Suppose a doctor wants to diagnose whether a particular patient B has a certain disease D. The patient belongs to the reference class of people having both symptoms S1 and S2. The doctor knows that the probability of having the disease given having a symptom S1 is 0.9 (P(D|S1)=0.9 ) and she knows that the probability of having the disease having a different symptom S2 is 0.4 (P(D|S2)=0.4). Unfortunately, that is all she knows. What is the probability that the patient has the disease? 0.9? 0.4? 0.65? Or some different value?
Month: December 2015
‘On the political dimension of scientific evidence’ – this is the title of a seminar I gave on 9th December 2015 at the University of Amsterdam, Philosophy and Public Affairs series.
As part of this seminar, I presented topics and ideas lied at the heart of the project ‘Evaluating evidence of mechanisms’ to an audience of a philosophers of science, medicine and other health scientists from different areas and backgrounds, including political and moral philosophers too.
The line of research that I have been developing over the last years, alongside other EBM+ colleagues, is clearly in the spirit of the ‘philosophy of science in practice’, where the “in practice” plays a major role. This led me and my colleagues in the EBM+ programme, to make contacts and work with practicing scientists. We wanted a philosophy of science that would be useful to make better science, and better medicine, for that matter.
But there are other disciplinary borders that we might need to cross. During the talk, I promoted the view that clarifying notions such as ‘evidence’, ‘mechanism’, or ‘causation’ can be of help to re-frame debates and controversies that, although generated within the practice of the health sciences, land in the broader ‘political’ domain. The term ‘political’ is used here not in a narrow sense, as the motives and the reasons for funding one project vs. another, or for revealing controversial conflicts of interest, but in a broader sense, as science that reaches to and engage with the public, the policy makers and students (in philosophy, the humanities, or the sciences)
Evidence, mechanisms and causation, all have an epistemic value and this value may well have a spill over effect on science communication or policy-making. Here are two examples. The distinction between generic and single-case causal claim is essential to understanding what kind of claim the International Agency for Research on Cancer (IARC) makes when it says that processed meat is probably carcinogenic to humans. But little effort has been made to explain what an ‘epidemiological fact’ is, and how is that different from a claim about any specific individual person. Similarly, the idea of a ‘mixed aetiology’ of diseases is key to provide a stronger theoretical basis to fields of study such as gender medicine or to design appropriate public health interventions. When disease aetiology is reduced to bio-chemical factors, we miss important explanatory factors that might enlighten exposure or intervention mechanisms.
These are clearly delicate topics that cannot be exhausted in a short blog post. Should you be interested in – or even puzzled by – evidence of mechanisms, contact us. We can point to relevant publications or indeed organise a seminar, workshop, or a roundtable to discuss these – and other things – together.