Full Idea
Old evidence seems to provide some confirmation, but Bayesianism does not allow for this, since old evidence will have a prior probability of one, and so have no effect on the posterior probability of the hypothesis.
Gist of Idea
Bayes seems to rule out prior evidence, since that has a probability of one
Source
Peter Lipton (Inference to the Best Explanation (2nd) [2004], 01 'Descr')
Book Reference
Lipton,Peter: 'Inference to the Best Explanation (2nd ed)' [Routledge 2004], p.17