Roman Frigg

Modelling and Representation


Models are of central importance in many scientific contexts. We study models and thereby discover features of the phenomena they stand for. For this to be possible models must be representational: they can instruct us about the nature of reality only if they represent the selected parts or aspects of the world we investigate. This raises important questions. What are scientific models? How do they represent? And how do they relate to scientific theories?


The currently dominant view, the structuralist version of the so-called semantic view of theories, takes models to be set-theoretical structures and construes representation as an isomorphism between model and reality. I offer an account of what the problem of representation is and then argue that the semantic conception suffers from a number of serious shortcomings: it cannot account for misrepresentation; it cannot account of idealisations that are crucial in models; it offers no tenable explanation of how mathematics is applied to the empirical world, and it is blind towards the pluralism of representational styles in scientific practice.


In response to these problems, I develop a view what has become known as the ‘fiction view of models’. Rather than being set-theoretical structures, models are conceptualised as fictional entities of the same kind as, say, Tolkien’s Middle Earth. To avoid metaphysical tangles, I develop a nominalist account of scientific fictions based on Pretence Theory and argue that this account is able to meet a number of important criteria of adequacy: the formulation of identity conditions, the explanation of property attribution, the stipulation of a semantics for comparative statements, the provision of a theory of truth in fiction, and the formulation of an epistemology of modelling. This view of models is complemented by an account of scientific representation that does not build on isomorphism and instead explains scientific representation in terms of denotation and translation-keys. I use Newton’s model of the solar system to illustrate how the account works and show that it is able to explain all relevant features of the practice of scientific modelling, in particular the limit-idealisations that lie at the heart of many physics models.


I take a deflationary view on recent claims that computer simulations raise a host of new philosophical issues and call into question our philosophical understanding of the semantics of models and scientific theories. These claims are overblown. Far from demanding a new philosophy of science, the use of computer simulations raises few new philosophical problems and does not necessitate a fundamental rethinking of our philosophical views about models.


Models and representation:

Models and Imagination:

Models and computer simulation:

Surveys and encyclopaedia entries: