How to make sense of broadly applied medical classification systems: introducing epistemic hubs.

What are medical classification systems good for? Taking this question as a starting point, this paper argues that different answers have to be given depending on the scope of application of the classification system. While the use of restricted and specialised classification systems can be described rather well with the existing scientific taxonomy account, this account falls short to make sense of the function that systems play that are heterogeneous and imprecise but broadly applied, such as the International Statistical Classification of Diseases and Health-Related Problems (ICD). Given that the causal complexity and inter-individual heterogeneity of disease manifestation and progression challenge obtaining unambiguous, universally applicable definitions of the units of classification, this paper aims to introduce a pluralist account that relies on the concept of "epistemic hubs." This epistemic hub account stresses that classification systems used in different settings by a variety of actors can mediate between them and thus provide important opportunities for exchange of information and integration of causal explanations. Therefore, broadly applied classifications have to be connective and compatible with additional use-specific epistemic strategies in order to facilitate interactions between different methodological approaches to diseases.