Evidence-based medicine is a redundant term to the extent that doctors have always claimed they practiced medicine on the basis of evidence. They have, however, disagreed about what exactly constitutes legitimate evidence and how to synthesize the totality of evidence in a way that supports clinical action. Despite claims to the contrary, little progress has been made in solving this hard problem in any sort of formal way. The reification of randomized clinical trials (RCTs) and the tight linkage of such evidence to the development of clinical guidelines have led to error. In part, this relates to statistical and funding issues, but it also reflects the fact that the clinical events that comprise RCTs are not isomorphic with most clinical practice. Two possible and partial solutions are proposed: (1) to test empirically in new patient populations whether guidelines have the desired effects and (2) to accept that a distributed ecosystem of opinion rather than a hierarchical or consensus model of truth might better underwrite good clinical practice.