Models

parables v fables

Nancy Cartwright

pp. 19-31

in: Roman Frigg, Matthew C. Hunter (eds), Beyond mimesis and convention, Berlin, Springer, 2010

Abstract

Models in physics and economics often offer descriptions of imaginary situations. The descriptions are both thin–not much about the situation is filled in–and unrealistic–what is filled in is not true of many real situations. Yet we want to use the results of these models to draw conclusions about actually occurring situations. In the past I have proposed that we interpret these models as fables. The happenings in the model are only one concrete instantiation of a lesson that is more widely applicable when expressed in more abstract language. But there is a big problem– and it is a problem that besets not only reasoning from models but reasoning from real experiments as well. How do we know which ladder of abstraction to climb and how far up to go? A fable generally comes with the abstract lesson attached; most well-known parables, by contrast, require an interpretation from outside. Models, unfortunately, tend to be more like parables than fables. The right abstract interpretation is not supplied by the model itself. Where then should it come from?