Ethical and epistemological problems when applying evidence-based medicine to pain management.

Epistemology, or the theory of knowledge, is a branch in philosophy concerned with the definitions of knowledge and evidence. Although evidence-based medicine (EBM) has a strong ethical imperative behind it, rooted in the concern to do no harm, to do one's best for one's patients, and by doing so--eliminating waste, it still harbors within it serious epistemological limits. These include methodological and ethical limits to perform randomized controlled trials, the idea of "hierarchy of evidence" which may provide conclusions well short of medical knowledge, and the unique use of a single particular theory of statistical inference which is far from consensual. In this article, we review these difficulties and suggest that EBM is at best a methodological solution to some clinical phenomena, but remains blind to mechanisms of explanation and causation needed, in order to advance our knowledge. Further research in the theory of evidence and inference, causation and correlation, clinical judgment and collective knowledge, the structure of medical theory, and the nature of clinical effectiveness are needed.