summa-contra-gentiles

CHAPTER XLIV 103
species does not result from things united accidentally,
because from such a union there does not result a thing
essentially
one : for white vian or clothed man is not a
It would follow, therefore, that man is not a species,
species.
nor yet the sun, nor the moon, nor anything of the kind.
Moreover. Those things which result from merit may
be changed for better or for worse : because merits and
demerits may increase or diminish, especially according to
Origen, who said that the free-will of every creature is
always flexible to either side. Wherefore, if a rational soul
has been allotted this body on account of preceding merit
or demerit, it will follow that it can be united again to
another body, and not only
that the human soul takes
may sometimes take
another human body, but also that it
a sidereal body, which is in accordance with the Pythagorean
fable, that any soul enters any — body} This is both
erroneous according to philosophy, which teaches that
determinate matters and movables are allotted to determinate
forms and movers,
— and heretical according to faith,
which declares that in the resurrection the soul resumes the
same body which it has left.
Further. Since there can be no multitude without distinction,
if from the beginning rational creatures were
formed in any number, they must have had some diversity.
Therefore one of them had something which another had
not. And if this was not the result of a difference in merit,
for the same reason neither was it
necessary for the difference
of grades to result from a difference of merits.
Again. Every distinction is either according to a division
of quantity, which is
only bodies,— in wherefore, according
to Origen, created,— it could not be in the bodies first or
according to formal division. But this latter cannot be
without distinction of grades, since such a distinction is
reduced to that of privation and form : and thus one of the
condivided forms must needs be better and the other less
good. Hence, according to the Philosopher,- the species
of things are like numbers, one of which is in addition to or
^ \ De Anima m. 23.
* 7 Metaph.
iii. 8.