Not to be in a subject is then the common characteristic of all
"being," if, by "not being in a subject," we mean "not to form part
of any subject," and "not to contribute to the formation of a unity
therewith." Indeed, that which contributes to the formation of a
composite being, with something else, could not be in that thing as
in a subject; form therefore is not in matter as in a subject, and
neither is "man" in Socrates as in a subject, because "man" forms part
of Socrates.[363] Thus, "being" is that which is not in a subject.
If we add that "being" is not predicated of any subject, we must also
add, "insofar as this subject is something different from itself;"
otherwise "man," predicated of some one man, would not be comprised
within the definition of "being," if (in asserting that "being" is not
predicated of any subject), we did not add, "so far as this subject
is something different from itself." When I say, "Socrates is a man,"
I am practically saying, "White is white," and not, "wood is white."
While actually asserting that "Socrates is a man," I am asserting that
a particular man is a man, and to say "The man who is in Socrates is a
man," amounts to saying "Socrates is Socrates," or, "that particular
reasonable living organism is a living organism."