summa-contra-gentiles

296 THE SUMMA CONTRA GENTILES
of things corporeal. Therefore one of them is not caused
by another, but all are produced immediately by God.
Hence, according to the foregoing, each of the separate
substances knows God by
its natural knowledge, according
to the mode of its substance, whereby they are like God as
their cause. But God knows them as their proper cause,
having in Himself the likeness of them all. Yet one separate
substance is unable to know another in this way, since one
is not the cause of another.
We must, therefore, observe that, since none of these
substances according to its essence is an adequate principle
of the knowledge of all other things, it is necessary for each
of them, in addition to its own substance, to have some
intelligible images, whereby each of them is enabled to
know another in its proper nature.
This can be made clear in the following manner. The
proper object of an intellect is an intelligible being: and
this includes all possible differences and species of being :
because whatever can be, is intelligible. Now, since all
knowledge is caused by some kind of likeness, the intellect
is unable to know its object wholly, unless it has in itself
the likeness of all being and of all its differences. But such
a likeness of all
being can only be an infinite nature, which
is not confined to any species or genus of being, but is the
universal principle and active force of all being and this is
:
the divine nature alone, as we proved in the First Book.^
And every other nature, since it is confined to some genus
or species of being, cannot be a universal likeness of all
being. It follows, therefore, that God alone, by His
essence, knows all things; while every separate substance,
by its nature, knows its own species alone with a perfect
knowledge : whereas the possible intellect does not know
itself at all thus, but by its intelligible species, as stated
above. ^
Now from the very fact that a particular substance is
intellectual, it is capable of understanding all being.
Wherefore, as a separate substance is not, by its nature,
1 Chs. XXV., xliii., 1.
•
In this ch., p. 294.