Response to Shafer’s comments

Abstract

I have to admit to being mystified as to what contradiction Shafer sees between his dictionary definition of ‘‘plausibility,’’ and my use of that term, as I can find none. More to the point, the charge of appropriating terminology could with more justice be leveled against the theory of belief functions, as Jaynes use of ‘‘plausibility’’ in the context of Cox s Theorem goes back at least as far as 1958 [1], which predates Dempster s seminal work on belief functions [2] by 10 years, and Shafer s work [3,4] by 15 years. From a pragmatic standpoint, though, I concur that it would be worthwhile to avoid using the term ‘‘plausibility’’ in future discussions of Cox s Theorem, due to that term s prominence in the theory of belief functions. The suggested replacement, ‘‘likeliness,’’ is too closely tied to the notion of probability: my dictionary explicitly defines it as the probability of an outcome. Looking for