The final version of my manuscript Philosophy of Epidemiology is off to the publishers, and I hope it counts as self-promotion rather than self-plagiarism if I post the Synopsis here:
The content of the book can be summarised as follows. Causation and causal inference are over-emphasized in epidemiology and in epidemiological methodology, and explanation and prediction deserve greater emphasis. Explanation is a much more useful concept for understanding measures of strength of association (Chapter 3) and the nature of causal inference (Chapters 4 and 5) than causation itself is, because causation is really only part of what we seek to measure and infer respectively. What epidemiologists really seek to do is explain, and their practices are seen much more clearly when described as such. Explanation is also the central notion to an adequate theory of prediction, a topic which has been sadly neglected by both philosophers and epidemiologists (Chapter 6). To predict, one must explain why what one predicts is going to happen, rather than some – but certainly not all – other possible outcomes (Chapter 7). Just like an adequate explanation, a good prediction must be sensitive to the alternative hypotheses it needs to dismiss and those it can safely ignore.
These themes are developed in Chapters 3-7. The remaining chapters tackle more specific problems, and apply the lessons learned where appropriate. Thus Chapter 8 concerns measures of attributability, which are not conceptually straightforward; and the lesson is that an outcome is attributable to an exposure to the extent that it is explained by it. Chapter 9 concerns “risk relativism”, an unfortunate degenerative tendency of thought some epidemiologists have identified in their peers. Risk relativism is diagnosed in Chapter 9 as a case of physics envy, exacerbated by a tendency to seek a univocal measure of causal strength, rather than a context-appropriate explanatory measure. Chapter 10 examines “multifactorialism”, another modern epidemiological ailment – though considered by most epidemiologists to be a profitable mutation. Multifactorialism is criticised for dropping the requirement that diseases be defined in relation to explanatory causes. Chapter 11 discusses the various embarrassments that lawyers have inflicted upon themselves in trying to use epidemiological evidence. Again, the lack of attendance to explanatory questions in favour of causal ones is partly to blame for the mess. Lawyers reasonably resist the explanation of particular trains of events by general statistical facts; but to refuse to admit those facts as evidence for the truth of particular causal explanations is plainly unreasonable. The theme, then, is that explanation deserves more attention epidemiological attention, and causation less. We will revisit the theme in the concluding Chapter 12.
[Philosophy of Epidemiology is being published by Palgrave Macmillan in the series New Directions in the Philosophy of Science and will appear in 2013.]