definition of man, for it is by this that man is man, and it is this
that humanity signifies, that, namely, whereby man is man. Now
individual matter, with all the individualizing accidents, is not
included in the definition of the species. For this particular flesh,
these bones, this blackness or whiteness, etc., are not included in
the definition of a man. Therefore this flesh, these bones, and the
accidental qualities distinguishing this particular matter, are not
included in humanity; and yet they are included in the thing which is
man. Hence the thing which is a man has something more in it than has
humanity. Consequently humanity and a man are not wholly identical;
but humanity is taken to mean the formal part of a man, because the
principles whereby a thing is defined are regarded as the formal
constituent in regard to the individualizing matter. On the other
hand, in things not composed of matter and form, in which
individualization is not due to individual matter--that is to say, to
_this_ matter--the very forms being individualized of themselves--it
is necessary the forms themselves should be subsisting _supposita._
Therefore _suppositum_ and nature in them are identified. Since God
then is not composed of matter and form, He must be His own Godhead,
His own Life, and whatever else is thus predicated of Him.

Reply Obj. 1: We can speak of simple things only as though
they were like the composite things from which we derive our
knowledge. Therefore in speaking of God, we use concrete nouns to
signify His subsistence, because with us only those things subsist
which are composite; and we use abstract nouns to signify His
simplicity. In saying therefore that Godhead, or life, or the like are
in God, we indicate the composite way in which our intellect
understands, but not that there is any composition in God.