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
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,
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.
SECOND ARTICLE [I, Q. 118, Art. 2]
Whether the Intellectual Soul Is Produced from the Semen?
Objection 1: It would seem that the intellectual soul is produced
from the semen. For it is written (Gen. 46:26): "All the souls that
came out of [Jacob's] thigh, sixty-six." But nothing is produced from
the thigh of a man, except from the semen. Therefore the intellectual
soul is produced from the semen.
Obj. 2: Further, as shown above (Q. 76, A. 3), the intellectual,
sensitive, and nutritive souls are, in substance, one soul in man.
But the sensitive soul in man is generated from the semen, as in
other animals; wherefore the Philosopher says (De Gener. Animal. ii,
3) that the animal and the man are not made at the same time, but
first of all the animal is made having a sensitive soul. Therefore
also the intellectual soul is produced from the semen.
Obj. 3: Further, it is one and the same agent whose action is
directed to the matter and to the form: else from the matter and
the form there would not result something simply one. But the
intellectual soul is the form of the human body, which is produced
by the power of the semen. Therefore the intellectual soul also is
produced by the power of the semen.
Obj. 4: Further, man begets his like in species. But the human
species is constituted by the rational soul. Therefore the rational
soul is from the begetter.
Obj. 5: Further, it cannot be said that God concurs in sin. But if
the rational soul be created by God, sometimes God concurs in the
sin of adultery, since sometimes offspring is begotten of illicit
intercourse. Therefore the rational soul is not created by God.
_On the contrary,_ It is written in De Eccl. Dogmat. xiv that "the
rational soul is not engendered by coition."
_I answer that,_ It is impossible for an active power existing in
matter to extend its action to the production of an immaterial
effect. Now it is manifest that the intellectual principle in man
transcends matter; for it has an operation in which the body takes no
part whatever. It is therefore impossible for the seminal power to
produce the intellectual principle.
Again, the seminal power acts by virtue of the soul of the begetter
according as the soul of the begetter is the act of the body, making
use of the body in its operation. Now the body has nothing whatever
to do in the operation of the intellect. Therefore the power of the
intellectual principle, as intellectual, cannot reach the semen.
Hence the Philosopher says (De Gener. Animal. ii, 3): "It follows
that the intellect alone comes from without."
Again, since the intellectual soul has an operation independent of
the body, it is subsistent, as proved above (Q. 75, A. 2): therefore
to be and to be made are proper to it. Moreover, since it is an
immaterial substance it cannot be caused through generation, but only
through creation by God. Therefore to hold that the intellectual soul
is caused by the begetter, is nothing else than to hold the soul to
be non-subsistent and consequently to perish with the body. It is
therefore heretical to say that the intellectual soul is transmitted
with the semen.
Reply Obj. 1: In the passage quoted, the part is put instead of the
whole, the soul for the whole man, by the figure of synecdoche.
Reply Obj. 2: Some say that the vital functions observed in the
embryo are not from its soul, but from the soul of the mother; or
from the formative power of the semen. Both of these explanations are
false; for vital functions such as feeling, nourishment, and growth
cannot be from an extrinsic principle. Consequently it must be said
that the soul is in the embryo; the nutritive soul from the
beginning, then the sensitive, lastly the intellectual soul.
Therefore some say that in addition to the vegetative soul which
existed first, another, namely the sensitive, soul supervenes; and in
addition to this, again another, namely the intellectual soul. Thus
there would be in man three souls of which one would be in
potentiality to another. This has been disproved above (Q. 76,
Therefore others say that the same soul which was at first merely
vegetative, afterwards through the action of the seminal power,
becomes a sensitive soul; and finally this same soul becomes
intellectual, not indeed through the active seminal power, but by
the power of a higher agent, namely God enlightening (the soul) from
without. For this reason the Philosopher says that the intellect
comes from without. But this will not hold. First, because no
substantial form is susceptible of more or less; but addition of
greater perfection constitutes another species, just as the addition
of unity constitutes another species of number. Now it is not
possible for the same identical form to belong to different species.
Secondly, because it would follow that the generation of an animal
would be a continuous movement, proceeding gradually from the
imperfect to the perfect, as happens in alteration. Thirdly, because
it would follow that the generation of a man or an animal is not
generation simply, because the subject thereof would be a being in
act. For if the vegetative soul is from the beginning in the matter
of offspring, and is subsequently gradually brought to perfection;
this will imply addition of further perfection without corruption of
the preceding perfection. And this is contrary to the nature of
generation properly so called. Fourthly, because either that which is
caused by the action of God is something subsistent: and thus it must
needs be essentially distinct from the pre-existing form, which was
non-subsistent; and we shall then come back to the opinion of those
who held the existence of several souls in the body - or else it is
not subsistent, but a perfection of the pre-existing soul: and from
this it follows of necessity that the intellectual soul perishes with
the body, which cannot be admitted.
There is again another explanation, according to those who held that
all men have but one intellect in common: but this has been disproved
above (Q. 76, A. 2).
We must therefore say that since the generation of one thing is the
corruption of another, it follows of necessity that both in men and
in other animals, when a more perfect form supervenes the previous
form is corrupted: yet so that the supervening form contains the
perfection of the previous form, and something in addition. It is in
this way that through many generations and corruptions we arrive at
the ultimate substantial form, both in man and other animals. This
indeed is apparent to the senses in animals generated from
putrefaction. We conclude therefore that the intellectual soul is
created by God at the end of human generation, and this soul is at
the same time sensitive and nutritive, the pre-existing forms being
Reply Obj. 3: This argument holds in the case of diverse agents not
ordered to one another. But where there are many agents ordered to
one another, nothing hinders the power of the higher agent from
reaching to the ultimate form; while the powers of the inferior
agents extend only to some disposition of matter: thus in the
generation of an animal, the seminal power disposes the matter, but
the power of the soul gives the form. Now it is manifest from what
has been said above (Q. 105, A. 5; Q. 110, A. 1) that the whole of
corporeal nature acts as the instrument of a spiritual power,
especially of God. Therefore nothing hinders the formation of the
body from being due to a corporeal power, while the intellectual soul
is from God alone.
Reply Obj. 4: Man begets his like, forasmuch as by his seminal power
the matter is disposed for the reception of a certain species of form.
Reply Obj. 5: In the action of the adulterer, what is of nature is
good; in this God concurs. But what there is of inordinate lust is
evil; in this God does not concur.
THIRD ARTICLE [I, Q. 118, Art. 3]
Whether Human Souls Were Created Together at the Beginning of the
Objection 1: It would seem that human souls were created together at
the beginning of the world. For it is written (Gen. 2:2): "God rested
Him from all His work which He had done." This would not be true if He
created new souls every day. Therefore all souls were created at the
Obj. 2: Further, spiritual substances before all others belong to the
perfection of the universe. If therefore souls were created with the
bodies, every day innumerable spiritual substances would be added to
the perfection of the universe: consequently at the beginning the
universe would have been imperfect. This is contrary to Gen. 2:2,
where it is said that "God ended" all "His work."
Obj. 3: Further, the end of a thing corresponds to its beginning. But
the intellectual soul remains, when the body perishes. Therefore it
began to exist before the body.
_On the contrary,_ It is said (De Eccl. Dogmat. xiv, xviii) that "the
soul is created together with the body."
_I answer that,_ Some have maintained that it is accidental to the
intellectual soul to be united to the body, asserting that the soul
is of the same nature as those spiritual substances which are not
united to a body. These, therefore, stated that the souls of men were
created together with the angels at the beginning. But this statement
is false. Firstly, in the very principle on which it is based. For if
it were accidental to the soul to be united to the body, it would
follow that man who results from this union is a being by accident;
or that the soul is a man, which is false, as proved above (Q. 75, A.
4). Moreover, that the human soul is not of the same nature as the
angels, is proved from the different mode of understanding, as shown
above (Q. 55, A. 2; Q. 85, A. 1): for man understands through
receiving from the senses, and turning to phantasms, as stated above
(Q. 84, AA. 6, 7; Q. 85, A. 1). For this reason the soul needs to be
united to the body, which is necessary to it for the operation of the
sensitive part: whereas this cannot be said of an angel.
Secondly, this statement can be proved to be false in itself. For if
it is natural to the soul to be united to the body, it is unnatural
to it to be without a body, and as long as it is without a body it is
deprived of its natural perfection. Now it was not fitting that God
should begin His work with things imperfect and unnatural, for He did
not make man without a hand or a foot, which are natural parts of a
man. Much less, therefore, did He make the soul without a body.
But if someone say that it is not natural to the soul to be united to
the body, he must give the reason why it is united to a body. And the
reason must be either because the soul so willed, or for some other
reason. If because the soul willed it - this seems incongruous. First,
because it would be unreasonable of the soul to wish to be united to
the body, if it did not need the body: for if it did need it, it would
be natural for it to be united to it, since "nature does not fail in
what is necessary." Secondly, because there would be no reason why,
having been created from the beginning of the world, the soul should,
after such a long time, come to wish to be united to the body. For a
spiritual substance is above time, and superior to the heavenly
revolutions. Thirdly, because it would seem that this body was united
to this soul by chance: since for this union to take place two wills
would have to concur - to wit, that of the incoming soul, and that of
the begetter. If, however, this union be neither voluntary nor natural
on the part of the soul, then it must be the result of some violent
cause, and to the soul would have something of a penal and afflicting
nature. This is in keeping with the opinion of Origen, who held that
souls were embodied in punishment of sin. Since, therefore, all these
opinions are unreasonable, we must simply confess that souls were not
created before bodies, but are created at the same time as they are
infused into them.
Reply Obj. 1: God is said to have rested on the seventh day, not from
all work, since we read (John 5:17): "My Father worketh until now";
but from the creation of any new genera and species, which may not
have already existed in the first works. For in this sense, the souls
which are created now, existed already, as to the likeness of the
species, in the first works, which included the creation of Adam's
Reply Obj. 2: Something can be added every day to the perfection of
the universe, as to the number of individuals, but not as to the
number of species.
Reply Obj. 3: That the soul remains without the body is due to the
corruption of the body, which was a result of sin. Consequently it
was not fitting that God should make the soul without the body from
the beginning: for as it is written (Wis. 1:13, 16): "God made not
death . . . but the wicked with works and words have called it to
OF THE PROPAGATION OF MAN AS TO THE BODY
(In Two Articles)
We now consider the propagation of man, as to the body. Concerning
this there are two points of inquiry:
(1) Whether any part of the food is changed into true human nature?
(2) Whether the semen, which is the principle of human generation,
is produced from the surplus food?
FIRST ARTICLE [I, Q. 119, Art. 1]
Whether Some Part of the Food Is Changed into True Human Nature?
Objection 1: It would seem that none of the food is changed into true
human nature. For it is written (Matt. 15:17): "Whatsoever entereth
into the mouth, goeth into the belly, and is cast out into the privy."
But what is cast out is not changed into the reality of human nature.
Therefore none of the food is changed into true human nature.
Obj. 2: Further, the Philosopher (De Gener. i, 5) distinguishes flesh
belonging to the species from flesh belonging to "matter"; and says
that the latter "comes and goes." Now what is formed from food comes
and goes. Therefore what is produced from food is flesh belonging to
matter, not to the species. But what belongs to true human nature
belongs to the species. Therefore the food is not changed into true
Obj. 3: Further, the "radical humor" seems to belong to the reality
of human nature; and if it be lost, it cannot be recovered, according
to physicians. But it could be recovered if the food were changed
into the humor. Therefore food is not changed into true human nature.
Obj. 4: Further, if the food were changed into true human nature,
whatever is lost in man could be restored. But man's death is due
only to the loss of something. Therefore man would be able by taking
food to insure himself against death in perpetuity.
Obj. 5: Further, if the food is changed into true human nature, there
is nothing in man which may not recede or be repaired: for what is
generated in a man from his food can both recede and be repaired. If
therefore a man lived long enough, it would follow that in the end
nothing would be left in him of what belonged to him at the
beginning. Consequently he would not be numerically the same man
throughout his life; since for the thing to be numerically the same,
identity of matter is necessary. But this is incongruous. Therefore
the food is not changed into true human nature.
_On the contrary,_ Augustine says (De Vera Relig. xi): "The bodily
food when corrupted, that is, having lost its form, is changed into
the texture of the members." But the texture of the members belongs
to true human nature. Therefore the food is changed into the reality
of human nature.
_I answer that,_ According to the Philosopher (Metaph. ii), "The
relation of a thing to truth is the same as its relation to being."
Therefore that belongs to the true nature of any thing which enters
into the constitution of that nature. But nature can be considered in
two ways: firstly, in general according to the species; secondly, as
in the individual. And whereas the form and the common matter belong
to a thing's true nature considered in general; individual signate
matter, and the form individualized by that matter belong to the true
nature considered in this particular individual. Thus a soul and body
belong to the true human nature in general, but to the true human
nature of Peter and Martin belong this soul and this body.
Now there are certain things whose form cannot exist but in one
individual matter: thus the form of the sun cannot exist save in the
matter in which it actually is. And in this sense some have said that
the human form cannot exist but in a certain individual matter, which,
they said, was given that form at the very beginning in the first man.
So that whatever may have been added to that which was derived by
posterity from the first parent, does not belong to the truth of human
nature, as not receiving in truth the form of human nature.
But, said they, that matter which, in the first man, was the subject
of the human form, was multiplied in itself: and in this way the
multitude of human bodies is derived from the body of the first man.
According to these, the food is not changed into true human nature; we
take food, they stated, in order to help nature to resist the action
of natural heat, and prevent the consumption of the "radical humor";
just as lead or tin is mixed with silver to prevent its being consumed
But this is unreasonable in many ways. Firstly, because it comes to
the same that a form can be produced in another matter, or that it
can cease to be in its proper matter; wherefore all things that can
be generated are corruptible, and conversely. Now it is manifest that
the human form can cease to exist in this (particular) matter which
is its subject: else the human body would not be corruptible.
Consequently it can begin to exist in another matter, so that
something else be changed into true human nature. Secondly, because
in all beings whose entire matter is contained in one individual
there is only one individual in the species: as is clearly the case
with the sun, moon and such like. Thus there would only be one
individual of the human species. Thirdly, because multiplication of
matter cannot be understood otherwise than either in respect of
quantity only, as in things which are rarefied, so that their matter
increases in dimensions; or in respect of the substance itself of the
matter. But as long as the substance alone of matter remains, it
cannot be said to be multiplied; for multitude cannot consist in the
addition of a thing to itself, since of necessity it can only result
from division. Therefore some other substance must be added to
matter, either by creation, or by something else being changed into
it. Consequently no matter can be multiplied save either by
rarefaction as when air is made from water; or by the change of some
other things, as fire is multiplied by the addition of wood; or
lastly by creation. Now it is manifest that the multiplication of
matter in the human body does not occur by rarefaction: for thus the
body of a man of perfect age would be more imperfect than the body of
a child. Nor does it occur by creation of fresh matter: for,
according to Gregory (Moral. xxxii): "All things were created
together as to the substance of matter, but not as to the specific
form." Consequently the multiplication of the human body can only be
the result of the food being changed into the true human nature.
Fourthly, because, since man does not differ from animals and plants
in regard to the vegetative soul, it would follow that the bodies of
animals and plants do not increase through a change of nourishment