Further, if to a Form be added the qualification “bound up with, involved in Matter,” Matter separates that Form from other Forms: it does not however embrace the whole of SUBSTANTIAL FORM (as, to be the genus of Form, it must). Enneads VI,3,3
Equally the SUBSTANTIAL FORM is never a predicate, since it never acts as a modification of anything. Form is not an attribute of Matter hence, is not predicable of Matter it is simply a constituent of the Couplement. On the other hand, the Form of a man is not different from the man himself (and so does not “modify” the Couplement). Enneads VI,3,4