Whether the Sensitive Soul Is Transmitted with the Semen?
Objection 1: It would seem that the sensitive soul is not transmitted
with the semen, but created by God. For every perfect substance, not
composed of matter and form, that begins to exist, acquires existence
not by generation, but by creation: for nothing is generated save
from matter. But the sensitive soul is a perfect substance, otherwise
it could not move the body; and since it is the form of a body, it is
not composed of matter and form. Therefore it begins to exist not by
generation but by creation.
Obj. 2: Further, in living things the principle of generation is the
generating power; which, since it is one of the powers of the
vegetative soul, is of a lower order than the sensitive soul. Now
nothing acts beyond its species. Therefore the sensitive soul cannot
be caused by the animal's generating power.
Obj. 3: Further, the generator begets its like: so that the form of
the generator must be actually in the cause of generation. But
neither the sensitive soul itself nor any part thereof is actually in
the semen, for no part of the sensitive soul is elsewhere than in
some part of the body; while in the semen there is not even a
particle of the body, because there is not a particle of the body
which is not made from the semen and by the power thereof. Therefore
the sensitive soul is not produced through the semen.
Obj. 4: Further, if there be in the semen any principle productive of
the sensitive soul, this principle either remains after the animal is
begotten, or it does not remain. Now it cannot remain. For either it
would be identified with the sensitive soul of the begotten animal;
which is impossible, for thus there would be identity between
begetter and begotten, maker and made: or it would be distinct
therefrom; and again this is impossible, for it has been proved above
(Q. 76, A. 4) that in one animal there is but one formal principle,
which is the soul. If on the other hand the aforesaid principle does
not remain, this again seems to be impossible: for thus an agent
would act to its own destruction, which cannot be. Therefore the
sensitive soul cannot be generated from the semen.
_On the contrary,_ The power in the semen is to the animal seminally
generated, as the power in the elements of the world is to animals
produced from these elements--for instance by putrefaction. But in
the latter animals the soul is produced by the elemental power,
according to Gen. 1:20: "Let the waters bring forth the creeping
creatures having life." Therefore also the souls of animals seminally
generated are produced by the seminal power.
_I answer that,_ Some have held that the sensitive souls of animals
are created by God (Q. 65, A. 4). This opinion would hold if the
sensitive soul were subsistent, having being and operation of itself.
For thus, as having being and operation of itself, to be made would
needs be proper to it. And since a simple and subsistent thing cannot
be made except by creation, it would follow that the sensitive soul
would arrive at existence by creation.
But this principle is false--namely, that being and operation are
proper to the sensitive soul, as has been made clear above (Q. 75,
A. 3): for it would not cease to exist when the body perishes. Since,
therefore, it is not a subsistent form, its relation to existence is
that of the corporeal forms, to which existence does not belong as
proper to them, but which are said to exist forasmuch as the
subsistent composites exist through them.
Wherefore to be made is proper to composites. And since the generator
is like the generated, it follows of necessity that both the
sensitive soul, and all other like forms are naturally brought into
existence by certain corporeal agents that reduce the matter from
potentiality to act, through some corporeal power of which they are
possessed.
Now the more powerful an agent, the greater scope its action has: for
instance, the hotter a body, the greater the distance to which its
heat carries. Therefore bodies not endowed with life, which are the
lowest in the order of nature, generate their like, not through some
medium, but by themselves; thus fire by itself generates fire. But
living bodies, as being more powerful, act so as to generate their
like, both without and with a medium. Without a medium--in the work
of nutrition, in which flesh generates flesh: with a medium--in the
act of generation, because the semen of the animal or plant derives
a certain active force from the soul of the generator, just as the
instrument derives a certain motive power from the principal agent.
And as it matters not whether we say that something is moved by the
instrument or by the principal agent, so neither does it matter
whether we say that the soul of the generated is caused by the soul
of the generator, or by some seminal power derived therefrom.
Reply Obj. 1: The sensitive soul is not a perfect self-subsistent
substance. We have said enough (Q. 25, A. 3) on this point, nor need
we repeat it here.
Reply Obj. 2: The generating power begets not only by its own virtue
but by that of the whole soul, of which it is a power. Therefore the
generating power of a plant generates a plant, and that of an animal
begets an animal. For the more perfect the soul is, to so much a more
perfect effect is its generating power ordained.
Reply Obj. 3: This active force which is in the semen, and which is
derived from the soul of the generator, is, as it were, a certain
movement of this soul itself: nor is it the soul or a part of the
soul, save virtually; thus the form of a bed is not in the saw or the
axe, but a certain movement towards that form. Consequently there is
no need for this active force to have an actual organ; but it is
based on the (vital) spirit in the semen which is frothy, as is
attested by its whiteness. In which spirit, moreover, there is a
certain heat derived from the power of the heavenly bodies, by virtue
of which the inferior bodies also act towards the production of the
species as stated above (Q. 115, A. 3, ad 2). And since in this
(vital) spirit the power of the soul is concurrent with the power of
a heavenly body, it has been said that "man and the sun generate
man." Moreover, elemental heat is employed instrumentally by the
soul's power, as also by the nutritive power, as stated (De Anima ii,
4).
Reply Obj. 4: In perfect animals, generated by coition, the active
force is in the semen of the male, as the Philosopher says (De Gener.
Animal. ii, 3); but the foetal matter is provided by the female. In
this matter, the vegetative soul exists from the very beginning, not
as to the second act, but as to the first act, as the sensitive soul
is in one who sleeps. But as soon as it begins to attract
nourishment, then it already operates in act. This matter therefore
is transmuted by the power which is in the semen of the male, until
it is actually informed by the sensitive soul; not as though the
force itself which was in the semen becomes the sensitive soul; for
thus, indeed, the generator and generated would be identical;
moreover, this would be more like nourishment and growth than
generation, as the Philosopher says. And after the sensitive soul, by
the power of the active principle in the semen, has been produced in
one of the principal parts of the thing generated, then it is that
the sensitive soul of the offspring begins to work towards the
perfection of its own body, by nourishment and growth. As to the
active power which was in the semen, it ceases to exist, when the
semen is dissolved and the (vital) spirit thereof vanishes. Nor is
there anything unreasonable in this, because this force is not the
principal but the instrumental agent; and the movement of an
instrument ceases when once the effect has been produced.
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