ent.

In like manner with regard to sciences and virtues, some held that
they are wholly from within, so that all virtues and sciences would
pre-exist in the soul naturally, but that the hindrances to science
and virtue, which are due to the soul being weighed down by the body,
are removed by study and practice, even as iron is made bright by
being polished. This was the opinion of the Platonists. Others said
that they are wholly from without, being due to the inflow of the
active intellect, as Avicenna maintained. Others said that sciences
and virtues are within us by nature, so far as we are adapted to
them, but not in their perfection: this is the teaching of the
Philosopher (Ethic. ii, 1), and is nearer the truth.

To make this clear, it must be observed that there are two ways in
which something is said to be natural to a man; one is according to
his specific nature, the other according to his individual nature.
And, since each thing derives its species from its form, and its
individuation from matter, and, again, since man's form is his
rational soul, while his matter is his body, whatever belongs to him
in respect of his rational soul, is natural to him in respect of his
specific nature; while whatever belongs to him in respect of the
particular temperament of his body, is natural to him in respect of
his individual nature. For whatever is natural to man in respect of
his body, considered as part of his species, is to be referred, in a
way, to the soul, in so far as this particular body is adapted to
this particular soul.

In both these ways virtue is natural to man inchoatively. This is so
in respect of the specific nature, in so far as in man's reason are
to be found instilled by nature certain naturally known principles of
both knowledge and action, which are the nurseries of intellectual
and moral virtues, and in so far as there is in the will a natural
appetite for good in accordance with reason. Again, this is so in
respect of the individual nature, in so far as by reason of a
disposition in the body, some are disposed either well or ill to
certain virtues: because, to wit, certain sensitive powers are acts
of certain parts of the body, according to the disposition of which
these powers are helped or hindered in the exercise of their acts,
and, in consequence, the rational powers also, which the aforesaid
sensitive powers assist. In this way one man has a natural aptitude
for science, another for fortit