The Ontology of Models

Abstract

The term scientific model picks out a great many things, including scale models, physical models, sets of mathematical equations, theoretical models, toy models, and so forth. This raises the question of whether a general answer to the question What is a model? is even possible. This chapter surveys a number of philosophical approaches that bear on the question of what, in general, a scientific model is. While some approaches aim for a unitary account that would apply to models in general, regardless of their specific features, others take as their basic starting point the manifest heterogeneity of models in scientific practice. This chapter first motivates the ontological question of what models are by reflecting on the diversity of different kinds of models and arguing that models are best understood as functional entities. It then provides some historical background regarding the use of analogy in science as a precursor to contemporary notions of scientific model. This is followed by a contrast between the syntactic and the semantic views of theories and models and their different stances toward the question of what a model is. Scientists, too, typically operate with tacit assumptions about the ontological status of models: this gives rise to what has been called the folk ontology of models, according to which models may be thought of as descriptions of missing (i. e., uninstantiated) systems. There is a close affinity between this view and recent philosophical positions (to be discussed in the penultimate section) according to which models are fictions. This chapter concludes by considering various pragmatic conceptions of models, which are typically associated with what may be called mixed ontologies, that is, with the view that any quest for a unitary account of the nature of models is bound to be fruitless.