When Plato, rightfully, calls matter "the location of forms," he is
not thereby attributing any passion to matter; he only indicates that
matters go on in a different manner. How? Since matter, however, by
its nature, cannot be any of the beings, and as it must flee from
the "being" of all beings, and be entirely different from them--for
("seminal) reasons" are genuine beings--it must necessarily preserve
its nature by virtue of this very difference. It must not only contain
all beings, but also not appropriate what is their image; for this is
that by which matter differs from all beings. Otherwise, if the images
that fill a mirror were not transient, and if the mirror remained
invisible, evidently we would believe that the things the mirror
presents to us existed really. If then there be something in a mirror,
that is that which sense-forms are in matter. If in a mirror there be
nothing but appearance, then there is nothing in matter but appearance,
recognizing that this appearance is the cause of the existence of
beings, an existence in which the things that exist always really
participate, and in which the things which do not really exist do not
participate; for they could not be in the condition where they would be
if they existed without the existence of existence in itself.