LAUSR

ABSTRACT In “Representing instances: The case for reengineering conceptual modelling grammars”, Lukyanenko et al. (2019) argue that conceptual modelling has been biased towards a focus on knowledge about general phenomena (classes) rather than about specific instances. While we agree that more attention needs to be paid to instances, we critically reflect on their underlying assumptions about instances and classes. Lukyanenko et al. (2019) assume that instances are mainly material things, and also assume that class-based modelling typically requires that class definitions include comprehensive attribute structures that are expected to be stable over time. Based on these assumptions, they conclude that classes are not needed for modelling instances. As an alternative to these assumptions, we suggest that instances can be viewed as language constructs, i.e., as objects that may be anything that is uniquely referred to and identified in human communication. Based on this assumption, we introduce an identity-oriented view of classes, implying that classes are required for modelling objects (instances). We agree with Lukyanenko et al. (2019) that a reengineering of conceptual modelling grammars is required. This reengineering would benefit from approaches such as an identity-oriented view of classes and a class-instance modelling grammar.