 Although his defense of virtuous predictivism is the centerpiece of his account, Barnes claims that predictivism can hold true of actual theory evaluation in a variety of ways. He maintains that the position deemed ‘weak predictivism’ is actually ambiguous—it could refer to the claim that scientists actually rely on knowledge that evidence was (or was not) predicted because prediction is symptomatic of a some other feature(s) of theories that is epistemically important (‘tempered  predictivism’[13])  or simply to the fact that there is a correlation between prediction and this other feature(s) (‘thin predictivism’). The distinction between tempered and thin predictivism cross classifies with the distinction between virtuous and unvirtuous predictivism to produce four varieties of weak predictivism. Barnes then turns to the case of Mendeleev’s periodic law and argues that all four varieties can be distinguished in the scientific community’s reaction to Mendeleev’s theory of the elements (2008: 82–122). In particular, he argues that it was specifically Mendeleev’s predicted evidence, not his accommodated evidence, that had the power to confirm his scientific and methodological background beliefs from the standpoint of the scientific community. 