Models: Parables v Fables

A good many models used in physics and economics offer descriptions of imaginary situations, using a combination of mathematics and natural language. 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 inform our conclusions about a range of actually occurring situations. I propose we interpret many of these models as fables. The actual happenings in the model are only one concrete instantiation of a lesson that is more widely applicable ‘when expressed in more abstract language.' A fable generally comes with the abstract lesson attached; parables, by contrast, usually require an interpretation from outside. Models, then, tend to be more like parables than fables. The right abstract interpretation is not supplied by the model itself. The central problem, then, is where shall it come from?