It’s online!

Brendan Clarke, Donald Gillies, Phyllis Illari, Federica Russo, Jon Williamson

Mechanisms and the Evidence Hierarchy

Evidence-based medicine (EBM) makes use of explicit procedures for grading evidence for causal claims. Normally, these procedures categorise evidence of correlation produced by statistical trials as better evidence for a causal claim than evidence of mechanisms produced by other methods. We argue, in contrast, that evidence of mechanisms needs to be viewed as complementary to, rather than inferior to, evidence of correlation. In this paper we first set out the case for treating evidence of mechanisms alongside evidence of correlation in explicit protocols for evaluating evidence. Next we provide case studies which exemplify the ways in which evidence of mechanisms complements evidence of correlation in practice. Finally, we put forward some general considerations as to how the two sorts of evidence can be more closely integrated by EBM.


Launch: Society for the Philosophy of Information

Following a 10-year period of formal and informal collaboration between several researchers, the establishment of the Society for the Philosophy of Information (SPI, [1]) inaugurates the next phase in the development of the philosophy of information as an independent and self-sustained philosophical field.

The Society was founded during the fourth workshop on the philosophy of information [2] held at the University of Hertfordshire in May 2012, and is now ready to open its membership to anyone interested in the philosophy of information while promoting its scientific and educational activities.

Prior collaborations, including part of the work done at the Oxford-based IEG research-group [3], several editorial projects [4-8], and a highly successful workshop-series [9], will find a new home in this society. In addition to this legacy, several new activities will be launched and led by some of the current members of the society [10].

Concretely, the SPI:

– brings together scholars in the area harnessing the multidisciplinary
and international nature of the Philosophy of Information;
– organises workshops, seminars, conferences and other similar
activities to explore the philosophical issues concerning the concept
of information and its cognate notions;
– publishes teaching material for undergraduate and graduate courses on
the Philosophy of Information;
– maintains a state-of-the-art collection of bibliographic resources;
fosters editorial projects and funding proposals.

In this way, the SPI offers learning and research instruments to undergraduate and graduate students, while promoting the academic network and activities of junior and senior academics whose work focuses on the Philosophy of Information.

The website of the SPI ( is the main centre of activity where we present the aim and focus of the philosophy of information, the mission of its society, and, most importantly, provide information about the current and soon to be launched activities of the SPI. The current activities include:

– a regularly updated PI-related news feed;
– an overview of previous workshops in the philosophy of information,
and an announcement of the fifth workshop;
– a brand new textbook [11] on the philosophy of information that forms
the cornerstone of our teaching resources;

While the soon to be launched activities include:

– a sustained presence of SPI-sponsored sessions at international
– a repository of teaching resources, including an overview of courses
in the philosophy of information that are currently taught;
– bibliographic resources on the philosophy of information, including
an annotated bibliography;
– an overview of the many edited volumes and monographs on the
philosophy of information that were published during the last ten
– book-reviews and book-symposia on notable publications that fit
within or are relevant to the philosophy of information.

Interested researchers and students are encouraged to support this enterprise by becoming a member (link) and by taking part in the activities of the society.

Best regards,


Freshly published!

The evidence that evidence-based medicine omits
Brendan Clarke, Donald Gillies, Phyllis Illari, Federica Russo, Jon Williamson

According to current hierarchies of evidence for EBM, evidence of correlation (e.g., from RCTs) is always more important than evidence of mechanisms when evaluating and establishing causal claims. We argue that evidence of mechanisms needs to be treated alongside evidence of correlation. This is for three reasons. First, correlation is always a fallible indicator of causation, subject in particular to the problem of confounding; evidence of mechanisms can in some cases be more important than evidence of correlation when assessing a causal claim. Second, evidence of mechanisms is often required in order to obtain evidence of correlation (for example, in order to set up and evaluate RCTs). Third, evidence of mechanisms is often required in order to generalise and apply causal claims.

While the EBM movement has been enormously successful in making explicit and critically examining one aspect of our evidential practice, i.e., evidence of correlation, we wish to extend this line of work to make explicit and critically examine a second aspect of our evidential practices: evidence of mechanisms.

Public engagement event: Your health, what is the evidence?

Archaeology Lecture Theatre, Archaeology building, UCL, 5.30pm Monday 10th September 2012

The most wide-ranging change in medical practice in the past two decades has been the introduction of evidence-based medicine (EBM). The EBM project, which calls for the explicit examination of evidence to guide healthcare decisions, has made a significant difference to the practice of healthcare. However, the complexity and sheer quantity of medical evidence means that tools for assessing this evidence are of crucial importance to this project. For example, the quality of evidence supporting a particularly health intervention might be assessed by examining the method by which that evidence is produced. Typically, this kind of ranking suggests that randomised control trials (or meta-analysis of randomised control trials) will produce better evidence than other trial methodologies. This means that evidence produced by other means, such as that arising from laboratory science, or from observational studies, is usually regarded as unsuitable when it comes to clinical decision making.

However, recent philosophical work has cast some doubt on the wisdom of relying on just one form of evidence when considering complex medical interventions. For instance, it seems possible to improve the reliability of evidence gained from clinical trials by judicious use of evidence gleaned from laboratory investigation. This suggests that current schemes of ranking biomedical evidence may be capable of some improvement.

This evening event presents some results of a preliminary project designed to investigate these questions, together with some lively discussion between philosophers and medical practitioners about the role of ranking evidence in supporting good scientific practice.

Participants: Brendan Clarke, Phyllis Illari, Federica Russo, Jan Vandenbroucke, Jon Williamson.

Thanks to the generosity of the Arts and Humanities Research Council, the event will be followed by a reception in the Wilkins Lower Refectory [see here for directions].

The event is free, and there is no need to book. Contact Brendan Clarke ( for any queries.