Book Book

How Scientists Explain Disease

BMJ 2001; 322 doi: (Published 09 June 2001) Cite this as: BMJ 2001;322:1431
  1. Julia Lowe, director of general medicine
  1. John Hunter Hospital, Newcastle, New South Wales, Australia

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    Paul Thagard

    Princeton University Press, £11.50, pp 268

    ISBN 0 691 05083 X

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    Why do scientists acquire new beliefs, sometimes abandoning old ones? For anyone who has practised medicine long enough to wonder how and why some theories become fashionable and others fail to thrive, this book will make an interesting read. Paul Thagard finds both the traditional view of science as logic and the postmodern view of science as power inadequate for understanding how science develops.

    He starts his exploration by considering various explanatory models before proposing his own. I found his integrated cognitive-social approach intuitively satisfying and the examples he uses are in keeping with my personal experience of changes in medical tenets over the past 30 years. Having struggled with some tracts on postmodernist theory, I found the book an easy read, light on sociological jargon.

    Anyone who remembers reading Warren and Marshall's original description of Helicobacter pylori in the Lancet in 1983 and the subsequent resistance to the reclassification of peptic ulcer disease as a bacterial disease will enjoy the use of this episode in medical history to illustrate Thagard's explanation of how scientists change their minds. Those who assume that only logic can change scientific belief will find little to please them. Personally, I think the chapter on the role played by social processes in this underplays the influence of the pharmaceutical industry. It is interesting to speculate how much more quickly the treatment of peptic ulcers would have changed had the therapy been under patent to a drug manufacturer.

    Non-medical readers will find much to inform them but should be aware that Thagard underestimates the role of the drug companies, particularly their role in the dissemination of new knowledge and the development of consensus. Like the pedlars of yesteryear, today's drug representatives play a key role in spreading ideas.

    There is the obligatory chapter on the internet. For most scientists the dubious quality of many websites is probably irrelevant, as most are well able to judge this for themselves. The illustrations Thagard uses are a valuable way of demonstrating to those who think we spend all our time gossiping, trading online, or downloading pornography that the internet is now as critical as a freezer or centrifuge to the conduct of research. This section would make useful reading for hospital boards reluctant to invest in information technology.

    Doctors who remember a little history of medicine, a little philosophy, and a little sociology should enjoy this book. Those with greater knowledge will find a scholarly work that advances the theory of how medical knowledge grows.

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