This article is an attempt to clarify and possibly extend Achinstein's
idea of subjective evidence. The argument is made that even though th
e idea of subjective evidence is ambiguous in many respects, if clarif
ied, it holds potentially important consequences for various branches
of knowledge. An attempt is made to show how the concept of subjective
evidence may be given a probabilistic interpretation. This is done by
introducing the idea of a potentially relevant class of evidence stat
ements.