Therefore
a form cannot be without its own proper matter.
Summa Theologica
I
say this, forasmuch as some held that the form alone belongs to the
species; while matter is part of the individual, and not the species.
This cannot be true; for to the nature of the species belongs what the
definition signifies; and in natural things the definition does not
signify the form only, but the form and the matter. Hence in natural
things the matter is part of the species; not, indeed, signate matter,
which is the principle of individuality; but the common matter. For as
it belongs to the notion of this particular man to be composed of this
soul, of this flesh, and of these bones; so it belongs to the notion of
man to be composed of soul, flesh, and bones; for whatever belongs in
common to the substance of all the individuals contained under a given
species, must belong to the substance of the species.
It may also be understood in this sense, that this soul is this man;
and this could be held if it were supposed that the operation of the
sensitive soul were proper to it, apart from the body; because in that
case all the operations which are attributed to man would belong to the
soul only; and whatever performs the operations proper to a thing, is
that thing; wherefore that which performs the operations of a man is
man. But it has been shown above [601](A[3]) that sensation is not the
operation of the soul only. Since, then, sensation is an operation of
man, but not proper to him, it is clear that man is not a soul only,
but something composed of soul and body. Plato, through supposing that
sensation was proper to the soul, could maintain man to be a soul
making use of the body.
Reply to Objection 1: According to the Philosopher (Ethic. ix, 8), a
thing seems to be chiefly what is principle in it; thus what the
governor of a state does, the state is said to do. In this way
sometimes what is principle in man is said to be man; sometimes,
indeed, the intellectual part which, in accordance with truth, is
called the "inward" man; and sometimes the sensitive part with the body
is called man in the opinion of those whose observation does not go
beyond the senses. And this is called the "outward" man.
Reply to Objection 2: Not every particular substance is a hypostasis or
a person, but that which has the complete nature of its species. Hence
a hand, or a foot, is not called a hypostasis, or a person; nor,
likewise, is the soul alone so called, since it is a part of the human
species.
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Whether the soul is composed of matter and form?
Objection 1: It would seem that the soul is composed of matter and
form. For potentiality is opposed to actuality. Now, whatsoever things
are in actuality participate of the First Act, which is God; by
participation of Whom, all things are good, are beings, and are living
things, as is clear from the teaching of Dionysius (Div. Nom. v).
Therefore whatsoever things are in potentiality participate of the
first potentiality. But the first potentiality is primary matter.
Therefore, since the human soul is, after a manner, in potentiality;
which appears from the fact that sometimes a man is potentially
understanding; it seems that the human soul must participate of primary
matter, as part of itself.
Objection 2: Further, wherever the properties of matter are found,
there matter is. But the properties of matter are found in the
soul---namely, to be a subject, and to be changed, for it is a subject
to science, and virtue; and it changes from ignorance to knowledge and
from vice to virtue. Therefore matter is in the soul.
Objection 3: Further, things which have no matter, have no cause of
their existence, as the Philosopher says Metaph. viii (Did. vii, 6).
But the soul has a cause of its existence, since it is created by God.
Therefore the soul has matter.
Objection 4: Further, what has no matter, and is a form only, is a pure
act, and is infinite. But this belongs to God alone. Therefore the soul
has matter.
On the contrary, Augustine (Gen. ad lit. vii, 7,8,9) proves that the
soul was made neither of corporeal matter, nor of spiritual matter.
I answer that, The soul has no matter. We may consider this question in
two ways. First, from the notion of a soul in general; for it belongs
to the notion of a soul to be the form of a body. Now, either it is a
form by virtue of itself, in its entirety, or by virtue of some part of
itself. If by virtue of itself in its entirety, then it is impossible
that any part of it should be matter, if by matter we understand
something purely potential: for a form, as such, is an act; and that
which is purely potentiality cannot be part of an act, since
potentiality is repugnant to actuality as being opposite thereto. If,
however, it be a form by virtue of a part of itself, then we call that
part the soul: and that matter, which it actualizes first, we call the
"primary animate. "
Secondly, we may proceed from the specific notion of the human soul
inasmuch as it is intellectual. For it is clear that whatever is
received into something is received according to the condition of the
recipient. Now a thing is known in as far as its form is in the knower.
But the intellectual soul knows a thing in its nature absolutely: for
instance, it knows a stone absolutely as a stone; and therefore the
form of a stone absolutely, as to its proper formal idea, is in the
intellectual soul. Therefore the intellectual soul itself is an
absolute form, and not something composed of matter and form. For if
the intellectual soul were composed of matter and form, the forms of
things would be received into it as individuals, and so it would only
know the individual: just as it happens with the sensitive powers which
receive forms in a corporeal organ; since matter is the principle by
which forms are individualized. It follows, therefore, that the
intellectual soul, and every intellectual substance which has knowledge
of forms absolutely, is exempt from composition of matter and form.
Reply to Objection 1: The First Act is the universal principle of all
acts; because It is infinite, virtually "precontaining all things," as
Dionysius says (Div. Nom. v). Wherefore things participate of It not as
a part of themselves, but by diffusion of Its processions. Now as
potentiality is receptive of act, it must be proportionate to act. But
the acts received which proceed from the First Infinite Act, and are
participations thereof, are diverse, so that there cannot be one
potentiality which receives all acts, as there is one act, from which
all participated acts are derived; for then the receptive potentiality
would equal the active potentiality of the First Act. Now the receptive
potentiality in the intellectual soul is other than the receptive
potentiality of first matter, as appears from the diversity of the
things received by each. For primary matter receives individual forms;
whereas the intelligence receives absolute forms. Hence the existence
of such a potentiality in the intellectual soul does not prove that the
soul is composed of matter and form.
Reply to Objection 2: To be a subject and to be changed belong to
matter by reason of its being in potentiality. As, therefore, the
potentiality of the intelligence is one thing and the potentiality of
primary matter another, so in each is there a different reason of
subjection and change. For the intelligence is subject to knowledge,
and is changed from ignorance to knowledge, by reason of its being in
potentiality with regard to the intelligible species.
Reply to Objection 3: The form causes matter to be, and so does the
agent; wherefore the agent causes matter to be, so far as it actualizes
it by transmuting it to the act of a form. A subsistent form, however,
does not owe its existence to some formal principle, nor has it a cause
transmuting it from potentiality to act. So after the words quoted
above, the Philosopher concludes, that in things composed of matter and
form "there is no other cause but that which moves from potentiality to
act; while whatsoever things have no matter are simply beings at once. "
[*The Leonine edition has, "simpliciter sunt quod vere entia aliquid. "
The Parma edition of St. Thomas's Commentary on Aristotle has, "statim
per se unum quiddam est . . . et ens quiddam. "]
Reply to Objection 4: Everything participated is compared to the
participator as its act. But whatever created form be supposed to
subsist "per se," must have existence by participation; for "even
life," or anything of that sort, "is a participator of existence," as
Dionysius says (Div. Nom. v). Now participated existence is limited by
the capacity of the participator; so that God alone, Who is His own
existence, is pure act and infinite. But in intellectual substances
there is composition of actuality and potentiality, not, indeed, of
matter and form, but of form and participated existence. Wherefore some
say that they are composed of that "whereby they are" and that "which
they are"; for existence itself is that by which a thing is.
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Whether the human soul is incorruptible?
Objection 1: It would seem that the human soul is corruptible. For
those things that have a like beginning and process seemingly have a
like end. But the beginning, by generation, of men is like that of
animals, for they are made from the earth. And the process of life is
alike in both; because "all things breathe alike, and man hath nothing
more than the beast," as it is written (Eccles. 3:19). Therefore, as
the same text concludes, "the death of man and beast is one, and the
condition of both is equal. " But the souls of brute animals are
corruptible. Therefore, also, the human soul is corruptible.
Objection 2: Further, whatever is out of nothing can return to
nothingness; because the end should correspond to the beginning. But as
it is written (Wis. 2:2), "We are born of nothing"; which is true, not
only of the body, but also of the soul. Therefore, as is concluded in
the same passage, "After this we shall be as if we had not been," even
as to our soul.
Objection 3: Further, nothing is without its own proper operation. But
the operation proper to the soul, which is to understand through a
phantasm, cannot be without the body. For the soul understands nothing
without a phantasm; and there is no phantasm without the body as the
Philosopher says (De Anima i, 1). Therefore the soul cannot survive the
dissolution of the body.
On the contrary, Dionysius says (Div. Nom. iv) that human souls owe to
Divine goodness that they are "intellectual," and that they have "an
incorruptible substantial life. "
I answer that, We must assert that the intellectual principle which we
call the human soul is incorruptible. For a thing may be corrupted in
two ways---"per se," and accidentally. Now it is impossible for any
substance to be generated or corrupted accidentally, that is, by the
generation or corruption of something else. For generation and
corruption belong to a thing, just as existence belongs to it, which is
acquired by generation and lost by corruption. Therefore, whatever has
existence "per se" cannot be generated or corrupted except 'per se';
while things which do not subsist, such as accidents and material
forms, acquire existence or lost it through the generation or
corruption of composite things. Now it was shown above ([602]AA[2],3)
that the souls of brutes are not self-subsistent, whereas the human
soul is; so that the souls of brutes are corrupted, when their bodies
are corrupted; while the human soul could not be corrupted unless it
were corrupted "per se. " This, indeed, is impossible, not only as
regards the human soul, but also as regards anything subsistent that is
a form alone. For it is clear that what belongs to a thing by virtue of
itself is inseparable from it; but existence belongs to a form, which
is an act, by virtue of itself. Wherefore matter acquires actual
existence as it acquires the form; while it is corrupted so far as the
form is separated from it. But it is impossible for a form to be
separated from itself; and therefore it is impossible for a subsistent
form to cease to exist.
Granted even that the soul is composed of matter and form, as some
pretend, we should nevertheless have to maintain that it is
incorruptible. For corruption is found only where there is contrariety;
since generation and corruption are from contraries and into
contraries. Wherefore the heavenly bodies, since they have no matter
subject to contrariety, are incorruptible. Now there can be no
contrariety in the intellectual soul; for it receives according to the
manner of its existence, and those things which it receives are without
contrariety; for the notions even of contraries are not themselves
contrary, since contraries belong to the same knowledge. Therefore it
is impossible for the intellectual soul to be corruptible. Moreover we
may take a sign of this from the fact that everything naturally aspires
to existence after its own manner. Now, in things that have knowledge,
desire ensues upon knowledge. The senses indeed do not know existence,
except under the conditions of "here" and "now," whereas the intellect
apprehends existence absolutely, and for all time; so that everything
that has an intellect naturally desires always to exist. But a natural
desire cannot be in vain. Therefore every intellectual substance is
incorruptible.
Reply to Objection 1: Solomon reasons thus in the person of the
foolish, as expressed in the words of Wisdom 2. Therefore the saying
that man and animals have a like beginning in generation is true of the
body; for all animals alike are made of earth. But it is not true of
the soul. For the souls of brutes are produced by some power of the
body; whereas the human soul is produced by God. To signify this it is
written as to other animals: "Let the earth bring forth the living
soul" (Gn. 1:24): while of man it is written (Gn. 2:7) that "He
breathed into his face the breath of life. " And so in the last chapter
of Ecclesiastes (12:7) it is concluded: "(Before) the dust return into
its earth from whence it was; and the spirit return to God Who gave
it. " Again the process of life is alike as to the body, concerning
which it is written (Eccles. 3:19): "All things breathe alike," and
(Wis. 2:2), "The breath in our nostrils is smoke. " But the process is
not alike of the soul; for man is intelligent, whereas animals are not.
Hence it is false to say: "Man has nothing more than beasts. " Thus
death comes to both alike as to the body, by not as to the soul.
Reply to Objection 2: As a thing can be created by reason, not of a
passive potentiality, but only of the active potentiality of the
Creator, Who can produce something out of nothing, so when we say that
a thing can be reduced to nothing, we do not imply in the creature a
potentiality to non-existence, but in the Creator the power of ceasing
to sustain existence. But a thing is said to be corruptible because
there is in it a potentiality to non-existence.
Reply to Objection 3: To understand through a phantasm is the proper
operation of the soul by virtue of its union with the body. After
separation from the body it will have another mode of understanding,
similar to other substances separated from bodies, as will appear later
on ([603]Q[89], A[1]).
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Whether the soul is of the same species as an angel?
Objection 1: It would seem that the soul is of the same species as an
angel. For each thing is ordained to its proper end by the nature of
its species, whence is derived its inclination for that end. But the
end of the soul is the same as that of an angel---namely, eternal
happiness. Therefore they are of the same species.
Objection 2: Further, the ultimate specific difference is the noblest,
because it completes the nature of the species. But there is nothing
nobler either in an angel or in the soul than their intellectual
nature. Therefore the soul and the angel agree in the ultimate specific
difference: therefore they belong to the same species.
Objection 3: Further, it seems that the soul does not differ from an
angel except in its union with the body. But as the body is outside the
essence of the soul, it seems that it does not belong to its species.
Therefore the soul and angel are of the same species.
On the contrary, Things which have different natural operations are of
different species. But the natural operations of the soul and of an
angel are different; since, as Dionysius says (Div. Nom. vii), "Angelic
minds have simple and blessed intelligence, not gathering their
knowledge of Divine things from visible things. " Subsequently he says
the contrary to this of the soul. Therefore the soul and an angel are
not of the same species.
I answer that, Origen (Peri Archon iii, 5) held that human souls and
angels are all of the same species; and this because he supposed that
in these substances the difference of degree was accidental, as
resulting from their free-will: as we have seen above ([604]Q[47],
A[2]). But this cannot be; for in incorporeal substances there cannot
be diversity of number without diversity of species and inequality of
nature; because, as they are not composed of matter and form, but are
subsistent forms, it is clear that there is necessarily among them a
diversity of species. For a separate form cannot be understood
otherwise than as one of a single species; thus, supposing a separate
whiteness to exist, it could only be one; forasmuch as one whiteness
does not differ from another except as in this or that subject. But
diversity of species is always accompanied with a diversity of nature;
thus in species of colors one is more perfect than another; and the
same applies to other species, because differences which divide a
"genus" are contrary to one another. Contraries, however, are compared
to one another as the perfect to the imperfect, since the "principle of
contrariety is habit, and privation thereof," as is written Metaph. x
(Did. ix, 4). The same would follow if the aforesaid substances were
composed of matter and form. For if the matter of one be distinct from
the matter of another, it follows that either the form is the principle
of the distinction of matter---that is to say, that the matter is
distinct on account of its relation to divers forms; and even then
there would result a difference of species and inequality of nature: or
else the matter is the principle of the distinction of forms. But one
matter cannot be distinct from another, except by a distinction of
quantity, which has no place in these incorporeal substances, such as
an angel and the soul. So that it is not possible for the angel and the
soul to be of the same species. How it is that there can be many souls
of one species will be explained later ([605]Q[76], A[2], ad 1).
Reply to Objection 1: This argument proceeds from the proximate and
natural end. Eternal happiness is the ultimate and supernatural end.
Reply to Objection 2: The ultimate specific difference is the noblest
because it is the most determinate, in the same way as actuality is
nobler than potentiality. Thus, however, the intellectual faculty is
not the noblest, because it is indeterminate and common to many degrees
of intellectuality; as the sensible faculty is common to many degrees
in the sensible nature. Hence, as all sensible things are not of one
species, so neither are all intellectual things of one species.
Reply to Objection 3: The body is not of the essence of the soul; but
the soul by the nature of its essence can be united to the body, so
that, properly speaking, not the soul alone, but the "composite," is
the species. And the very fact that the soul in a certain way requires
the body for its operation, proves that the soul is endowed with a
grade of intellectuality inferior to that of an angel, who is not
united to a body.
__________________________________________________________________
OF THE UNION OF BODY AND SOUL (EIGHT ARTICLES)
We now consider the union of the soul with the body; and concerning
this there are eight points of inquiry:
(1) Whether the intellectual principle is united to the body as its
form?
(2) Whether the intellectual principle is multiplied numerically
according to the number of bodies; or is there one intelligence for all
men?
(3) Whether in the body the form of which is an intellectual principle,
there is some other soul?
(4) Whether in the body there is any other substantial form?
(5) Of the qualities required in the body of which the intellectual
principle is the form?
(6) Whether it be united to such a body by means of another body?
(7) Whether by means of an accident?
(8) Whether the soul is wholly in each part of the body?
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Whether the intellectual principle is united to the body as its form?
Objection 1: It seems that the intellectual principle is not united to
the body as its form. For the Philosopher says (De Anima iii, 4) that
the intellect is "separate," and that it is not the act of any body.
Therefore it is not united to the body as its form.
Objection 2: Further, every form is determined according to the nature
of the matter of which it is the form; otherwise no proportion would be
required between matter and form. Therefore if the intellect were
united to the body as its form, since every body has a determinate
nature, it would follow that the intellect has a determinate nature;
and thus, it would not be capable of knowing all things, as is clear
from what has been said ([606]Q[75], A[2]); which is contrary to the
nature of the intellect. Therefore the intellect is not united to the
body as its form.
Objection 3: Further, whatever receptive power is an act of a body,
receives a form materially and individually; for what is received must
be received according to the condition of the receiver. But the form of
the thing understood is not received into the intellect materially and
individually, but rather immaterially and universally: otherwise the
intellect would not be capable of the knowledge of immaterial and
universal objects, but only of individuals, like the senses. Therefore
the intellect is not united to the body as its form.
Objection 4: Further, power and action have the same subject; for the
same subject is what can, and does, act. But the intellectual action is
not the action of a body, as appears from above ([607]Q[75], A[2]).
Therefore neither is the intellectual faculty a power of the body. But
virtue or power cannot be more abstract or more simple than the essence
from which the faculty or power is derived. Therefore neither is the
substance of the intellect the form of a body.
Objection 5: Further, whatever has "per se" existence is not united to
the body as its form; because a form is that by which a thing exists:
so that the very existence of a form does not belong to the form by
itself. But the intellectual principle has "per se" existence and is
subsistent, as was said above ([608]Q[75], A[2]). Therefore it is not
united to the body as its form.
Objection 6: Further, whatever exists in a thing by reason of its
nature exists in it always. But to be united to matter belongs to the
form by reason of its nature; because form is the act of matter, not by
an accidental quality, but by its own essence; otherwise matter and
form would not make a thing substantially one, but only accidentally
one.
Therefore a form cannot be without its own proper matter. But the
intellectual principle, since it is incorruptible, as was shown above
([609]Q[75], A[6]), remains separate from the body, after the
dissolution of the body. Therefore the intellectual principle is not
united to the body as its form.
On the contrary, According to the Philosopher, Metaph. viii (Did. vii
2), difference is derived from the form. But the difference which
constitutes man is "rational," which is applied to man on account of
his intellectual principle. Therefore the intellectual principle is the
form of man.
I answer that, We must assert that the intellect which is the principle
of intellectual operation is the form of the human body. For that
whereby primarily anything acts is a form of the thing to which the act
is to be attributed: for instance, that whereby a body is primarily
healed is health, and that whereby the soul knows primarily is
knowledge; hence health is a form of the body, and knowledge is a form
of the soul. The reason is because nothing acts except so far as it is
in act; wherefore a thing acts by that whereby it is in act. Now it is
clear that the first thing by which the body lives is the soul. And as
life appears through various operations in different degrees of living
things, that whereby we primarily perform each of all these vital
actions is the soul. For the soul is the primary principle of our
nourishment, sensation, and local movement; and likewise of our
understanding. Therefore this principle by which we primarily
understand, whether it be called the intellect or the intellectual
soul, is the form of the body. This is the demonstration used by
Aristotle (De Anima ii, 2).
But if anyone says that the intellectual soul is not the form of the
body he must first explain how it is that this action of understanding
is the action of this particular man; for each one is conscious that it
is himself who understands. Now an action may be attributed to anyone
in three ways, as is clear from the Philosopher (Phys. v, 1); for a
thing is said to move or act, either by virtue of its whole self, for
instance, as a physician heals; or by virtue of a part, as a man sees
by his eye; or through an accidental quality, as when we say that
something that is white builds, because it is accidental to the builder
to be white. So when we say that Socrates or Plato understands, it is
clear that this is not attributed to him accidentally; since it is
ascribed to him as man, which is predicated of him essentially. We must
therefore say either that Socrates understands by virtue of his whole
self, as Plato maintained, holding that man is an intellectual soul; or
that intelligence is a part of Socrates. The first cannot stand, as was
shown above ([610]Q[75], A[4]), for this reason, that it is one and the
same man who is conscious both that he understands, and that he senses.
But one cannot sense without a body: therefore the body must be some
part of man. It follows therefore that the intellect by which Socrates
understands is a part of Socrates, so that in some way it is united to
the body of Socrates.
The Commentator held that this union is through the intelligible
species, as having a double subject, in the possible intellect, and in
the phantasms which are in the corporeal organs. Thus through the
intelligible species the possible intellect is linked to the body of
this or that particular man. But this link or union does not
sufficiently explain the fact, that the act of the intellect is the act
of Socrates. This can be clearly seen from comparison with the
sensitive faculty, from which Aristotle proceeds to consider things
relating to the intellect. For the relation of phantasms to the
intellect is like the relation of colors to the sense of sight, as he
says De Anima iii, 5,7. Therefore, as the species of colors are in the
sight, so are the species of phantasms in the possible intellect. Now
it is clear that because the colors, the images of which are in the
sight, are on a wall, the action of seeing is not attributed to the
wall: for we do not say that the wall sees, but rather that it is seen.
Therefore, from the fact that the species of phantasms are in the
possible intellect, it does not follow that Socrates, in whom are the
phantasms, understands, but that he or his phantasms are understood.
Some, however, tried to maintain that the intellect is united to the
body as its motor; and hence that the intellect and body form one thing
so that the act of the intellect could be attributed to the whole. This
is, however, absurd for many reasons. First, because the intellect does
not move the body except through the appetite, the movement of which
presupposes the operation of the intellect. The reason therefore why
Socrates understands is not because he is moved by his intellect, but
rather, contrariwise, he is moved by his intellect because he
understands. Secondly, because since Socrates is an individual in a
nature of one essence composed of matter and form, if the intellect be
not the form, it follows that it must be outside the essence, and then
the intellect is the whole Socrates as a motor to the thing moved.
Whereas the act of intellect remains in the agent, and does not pass
into something else, as does the action of heating. Therefore the
action of understanding cannot be attributed to Socrates for the reason
that he is moved by his intellect. Thirdly, because the action of a
motor is never attributed to the thing moved, except as to an
instrument; as the action of a carpenter to a saw. Therefore if
understanding is attributed to Socrates, as the action of what moves
him, it follows that it is attributed to him as to an instrument. This
is contrary to the teaching of the Philosopher, who holds that
understanding is not possible through a corporeal instrument (De Anima
iii, 4). Fourthly, because, although the action of a part be attributed
to the whole, as the action of the eye is attributed to a man; yet it
is never attributed to another part, except perhaps indirectly; for we
do not say that the hand sees because the eye sees. Therefore if the
intellect and Socrates are united in the above manner, the action of
the intellect cannot be attributed to Socrates. If, however, Socrates
be a whole composed of a union of the intellect with whatever else
belongs to Socrates, and still the intellect be united to those other
things only as a motor, it follows that Socrates is not one absolutely,
and consequently neither a being absolutely, for a thing is a being
according as it is one.
There remains, therefore, no other explanation than that given by
Aristotle---namely, that this particular man understands, because the
intellectual principle is his form. Thus from the very operation of the
intellect it is made clear that the intellectual principle is united to
the body as its form.
The same can be clearly shown from the nature of the human species. For
the nature of each thing is shown by its operation. Now the proper
operation of man as man is to understand; because he thereby surpasses
all other animals. Whence Aristotle concludes (Ethic. x, 7) that the
ultimate happiness of man must consist in this operation as properly
belonging to him. Man must therefore derive his species from that which
is the principle of this operation. But the species of anything is
derived from its form. It follows therefore that the intellectual
principle is the proper form of man.
But we must observe that the nobler a form is, the more it rises above
corporeal matter, the less it is merged in matter, and the more it
excels matter by its power and its operation; hence we find that the
form of a mixed body has another operation not caused by its elemental
qualities. And the higher we advance in the nobility of forms, the more
we find that the power of the form excels the elementary matter; as the
vegetative soul excels the form of the metal, and the sensitive soul
excels the vegetative soul. Now the human soul is the highest and
noblest of forms. Wherefore it excels corporeal matter in its power by
the fact that it has an operation and a power in which corporeal matter
has no share whatever. This power is called the intellect.
It is well to remark that if anyone holds that the soul is composed of
matter and form, it would follow that in no way could the soul be the
form of the body. For since the form is an act, and matter is only in
potentiality, that which is composed of matter and form cannot be the
form of another by virtue of itself as a whole. But if it is a form by
virtue of some part of itself, then that part which is the form we call
the soul, and that of which it is the form we call the "primary
animate," as was said above ([611]Q[75], A[5]).
Reply to Objection 1: As the Philosopher says (Phys. ii, 2), the
ultimate natural form to which the consideration of the natural
philosopher is directed is indeed separate; yet it exists in matter. He
proves this from the fact that "man and the sun generate man from
matter. " It is separate indeed according to its intellectual power,
because the intellectual power does not belong to a corporeal organ, as
the power of seeing is the act of the eye; for understanding is an act
which cannot be performed by a corporeal organ, like the act of seeing.
But it exists in matter so far as the soul itself, to which this power
belongs, is the form of the body, and the term of human generation. And
so the Philosopher says (De Anima iii) that the intellect is separate,
because it is not the faculty of a corporeal organ.
From this it is clear how to answer the Second and Third objections:
since, in order that man may be able to understand all things by means
of his intellect, and that his intellect may understand immaterial
things and universals, it is sufficient that the intellectual power be
not the act of the body.
Reply to Objection 4: The human soul, by reason of its perfection, is
not a form merged in matter, or entirely embraced by matter. Therefore
there is nothing to prevent some power thereof not being the act of the
body, although the soul is essentially the form of the body.
Reply to Objection 5: The soul communicates that existence in which it
subsists to the corporeal matter, out of which and the intellectual
soul there results unity of existence; so that the existence of the
whole composite is also the existence of the soul. This is not the case
with other non-subsistent forms. For this reason the human soul retains
its own existence after the dissolution of the body; whereas it is not
so with other forms.
Reply to Objection 6: To be united to the body belongs to the soul by
reason of itself, as it belongs to a light body by reason of itself to
be raised up. And as a light body remains light, when removed from its
proper place, retaining meanwhile an aptitude and an inclination for
its proper place; so the human soul retains its proper existence when
separated from the body, having an aptitude and a natural inclination
to be united to the body.
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Whether the intellectual principle is multiplied according to the number of
bodies?
Objection 1: It would seem that the intellectual principle is not
multiplied according to the number of bodies, but that there is one
intellect in all men. For an immaterial substance is not multiplied in
number within one species. But the human soul is an immaterial
substance; since it is not composed of matter and form as was shown
above ([612]Q[75], A[5]). Therefore there are not many human souls in
one species. But all men are of one species. Therefore there is but one
intellect in all men.
Objection 2: Further, when the cause is removed, the effect is also
removed. Therefore, if human souls were multiplied according to the
number of bodies, it follows that the bodies being removed, the number
of souls would not remain; but from all the souls there would be but a
single remainder. This is heretical; for it would do away with the
distinction of rewards and punishments.
Objection 3: Further, if my intellect is distinct from your intellect,
my intellect is an individual, and so is yours; for individuals are
things which differ in number but agree in one species. Now whatever is
received into anything must be received according to the condition of
the receiver. Therefore the species of things would be received
individually into my intellect, and also into yours: which is contrary
to the nature of the intellect which knows universals.
Objection 4: Further, the thing understood is in the intellect which
understands. If, therefore, my intellect is distinct from yours, what
is understood by me must be distinct from what is understood by you;
and consequently it will be reckoned as something individual, and be
only potentially something understood; so that the common intention
will have to be abstracted from both; since from things diverse
something intelligible common to them may be abstracted. But this is
contrary to the nature of the intellect; for then the intellect would
seem not to be distinct from the imagination. It seems, therefore, to
follow that there is one intellect in all men.
Objection 5: Further, when the disciple receives knowledge from the
master, it cannot be said that the master's knowledge begets knowledge
in the disciple, because then also knowledge would be an active form,
such as heat is, which is clearly false. It seems, therefore, that the
same individual knowledge which is in the master is communicated to the
disciple; which cannot be, unless there is one intellect in both.
Seemingly, therefore, the intellect of the disciple and master is but
one; and, consequently, the same applies to all men.
Objection 6: Further, Augustine (De Quant. Animae xxxii) says: "If I
were to say that there are many human souls, I should laugh at myself. "
But the soul seems to be one chiefly on account of the intellect.
Therefore there is one intellect of all men.
On the contrary, The Philosopher says (Phys. ii, 3) that the relation
of universal causes to universals is like the relation of particular
causes to individuals. But it is impossible that a soul, one in
species, should belong to animals of different species. Therefore it is
impossible that one individual intellectual soul should belong to
several individuals.
I answer that, It is absolutely impossible for one intellect to belong
to all men. This is clear if, as Plato maintained, man is the intellect
itself. For it would follow that Socrates and Plato are one man; and
that they are not distinct from each other, except by something outside
the essence of each. The distinction between Socrates and Plato would
be no other than that of one man with a tunic and another with a cloak;
which is quite absurd.
It is likewise clear that this is impossible if, according to the
opinion of Aristotle (De Anima ii, 2), it is supposed that the
intellect is a part or a power of the soul which is the form of man.
For it is impossible for many distinct individuals to have one form, as
it is impossible for them to have one existence, for the form is the
principle of existence.
Again, this is clearly impossible, whatever one may hold as to the
manner of the union of the intellect to this or that man. For it is
manifest that, supposing there is one principal agent, and two
instruments, we can say that there is one agent absolutely, but several
actions; as when one man touches several things with his two hands,
there will be one who touches, but two contacts. If, on the contrary,
we suppose one instrument and several principal agents, we might say
that there are several agents, but one act; for example, if there be
many drawing a ship by means of a rope; there will be many drawing, but
one pull. If, however, there is one principal agent, and one
instrument, we say that there is one agent and one action, as when the
smith strikes with one hammer, there is one striker and one stroke. Now
it is clear that no matter how the intellect is united or coupled to
this or that man, the intellect has the precedence of all the other
things which appertain to man; for the sensitive powers obey the
intellect, and are at its service. Therefore, if we suppose two men to
have several intellects and one sense---for instance, if two men had
one eye---there would be several seers, but one sight. But if there is
one intellect, no matter how diverse may be all those things of which
the intellect makes use as instruments, in no way is it possible to say
that Socrates and Plato are otherwise than one understanding man. And
if to this we add that to understand, which is the act of the
intellect, is not affected by any organ other than the intellect
itself; it will further follow that there is but one agent and one
action: that is to say that all men are but one "understander," and
have but one act of understanding, in regard, that is, of one
intelligible object.
However, it would be possible to distinguish my intellectual action
form yours by the distinction of the phantasms---that is to say, were
there one phantasm of a stone in me, and another in you---if the
phantasm itself, as it is one thing in me and another in you, were a
form of the possible intellect; since the same agent according to
divers forms produces divers actions; as, according to divers forms of
things with regard to the same eye, there are divers visions. But the
phantasm itself is not a form of the possible intellect; it is the
intelligible species abstracted from the phantasm that is a form. Now
in one intellect, from different phantasms of the same species, only
one intelligible species is abstracted; as appears in one man, in whom
there may be different phantasms of a stone; yet from all of them only
one intelligible species of a stone is abstracted; by which the
intellect of that one man, by one operation, understands the nature of
a stone, notwithstanding the diversity of phantasms. Therefore, if
there were one intellect for all men, the diversity of phantasms which
are in this one and that one would not cause a diversity of
intellectual operation in this man and that man. It follows, therefore,
that it is altogether impossible and unreasonable to maintain that
there exists one intellect for all men.
Reply to Objection 1: Although the intellectual soul, like an angel,
has no matter from which it is produced, yet it is the form of a
certain matter; in which it is unlike an angel. Therefore, according to
the division of matter, there are many souls of one species; while it
is quite impossible for many angels to be of one species.
Reply to Objection 2: Everything has unity in the same way that it has
being; consequently we must judge of the multiplicity of a thing as we
judge of its being. Now it is clear that the intellectual soul, by
virtue of its very being, is united to the body as its form; yet, after
the dissolution of the body, the intellectual soul retains its own
being. In like manner the multiplicity of souls is in proportion to the
multiplicity of the bodies; yet, after the dissolution of the bodies,
the souls retain their multiplied being.
Reply to Objection 3: Individuality of the intelligent being, or of the
species whereby it understands, does not exclude the understanding of
universals; otherwise, since separate intellects are subsistent
substances, and consequently individual, they could not understand
universals. But the materiality of the knower, and of the species
whereby it knows, impedes the knowledge of the universal. For as every
action is according to the mode of the form by which the agent acts, as
heating is according to the mode of the heat; so knowledge is according
to the mode of the species by which the knower knows. Now it is clear
that common nature becomes distinct and multiplied by reason of the
individuating principles which come from the matter. Therefore if the
form, which is the means of knowledge, is material---that is, not
abstracted from material conditions---its likeness to the nature of a
species or genus will be according to the distinction and
multiplication of that nature by means of individuating principles; so
that knowledge of the nature of a thing in general will be impossible.
But if the species be abstracted from the conditions of individual
matter, there will be a likeness of the nature without those things
which make it distinct and multiplied; thus there will be knowledge of
the universal. Nor does it matter, as to this particular point, whether
there be one intellect or many; because, even if there were but one, it
would necessarily be an individual intellect, and the species whereby
it understands, an individual species.
Reply to Objection 4: Whether the intellect be one or many, what is
understood is one; for what is understood is in the intellect, not
according to its own nature, but according to its likeness; for "the
stone is not in the soul, but its likeness is," as is said, De Anima
iii, 8. Yet it is the stone which is understood, not the likeness of
the stone; except by a reflection of the intellect on itself:
otherwise, the objects of sciences would not be things, but only
intelligible species. Now it happens that different things, according
to different forms, are likened to the same thing. And since knowledge
is begotten according to the assimilation of the knower to the thing
known, it follows that the same thing may happen to be known by several
knowers; as is apparent in regard to the senses; for several see the
same color, according to different likenesses. In the same way several
intellects understand one object understood. But there is this
difference, according to the opinion of Aristotle, between the sense
and the intelligence---that a thing is perceived by the sense according
to the disposition which it has outside the soul ---that is, in its
individuality; whereas the nature of the thing understood is indeed
outside the soul, but the mode according to which it exists outside the
soul is not the mode according to which it is understood. For the
common nature is understood as apart from the individuating principles;
whereas such is not its mode of existence outside the soul. But,
according to the opinion of Plato, the thing understood exists outside
the soul in the same condition as those under which it is understood;
for he supposed that the natures of things exist separate from matter.
Reply to Objection 5: One knowledge exists in the disciple and another
in the master. How it is caused will be shown later on ([613]Q[117],
A[1]).
Reply to Objection 6: Augustine denies a plurality of souls, that would
involve a plurality of species.
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Whether besides the intellectual soul there are in man other souls
essentially different from one another?
Objection 1: It would seem that besides the intellectual soul there are
in man other souls essentially different from one another, such as the
sensitive soul and the nutritive soul. For corruptible and
incorruptible are not of the same substance. But the intellectual soul
is incorruptible; whereas the other souls, as the sensitive and the
nutritive, are corruptible, as was shown above ([614]Q[75], A[6]).
Therefore in man the essence of the intellectual soul, the sensitive
soul, and the nutritive soul, cannot be the same.
Objection 2: Further, if it be said that the sensitive soul in man is
incorruptible; on the contrary, "corruptible and incorruptible differ
generically," says the Philosopher, Metaph. x (Did. ix, 10). But the
sensitive soul in the horse, the lion, and other brute animals, is
corruptible. If, therefore, in man it be incorruptible, the sensitive
soul in man and brute animals will not be of the same "genus. " Now an
animal is so called from its having a sensitive soul; and, therefore,
"animal" will not be one genus common to man and other animals, which
is absurd.
Objection 3: Further, the Philosopher says, Metaph. viii (Did. vii, 2),
that the genus is taken from the matter, and difference from the form.
But "rational," which is the difference constituting man, is taken from
the intellectual soul; while he is called "animal" by reason of his
having a body animated by a sensitive soul. Therefore the intellectual
soul may be compared to the body animated by a sensitive soul, as form
to matter. Therefore in man the intellectual soul is not essentially
the same as the sensitive soul, but presupposes it as a material
subject.
On the contrary, It is said in the book De Ecclesiasticis Dogmatibus
xv: "Nor do we say that there are two souls in one man, as James and
other Syrians write; one, animal, by which the body is animated, and
which is mingled with the blood; the other, spiritual, which obeys the
reason; but we say that it is one and the same soul in man, that both
gives life to the body by being united to it, and orders itself by its
own reasoning. "
I answer that, Plato held that there were several souls in one body,
distinct even as to organs, to which souls he referred the different
vital actions, saying that the nutritive power is in the liver, the
concupiscible in the heart, and the power of knowledge in the brain.
Which opinion is rejected by Aristotle (De Anima ii, 2), with regard to
those parts of the soul which use corporeal organs; for this reason,
that in those animals which continue to live when they have been
divided in each part are observed the operations of the soul, as sense
and appetite. Now this would not be the case if the various principles
of the soul's operations were essentially different, and distributed in
the various parts of the body. But with regard to the intellectual
part, he seems to leave it in doubt whether it be "only logically"
distinct from the other parts of the soul, "or also locally. "
The opinion of Plato might be maintained if, as he held, the soul was
supposed to be united to the body, not as its form, but as its motor.
For it involves nothing unreasonable that the same movable thing be
moved by several motors; and still less if it be moved according to its
various parts. If we suppose, however, that the soul is united to the
body as its form, it is quite impossible for several essentially
different souls to be in one body. This can be made clear by three
different reasons.
In the first place, an animal would not be absolutely one, in which
there were several souls. For nothing is absolutely one except by one
form, by which a thing has existence: because a thing has from the same
source both existence and unity; and therefore things which are
denominated by various forms are not absolutely one; as, for instance,
"a white man. " If, therefore, man were 'living' by one form, the
vegetative soul, and 'animal' by another form, the sensitive soul, and
"man" by another form, the intellectual soul, it would follow that man
is not absolutely one. Thus Aristotle argues, Metaph. viii (Did. vii,
6), against Plato, that if the idea of an animal is distinct from the
idea of a biped, then a biped animal is not absolutely one. For this
reason, against those who hold that there are several souls in the
body, he asks (De Anima i, 5), "what contains them? "---that is, what
makes them one? It cannot be said that they are united by the one body;
because rather does the soul contain the body and make it one, than the
reverse.
Secondly, this is proved to be impossible by the manner in which one
thing is predicated of another. Those things which are derived from
various forms are predicated of one another, either accidentally, (if
the forms are not ordered to one another, as when we say that something
white is sweet), or essentially, in the second manner of essential
predication, (if the forms are ordered one to another, the subject
belonging to the definition of the predicate; as a surface is
presupposed to color; so that if we say that a body with a surface is
colored, we have the second manner of essential predication. )
Therefore, if we have one form by which a thing is an animal, and
another form by which it is a man, it follows either that one of these
two things could not be predicated of the other, except accidentally,
supposing these two forms not to be ordered to one another---or that
one would be predicated of the other according to the second manner of
essential predication, if one soul be presupposed to the other. But
both of these consequences are clearly false: because "animal" is
predicated of man essentially and not accidentally; and man is not part
of the definition of an animal, but the other way about. Therefore of
necessity by the same form a thing is animal and man; otherwise man
would not really be the thing which is an animal, so that animal can be
essentially predicated of man.
Thirdly, this is shown to be impossible by the fact that when one
operation of the soul is intense it impedes another, which could never
be the case unless the principle of action were essentially one.
We must therefore conclude that in man the sensitive soul, the
intellectual soul, and the nutritive soul are numerically one soul.
This can easily be explained, if we consider the differences of species
and forms. For we observe that the species and forms of things differ
from one another, as the perfect and imperfect; as in the order of
things, the animate are more perfect than the inanimate, and animals
more perfect than plants, and man than brute animals; and in each of
these genera there are various degrees. For this reason Aristotle,
Metaph. viii (Did. vii, 3), compares the species of things to numbers,
which differ in species by the addition or subtraction of unity. And
(De Anima ii, 3) he compares the various souls to the species of
figures, one of which contains another; as a pentagon contains and
exceeds a tetragon. Thus the intellectual soul contains virtually
whatever belongs to the sensitive soul of brute animals, and to the
nutritive souls of plants. Therefore, as a surface which is of a
pentagonal shape, is not tetragonal by one shape, and pentagonal by
another---since a tetragonal shape would be superfluous as contained in
the pentagonal---so neither is Socrates a man by one soul, and animal
by another; but by one and the same soul he is both animal and man.
Reply to Objection 1: The sensitive soul is incorruptible, not by
reason of its being sensitive, but by reason of its being intellectual.
When, therefore, a soul is sensitive only, it is corruptible; but when
with sensibility it has also intellectuality, it is incorruptible. For
although sensibility does not give incorruptibility, yet it cannot
deprive intellectuality of its incorruptibility.
Reply to Objection 2: Not forms, but composites, are classified either
generically or specifically.
say this, forasmuch as some held that the form alone belongs to the
species; while matter is part of the individual, and not the species.
This cannot be true; for to the nature of the species belongs what the
definition signifies; and in natural things the definition does not
signify the form only, but the form and the matter. Hence in natural
things the matter is part of the species; not, indeed, signate matter,
which is the principle of individuality; but the common matter. For as
it belongs to the notion of this particular man to be composed of this
soul, of this flesh, and of these bones; so it belongs to the notion of
man to be composed of soul, flesh, and bones; for whatever belongs in
common to the substance of all the individuals contained under a given
species, must belong to the substance of the species.
It may also be understood in this sense, that this soul is this man;
and this could be held if it were supposed that the operation of the
sensitive soul were proper to it, apart from the body; because in that
case all the operations which are attributed to man would belong to the
soul only; and whatever performs the operations proper to a thing, is
that thing; wherefore that which performs the operations of a man is
man. But it has been shown above [601](A[3]) that sensation is not the
operation of the soul only. Since, then, sensation is an operation of
man, but not proper to him, it is clear that man is not a soul only,
but something composed of soul and body. Plato, through supposing that
sensation was proper to the soul, could maintain man to be a soul
making use of the body.
Reply to Objection 1: According to the Philosopher (Ethic. ix, 8), a
thing seems to be chiefly what is principle in it; thus what the
governor of a state does, the state is said to do. In this way
sometimes what is principle in man is said to be man; sometimes,
indeed, the intellectual part which, in accordance with truth, is
called the "inward" man; and sometimes the sensitive part with the body
is called man in the opinion of those whose observation does not go
beyond the senses. And this is called the "outward" man.
Reply to Objection 2: Not every particular substance is a hypostasis or
a person, but that which has the complete nature of its species. Hence
a hand, or a foot, is not called a hypostasis, or a person; nor,
likewise, is the soul alone so called, since it is a part of the human
species.
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Whether the soul is composed of matter and form?
Objection 1: It would seem that the soul is composed of matter and
form. For potentiality is opposed to actuality. Now, whatsoever things
are in actuality participate of the First Act, which is God; by
participation of Whom, all things are good, are beings, and are living
things, as is clear from the teaching of Dionysius (Div. Nom. v).
Therefore whatsoever things are in potentiality participate of the
first potentiality. But the first potentiality is primary matter.
Therefore, since the human soul is, after a manner, in potentiality;
which appears from the fact that sometimes a man is potentially
understanding; it seems that the human soul must participate of primary
matter, as part of itself.
Objection 2: Further, wherever the properties of matter are found,
there matter is. But the properties of matter are found in the
soul---namely, to be a subject, and to be changed, for it is a subject
to science, and virtue; and it changes from ignorance to knowledge and
from vice to virtue. Therefore matter is in the soul.
Objection 3: Further, things which have no matter, have no cause of
their existence, as the Philosopher says Metaph. viii (Did. vii, 6).
But the soul has a cause of its existence, since it is created by God.
Therefore the soul has matter.
Objection 4: Further, what has no matter, and is a form only, is a pure
act, and is infinite. But this belongs to God alone. Therefore the soul
has matter.
On the contrary, Augustine (Gen. ad lit. vii, 7,8,9) proves that the
soul was made neither of corporeal matter, nor of spiritual matter.
I answer that, The soul has no matter. We may consider this question in
two ways. First, from the notion of a soul in general; for it belongs
to the notion of a soul to be the form of a body. Now, either it is a
form by virtue of itself, in its entirety, or by virtue of some part of
itself. If by virtue of itself in its entirety, then it is impossible
that any part of it should be matter, if by matter we understand
something purely potential: for a form, as such, is an act; and that
which is purely potentiality cannot be part of an act, since
potentiality is repugnant to actuality as being opposite thereto. If,
however, it be a form by virtue of a part of itself, then we call that
part the soul: and that matter, which it actualizes first, we call the
"primary animate. "
Secondly, we may proceed from the specific notion of the human soul
inasmuch as it is intellectual. For it is clear that whatever is
received into something is received according to the condition of the
recipient. Now a thing is known in as far as its form is in the knower.
But the intellectual soul knows a thing in its nature absolutely: for
instance, it knows a stone absolutely as a stone; and therefore the
form of a stone absolutely, as to its proper formal idea, is in the
intellectual soul. Therefore the intellectual soul itself is an
absolute form, and not something composed of matter and form. For if
the intellectual soul were composed of matter and form, the forms of
things would be received into it as individuals, and so it would only
know the individual: just as it happens with the sensitive powers which
receive forms in a corporeal organ; since matter is the principle by
which forms are individualized. It follows, therefore, that the
intellectual soul, and every intellectual substance which has knowledge
of forms absolutely, is exempt from composition of matter and form.
Reply to Objection 1: The First Act is the universal principle of all
acts; because It is infinite, virtually "precontaining all things," as
Dionysius says (Div. Nom. v). Wherefore things participate of It not as
a part of themselves, but by diffusion of Its processions. Now as
potentiality is receptive of act, it must be proportionate to act. But
the acts received which proceed from the First Infinite Act, and are
participations thereof, are diverse, so that there cannot be one
potentiality which receives all acts, as there is one act, from which
all participated acts are derived; for then the receptive potentiality
would equal the active potentiality of the First Act. Now the receptive
potentiality in the intellectual soul is other than the receptive
potentiality of first matter, as appears from the diversity of the
things received by each. For primary matter receives individual forms;
whereas the intelligence receives absolute forms. Hence the existence
of such a potentiality in the intellectual soul does not prove that the
soul is composed of matter and form.
Reply to Objection 2: To be a subject and to be changed belong to
matter by reason of its being in potentiality. As, therefore, the
potentiality of the intelligence is one thing and the potentiality of
primary matter another, so in each is there a different reason of
subjection and change. For the intelligence is subject to knowledge,
and is changed from ignorance to knowledge, by reason of its being in
potentiality with regard to the intelligible species.
Reply to Objection 3: The form causes matter to be, and so does the
agent; wherefore the agent causes matter to be, so far as it actualizes
it by transmuting it to the act of a form. A subsistent form, however,
does not owe its existence to some formal principle, nor has it a cause
transmuting it from potentiality to act. So after the words quoted
above, the Philosopher concludes, that in things composed of matter and
form "there is no other cause but that which moves from potentiality to
act; while whatsoever things have no matter are simply beings at once. "
[*The Leonine edition has, "simpliciter sunt quod vere entia aliquid. "
The Parma edition of St. Thomas's Commentary on Aristotle has, "statim
per se unum quiddam est . . . et ens quiddam. "]
Reply to Objection 4: Everything participated is compared to the
participator as its act. But whatever created form be supposed to
subsist "per se," must have existence by participation; for "even
life," or anything of that sort, "is a participator of existence," as
Dionysius says (Div. Nom. v). Now participated existence is limited by
the capacity of the participator; so that God alone, Who is His own
existence, is pure act and infinite. But in intellectual substances
there is composition of actuality and potentiality, not, indeed, of
matter and form, but of form and participated existence. Wherefore some
say that they are composed of that "whereby they are" and that "which
they are"; for existence itself is that by which a thing is.
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Whether the human soul is incorruptible?
Objection 1: It would seem that the human soul is corruptible. For
those things that have a like beginning and process seemingly have a
like end. But the beginning, by generation, of men is like that of
animals, for they are made from the earth. And the process of life is
alike in both; because "all things breathe alike, and man hath nothing
more than the beast," as it is written (Eccles. 3:19). Therefore, as
the same text concludes, "the death of man and beast is one, and the
condition of both is equal. " But the souls of brute animals are
corruptible. Therefore, also, the human soul is corruptible.
Objection 2: Further, whatever is out of nothing can return to
nothingness; because the end should correspond to the beginning. But as
it is written (Wis. 2:2), "We are born of nothing"; which is true, not
only of the body, but also of the soul. Therefore, as is concluded in
the same passage, "After this we shall be as if we had not been," even
as to our soul.
Objection 3: Further, nothing is without its own proper operation. But
the operation proper to the soul, which is to understand through a
phantasm, cannot be without the body. For the soul understands nothing
without a phantasm; and there is no phantasm without the body as the
Philosopher says (De Anima i, 1). Therefore the soul cannot survive the
dissolution of the body.
On the contrary, Dionysius says (Div. Nom. iv) that human souls owe to
Divine goodness that they are "intellectual," and that they have "an
incorruptible substantial life. "
I answer that, We must assert that the intellectual principle which we
call the human soul is incorruptible. For a thing may be corrupted in
two ways---"per se," and accidentally. Now it is impossible for any
substance to be generated or corrupted accidentally, that is, by the
generation or corruption of something else. For generation and
corruption belong to a thing, just as existence belongs to it, which is
acquired by generation and lost by corruption. Therefore, whatever has
existence "per se" cannot be generated or corrupted except 'per se';
while things which do not subsist, such as accidents and material
forms, acquire existence or lost it through the generation or
corruption of composite things. Now it was shown above ([602]AA[2],3)
that the souls of brutes are not self-subsistent, whereas the human
soul is; so that the souls of brutes are corrupted, when their bodies
are corrupted; while the human soul could not be corrupted unless it
were corrupted "per se. " This, indeed, is impossible, not only as
regards the human soul, but also as regards anything subsistent that is
a form alone. For it is clear that what belongs to a thing by virtue of
itself is inseparable from it; but existence belongs to a form, which
is an act, by virtue of itself. Wherefore matter acquires actual
existence as it acquires the form; while it is corrupted so far as the
form is separated from it. But it is impossible for a form to be
separated from itself; and therefore it is impossible for a subsistent
form to cease to exist.
Granted even that the soul is composed of matter and form, as some
pretend, we should nevertheless have to maintain that it is
incorruptible. For corruption is found only where there is contrariety;
since generation and corruption are from contraries and into
contraries. Wherefore the heavenly bodies, since they have no matter
subject to contrariety, are incorruptible. Now there can be no
contrariety in the intellectual soul; for it receives according to the
manner of its existence, and those things which it receives are without
contrariety; for the notions even of contraries are not themselves
contrary, since contraries belong to the same knowledge. Therefore it
is impossible for the intellectual soul to be corruptible. Moreover we
may take a sign of this from the fact that everything naturally aspires
to existence after its own manner. Now, in things that have knowledge,
desire ensues upon knowledge. The senses indeed do not know existence,
except under the conditions of "here" and "now," whereas the intellect
apprehends existence absolutely, and for all time; so that everything
that has an intellect naturally desires always to exist. But a natural
desire cannot be in vain. Therefore every intellectual substance is
incorruptible.
Reply to Objection 1: Solomon reasons thus in the person of the
foolish, as expressed in the words of Wisdom 2. Therefore the saying
that man and animals have a like beginning in generation is true of the
body; for all animals alike are made of earth. But it is not true of
the soul. For the souls of brutes are produced by some power of the
body; whereas the human soul is produced by God. To signify this it is
written as to other animals: "Let the earth bring forth the living
soul" (Gn. 1:24): while of man it is written (Gn. 2:7) that "He
breathed into his face the breath of life. " And so in the last chapter
of Ecclesiastes (12:7) it is concluded: "(Before) the dust return into
its earth from whence it was; and the spirit return to God Who gave
it. " Again the process of life is alike as to the body, concerning
which it is written (Eccles. 3:19): "All things breathe alike," and
(Wis. 2:2), "The breath in our nostrils is smoke. " But the process is
not alike of the soul; for man is intelligent, whereas animals are not.
Hence it is false to say: "Man has nothing more than beasts. " Thus
death comes to both alike as to the body, by not as to the soul.
Reply to Objection 2: As a thing can be created by reason, not of a
passive potentiality, but only of the active potentiality of the
Creator, Who can produce something out of nothing, so when we say that
a thing can be reduced to nothing, we do not imply in the creature a
potentiality to non-existence, but in the Creator the power of ceasing
to sustain existence. But a thing is said to be corruptible because
there is in it a potentiality to non-existence.
Reply to Objection 3: To understand through a phantasm is the proper
operation of the soul by virtue of its union with the body. After
separation from the body it will have another mode of understanding,
similar to other substances separated from bodies, as will appear later
on ([603]Q[89], A[1]).
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Whether the soul is of the same species as an angel?
Objection 1: It would seem that the soul is of the same species as an
angel. For each thing is ordained to its proper end by the nature of
its species, whence is derived its inclination for that end. But the
end of the soul is the same as that of an angel---namely, eternal
happiness. Therefore they are of the same species.
Objection 2: Further, the ultimate specific difference is the noblest,
because it completes the nature of the species. But there is nothing
nobler either in an angel or in the soul than their intellectual
nature. Therefore the soul and the angel agree in the ultimate specific
difference: therefore they belong to the same species.
Objection 3: Further, it seems that the soul does not differ from an
angel except in its union with the body. But as the body is outside the
essence of the soul, it seems that it does not belong to its species.
Therefore the soul and angel are of the same species.
On the contrary, Things which have different natural operations are of
different species. But the natural operations of the soul and of an
angel are different; since, as Dionysius says (Div. Nom. vii), "Angelic
minds have simple and blessed intelligence, not gathering their
knowledge of Divine things from visible things. " Subsequently he says
the contrary to this of the soul. Therefore the soul and an angel are
not of the same species.
I answer that, Origen (Peri Archon iii, 5) held that human souls and
angels are all of the same species; and this because he supposed that
in these substances the difference of degree was accidental, as
resulting from their free-will: as we have seen above ([604]Q[47],
A[2]). But this cannot be; for in incorporeal substances there cannot
be diversity of number without diversity of species and inequality of
nature; because, as they are not composed of matter and form, but are
subsistent forms, it is clear that there is necessarily among them a
diversity of species. For a separate form cannot be understood
otherwise than as one of a single species; thus, supposing a separate
whiteness to exist, it could only be one; forasmuch as one whiteness
does not differ from another except as in this or that subject. But
diversity of species is always accompanied with a diversity of nature;
thus in species of colors one is more perfect than another; and the
same applies to other species, because differences which divide a
"genus" are contrary to one another. Contraries, however, are compared
to one another as the perfect to the imperfect, since the "principle of
contrariety is habit, and privation thereof," as is written Metaph. x
(Did. ix, 4). The same would follow if the aforesaid substances were
composed of matter and form. For if the matter of one be distinct from
the matter of another, it follows that either the form is the principle
of the distinction of matter---that is to say, that the matter is
distinct on account of its relation to divers forms; and even then
there would result a difference of species and inequality of nature: or
else the matter is the principle of the distinction of forms. But one
matter cannot be distinct from another, except by a distinction of
quantity, which has no place in these incorporeal substances, such as
an angel and the soul. So that it is not possible for the angel and the
soul to be of the same species. How it is that there can be many souls
of one species will be explained later ([605]Q[76], A[2], ad 1).
Reply to Objection 1: This argument proceeds from the proximate and
natural end. Eternal happiness is the ultimate and supernatural end.
Reply to Objection 2: The ultimate specific difference is the noblest
because it is the most determinate, in the same way as actuality is
nobler than potentiality. Thus, however, the intellectual faculty is
not the noblest, because it is indeterminate and common to many degrees
of intellectuality; as the sensible faculty is common to many degrees
in the sensible nature. Hence, as all sensible things are not of one
species, so neither are all intellectual things of one species.
Reply to Objection 3: The body is not of the essence of the soul; but
the soul by the nature of its essence can be united to the body, so
that, properly speaking, not the soul alone, but the "composite," is
the species. And the very fact that the soul in a certain way requires
the body for its operation, proves that the soul is endowed with a
grade of intellectuality inferior to that of an angel, who is not
united to a body.
__________________________________________________________________
OF THE UNION OF BODY AND SOUL (EIGHT ARTICLES)
We now consider the union of the soul with the body; and concerning
this there are eight points of inquiry:
(1) Whether the intellectual principle is united to the body as its
form?
(2) Whether the intellectual principle is multiplied numerically
according to the number of bodies; or is there one intelligence for all
men?
(3) Whether in the body the form of which is an intellectual principle,
there is some other soul?
(4) Whether in the body there is any other substantial form?
(5) Of the qualities required in the body of which the intellectual
principle is the form?
(6) Whether it be united to such a body by means of another body?
(7) Whether by means of an accident?
(8) Whether the soul is wholly in each part of the body?
__________________________________________________________________
Whether the intellectual principle is united to the body as its form?
Objection 1: It seems that the intellectual principle is not united to
the body as its form. For the Philosopher says (De Anima iii, 4) that
the intellect is "separate," and that it is not the act of any body.
Therefore it is not united to the body as its form.
Objection 2: Further, every form is determined according to the nature
of the matter of which it is the form; otherwise no proportion would be
required between matter and form. Therefore if the intellect were
united to the body as its form, since every body has a determinate
nature, it would follow that the intellect has a determinate nature;
and thus, it would not be capable of knowing all things, as is clear
from what has been said ([606]Q[75], A[2]); which is contrary to the
nature of the intellect. Therefore the intellect is not united to the
body as its form.
Objection 3: Further, whatever receptive power is an act of a body,
receives a form materially and individually; for what is received must
be received according to the condition of the receiver. But the form of
the thing understood is not received into the intellect materially and
individually, but rather immaterially and universally: otherwise the
intellect would not be capable of the knowledge of immaterial and
universal objects, but only of individuals, like the senses. Therefore
the intellect is not united to the body as its form.
Objection 4: Further, power and action have the same subject; for the
same subject is what can, and does, act. But the intellectual action is
not the action of a body, as appears from above ([607]Q[75], A[2]).
Therefore neither is the intellectual faculty a power of the body. But
virtue or power cannot be more abstract or more simple than the essence
from which the faculty or power is derived. Therefore neither is the
substance of the intellect the form of a body.
Objection 5: Further, whatever has "per se" existence is not united to
the body as its form; because a form is that by which a thing exists:
so that the very existence of a form does not belong to the form by
itself. But the intellectual principle has "per se" existence and is
subsistent, as was said above ([608]Q[75], A[2]). Therefore it is not
united to the body as its form.
Objection 6: Further, whatever exists in a thing by reason of its
nature exists in it always. But to be united to matter belongs to the
form by reason of its nature; because form is the act of matter, not by
an accidental quality, but by its own essence; otherwise matter and
form would not make a thing substantially one, but only accidentally
one.
Therefore a form cannot be without its own proper matter. But the
intellectual principle, since it is incorruptible, as was shown above
([609]Q[75], A[6]), remains separate from the body, after the
dissolution of the body. Therefore the intellectual principle is not
united to the body as its form.
On the contrary, According to the Philosopher, Metaph. viii (Did. vii
2), difference is derived from the form. But the difference which
constitutes man is "rational," which is applied to man on account of
his intellectual principle. Therefore the intellectual principle is the
form of man.
I answer that, We must assert that the intellect which is the principle
of intellectual operation is the form of the human body. For that
whereby primarily anything acts is a form of the thing to which the act
is to be attributed: for instance, that whereby a body is primarily
healed is health, and that whereby the soul knows primarily is
knowledge; hence health is a form of the body, and knowledge is a form
of the soul. The reason is because nothing acts except so far as it is
in act; wherefore a thing acts by that whereby it is in act. Now it is
clear that the first thing by which the body lives is the soul. And as
life appears through various operations in different degrees of living
things, that whereby we primarily perform each of all these vital
actions is the soul. For the soul is the primary principle of our
nourishment, sensation, and local movement; and likewise of our
understanding. Therefore this principle by which we primarily
understand, whether it be called the intellect or the intellectual
soul, is the form of the body. This is the demonstration used by
Aristotle (De Anima ii, 2).
But if anyone says that the intellectual soul is not the form of the
body he must first explain how it is that this action of understanding
is the action of this particular man; for each one is conscious that it
is himself who understands. Now an action may be attributed to anyone
in three ways, as is clear from the Philosopher (Phys. v, 1); for a
thing is said to move or act, either by virtue of its whole self, for
instance, as a physician heals; or by virtue of a part, as a man sees
by his eye; or through an accidental quality, as when we say that
something that is white builds, because it is accidental to the builder
to be white. So when we say that Socrates or Plato understands, it is
clear that this is not attributed to him accidentally; since it is
ascribed to him as man, which is predicated of him essentially. We must
therefore say either that Socrates understands by virtue of his whole
self, as Plato maintained, holding that man is an intellectual soul; or
that intelligence is a part of Socrates. The first cannot stand, as was
shown above ([610]Q[75], A[4]), for this reason, that it is one and the
same man who is conscious both that he understands, and that he senses.
But one cannot sense without a body: therefore the body must be some
part of man. It follows therefore that the intellect by which Socrates
understands is a part of Socrates, so that in some way it is united to
the body of Socrates.
The Commentator held that this union is through the intelligible
species, as having a double subject, in the possible intellect, and in
the phantasms which are in the corporeal organs. Thus through the
intelligible species the possible intellect is linked to the body of
this or that particular man. But this link or union does not
sufficiently explain the fact, that the act of the intellect is the act
of Socrates. This can be clearly seen from comparison with the
sensitive faculty, from which Aristotle proceeds to consider things
relating to the intellect. For the relation of phantasms to the
intellect is like the relation of colors to the sense of sight, as he
says De Anima iii, 5,7. Therefore, as the species of colors are in the
sight, so are the species of phantasms in the possible intellect. Now
it is clear that because the colors, the images of which are in the
sight, are on a wall, the action of seeing is not attributed to the
wall: for we do not say that the wall sees, but rather that it is seen.
Therefore, from the fact that the species of phantasms are in the
possible intellect, it does not follow that Socrates, in whom are the
phantasms, understands, but that he or his phantasms are understood.
Some, however, tried to maintain that the intellect is united to the
body as its motor; and hence that the intellect and body form one thing
so that the act of the intellect could be attributed to the whole. This
is, however, absurd for many reasons. First, because the intellect does
not move the body except through the appetite, the movement of which
presupposes the operation of the intellect. The reason therefore why
Socrates understands is not because he is moved by his intellect, but
rather, contrariwise, he is moved by his intellect because he
understands. Secondly, because since Socrates is an individual in a
nature of one essence composed of matter and form, if the intellect be
not the form, it follows that it must be outside the essence, and then
the intellect is the whole Socrates as a motor to the thing moved.
Whereas the act of intellect remains in the agent, and does not pass
into something else, as does the action of heating. Therefore the
action of understanding cannot be attributed to Socrates for the reason
that he is moved by his intellect. Thirdly, because the action of a
motor is never attributed to the thing moved, except as to an
instrument; as the action of a carpenter to a saw. Therefore if
understanding is attributed to Socrates, as the action of what moves
him, it follows that it is attributed to him as to an instrument. This
is contrary to the teaching of the Philosopher, who holds that
understanding is not possible through a corporeal instrument (De Anima
iii, 4). Fourthly, because, although the action of a part be attributed
to the whole, as the action of the eye is attributed to a man; yet it
is never attributed to another part, except perhaps indirectly; for we
do not say that the hand sees because the eye sees. Therefore if the
intellect and Socrates are united in the above manner, the action of
the intellect cannot be attributed to Socrates. If, however, Socrates
be a whole composed of a union of the intellect with whatever else
belongs to Socrates, and still the intellect be united to those other
things only as a motor, it follows that Socrates is not one absolutely,
and consequently neither a being absolutely, for a thing is a being
according as it is one.
There remains, therefore, no other explanation than that given by
Aristotle---namely, that this particular man understands, because the
intellectual principle is his form. Thus from the very operation of the
intellect it is made clear that the intellectual principle is united to
the body as its form.
The same can be clearly shown from the nature of the human species. For
the nature of each thing is shown by its operation. Now the proper
operation of man as man is to understand; because he thereby surpasses
all other animals. Whence Aristotle concludes (Ethic. x, 7) that the
ultimate happiness of man must consist in this operation as properly
belonging to him. Man must therefore derive his species from that which
is the principle of this operation. But the species of anything is
derived from its form. It follows therefore that the intellectual
principle is the proper form of man.
But we must observe that the nobler a form is, the more it rises above
corporeal matter, the less it is merged in matter, and the more it
excels matter by its power and its operation; hence we find that the
form of a mixed body has another operation not caused by its elemental
qualities. And the higher we advance in the nobility of forms, the more
we find that the power of the form excels the elementary matter; as the
vegetative soul excels the form of the metal, and the sensitive soul
excels the vegetative soul. Now the human soul is the highest and
noblest of forms. Wherefore it excels corporeal matter in its power by
the fact that it has an operation and a power in which corporeal matter
has no share whatever. This power is called the intellect.
It is well to remark that if anyone holds that the soul is composed of
matter and form, it would follow that in no way could the soul be the
form of the body. For since the form is an act, and matter is only in
potentiality, that which is composed of matter and form cannot be the
form of another by virtue of itself as a whole. But if it is a form by
virtue of some part of itself, then that part which is the form we call
the soul, and that of which it is the form we call the "primary
animate," as was said above ([611]Q[75], A[5]).
Reply to Objection 1: As the Philosopher says (Phys. ii, 2), the
ultimate natural form to which the consideration of the natural
philosopher is directed is indeed separate; yet it exists in matter. He
proves this from the fact that "man and the sun generate man from
matter. " It is separate indeed according to its intellectual power,
because the intellectual power does not belong to a corporeal organ, as
the power of seeing is the act of the eye; for understanding is an act
which cannot be performed by a corporeal organ, like the act of seeing.
But it exists in matter so far as the soul itself, to which this power
belongs, is the form of the body, and the term of human generation. And
so the Philosopher says (De Anima iii) that the intellect is separate,
because it is not the faculty of a corporeal organ.
From this it is clear how to answer the Second and Third objections:
since, in order that man may be able to understand all things by means
of his intellect, and that his intellect may understand immaterial
things and universals, it is sufficient that the intellectual power be
not the act of the body.
Reply to Objection 4: The human soul, by reason of its perfection, is
not a form merged in matter, or entirely embraced by matter. Therefore
there is nothing to prevent some power thereof not being the act of the
body, although the soul is essentially the form of the body.
Reply to Objection 5: The soul communicates that existence in which it
subsists to the corporeal matter, out of which and the intellectual
soul there results unity of existence; so that the existence of the
whole composite is also the existence of the soul. This is not the case
with other non-subsistent forms. For this reason the human soul retains
its own existence after the dissolution of the body; whereas it is not
so with other forms.
Reply to Objection 6: To be united to the body belongs to the soul by
reason of itself, as it belongs to a light body by reason of itself to
be raised up. And as a light body remains light, when removed from its
proper place, retaining meanwhile an aptitude and an inclination for
its proper place; so the human soul retains its proper existence when
separated from the body, having an aptitude and a natural inclination
to be united to the body.
__________________________________________________________________
Whether the intellectual principle is multiplied according to the number of
bodies?
Objection 1: It would seem that the intellectual principle is not
multiplied according to the number of bodies, but that there is one
intellect in all men. For an immaterial substance is not multiplied in
number within one species. But the human soul is an immaterial
substance; since it is not composed of matter and form as was shown
above ([612]Q[75], A[5]). Therefore there are not many human souls in
one species. But all men are of one species. Therefore there is but one
intellect in all men.
Objection 2: Further, when the cause is removed, the effect is also
removed. Therefore, if human souls were multiplied according to the
number of bodies, it follows that the bodies being removed, the number
of souls would not remain; but from all the souls there would be but a
single remainder. This is heretical; for it would do away with the
distinction of rewards and punishments.
Objection 3: Further, if my intellect is distinct from your intellect,
my intellect is an individual, and so is yours; for individuals are
things which differ in number but agree in one species. Now whatever is
received into anything must be received according to the condition of
the receiver. Therefore the species of things would be received
individually into my intellect, and also into yours: which is contrary
to the nature of the intellect which knows universals.
Objection 4: Further, the thing understood is in the intellect which
understands. If, therefore, my intellect is distinct from yours, what
is understood by me must be distinct from what is understood by you;
and consequently it will be reckoned as something individual, and be
only potentially something understood; so that the common intention
will have to be abstracted from both; since from things diverse
something intelligible common to them may be abstracted. But this is
contrary to the nature of the intellect; for then the intellect would
seem not to be distinct from the imagination. It seems, therefore, to
follow that there is one intellect in all men.
Objection 5: Further, when the disciple receives knowledge from the
master, it cannot be said that the master's knowledge begets knowledge
in the disciple, because then also knowledge would be an active form,
such as heat is, which is clearly false. It seems, therefore, that the
same individual knowledge which is in the master is communicated to the
disciple; which cannot be, unless there is one intellect in both.
Seemingly, therefore, the intellect of the disciple and master is but
one; and, consequently, the same applies to all men.
Objection 6: Further, Augustine (De Quant. Animae xxxii) says: "If I
were to say that there are many human souls, I should laugh at myself. "
But the soul seems to be one chiefly on account of the intellect.
Therefore there is one intellect of all men.
On the contrary, The Philosopher says (Phys. ii, 3) that the relation
of universal causes to universals is like the relation of particular
causes to individuals. But it is impossible that a soul, one in
species, should belong to animals of different species. Therefore it is
impossible that one individual intellectual soul should belong to
several individuals.
I answer that, It is absolutely impossible for one intellect to belong
to all men. This is clear if, as Plato maintained, man is the intellect
itself. For it would follow that Socrates and Plato are one man; and
that they are not distinct from each other, except by something outside
the essence of each. The distinction between Socrates and Plato would
be no other than that of one man with a tunic and another with a cloak;
which is quite absurd.
It is likewise clear that this is impossible if, according to the
opinion of Aristotle (De Anima ii, 2), it is supposed that the
intellect is a part or a power of the soul which is the form of man.
For it is impossible for many distinct individuals to have one form, as
it is impossible for them to have one existence, for the form is the
principle of existence.
Again, this is clearly impossible, whatever one may hold as to the
manner of the union of the intellect to this or that man. For it is
manifest that, supposing there is one principal agent, and two
instruments, we can say that there is one agent absolutely, but several
actions; as when one man touches several things with his two hands,
there will be one who touches, but two contacts. If, on the contrary,
we suppose one instrument and several principal agents, we might say
that there are several agents, but one act; for example, if there be
many drawing a ship by means of a rope; there will be many drawing, but
one pull. If, however, there is one principal agent, and one
instrument, we say that there is one agent and one action, as when the
smith strikes with one hammer, there is one striker and one stroke. Now
it is clear that no matter how the intellect is united or coupled to
this or that man, the intellect has the precedence of all the other
things which appertain to man; for the sensitive powers obey the
intellect, and are at its service. Therefore, if we suppose two men to
have several intellects and one sense---for instance, if two men had
one eye---there would be several seers, but one sight. But if there is
one intellect, no matter how diverse may be all those things of which
the intellect makes use as instruments, in no way is it possible to say
that Socrates and Plato are otherwise than one understanding man. And
if to this we add that to understand, which is the act of the
intellect, is not affected by any organ other than the intellect
itself; it will further follow that there is but one agent and one
action: that is to say that all men are but one "understander," and
have but one act of understanding, in regard, that is, of one
intelligible object.
However, it would be possible to distinguish my intellectual action
form yours by the distinction of the phantasms---that is to say, were
there one phantasm of a stone in me, and another in you---if the
phantasm itself, as it is one thing in me and another in you, were a
form of the possible intellect; since the same agent according to
divers forms produces divers actions; as, according to divers forms of
things with regard to the same eye, there are divers visions. But the
phantasm itself is not a form of the possible intellect; it is the
intelligible species abstracted from the phantasm that is a form. Now
in one intellect, from different phantasms of the same species, only
one intelligible species is abstracted; as appears in one man, in whom
there may be different phantasms of a stone; yet from all of them only
one intelligible species of a stone is abstracted; by which the
intellect of that one man, by one operation, understands the nature of
a stone, notwithstanding the diversity of phantasms. Therefore, if
there were one intellect for all men, the diversity of phantasms which
are in this one and that one would not cause a diversity of
intellectual operation in this man and that man. It follows, therefore,
that it is altogether impossible and unreasonable to maintain that
there exists one intellect for all men.
Reply to Objection 1: Although the intellectual soul, like an angel,
has no matter from which it is produced, yet it is the form of a
certain matter; in which it is unlike an angel. Therefore, according to
the division of matter, there are many souls of one species; while it
is quite impossible for many angels to be of one species.
Reply to Objection 2: Everything has unity in the same way that it has
being; consequently we must judge of the multiplicity of a thing as we
judge of its being. Now it is clear that the intellectual soul, by
virtue of its very being, is united to the body as its form; yet, after
the dissolution of the body, the intellectual soul retains its own
being. In like manner the multiplicity of souls is in proportion to the
multiplicity of the bodies; yet, after the dissolution of the bodies,
the souls retain their multiplied being.
Reply to Objection 3: Individuality of the intelligent being, or of the
species whereby it understands, does not exclude the understanding of
universals; otherwise, since separate intellects are subsistent
substances, and consequently individual, they could not understand
universals. But the materiality of the knower, and of the species
whereby it knows, impedes the knowledge of the universal. For as every
action is according to the mode of the form by which the agent acts, as
heating is according to the mode of the heat; so knowledge is according
to the mode of the species by which the knower knows. Now it is clear
that common nature becomes distinct and multiplied by reason of the
individuating principles which come from the matter. Therefore if the
form, which is the means of knowledge, is material---that is, not
abstracted from material conditions---its likeness to the nature of a
species or genus will be according to the distinction and
multiplication of that nature by means of individuating principles; so
that knowledge of the nature of a thing in general will be impossible.
But if the species be abstracted from the conditions of individual
matter, there will be a likeness of the nature without those things
which make it distinct and multiplied; thus there will be knowledge of
the universal. Nor does it matter, as to this particular point, whether
there be one intellect or many; because, even if there were but one, it
would necessarily be an individual intellect, and the species whereby
it understands, an individual species.
Reply to Objection 4: Whether the intellect be one or many, what is
understood is one; for what is understood is in the intellect, not
according to its own nature, but according to its likeness; for "the
stone is not in the soul, but its likeness is," as is said, De Anima
iii, 8. Yet it is the stone which is understood, not the likeness of
the stone; except by a reflection of the intellect on itself:
otherwise, the objects of sciences would not be things, but only
intelligible species. Now it happens that different things, according
to different forms, are likened to the same thing. And since knowledge
is begotten according to the assimilation of the knower to the thing
known, it follows that the same thing may happen to be known by several
knowers; as is apparent in regard to the senses; for several see the
same color, according to different likenesses. In the same way several
intellects understand one object understood. But there is this
difference, according to the opinion of Aristotle, between the sense
and the intelligence---that a thing is perceived by the sense according
to the disposition which it has outside the soul ---that is, in its
individuality; whereas the nature of the thing understood is indeed
outside the soul, but the mode according to which it exists outside the
soul is not the mode according to which it is understood. For the
common nature is understood as apart from the individuating principles;
whereas such is not its mode of existence outside the soul. But,
according to the opinion of Plato, the thing understood exists outside
the soul in the same condition as those under which it is understood;
for he supposed that the natures of things exist separate from matter.
Reply to Objection 5: One knowledge exists in the disciple and another
in the master. How it is caused will be shown later on ([613]Q[117],
A[1]).
Reply to Objection 6: Augustine denies a plurality of souls, that would
involve a plurality of species.
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Whether besides the intellectual soul there are in man other souls
essentially different from one another?
Objection 1: It would seem that besides the intellectual soul there are
in man other souls essentially different from one another, such as the
sensitive soul and the nutritive soul. For corruptible and
incorruptible are not of the same substance. But the intellectual soul
is incorruptible; whereas the other souls, as the sensitive and the
nutritive, are corruptible, as was shown above ([614]Q[75], A[6]).
Therefore in man the essence of the intellectual soul, the sensitive
soul, and the nutritive soul, cannot be the same.
Objection 2: Further, if it be said that the sensitive soul in man is
incorruptible; on the contrary, "corruptible and incorruptible differ
generically," says the Philosopher, Metaph. x (Did. ix, 10). But the
sensitive soul in the horse, the lion, and other brute animals, is
corruptible. If, therefore, in man it be incorruptible, the sensitive
soul in man and brute animals will not be of the same "genus. " Now an
animal is so called from its having a sensitive soul; and, therefore,
"animal" will not be one genus common to man and other animals, which
is absurd.
Objection 3: Further, the Philosopher says, Metaph. viii (Did. vii, 2),
that the genus is taken from the matter, and difference from the form.
But "rational," which is the difference constituting man, is taken from
the intellectual soul; while he is called "animal" by reason of his
having a body animated by a sensitive soul. Therefore the intellectual
soul may be compared to the body animated by a sensitive soul, as form
to matter. Therefore in man the intellectual soul is not essentially
the same as the sensitive soul, but presupposes it as a material
subject.
On the contrary, It is said in the book De Ecclesiasticis Dogmatibus
xv: "Nor do we say that there are two souls in one man, as James and
other Syrians write; one, animal, by which the body is animated, and
which is mingled with the blood; the other, spiritual, which obeys the
reason; but we say that it is one and the same soul in man, that both
gives life to the body by being united to it, and orders itself by its
own reasoning. "
I answer that, Plato held that there were several souls in one body,
distinct even as to organs, to which souls he referred the different
vital actions, saying that the nutritive power is in the liver, the
concupiscible in the heart, and the power of knowledge in the brain.
Which opinion is rejected by Aristotle (De Anima ii, 2), with regard to
those parts of the soul which use corporeal organs; for this reason,
that in those animals which continue to live when they have been
divided in each part are observed the operations of the soul, as sense
and appetite. Now this would not be the case if the various principles
of the soul's operations were essentially different, and distributed in
the various parts of the body. But with regard to the intellectual
part, he seems to leave it in doubt whether it be "only logically"
distinct from the other parts of the soul, "or also locally. "
The opinion of Plato might be maintained if, as he held, the soul was
supposed to be united to the body, not as its form, but as its motor.
For it involves nothing unreasonable that the same movable thing be
moved by several motors; and still less if it be moved according to its
various parts. If we suppose, however, that the soul is united to the
body as its form, it is quite impossible for several essentially
different souls to be in one body. This can be made clear by three
different reasons.
In the first place, an animal would not be absolutely one, in which
there were several souls. For nothing is absolutely one except by one
form, by which a thing has existence: because a thing has from the same
source both existence and unity; and therefore things which are
denominated by various forms are not absolutely one; as, for instance,
"a white man. " If, therefore, man were 'living' by one form, the
vegetative soul, and 'animal' by another form, the sensitive soul, and
"man" by another form, the intellectual soul, it would follow that man
is not absolutely one. Thus Aristotle argues, Metaph. viii (Did. vii,
6), against Plato, that if the idea of an animal is distinct from the
idea of a biped, then a biped animal is not absolutely one. For this
reason, against those who hold that there are several souls in the
body, he asks (De Anima i, 5), "what contains them? "---that is, what
makes them one? It cannot be said that they are united by the one body;
because rather does the soul contain the body and make it one, than the
reverse.
Secondly, this is proved to be impossible by the manner in which one
thing is predicated of another. Those things which are derived from
various forms are predicated of one another, either accidentally, (if
the forms are not ordered to one another, as when we say that something
white is sweet), or essentially, in the second manner of essential
predication, (if the forms are ordered one to another, the subject
belonging to the definition of the predicate; as a surface is
presupposed to color; so that if we say that a body with a surface is
colored, we have the second manner of essential predication. )
Therefore, if we have one form by which a thing is an animal, and
another form by which it is a man, it follows either that one of these
two things could not be predicated of the other, except accidentally,
supposing these two forms not to be ordered to one another---or that
one would be predicated of the other according to the second manner of
essential predication, if one soul be presupposed to the other. But
both of these consequences are clearly false: because "animal" is
predicated of man essentially and not accidentally; and man is not part
of the definition of an animal, but the other way about. Therefore of
necessity by the same form a thing is animal and man; otherwise man
would not really be the thing which is an animal, so that animal can be
essentially predicated of man.
Thirdly, this is shown to be impossible by the fact that when one
operation of the soul is intense it impedes another, which could never
be the case unless the principle of action were essentially one.
We must therefore conclude that in man the sensitive soul, the
intellectual soul, and the nutritive soul are numerically one soul.
This can easily be explained, if we consider the differences of species
and forms. For we observe that the species and forms of things differ
from one another, as the perfect and imperfect; as in the order of
things, the animate are more perfect than the inanimate, and animals
more perfect than plants, and man than brute animals; and in each of
these genera there are various degrees. For this reason Aristotle,
Metaph. viii (Did. vii, 3), compares the species of things to numbers,
which differ in species by the addition or subtraction of unity. And
(De Anima ii, 3) he compares the various souls to the species of
figures, one of which contains another; as a pentagon contains and
exceeds a tetragon. Thus the intellectual soul contains virtually
whatever belongs to the sensitive soul of brute animals, and to the
nutritive souls of plants. Therefore, as a surface which is of a
pentagonal shape, is not tetragonal by one shape, and pentagonal by
another---since a tetragonal shape would be superfluous as contained in
the pentagonal---so neither is Socrates a man by one soul, and animal
by another; but by one and the same soul he is both animal and man.
Reply to Objection 1: The sensitive soul is incorruptible, not by
reason of its being sensitive, but by reason of its being intellectual.
When, therefore, a soul is sensitive only, it is corruptible; but when
with sensibility it has also intellectuality, it is incorruptible. For
although sensibility does not give incorruptibility, yet it cannot
deprive intellectuality of its incorruptibility.
Reply to Objection 2: Not forms, but composites, are classified either
generically or specifically.
