   The important methodological implication of empirical adaptationism stems from the causal power that it assigns to natural selection: an apparent discrepancy between data and the predictions of an optimality model should be resolved by rejection of that model and development of a new model. This is justified by an appeal to our “always” imperfect knowledge of nature (e.g. see Cain 1989). This contrasts with the pluralist perspective: such a discrepancy might well provide evidence against natural selection.