Aristotle, in Chapter 7 of his Categories, classifies habits and dispositions, as well as knowledge, among relatives. However, in Chapter 8 of the Categories, he affirms that habits, including knowledge, and dispositions, including unstable knowledge, are qualities. Thus, habits and dispositions in general, and knowledge in particular, seem to be subject to a ‘dual categorization’. At the end of Chapter 8 of the treatise, the issue of the dual categorization is explicitly raised. How can one and the same thing be a quality and a relative? Aristotle gives two distinct solutions to this problem. Both have been criticized by some modern commentators : these solutions would amount to a rejection of the basic principles of the categorial system and, as such, to a sort of philosophical suicide. However, Aristotle’s early commentators, notably the Greek Neoplatonists and Boethius, made attempts to render both solutions plausible and compatible with the rest of the doctrine. Their attempts are not only of exegetical interest, they also contain some significant philosophical analyses concerning the categories. In what follows, I will present the abovementioned problem of dual categorization in Aristotle and the two solutions offered to it in Categories, 8, 11a20-38. I will then turn to the early reception of this text, and focus on the way the Greek Neoplatonists and Boethius tried to make Aristotle’s solutions more plausible. Throughout, I will try to establish in what sense habits and dispositions in general, and knowledge in particular, are relative. I will conclude with some remarks on the later reception of Categories, 8, 11a20-38 and on the problem of the ontological status of mental acts and states.