   There is some controversy over the protocol for testing whether natural selection is a sufficient explanation of a trait. Brandon and Rausher (1996) objected that local optimality is a distinct claim and so tests for the importance of natural selection should not use optimality models, whose use they equate to “theft”, which they believe means that such models are generically incompatible with universal aspects of the biology of organisms. They also take issue with how the predictive accuracy of censored and uncensored models should be assessed. Godfrey-Smith (2001) makes the observation that the censored and uncensored test models typically have different complexity. More complex models usually fit the data better, but risk obscuring the underlying trend or comprising predictive accuracy—there may be a problem of over-fitting lurking here (see, e.g., Gauch 2003 for an overview of the curve-fitting problem).