Generality and What Porphyry Defines. On a Recurring Question in Realist Isagoge Commentaries around 1100

Realist logical commentaries from 1080–1150 mention properties corresponding to the five Porphyrian predicables (genus, species, difference, proprium, and accident), properties such as generality (generalitas), speciality (specialitas), etc. These properties are mentioned in commentaries on Porphyry's Isagoge, particularly in relation to the description of 'genus': 'genus is what is predicated of many differing in species in answer to the question ‘What is it?’'. This paper analyses part of the debate concerning the role that generality is supposed to play in identifying what exactly in designated as the subject of Porphyry's description.