Statistical
literacy is becoming an issue of growing concern for scientists and
philosophers alike, the underlying drive being the social impact it has on a
variety of realms. Sociologists (e.g. Beck) have made us aware of the relevance
of risk assessment in our everyday life, while psychologists (e.g. Gigerenzer)
revealed that our statistical estimations are usually biased, albeit for good
evolutionary reasons. To trust in the statistical expertise of scientists might
then seem a wise choice when their empirical findings are invoked to support
such decisions as, say, the promotion of vitamin C for our health improvement
or a conviction on the basis of DNA identification. The immediate question is
to what extent this public trust is justified.

The
improvement of our understanding of statistical evidence in biology and
medicine is precisely the goal of How Science Works and the
argumentative strategy of the biologist Stephen H. Jenkins could not have been
more effective. Each of the nine chapters of his book provide an introductory
presentation of the evidence available concerning an equal number of
fascinating topics: besides the two mentioned above, Jenkins discusses
environmental and ethological issues (such as the decline of certain amphibian
populations or the cognitive mechanisms that control the storage of food in
certain species), medical subjects (the causes of cancer and aging, the effects
of coffee), or a combination of both (the influence of climate change on the
spread of malaria). Intended as brief reports on the work in progress in all
these areas, each one of them contributes to the making of a single
methodological point: what the statistical analysis proves in these nine cases
is that there are as yet no ultimate answers.

What
Jenkins argues is that this inconclusiveness arises from the very complexity of
biological and medical research, even after being tamed by the most
sophisticated statistical techniques available. There are many sources of
evidence and various possibilities to incorporate them into our theories. On
the one hand, Jenkins presents a number of standard bio-statistical methods
that allow us to design experiments and analyze data with various degrees of
reliability. The art of the biomedical scientist would lie in the achievement
of a certain consilience between all these sources, together with more
traditional ones, such as fieldwork. Jenkins shows that this is not an easy
task, as the evidence might prove unavoidably conflicting. Several
philosophical dilemmas come to complicate even more data analysis. To name just
three, let us think of the typical disjunction (sometimes inclusive, often
exclusive) between case studies and all-encompassing theoretical approaches,
the difficulties of accounting for the simultaneous interaction of various
levels of causality and the pros and cons of purely statistical vs.
mechanism-based modeling.

Though
it might seem impossible to compress such a range of topics into about 200 very
readable pages, Jenkins succeeds in providing a survey that might be of equal
interest both for the curious reader in search for a popular state of the art
discussion of the nine mentioned topics and for the methodologically-minded
scholar looking for an introduction to the beauty and perplexities of
biomedical research. Footnotes are kept to a minimum and several suggested
readings complement each chapter. Jenkins’s approach might well be deemed
"ecological": though he clearly favors certain approaches, his main
concern throughout the book is to show us how many of them proliferate now in his
field and what sort of results they yield. Only by taking all this into account
will we be able to qualify our trust in the alleged scientific grounds of many
policies currently under discussion. In other words, the idea of informed
consent should be generalized as to encompass (and legitimate) every public
decision on environmental and medical matters.

Though
Jenkins’ case is articulated and convincing, it might be also a bit puzzling.
We may well be aware of the difficulties of attaining conclusive results in the
biomedical sciences, but to whom are we rely on to assess them? Jenkins’s
implicit assumption seems to be that there will always be non-partisan
scientific experts to provide a reliable assessment. Yet, it might happen that
controversy among scientists could prevent general audiences from discerning
whom to trust. This is a classical dilemma: quis custodet ipsos custodes?
Be it what it may, Jenkins’ proposal will probably be part of the solution to
this problem.

© 2004 David Teira

David Teira, Ph.D., Department of Philosophy,
University of Salamanca (Spain)

Categories: General, Philosophical