ABSTRACT
The question of what models are is ambiguous between a functional and an ontological reading. We begin with a discussion of functional characterisations of models, and we examine views that see models as objects that function representationally. Turning to ontological characterisations of models, we reflect on what one would expect from such a characterisation and formulate five questions that every account of the ontology of models must answer. Some models are material objects: they are things like ship-shaped wood blocks or biological organisms. There are at least eight prima facie candidates for an ontology of non-material models: set-theoretical structures, abstract objects, descriptions, mathematical objects, equations, computational structures, fictional objects, and artefacts. We introduce these proposals and discuss their relation to each other, concluding that upon closer analysis they can be reduced to two: mathematical models and fictional models. Unless a worked-out account of fictional models is formulated, the appeal to fiction remains little more than a promissory note. We meet this challenge by formulating an account of fictional models based on Walton’s pretence theory and we show how this account integrates with the DEKI account of representation.
