summa-contra-gentiles

250 THE SUMMA CONTRA GENTILES
the eternity of a truth understood may be taken in two
ways in one way, as to the thing understood in another
: ;
as to that whereby
it is understood. If the understood
truth be eternal as regards the thing understood, it follows
that the thing understood is eternal, but not the one who
understands : whereas if the understood truth be eternal as
to that whereby it is understood, it would follow that the
soul which understands it is eternal. Now the understood
truth is eternal not in the latter but in the former way : for
it is clear from what has been said that the intelligible
species, by which our soul understands truth, are acquired
by us from the phantasms through the active intellect.^
Henoe it cannot be inferred that the soul is eternal, but that
the truths understood are based on something eternal, for
their foundation is in the first truth, as in the universal
cause which contains all truth. But the soul is
compared
to this eternal thing, not as subject to form, but as a thing
to its
proper end, because the true is the good of the intellect
and the end thereof.^ Now from a thing's end we can
argue about its duration, just as we can argue about its
beginning from its efficient cause : since what is directed to
an eternal end must be capable of enduring for ever. Consequently,
from the eternity of intelligible truth we can
prove that the soul is immortal, but not that it is eternal.
That neither can the latter be proved from the eternity of
the agent
is clear from what has been said above^ when we
were discussing the eternity of creatures.
The third objection which refers to the perfection of the
universe is not cogent. For the perfection of the universe
regards the species, not the individuals : since the universe
is continually receiving an addition of individuals to the
pre-existing species. Now human souls do not differ
specifically among themselves, but only numerically, as we
have proved.* Consequently
it is not inconsistent with the
perfection of the universe, if new souls be created.
Hence we may gather the reply to the fourth objection.
» C/. ch. Ixivi.
• Cf. 6 Ethic, ii. 3.
'
Ch. xxxi. ^eqq. * Ch. Ixxxi.