Where is the subject stored?

Aristotle: Categories , Part 3 "But where one genus is subordinate to another, there is nothing to prevent their having the same differentiae: for the greater class is predicated of the lesser, so that all the differentiae of the predicate will be differentiae also of the subject. " Explanation?

• How I understand it is as follows - e.g. Take two genera 'man' and 'animal' . Genus 'man' is subordinate to genus 'animal' . Dfifferentia for 'man' are white color , small eyes , vegetarian . Differentia for animal are 'two footed ' , 'wings ' , 'aquatic' etc. Now Aristotle says -"for the greater class is predicated of the lesser, so that all the differentiae of the predicate will be differentiae also of the subject. " Greater class is 'animal' and the subject is 'man' . But all the differentia of 'animal' are not the differentia of 'man' . For example, 'wings' - this is not an attribute to distinguish species under the genus 'man' . Should it be -"But where one genus is subordinate to another, there is nothing to prevent their having the same differentiae: for the greater class is predicated of the lesser, so that all the differentiae of the subject will be differentiae also of the predicate. " Where am I committing the mistake ?

• Answer:

  By "differentia" Aristotle doesn't mean features that divide a species into subspecies, but features that distinguish a species from other species. So, the differentia of "animal" is not "mammals" etc., but the power of perception which all animals share and plants lack. Since humans are animals, the power of perception applies to them as well - beside their own differentia, "rationality".