Can structural realism leave the comfort zone?

This essay critically examines the recent interpretation of the transition from phlogiston theory to contemporary chemistry developed through the lens of structural realism. This interpretation seeks to establish a correspondence between phlogistication/dephlogistication and reduction/oxidation processes, lending support to the preservation of structures amidst theory change. Here, we argue against the tenability of such a structuralist view on several grounds. First, we identify an ambiguity inherent to the parallelism between dephlogistication and oxidation. Second, we cast doubt on the generality of the structural correspondence by showing its vulnerability to the specific formulation of phlogiston theory adopted. Third, we argue that the term 'phlogiston' can be better classified in the empirical vocabulary, instead of theoretical vocabulary, hence undermining the structural correspondence that, by construction, only bridges theoretical terms across subsequent theories. Fourth, we suggest that, even if accepted, the structural correspondence fails to support scientific realism, which should aim to identify continuity between scientific theories, while oxidation-reduction chemistry remains merely an instrumental framework. Overall, this essay underscores the limitations of structural realism in accommodating the ontological disruptions in non-mathematized sciences, such as certain areas of chemistry, ultimately questioning its ability to 'leave the comfort zone' of theoretical physics where it originated.