A Common Framework for Qualitative and Quantitative Modelling

The paper introduces model ensembles as a common framework for understanding qualitative differential equations (QDEs) and differential inclusions in a precise mathematical sense. It provides basic insights into the communalities and differences of both approaches to model under uncertainty. On this basis, a set of established methods for QDEs, some hybrid methods and standard quantitative methods can be classified, the notion of a “spurious behaviour” is clarified more thoroughly, and the importance of generality as a concept complementary to uncertainty is underpinned. Further paths for extending qualitative reasoning are outlined.