ABSTRACT
These instances of violations in genuine science of the sorts of continuity usually required by realists are by themselves suffi cient to show that the form of scientifi c growth which the convergent realist takes as his explicandum is often absent, even in the ‘mature’ sciences. But we can move beyond these specifi c cases to show in principle that the kind of cumulation demanded by the realist is unattainable. Specifi cally, by drawing on some results established by David Miller and others, the following can be shown:
a) the familiar requirement that a successor theory, T 2 , must both preserve as true the true consequences of its predecessor, T 1 , and explain T 1 ’s anomalies is contradictory;
b) that if a new theory, T 2 , involves a change in the ontology or conceptual framework of a predecessor, T 1 , then T 1 will have true and determinate consequences not possessed by T 2 ;
c) that if two theories, T 1 and T 2 , disagree, then each will have true and determinate consequences not exhibited by the other.
