Philosophical Studies

, Volume 164, Issue 3, pp 643-651

First online:

A problem for the alternative difference measure of confirmation

  • Nevin ClimenhagaAffiliated withDepartment of Philosophy, University of Notre Dame Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Among Bayesian confirmation theorists, several quantitative measures of the degree to which an evidential proposition E confirms a hypothesis H have been proposed. According to one popular recent measure, s, the degree to which E confirms H is a function of the equation P(H|E) − P(H|~E). A consequence of s is that when we have two evidential propositions, E1 and E2, such that P(H|E1) = P(H|E2), and P(H|~E1) ≠ P(H|~E2), the confirmation afforded to H by E1 does not equal the confirmation afforded to H by E2. I present several examples that demonstrate the unacceptability of this result, and conclude that we should reject s (and other measures that share this feature) as a measure of confirmation.


Confirmation Evidence Bayesian epistemology Probability