Philosophers should prefer simpler theories

Recent years have seen considerable attention paid to the methodology of philosophy. The puzzle is simple—if philosophy is not an empirical discipline, how can one philosophical theory be rationally preferred over another? One answer to this question is that we should apply the theoretical virtues. Foremost among these theoretical virtues is simplicity—so perhaps we should prefer simpler philosophical theories to more complex ones. Huemer (Philos Q 59:216–236, 2009) objects that the reasons to prefer simpler theories in science do not apply in philosophy. I will argue that Huemer is mistaken—the arguments he marshals for preferring simpler theories in science can also be applied in philosophy. Like Huemer, I will focus on the philosophy of mind and the nominalism/Platonism debate. But I want to engage with the broader issue of whether simplicity is relevant to philosophy.