Abstract
In the Categories, Aristotle addresses two different cases of dual categorization, cases in which the same thing might appear in two different categories: relatives and secondary substances in the first case, qualities and relatives in the second. His treatment of these two cases is markedly different. Ackrill thinks dual categorization poses a dilemma for Aristotle’s project as a whole, but I argue that there is a dilemma only on particular understandings of Aristotle’s purpose in compiling the list of categories. I investigate various interpretations of the categories to find one that explains Aristotle’s reactions to dual categorization, and suggest an interpretation of the peculiar four-fold system of classification in Chapter 2.