual and humankind as a whole can progress to perfection and that all people are equal in respect of their rationality and thus that they should be granted equality before the law and individual liberty. They argued for tolerance to be extended to other ways of life and devalued local customs and prejudices in favour of a universalism which depends on the exercise of reason.

Kenan Malik contrasts the humanism of the Renaissance period with that of the Enlightenment. The former, he states, was a movement which aimed to reform learning by close inspection of ancient Greek and Latin texts believing that previous scholars had mistranslated them. Renaissance humanists such as Petrach, Erasmus and Thomas More were often intensely devotional men rooted in Aristotelian philosophy. Enlightenment philosophy, whilst also humanist in nature, was based on the rejection of divine authority and associated itself with science and reason. Where both strands are united is in the desire to place human beings at the centre of philosophical debate, to glorify human abilities and to view human reason as a tool to understand nature and, ultimately, human nature.


In 1859 Charles Darwin published On the Origin of Species by Means of Natural Selection, further displacing our special position in the natural order while at the same time exorcising the need for a creator from our understanding of biology. The idea of evolution itself was not new, but Darwin’s central thesis was. He argued that evolution is driven by natural selection; the process by which those organisms who possess some attribute that makes them better adapted to their environment than their counterparts are more likely to survive for long enough to reproduce than those counterparts. These adaptations are thus likely to spread through a population since the offspring in their turn possess that inherited advantage. Thus this entirely blind process results in organisms who are increasingly well suited to living in a particular environment over the generations.

In Origin of Species the implications for humanity were clear - humankind had evolved just as had all other species and we are placed firmly in the animal kingdom. However, realising the furore that this idea would generate, Darwin shied away from discussing humanity in Origin of Species in the hope that this would give the idea of natural selection a better chance of getting established. It is only some twelve years later in The Descent of Man and Selection in Relation to Sex (1871) that Darwin discussed the implications for humanity in more detail.

The Descent of Man went beyond Darwin’s original thesis and proposed the idea of sexual selection. The archetypal example of sexual selection in the animal kingdom is the peacock’s tail, for this is such a cumbersome object to carry around that it raises the question of what its adaptive function could possibly be. The answer Darwin proposed is simple - the extravagant tail does not offer a survival advantage to the peacock, it offers a reproductive advantage - the tail is simply attractive to females. This attraction may have originated in a way that was related to survival - a slightly longer tail may have indicated a healthy constitution or a better ability to escape predators - but once such a feature became attractive to females it carried the advantage that males with longer tails were more likely to find mates, and this in turn had the potential to cause a general increase in tail length generation to generation solely on the basis of attractiveness. The notion of sexual selection is by no means as universally accepted in evolutionary theory as natural selection, but has nevertheless been highly influential in the last few years especially in Evolutionary Psychology, which will be discussed later.

Social Darwinism

Perhaps the most interesting thing about Social Darwinism is that it is a term associated with a set of ideas that actually precede Origin of Species and thus is something of a misnomer. Broadly speaking Social Darwinism refers to a diverse collection of 19th and early 20th century doctrines that applied the concept of evolution to the historical development of human societies the best known of which laid particular emphasis on society and the political economy as a competitive arena in which only the ‘fittest’ people rise to the top. Thus social success was conflated with reproductive fitness.

Social Darwinian ideas were highly reactionary in that they represented, at least for some, an attempt to excuse capitalism for failing to provide decent standards of living to the poorer members of society. It was even argued that social reforms aimed at providing for the poor would undermine natural selection and promote degeneration of the species - an idea closely associated with so-called scientific racism and eugenics. They were used to provide pseudo-biological explanations for rivalries between the European powers and to justify imperialism and war. Hitler was one of many leaders to pick up Social Darwinian ideas, and it was their integration into Nazi ideology that ultimately led to their demise, since such ideas came to be seen as unacceptable after the experience of the Holocaust and the Second World War.

However, Social Darwinism was not associated only with the far right. Herbert Spencer (1820-1903), who was instrumental in developing the notion of evolution in the mid 18th century, supported several liberal and progressive causes such as universal suffrage, women’s rights and free trade and was closely associated with Social Darwinism. In fact Spencer’s promotion of the idea of evolution was driven largely by his belief in social progress. Spencer was very highly regarded in his time and was an important influence on Darwin. However Spencer was a product of his time and was influenced by the prudish Victorian values of the society he lived in. He argued that higher fertility was offset by a lower competitive edge in the struggle for existence and that evolution is progressive and leads inexorably to a society of large brained people with small sexual appetites!

Of Blank Slates and Zombies - Modern Theories of Human Nature
Caspar J M Hewett

Is there a universal human nature? If so, what defines it? Is it consciousness? Is it our capacity for rational thought? Is it our ability to adapt our environment rather than adapt to it?

The last decade has seen an explosion of theories making claims about human nature from areas as diverse as evolutionary theory, genetics, neuroscience and artificial intelligence. Reading any one of the many popular texts on the human mind and behaviour, one could be forgiven for thinking that many questions about ourselves now have definitive answers. Kenan Malik, in his book Man, Beast and Zombie: What Science Can and Cannot Tell Us About Human Nature, demonstrates that this is far from the case, highlighting the fact that, while the great majority of theorists today accept that a combination of genetic and environmental factors determine what we are, few agree on the level of determination and on what conclusions can be drawn about ourselves. So where are the appropriate places to look if we want to understand human nature?

Malik explains the histories and underpinning philosophies of disciplines such as evolutionary biology, cognitive psychology and artificial intelligence, and this provides the background for his analysis of modern theories of human nature. He investigates some fundamental questions about human uniqueness, our relationship to the natural world and the human mind, tracing how ideas on these questions have developed over the centuries.

Sociobiology and Evolutionary Psychology

Sociobiology is the approach to understanding animal behaviour using methods derived from game theory which emerged in the 1960s and 70s (see for example John Maynard Smith). Richard Dawkins popularised this methodology in his 1976 best-seller The Selfish Gene, the clever title of which captures well the principles underlying the new model: the theory provided a link between genes and behaviour. Niles Eldredge, one of the critics of the selfish gene model, concedes that sociobiology ‘is the outstanding achievement of ultra-Darwinian biology' but writes that he thinks the attention it has attracted ‘is a reflection . . . of the general cultural infatuation with gene-centred explanations that has become one of the legacies of the molecular biological era.'

There was a great deal of ambivalence towards this approach because the sociobiologists, led by Edward O Wilson (who first introduced the term sociobiology), also made claims regarding human beings - they attempted to explain human behaviour in terms of adaptation. They argued that since we are evolved beings human behaviour must be adaptive - that is, that it must contribute to whether or not we successfully reproduce. This expansion of theory into the human realm was regarded with some suspicion - it was seen by many to be too like Social Darwinism and as such was attacked as reactionary and racist.

Evolutionary Psychology (EP) is a school of thought which emerged in the 1990s pioneered by John Tooby and Leda Cosmides. The methodology of EP is based on the following five tenets (after Tooby and Cosmides)

  1. The brain is a physical system and thus the laws of physics and chemistry govern its operation. Its function is to process information (for which the computer provides a perfect analogy) and its neural circuits are designed to generate motion (behaviour) in response to environmental circumstances.
  2. Human neural circuitry was designed by natural selection to solve problems our ancestors faced during our evolutionary history.
  3. Most of what goes on in the human mind is hidden from the conscious self. Conscious experience can mislead us into thinking that the underlying circuitry is simpler than it really is.
  4. Different neural circuits are dedicated to solving different adaptive problems (for example for vision, language, taste, sexual attraction); the metaphor of a Swiss army knife is a popular one for this idea. Like a Swiss army knife, which has many tools, each designed for a specific purpose, the brain is considered to consist of specialised modules, each evolved for an adaptive purpose.
  5. Modern human beings have stone age minds.

EP thus attempts to explain human nature exclusively in terms of evolved predispositions to behave in a particular way. Evolutionary psychologists begin by noting that modern humans (homo sapiens sapiens) first appeared about 100,000 years ago and that those first human beings had evolved in our environment of evolutionary adaptedness (EEA), presumed to be the savannahs of Africa. A series of assumptions are made regarding the way of life of our ancestors of that period; that they lived as hunter gatherers in small kin-based groups, were nomadic or semi-nomadic, had stone age technology (at most), short life expectancy and a high infant mortality rate. The argument runs that our minds as well as our bodies should be adapted for this lifestyle and thus that human mental attributes can be explained in terms of the advantages they conferred on our ancestors living in the EEA. Various aspects of human behaviour are explained in terms of evolved tendencies or predispositions to behave and think in particular ways. To obtain clues evolutionary psychologists look to the behaviour of our closest cousins, the great apes, and to anthropological data related to the way of life of modern hunter gatherers. Implicit in their work is a search for aspects of human nature which are universal.

The evolutionary psychologists go to great lengths to distinguish their approach from that of the sociobiologists and it is fair to say that it does differ. What the two methodologies do have in common is that they attempt to understand the modern human mind in evolutionary terms.

Malik points to the methodological flaws of both approaches and looks at how Sociobiology was treated with suspicion because of its apparent similarity to Social Darwinism while Evolutionary Psychology has been able to capture the popular imagination, partly because of changes in the way we view our nature which have taken place in the past three decades.

Neuroscience and Artificial Intelligence

One model of the mind that has become increasingly popular in recent years is to consider the mind as analogous to a computer. Since the dawn of the digital age claims have been made about artificial intelligence (AI). The AI movement started in the 1950s. Its aim is to create a computer capable of thinking like a human and thus to explain how humans think. The computer thus becomes the model of the mind. Especially in this age of brain scanning technology, where the path of a thought can be traced as it moves through the brain, it is indeed tempting to think of the brain as a computer and of the mind as a function of the brain. Why then, the proponents of AI argue, should a computer not be able to mimic the human mind?

It is interesting to note that, following early attempts to produce a general problem solver, there was a move in the 1970s towards developing Expert Systems; programs designed for specific types of problem. It is here that we see the seeds of the modern idea of the modular mind discussed above. In the 1980s neural networks became the next generation of AI methods and represented an attempt to mimic the architecture of the brain more closely.

Despite claims to the contrary the evidence suggests that we are still a long way from creating sentient, intelligent artificial minds - if only because of the enormous computational power that would be required to get anywhere near the complexity of a human brain.

Malik interrogates the claims of some that the mind and brain are one and that neurobiology and artificial intelligence can reveal the nature of the human mind.

What Science Can and Cannot Tell Us About Human Nature

So what is Malik’s thesis? Throughout Man, Beast and Zombie he attempts to clarify what science can and cannot tell us about human nature. He breaks this down into the question of how science knows about the world and how human nature fits into the world. He examines the tools science possesses, and asks if those tools are sufficient for understanding what constitutes human nature. He suggests that ‘the way that science understands the world places constraints upon the way it can understand human beings. A paradox of science is that its success in understanding nature has created problems for its understanding of human nature.’

Looking at the question of how science knows about the world, Malik shows how the scientific revolution transformed our view of the universe from one full of purpose and desire into one in which nature is inert, mindless and purposeless entity. Science is mechanistic; it views nature and natural organisms as ‘machines’ and it is precisely this view that leads to much of the success of science. Implicit in this understanding is the idea that the natural world lacks agency and will. ‘Animals are objects of natural forces, not potential subjects of their own destiny. They act out a drama, not create one.’

Humans, in contrast, do possess purpose, agency and will. We may be biological beings subject to biological and physical laws, but we are also conscious beings who do things for reasons and as such are unique among organisms; human beings are both objects of nature and subjects that can shape our own fate. Malik points to two important ways that human subjectivity distinguishes us from the rest of the natural world: our ability to make history, and our ability to advance science.

'In the six million years since the human and chimpanzee lines first diverged on either side of Africa’s Great Rift Valley, the behaviour and lifestyles of chimpanzees have barely changed. Human behaviour and lifestyles clearly have. Humans learn from previous generations, improve upon their work, and have established a momentum to human life and culture that has taken us from cave art to quantum physics and the conquest of space. It is this capacity for constant innovation that distinguishes humans from all other animals. All animals have an evolutionary past. Only humans make history.'

Malik argues that all other animals are constrained by the tools with which natural selection has provided them. They absorb information and their behaviour is adaptive - it is ‘designed’ by natural selection to enable them to survive for long enough to pass on their genes. The kinds of knowledge they are able to acquire are largely pre-selected. Unlike humans, animals cannot ask questions or relate to anything irrelevant to their immediate circumstances or their evolutionarily-designed needs. Humans ask all kinds of questions, many of which have no relevance, indeed make little sense, in the context of evolved needs and goals. What makes us unique is our capacity to establish our own goals - ones that go beyond naturally-defined goals such as the need to find food, shelter or a mate.

Some theorists believe that there are indeed certain questions that humans are incapable of answering because of our evolved nature. ‘Our minds evolved by natural selection to solve problems that were life-and-death matters to our ancestors, not to commune with correctness or to answer any question we are capable of asking’, argues Steven Pinker. ‘We cannot hold ten thousand words in our short-term memory. We cannot see ultra-violet light. We cannot mentally rotate an object in the fourth dimension. And perhaps we cannot solve conundrums like free will and sentience.’

Malik sees things very differently - he points out that we have solved all kinds of problems, from the structure of DNA, to the physical composition of the sun despite our evolutionary legacy, not because of it. It is true that the development of science requires mental skills, many of which are evolved adaptations, but science has enabled us to go well beyond those adaptations. We can do science only because we can transcend our evolutionary heritage and act as subjects, rather than as objects.

This idea of humans as distinct from the rest of nature by virtue of being subjects lies at the core of Malik’s view of what science can tell us about human nature. Science understands phenomena by treating them as objects or machines and thus inevitably finds itself attempting to understand human beings in the same mechanistic way. So, can a tool designed to understand objects tell us anything about phenomena that are also subjects?

One view is that humans are not really subjects, that in reality we are simply objects like every other natural being. Purpose and free will are interpreted as illusions that natural selection has designed us to believe in, not because they really exist but because it is useful from an evolutionary perspective. Medical writer Rita Carter is firmly in this camp; she argues that the illusion of free will ‘like the illusion that the objects around us are solid, or have some integral colour - is deeply wired into the brain as a set of mechanisms which automatically create the sense of self/subjectivity and agency that makes it feel as though we decide what our acts will be rather than merely respond to stimuli.’ The psychologist Susan Blackmore comes to similar conclusions in her book The Meme Machine. Richard Dawkins first introduced the idea of the meme in The Selfish Gene partly because of his discomfort with the sociobiologists approach to human behaviour. A meme is a unit of cultural transmission or imitation. Like the gene, which is a self-replicating molecule, the meme is a replicator; when a meme is imitated it has replicated itself. Examples of memes are as diverse as the god meme, the idea of evolution, ways of cooking sausages. Developing this notion Blackmore suggests that ‘Instead of thinking of our ideas as our own creations, and working for us, we have to think of them as autonomous selfish memes, working only to get themselves copied.’ Since we cannot find either beliefs or the self that believes’ by looking into somebody’s head, she argues, so we must conclude that there are no such things as beliefs or selves, ‘only a person arguing, a brain processing the information, memes being copied or not.’ Writer James Heartfield takes issue with this notion in The ‘Death of the Subject’ Explained; ‘The weakness of the meme theory is that it describes the reproduction of unconscious, routine behaviour rather than more deliberate, higher functions . . . It would be truer to say that memes are the product of the human mind. They are routines laid down to avoid reinventing the wheel each time. Of course, to the extent that subjectivity is evacuated, then the mind will reduce to the level of a collection of memes.’

The argument that consciousness and free will are illusions designed by natural selection rests on the idea that evolution can select for untruths about the world because such untruths aid survival. If our mental capacities are simply evolved dispositions, then there can be no way of knowing which of these capacities leads to true beliefs and which to false ones. For one thing, science itself would have to be an evolved way of thinking rather than a means to reach objective knowledge about the world. There would be no basis on which to trust reason itself. To accept the truth of reasoning, the philosopher Thomas Nagel observes, ‘I have to be able to believe . . . that I follow the rules of logic because they are correct - not merely because I am biologically programmed to do so.’ Thus Malik questions how we can have any confidence in the claim that we are only sophisticated animals or machines if that is truly what we are. For him ‘We are only able to do science because we are able to transcend our evolutionary heritage, because we are able to act as subjects, rather than as objects.’

Steven Pinker does not believe that human agency is merely an illusion. He is ‘as certain that I am sentient as I am certain of anything.’ He points out that moral reasoning depends on our acknowledgement of ourselves as sentient beings. Without the concept of sentience there would be no reason to consider torture to be wrong or to think ‘that disabling a robot is the destruction of property but disabling a person is murder.’ However, while Pinker acknowledges that we do not have the tools to explain sentience scientifically at present he argues that ‘Our incomprehension of sentience does not impede our understanding of how our mind works.’

Writer and neuroscientist Raymond Tallis points out that ignoring sentience when attempting to construct a theory of the human mind is like ‘trying to build a house by starting at the second floor.’ Sentience, Tallis argues, ‘is the first, not the last, problem . . . of psychology. It is not merely the most difficult of the problems of consciousness or mind; it is also the pivotal one and addressing it cannot be postponed until one has solved the "easier" problems such as those pertaining to "cognitive functions" like intelligence, memory, thinking etc.’

For Malik this ‘raises the central problem in trying to apply to the subjective world the types of reductions that one applies to the natural world.’ The reductionist approach is essential to science and to physics in particular since the ‘natural world works essentially from the ‘bottom up’.’ The laws of physics are the most fundamental because they constrain all other natural phenomena. A biologist may understand animal behaviour in its own terms, but also understands that it ‘can be understood in neurophysiological terms, and that the physiology of neurones can in turn be understood at a more fundamental level through the laws of chemistry, and so on.’ In contrast the social world embodies purposiveness and thus often works from the ‘top down’. For example social norms and rules influence the behaviour of individuals. Individual behaviour is also driven by will and purpose. ‘Social and historical forces can determine how individuals think or behave. Humans make history, but in the process history helps remake the kind of humans that we are.’

Malik concludes that natural science can tell us a great deal about being human since we are biological beings and as such are objects, but it is constrained in what it can tell us about ourselves as subjects; ‘a discipline such as evolutionary psychology or genetics inevitably understands us simply as objects, rather than as subjects, and hence is limited in its understanding of the human condition.’

Malik’s is a materialist, humanistic view - one that both understands humans beings without resort to mystical explanations and sees humans as exceptional because we, unlike other animals, possess consciousness and agency. For Malik, only by understanding that we are historical and social beings as well as natural beings can we hope to understand human consciousness and agency.


Blackmore, Susan, The Meme Machine, 1999
Bullock, Alan and Stephen Trombley, The New Fontana Dictionary of Modern Thought (3rd edition), 1999
Carter, Rita, Mapping The Mind, 1998
Cosmides, Leda and John Tooby, Evolutionary Psychology: A Primer, 1997
Darwin, Charles, On the Origin of Species by Means of Natural Selection, 1859
Darwin, Charles, The Descent of Man and Selection in Relation to Sex, 1871
Dawkins, Richard, The Selfish Gene, 1976
Eldredge, Niles, Reinventing Darwin, 1995
Heartfield, James, The ‘Death of the Subject’ Explained, 2002
Honderich, Ted (ed.), The Oxford Companion to Philosophy, 1995
Malik, Kenan, Man, Beast and Zombie: What Science Can and Cannot Tell Us About Human Nature, 2000
Pinker, Steven, How the Mind Works, 1997
Pinker, Steven, The Blank Slate: The Modern Denial of Human Nature, 2002
Tallis, Raymond, The Explicit Animal, 1991
Wilson, Edward O., Sociobiology: The Abridged Edition, 1980

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Buy these books from Amazon
Man, Beast and Zombie The Blank Slate Evolutionary Psychology: A Critical Introduction Alas Poor Darwin Nature via Nurture
Consciousness Mapping the Mind Not In Our Genes Death of the Subject Explained The Hand: A Philosophical Enquiry into Human Being
The Enemies of Hope: A Critique of Contemporary Pessimism In Defence of Realism The Raymond Tallis Reader A Conversation with Martin Heidegger The Meme Machine

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