Journeys into 'terra incognita' of the mind

Susan Blackmore struggles with the philosophical pitfalls of neurotheorists' quest for the 'sparkling jewel' of consciousness

Neuroscience is now a billion-pound business, so maybe it is time to steal up on what Steven Rose calls "that final terra incognita , the nature of consciousness itself". In his fiery introduction to The New Brain Sciences: Perils and Prospects , Rose claims that developments in neurology, molecular biology and other neurosciences have been isolated from their socioeconomic context and dominated by the search for genetic and pharmacological quick fixes. This, he says, celebrates and reinforces "the simplistic reductionist agendas of neuroscience and neurotechnology".

Although he warns that "you will find no gung-ho overoptimistic forecasts of the wondrous cornucopia of benefits that neuroscience might bring here", the book is not as depressing as this implies, and there is only the odd hint of postmodernist ranting.

The book is based on two meetings that explored neuroscience and neuro-ethics. The first of three main sections, "Freedom to change", considers the effects of neuroscience on our concepts of human agency, responsibility and free will. Philosopher Mary Midgley asks, "Do we ever really act?" For, if the true cause of our action is always a physical event, we might not really be active agents at all but like people hypnotised or possessed by an alien force. She takes Colin Blakemore to task for claiming that "the human brain is a machine that alone accounts for all our actions". She admits that the brain is necessary but objects to the word "alone" (although I doubt that Blakemore really meant that the brain acts alone, without a world to act in).

Other contributors discuss the limits of neurobiology and the goals and values of the neurosciences, while Peter Lipton gives a wonderfully clear exposition of the problem of free will. He argues that, as traditionally conceived, free will is impossible, so nothing we learn about genetics or innate dispositions poses a special threat to free will.

The second section takes these issues as they affect the (mainly English) law. Knowing little about this topic, I found these chapters interesting and informative. Patrick Bateson rejects the idea that "all shreds of human agency succumb in the face of advances in the understanding of evolutionary process, genetics and brain function". He explores the notion of diminished responsibility and urges us to assume intentionality and responsibility until we have very good reason not to. I especially enjoyed his explanation of what Richard Dawkins meant by his selfish gene theory and of how people have misinterpreted this powerful metaphor.

Alexander McCall Smith goes deeper into the concept of responsibility, voluntary action and blame. Describing voluntary acts as those that we take ourselves to be doing, he argues that responsibility may remain intact even when we understand the causes of actions. He describes the compromises the law has to make when intervening in personal life. Stephen Sedley examines such compromises in the context of homicide and manslaughter; the law has to draw lines between them even though science recognises the multiple, interacting and complex causes of violent action.

Men are the main perpetrators and victims of violence, and Lorraine Radford gives some fascinating figures. In England and Wales, 70 per cent of homicide victims are men. Women kill less often and are far more likely to be killed by a partner. Evolutionary psychology has explanations for this, for example that women might choose dominant and violent men as partners because they may make better providers and protectors, and men may attack a partner who threatens to leave as a way of ensuring ownership. This does not, Radford points out, account for large differences between cultures, but she does not dismiss such explanations as deterministic positivism.

The last section concerns the stewardship of the new brain sciences - who should protect society against errors, oversimplifications, false optimism and political manipulation? Yadin Dudai describes the case of the "smart mouse", which was produced using gene therapy. People expected wonderful enhancements of human intelligence to follow until this gene change was found to increase sensitivity to pain. Dudai warns against the "lobotomy attitude" that once led surgeons to make irreversible changes to patients' brains with no idea of the consequences.

Angus Clarke tackles the ever-controversial topic of the genetic basis of intelligence, using doubts over definitions and fears of the social implications to conclude that it is inappropriate to pursue research into it. He says he would not ban such research - so what could "inappropriate" mean? Claims of racial differences are problematic and sometimes politically motivated, but people are fascinated by intelligence and will not stop researching because someone deems it "inappropriate".

The first of two chapters on stem-cell research gives an overview of what stem cells are, what can be done with them and the risks entailed in using them to repair brain degeneration. The second explores ethical problems such as the moral status of embryos, the ethics of cloning and the slippery slope that some fear will lead to human cloning. Once more, the difficult issue is raised of who decides which research should or should not be done.

Turning to drugs, we read of a fascinating multiple murder involving the antidepressant Prozac, which illustrates the clash between biology and the market in the selling of drugs for anxiety and depression. Some scary changes are going on, from increases in depression and consequent prescribing of mind-altering drugs to ghost-writing of scientific articles, which undermines scientific integrity and raises fears about the power of pharmaceutical companies. David Healy argues that the same process is leading to a medicalisation of childhood distress, as seen with the spread of Ritalin to control attention deficit hyperactivity disorder. Paul Cooper notes that between 2 per cent and 2.5 per cent of children are prescribed medication for hyperactivity in the US - though less than 1 per cent in the UK. He provides some chilling comments from children - such as a 15-year-old girl who likes Ritalin at school because it helps her work but does not like it at home because it stops her wanting to go out and play with her friends. He sketches a picture of young people the world over being increasingly stressed and isolated, while society uses drugs to make them conform to the demands of educational achievement.

These issues are serious, and this book will interest everyone who worries about them, but in the end, it never gets to grips with those tricky issues of consciousness and free will that underlie all the arguments. Although the book starts with the search for that "final terra incognita " and with Hilary Rose calling consciousness "a sparkling jewel irresistible to the neurotheorists", no real light is shed on it. Midgley stresses "that conscious thought has a legitimate and essential place among the causal factors that work in the world" without any appreciation of the philosophical difficulties involved in saying that subjective experience is causal.

In his otherwise useful summary of his three-stage theory of human evolution, Merlin Donald suggests that the flexibility of human nature "is due largely to the overdevelopment of conscious processing, and those parts of the brain that support it"; and he talks about things being processed "in consciousness" as though this were a special place in the brain. Hilary Rose is the only contributor to reject this simplistic assumption, but she does not consider the implications for neuroscience in her discussion of fiction, feminist consciousness-raising and the Black Consciousness movement.

In their concluding chapter, Dai Rees and Barbro Westerholm claim that although the philosophical case against free will might seem watertight, it makes such a nonsense of human experience that they "are driven to accept that there must be limitations in a philosophical method that has somehow arrived at the denial of this quality that we value so much." In other words, they will stick with their intuitions regardless of arguments against them. It is just this kind of clash that makes a book such as The New Brain Sciences necessary.

Susan Blackmore is visiting lecturer in psychology, University of the West of England.