Knowing what not to believe

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  • Perspectives

    www.thelancet.com Vol 383 March 22, 2014 1029

    BookKnowing what not to believeTo advocates of the use of standard scienti c procedures to judge whether exposure A causes disease B, or whether treatment X is e ective in disease Y, there may be no more discouraging problem than the indi erence, or even hostility, of some lay people both to our conclusions and to our approach to drawing them. Scienti c and medical authorities will insist that they have examined the records of thousands of vaccinated and unvaccinated children from several parts of the world and have found no hint of any di erence in the incidence of autism in the two groups, but they will be trumped by a celebrity asserting that her child was vaccinated and later got autism, and she knows better. The consequence is a decline in vaccination rates, and a rise in unnecessary deaths from measles and whooping cough. The scienti c and medical world will take as established fact that HIV is a necessary cause of AIDS, and devise e ective treatments, but their views do not matter when a politician embraces AIDS denialism. The consequence is failure to undertake e ective HIV prevention and treat ment and the tragic loss of many lives.

    Of what value is our research if no one is listening? Worse yet, what if the very foundations of the way we draw inferences are suspect? It is to confront this gap between the scienti c talkers and the public non-listeners that Michael Bracken has shaped this excellent book, and few are as qualified as he to undertake this supremely difficult assignment. Bracken is a leading gure in the world of epidemiology, but unlike most practitioners of classical aetiological epidemiology, he has embraced the world of medical treatment as part of the scope of his work and thought. His 1992 book Effective Care of the Newborn Infant, co-authored with the neonatologist Jack Sinclair, was one of the first evidence-based medical

    textbooks. And in Risk, Chance, and Causation, which patiently and lucidly explains how epidemiologists think, he illustrates his themes with examples that relate both to the origins of disease and to the treatment of disease.

    The book is partly a straightforward exposition of key logical and statistical concepts along with a solid dose of epidemiological study design and causal inference. It is written with careful intelligence, with many useful and clarifying examples, and without resort to academic paraphernalia. But the book is also an expression of

    deep frustration at the mix of actors, musicians, vitamin salesmen, members of the royal family, and yes, physicians and scientists, who leap in to proclaim with con dence on matters on which they know little and have thought less.

    Among the topics covered are randomised trials, meta-analysis, disease clusters, screening tests, statistical signi cance, e ect sizes, and, at the heart of it all, the elusive notions of risk and randomness. Bias and confoundingperhaps the topics of which critics of the biomedical scienti c establishment are most innocentare particularly well discussed, with an especially strong treatment of publication bias. Cause and ultimate cause are also explored, and Bracken provides an excellent overview of some of the thinking by noted epidemiologists on this complex topic.

    Genomic research, of which Bracken is supportive, and animal research, of which he is quite sceptical, also feature. The extent to which animal studies and human studies are contradictory, with

    toxicology tests in animals surprisingly often no better than a coin toss in predicting what will happen in human beings, is a message worthy of more dissemination. On the other hand, after conceding that the genomic revolution has yet to contribute anything substantial to public health, Bracken predicts great things for genomics in the next 20 years, claiming that there is no area of studying disease causation that looks more promising. This is the one place in the book where he strays from his evidence-based perspective.

    If you would like a book to o er to a thoughtful and open-minded person unfamiliar with how epidemiologists and statisticians develop, process, and think about human health information, this is a very good choice. Public understanding of science would be much advanced if this book were to be required reading in courses in science and journalism. But the dilemma we face is not so much that people are insu ciently educated in statistics, epidemiology, or even plain logic, though that is undoubtedly the case; the real problem is that the disinterestedness and organised scepticism that Robert K Merton described as central tenets of science are in such rare supply.

    Critics of biomedical science often claim that our inferences are invalid because they are the product of collusion by biomedical scientists with the pharmaceutical industry to sell expensive drugs. And, indeed, greed and avarice have played a regrettable part in shaping some medical recommendations. But the real mortal sin is the rejection of the logic of scientific procedure, and its companion, denial of the possibility of even-handed examination of evidence. The accusations that the conventional scienti c approach to nature is Western (with all that connotes), or that there is no such thing as scientific truth,

    Risk, Chance, and Causation Investigating the Origins and Treatment of DiseaseMichael B BrackenYale University Press, 2013.Pp 344. US$6000. ISBN 9780300188844the real problem is that the

    disinterestedness and organised scepticism that Robert K Merton described as central tenets of science are in such rare supply.

    Further reading

    Chigwedere P, Seage GR 3rd, Gruskin S, Lee TH, Essex M. Estimating the lost bene ts of antiretroviral drug use in South Africa. J Acquir Immune De c Syndr 2008; 49: 41015

    Merton RK. Science and technology in a democratic order. J Legal Political Sociol 1942; 1: 11526

  • Perspectives

    1030 www.thelancet.com Vol 383 March 22, 2014

    In briefconfusion of subjective and objective reality is actually Cohles.

    In one of his case histories, Freud describes projection as when we refer the causes of certain sensations to the external world, instead of looking for them (as we do in the case of others) inside ourselves. Just as Freuds case histories can resemble detective stories, True Detective is itself like a case history. Its the history of a murder case, but, more deeply, its also the history of a case of psychological trauma, addiction, and depression, with Cohle as both storyteller and subject. The seductive, dark reality of the show can be seen, at times, as a projection of the inner life of Cohle, creating a distorted world where hope remains in the chance that he, and it, might shift back towards the light.

    Caleb Gardner

    Television Case history Although visually striking, True Detective, the gripping HBO show, has a way of making the world seem pretty bleak. Set in the literal and gurative swamps of Louisiana, the rst season follows state detectives Rustin Cohle (Mathew McConaughey) and Martin Hart (Woody Harrelson) as they work the case of an occult murder of a young woman in 1995.

    Nothing is as it seems, of course, and as the events of 1995 unfold, we are shuttled between 2002 and 2012 where Cohle and Hart must examine their work and lives through the re ning lens of the past, revealing thoughts and events they have long kept hidden from the world and, sometimes, themselves. Aside from the deft storytelling and mesmerising cinematography, what distinguishes the show from others of this genre is

    the psychological depth plumbed by the main characters.

    Whilst Harrelson convincingly portrays Harts battles with the predictable demons of in delity, alcohol, and ennui, its McConaughey who pushes forward the frontier of mental anguish in his performance as the brilliant but traumatised and demonstratively nihilistic Cohle, who struggles with drug and alcohol use and the accidental death of his daughter years ago. In fact, you cant listen to too much of Cohles non-stop negativity without either wanting, like Hart, to tell him to shut up, or beginning to share some of his despondency. His words almost begin to sound like wisdom describing the ontological fallacy of expecting a light at the end of the tunnel, well thats what the preacher sells, same as a shrink, until you realise that the

    True DetectiveHBO, 2014. Written by

    Nic Pizzolatto, directed by Cary Joji Fukunaga, with executive

    producers Nic Pizzolatto, Cary Joji Fukunaga,

    Matthew McConaughey, Woody Harrelson, Steve Golin,

    Scott Stephens, Richard Brown.Showing on Sky Atlantic in the UK

    http://www.sky.com/tv/show/true-detective

    or that there are alternative ways of understanding causality in the universe that normative science does not usenotwithstanding the small kernel of truth buried in each accusationstrike centrally at the core of science. Without scienti c methods and con dence in these methods, we in science have nothing to contribute to the world.

    Admittedly, there is no simple dichotomy between agreed-upon scienti c truth and what amounts to one persons opinion. The resolution of the many problems that lie in the long stretch between these two poles must be made with disinterested judgment, or as close an approximation to it as we fragile human beings are capable of. Having a common sets of principles to work from is essential. Were science not open to variant hypotheses, none of the scienti c progress we so take for granted would have taken place. Science therefore encourages variant hypotheses, but is rightly not sympathetic to variant, in fact

    rigged, ways of testing hypotheses. An important component of this book is Brackens confidence in the conventional scienti c approach in use by epidemiologists and statisticians. Bracken nowhere attempts to formally justify this philosophical stance, but it is implicit in the book, and his common sense and disinterested approach to the health problems under discussion serves as a robust argument in favour of the approaches he takes.

    A distinctive feature of many of the proclaimers of anti-science is the absence of the introspection and scepticism that is required if evidence is to be judged fairly. One AIDS denialist writes: The truth is that people arent dying of AIDS. People are getting sick and dying from hormone contaminated meat, carcinogenic car fumes, the overuse of antibiotics, and numerous other immunosuppressive aspects of everyday life in our toxic, fur worshipping, ozone depleting, money driven, consumerist society. This

    language is a cry for simpli cation, for a perfect alignment of mortal ailments with political and social ailments, for a world in which diseases are caused by what we dislike in society. It is an echo of the Victorian Sanitarians cry: all lth is disease. The determination to yoke the messy world of reality to a particular worldview forces AIDS denialists, autism-vaccine linkers, and creationists to share a common traitan inability to change ones mind. This book, unfortunately, is unlikely to change such patterns of thought. Bracken represents the antithesis of such thinking and uses well-chosen epigraphs throughout the book to illustrate his perspective. My favourite is the oldest, the words of a character in Helen, a play by the Greek tragedian Euripides, who told us some 2500 years ago that Mans most valuable trait is a judicious sense of what not to believe.

    Nigel Panethpaneth@epi.msu.edu

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