by Richard Lewontin
Penguin books ISBN: 0140232192
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 scrutinizes the
dominance acquired by genetic determinism as a mechanism of causation.
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.
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 recognizes what few scientists do,
that the respectability attained by biological, and particularly
genetic, determinism is not simply an error of scientific judgment. It
is instead an example of the tendency for interactions between
scientists and those with power to be mutually accommodating.
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.
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.
Here is a link to Lewontin's lectures on the topic, which I think are brilliant (rc) : Biology as Ideology