BAYESIANISM AND DIVERSE EVIDENCE

A common methodological adage holds that diverse evidence better confi rms a hypothesis than does the same amount of similar evidence. Propon ents of Bayesian approaches to scientific reasoning such as Horwich, H owson and Urbach, and Earman claim to offer both a precise rendering o f this maxim in probabilistic terms and an explanation of why the maxi m should be part of the methodological canon of good science. This pap er contends that these claims are mistaken and that, at best, Bayesian accounts of diverse evidence are crucially incomplete. This failure s hould lend renewed force to a long-neglected global worry about Bayesi an approaches.