Aristotle regularly identifies philosophical concepts as homonymous. Although the force of this appraisal is not always immediately clear, it is surely noteworthy that when offering this sort of claim Aristotle very often has a critical target in sight. Most often, though not always, he has Plato in mind, because he believes that Plato systematically underappreciates the complexity of core philosophical concepts. As a typical example, Aristotle argues that Plato incorrectly posits a single Form of Goodness which is the same for all good things; on this approach, everything which is good is good because it participates in a single, common Form, Goodness. According to Aristotle, Plato wrongly assumes that all good things are good in the same way, that their goodness is somehow common across all cases. When criticizing Plato for failing to appreciate homonymy, then, Aristotle means to assail this assumption by showing, as he often says, that goodness is 'spoken of in many ways' (EN 1096a23-4). If Aristotle's criticisms are justified, Plato goes wrong in analysing Goodness, as in other cases, by assuming a form of unity unsustained by reflective philosophical analysis.
Although most prominent in critical contexts, homonymy finds equal employment in Aristotle's own positive philosophy. For he does not infer, as some later figures do, that complexity impedes philosophical analysis. On the contrary, he argues that certain homonymous concepts, while complex, are nevertheless ordered around a core. That is, Aristotle appeals to homonymy to find order in multiplicity; and he thinks that the order he finds permits genuine analysis of a sort which makes scientific inquiry legitimate and philosophical progress possible. Thus, for example, Aristotle evidently exploits the homonymy of being when arguing for the possibility of a unified science of metaphysics, whose object of study is being qua being rather than some portion of being considered in isolation (Met. 1003a21-6). Aristotle's appeal to homonymy in this context is especially significant, since he had earlier called into question the possibility of a science of being on the grounds that there is no genus of being (An. Post. 92b14, Top. 121a16-19, b7-9). Aristotle evidently thinks that a science of being qua being is made possible at least in part by the recognition of being's homonymy (Met. 1003a34-b10). This appeal may