summa-contra-gentiles

CHAPTER LX
understood, since this pertains to being able to act ;
I55
for the
phantasms move the possible intellect.
Again. A potentiality consequent on the species of a
thing does not belong to it by reason of that which does not
give that thing its species. Now ability to understand is
consequent on the human species, for understanding is an
operation of man as such. Whereas the phantasms do not
give man his species, on the contrary they are consequent
on his operation. Therefore the child cannot be said to be
potentially understanding by reason of the phantasms.
Likewise, neither can a child be said to be potentially
understanding, because the possible intellect is able to be
in touch with him. For a person
is said to be able to act or
to be passive by active or passive potentiality, just as he is
whiteness. Now he is not said to be
said to be white by
white before whiteness is united to him.
Therefore neither
is one said to be able to act or to be passive before the active
or passive potentiality is in him. Consequently
it cannot
be said of a child that he is able to understand before the
possible intellect, which is the power of understanding, is
in touch with him.
Further. A person
is said in one way
to be able to act
before having the nature whereby he acts, and in another
way after he has the nature already, but is accidentally
hindered from acting
: even as a body is said in one way to
be able to be lifted upwards before it is light, and in another
way after it is made light, but is hindered in its movement.
Now a child is potentially understanding, not as though he
has not yet the nature to understand, but as having an
obstacle to understanding, for he is hindered from understanding
on account of the manifold movements in him, as
stated in 7 Physic.^ Wherefore he is not said to be potentially
understanding, on account of the possibility of coming
in touch with the possible intellect which is the principle of
understanding, but because it is already in touch with him
and is hindered from its
proper action so
;
that as soon as
the obstacle is removed, he understands.