Dual Categorization and the Role of Aristotle’s Categories

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.