 The problem with this kind of argument is that the historical premise should be borne out by the actual history of theory-change in science. It’s not enough to say that scientific theories change over time; these changes should be such that the newer theories are incompatible with the past ones. Or, to use Hesse’s idiom, it should be shown that past and current scientific ‘ontologies’ are incompatible with each other. Showing incompatibility between the claims made by current theory T and a past theory T′ requires a theory of reference of theoretical terms which does not allow that terms featuring in different theories can nonetheless refer to the same entity in the world. Hence, it is question-begging to adopt a theory of reference which makes it inevitable that there is radical-reference variance in theory-change.