Full Idea
It is reasonable that, after the primary substances, their species and genera should be the only other things called (secondary) substances. For only they, of things predicated, reveal the primary substance.
Gist of Idea
We call them secondary 'substances' because they reveal the primary substances
Source
Aristotle (Categories [c.331 BCE], 02b29)
Book Reference
Aristotle: 'Categories and De Interpretatione', ed/tr. Ackrill,J.R. [OUP 1963], p.7
A Reaction
This is the key passage in all of Aristotle for sortal essentialists like Wiggins, especially the word 'only'. I take it that this observation is superseded by the Metaphysics. Definition is the route to substance (which involves general terms).
Related Idea
Idea 16495 The only singling out is singling out 'as' something [Wiggins]