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 PrintableVersion Nature via nurture: genes, experience and what makes us humanThe light's on, but nobody's homeNATURE VIA NURTURE: Matt Ridley is a gifted science writer who specialises in exploring evolutionary themes. The trigger for 'Nature via Nurture' was the media attention given to the Human Genome Project in 2000. Instead of the expected 100,000 genes, the researchers could only identify about 30,000. This leaves humans undistinguished in terms of our genetic library - we have parity with the mouse, less genes than a mustard weed and much less than a rice plant. Questions are being asked about what really makes us human. Can it be our genes? Or, is our environment the secret of human behaviour? This 'Nature versus Nurture' approach to these questions goes back to Francis Galton, who coined the phrase in 1874. Now, with only a third of the genes we were thought to have (and possibly only 500 genes) distinguishing us from chimpanzees, people have concluded that the environment must be determinative in making us essentially human. Enablers, not constrainersRidley, who is known as a committed advocate of genetic influences, has put together a case for synthesising the polarised nature versus nurture debate. He champions an approach that seeks to integrate the apparently mutually exclusive positions. He describes genes as enablers, not constrainers. Environmental factors influence the way the genes function. As a consequence, genetic determinism can be replaced by a finite set of potentialities, with the particulars selected by the environment (nurture). 'Nature via Nurture' carefully interweaves many related stories using an anecdotal style. There are the key historical figures that have contributed to the nature/nurture debate. We meet Galton developing ideas about heredity, De Vries becoming the father of the gene, and Lorenz trail-blazing with his work on imprinting. On the nurture side, we have Watson's associations, Pavlov's reflexes and Freud's formative experiences. In all, we meet a dozen pioneers (all male) who founded the disciplines of ethology, neurobiology, anthropology and psychoanalysis. Alongside this, Ridley dips into contemporary research and recounts other incidents and findings to build his argument. The title of the book is 'Nature via Nurture', not Nurture via Nature. Ridley seeks to prove to his readers that there is a robust genetic basis for behaviour. 'The spooky truth is dawning on scientists that they can regard behaviour as an extreme form of development' and 'development seems to be a rather well-determined process planned and plotted by genes'. Although Ridley rejects traditional genetic determinism, he replaces it with a softer form where genes can be both cause and consequence of behaviour. 'Nature does not prevail over nurture; they do not compete; they are not rivals; it is not nature versus nurture at all'. Hyped resultsModern-day research is interpreted as supporting this basic position. Although the findings are occasionally acknowledged to be tentative, they are often cited as fact. A spelling change in the DNA code can result in a different personality: 'that it does so seems all but certain'. In a study of criminality, Ridley concludes: 'Genetic factors are predisposing the way people react to crimino-genic environments'. It is significant that numerous much-publicised claims by genetic reductionists get little or no airing in this book. Over the years, headlines have repeatedly appeared announcing 'genes for (being gay), (violent), (depressed), (intelligent), etc.'. A study of the hype associated with these studies, and the subsequent back-tracking as to what the results actually mean, would make an interesting chapter. Unfortunately, it is not to be found in Ridley's book, as his critical comments are reserved for pioneers, not contemporary researchers. Furthermore, most of his case studies involve animal subjects, and the unquestioned assumption is that what applies to animals is likely to apply to humans. If genes influence behaviour via nurture, then a probabilistic connection between the two is inevitable. This is one aspect of the book that I found both puzzling and frustrating. In a few cases, Ridley gives us the probabilities emerging from the research. However, in most cases, these figures are absent. Instead, we have words like 'unusually', 'more likely', and reassurances such as 'it is reasonable to hypothesise'. At best, Ridley has some correlations to discuss, but because the statistics are largely hidden, readers are left fumbling with concepts and feelings. The ability of this soft genetic determinism to predict the behaviour of any human being would appear to be very low. Is Ridley really any closer to answering the question: 'What makes us human?' A heartless creedBoth 'genetic determinism' and 'environmental determinism' are described as a 'heartless creed'. Elsewhere, Ridley refers to the idea of an inherited individual destiny as a 'neo-Calvinist notion'. Obviously liking the allusion, he later comments on 'the bleak Calvinism of genes'. Apart from revealing Ridley's theological education to be deficient, these comments make it clear that his book is opposed to all types of determinism. Basically, he says, if we are determined by nature or nurture, then we are not free. To resolve the conundrum of freedom using the nature via nurture scheme, Ridley adopts an argument that considers causality to be circular. Free will 'is the sum and product of circular influences with varying networks of neurons, immanent in a circular relationship between genes'. There is no linear chain of causality, but a world in which thoughts and experiences feed off each other. The conclusion: 'free will is entirely compatible with a brain exquisitely prespecified by, and run by, genes.' Are we really free?However, does Ridley's approach to freedom match up with our own perception that humans are free agents? Does 'circular causality' really explain anything? The nature via nurture scenario still insists that we are the products of nature via nurture! Our responses to particular situations may be unique to our own mix of ingredients, but does that mean we escape being products of a deterministic smorgasbord? Ridley has another significant sentence showing that we still await a real explanation of free agency. 'There is no "me" inside my brain; there is only an ever-changing set of brain states, a distillation of history, emotion, instinct, experience and the influence of other people - not to mention chance.' In other words, this person I call 'me' is a slave of the past, the environment and chemistry. Release from bondage via circular causation is but an illusion. Ridley's GODReaders of Nature via Nurture quickly encounter Ridley's GOD: Genome Organising Device. Being a materialist, Ridley has no theistic implications for this word. Rather the GOD is introduced because the author has 'an aversion to the passive voice'. For stylistic reasons, he pretends 'that there is a teleological engineer thinking ahead and planning purposefully'. This GOD is actually a prominent figure in the book and, conveniently, it points the way for a different emphasis and different conclusions. Actually, it is difficult for materialists to be consistent because they are always making reference to design, fine-tuning, complex systems, purposeful activity and meaning. But to move from contrived pretence to a full theism requires abandoning the central tenet of materialism: matter is all there is. The question: 'What makes us human?' is a good one (Psalm 8.4). However, if we restrict the scope of our enquiry, as Ridley has done, the answers must remain obscure. Moving to a theistic science, we do not have to start with only the building blocks of 'nature' and 'nurture'. We do not have to understand humankind as essentially physical. There is another dimension to our existence that is absolutely fundamental to self-knowledge. In one place, Ridley comments: 'Something can be partly true without being a complete answer'. There are many partly true (and interesting) points in this book, but because its GOD is a pretend engineer who works only at the level of nature, for the complete answer we need to look elsewhere. David J. Tyler,
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