Bayesianism and Diverse Evidence

Abstract

A common methodological adage holds that diverse evidence better confirms a hypothesis than does the same amount of similar evidence. Proponents of Bayesian approaches to scientific reasoning such as Honvich, Howson and Urbach, and Earman claim to offer both a precise rendering of this maxim in probabilistic terms and an explanation of why the maxim should be part of the methodological canon of good science. This paper contends that these claims are mistaken and that, at best, Bayesian accounts of diverse evidence are crucially incomplete. This failure should lend renewed force to a long-neglected global worry about Bayesian approaches.

Bayesian Networks and the Problem of Unreliable Instruments

“…There are two Bayesian approaches to the problem of the variety of evidence present in the literature (Wayne 1995). On the correlation approach, the items of evidence E 1 , .…”

Wayne, Horwich, and Evidential Diversity

“…, H n , where the n hypotheses are assumed to be mutually exclusive and exhaustive. Wayne's (1995) reconstruction of Horwich's (1982) explication of CSED involves the following three propositions concerning such contexts:…”

“…3 I have taken the liberty of translating this passage from Wayne (1995) into my notation. 4 See the Appendix for all proofs and counterexamples.…”

“…1 Introduction Wayne (1995) gives one reconstruction of Horwich's (1982) Bayesian account of the value of evidential diversity. He then shows that there are counterexamples to this reconstruction of Horwich's explication of CSED.…”

“…According to Wayne (1995), H 3 captures the kernel of Horwich's account of CSED. In the next section, we will look at a counterexample to H 3 due to Wayne (1995 .…”