Full Idea
Met. Z.10-11 is committed to the complexity of form and suggests that the complexity is expressed in definitions that articulate, in the case of 'man', the salient faculties and functions, and none of these need mention 'man'.
Gist of Idea
Definitions need the complex features of form, and don't need to mention the category
Source
report of Aristotle (Metaphysics [c.324 BCE], 1034b20-1037b) by Michael V. Wedin - Aristotle's Theory of Substance X.5
Book Reference
Wedin,Michael V.: 'Aristotle's Theory of Substance' [OUP 2000], p.427
A Reaction
This is a very strong statement of the view that identifying genus and species are not at all what Aristotle wants in his final account of essence. The features mentioned here would, though, clearly count as 'differentiae'.