Jonathan Latham, PhD
Biologists know that complex traits are typically associated with genetic variation between individuals. Nevertheless, if we hear on the news that obesity, antisocial behaviour or some other disorder has a strong genetic component, we are likely to attach special significance to this ‘fact’. We may be less likely to attribute social factors as a cause and we may be more likely to accept a technological or pharmaceutical solution as a remedy. The disorder may also acquire a credibility and a sense of inevitability that it previously lacked. The reasoning that leads to these conclusions has a certain logic, after all we investigate causes primarily so that we can find remedies, but nevertheless we need to be careful that our thinking is well-founded.
In the six short chapters contained in Biology as Ideology, Richard Lewontin, a renowned geneticist, sets about clarifying the relationship between genes, society and genetics. In particular, he scrutinises the dominance acquired by genetic determinism as a mechanism of causation.
Biological traits, he argues, are the result of genes, chance and environment, and these elements are irreducibly intertwined. For example, it is simply not true (as many claim) that X-percent of height or IQ or any other characteristic is genetically determined and the rest is a result of environment. Nor is it true in some statistical sense for a population as a whole. That this is a fallacy can be demonstrated by considering height. If one feeds a group of individuals the same diet and measures variability in height among them, any variability will be due to genetic factors together with chance variations accrued during development. None of it will be due to environment, unless of course factors other than diet have an environmental influence. The ‘heritability’ of height will, under such circumstances, be very high. If, on the other hand each individual had been fed a different diet, especially diets varying greatly in quantity or quality, the ‘heritability’ of height would appear to be very low. ‘Heritability’ therefore is not an absolute value but depends in fact on the environment. As a measurable value it is therefore not generalisable. It is true only for a specific population under specific circumstances.
None of which is to say that genes are not important. Rather, that the trap into which genetic determinism falls is, in part, a trap of reductionism. It is a mindset that tends to obscure the myriad other causes of obesity, antisocial behaviour, schizophrenia and many other human ills. Many biologists, formally at least, disavow reductionism and will insist that genes are not ‘for’ obesity or any other trait, but they nevertheless write grants, publish and publicise exactly as if they were. Their disclaimers somehow get lost.
Biology as Ideology once earned the title ‘most subversive book’ of 1993. How is it that this book, indeed any science book, could earn such a title? The chief reason is that Lewontin recognises what few scientists do, that the respectability attained by biological, and particularly genetic, determinism is not simply an error of scientific judgement. It is instead an example of the tendency for interactions between scientists and those with power to be mutually accommodating.
This tendency is revealed most clearly in socio-biology, which, by a series of logical fallacies, arrives at a theory of human nature that allows its followers to argue that xenophobia, hierarchy and competition are the ‘natural’ state of human societies. Thus, by implication, if inequality and violence are ‘natural’ to human nature, then the fault does not after all lie with our social arrangements and institutions but with our genes. But socio-biology, as Lewontin shows, is not well grounded in science. It is wishful thinking with a scientific gloss. In this, Biology as Ideology showcases the conclusion that increasing numbers of philosophers and sociologists of science have also reached, though usually with infinitely less clarity and style-that scientists do not only (or even ever) generate their theories based solely on objective consideration of evidence. Their beliefs, values and financial prospects can also influence them to consistently ignore inconvenient facts, no matter how evident they may be.
Biology as Ideology is one of the finest books on genetics ever written. It illuminates the subject in a forthright and accessible way and continues the tradition of scientific scepticism that is so much admired outside of science. However, in so doing it demonstrates that scepticism in science is not equally distributed and that some areas of science consistently fail to receive the full dose.
ISBN: 0140232192 Publisher: Penguin books (1991)
Important scientific updates on the recent failures of human genomics and genetic determinism, much of it predicted by Richard Lewontin, are found at the project resource page: Human Genetic Predispositions – the hidden politics of genomic science