 This leads us to another facet of population genetics that has attracted philosophers’ attention: the way in which abstract models, that involve simplifying assumptions known to be false, can illuminate actual empirical phenomena. Idealized models of this sort play a central role in many sciences, including physics, economics and biology, and raise interesting methodological issues. In particular, there is often a trade-off between realism and tractability; the more realistic a model the more complicated it becomes, which typically limits its usefulness and its range of applicability. This general problem and others like it have been extensively discussed in the philosophical literature on modelling (e.g., Godfrey-Smith 2006, Weisberg 2006, Frigg and Hartmann 2006), and are related to population genetics by Plutynski (2006).