The Puzzle of Fictional Models

The use of fictional models is extensive and rewarding in modern science. This fact captured the attention of philosophers of science, who are focusing on questions such as the following: is it possible for a fictional model to be explanatory? And, if so, in virtue of what is such a fictional model explanatory? In this paper, I discuss these questions in relation to the realism vs. anti-realism debate in philosophy of science. I focus on work developed by Alisa Bokulich who has argued for the explanatory role played by fictional models, claiming that it can be accommodated by realism in ‘a broad sense’. To this end, Bokulich introduced what she called ‘an eikonic conception’ of explanation, as opposed to the so-called ‘ontic’ conception. This move, Bokulich claims, allows non-causal explanations to be acceptable to a modified version, as opposed to a ‘naïve’ brand of realism. Roughly, a fictional model can capture aspects of reality if it manages to act as a proxy for a theory targeting a physical system. As Bokulich explains with the example of James Clerk Maxwell’s use of mechanical models, this is due to structural correspondences between a model and a theory at a certain level of abstraction. However, Bokulich does not explain how the model grasps reality. In this paper, I fill this missing piece of the puzzle. While I agree with Bokulich on the explanatory function of fictional models, I shall invoke her reading of Maxwell’s work to draw a different conclusion. Specifically, I argue that structural correspondences at various levels form what I call ‘a ladder of abstractions’ which connects aspects of a target system to the corresponding depths of descriptions. Modifying in these terms the scope of ‘representing a system’, I suggest that Bokulich’s proposed modification of realism is obviated.