To be a subject is then a property common to matter, to form, and
to the combination. But this function of subject is fulfilled
differently by matter in respect to form, and by form in respect to
the modifications, and by the combination; or rather, matter is not a
subject in respect to form; form is the complement which completes it
when it still is only matter, and when it exists only potentially.[358]
To speak strictly, form is not in matter; for when one thing forms only
a unity with something else, one cannot say that one is in the other
(as some accident in its subject). Only when both are taken together
do matter and form form a subject for other things;[359] thus Man
in general, and a particular man constitute the subject of passive
modifications; they are anterior to the actions and consequences which
relate to them. "Being" therefore is the principle from which all other
things derive, and by which they exist; that to which all passive
modifications relate, and from which all actions proceed.[360]