Contemporary discussion commonly focuses on Laudan’s (1981) argument to the effect that the history of science furnishes vast evidence of empirically successful theories that were later rejected; from subsequent perspectives, their unobservable terms were judged not to refer and thus, they cannot not be regarded as true or even approximately true. (If one prefers to define realism in terms of scientific ontology rather than reference and truth, one may rephrase the worry in terms of the mistaken