ABSTRACT
How do differentiae fit into Aristotle’s system of predicables? This is a question worth asking since throughout the corpus Aristotle seems to answer it in different, and indeed incompatible, ways. In Top. I 4 and 8, he assimilates them to genera, which are essential predicates of their subjects. Elsewhere, however, he appears to suggest either that they are distinctive properties (ἴδια) and, therefore, non-essential predicates of the subject, or that they should rather be conceived as mere qualifications, and, thus, in the nomenclature of the table of predicables, as accidents of their subjects. In this chapter, I will try to show that Aristotle’s ambivalence on this matter is only apparent. In order to do so, I will put forward and argue for the following theses: (1) within the framework of the predicables, differentiae are always and only to be conceived as essential, “genus-like” predicates; (2) only in a highly qualified sense can differentiae be regarded as ἴδια; (3) although they may be regarded as qualifications, also in a qualified sense, differentiae can never be regarded as accidents, that is, as accidental to the subject of which they are predicated.
