No More Learning

Now, immutation is of two kinds, one natural, the other spiritual.
Natural immutation takes place by the form of the immuter being
received according to its natural existence, into the thing immuted, as
heat is received into the thing heated. Whereas spiritual immutation
takes place by the form of the immuter being received, according to a
spiritual mode of existence, into the thing immuted, as the form of
color is received into the pupil which does not thereby become colored.
Now, for the operation of the senses, a spiritual immutation is
required, whereby an intention of the sensible form is effected in the
sensile organ. Otherwise, if a natural immutation alone sufficed for
the sense's action, all natural bodies would feel when they undergo
alteration.

But in some senses we find spiritual immutation only, as in "sight"
while in others we find not only spiritual but also a natural
immutation; either on the part of the object only, or likewise on the
part of the organ. On the part of the object we find natural
immutation, as to place, in sound which is the object of "hearing"; for
sound is caused by percussion and commotion of air: and we find natural
immutation by alteration, in odor which is the object of "smelling";
for in order to exhale an odor, a body must be in a measure affected by
heat. On the part of an organ, natural immutation takes place in
"touch" and "taste"; for the hand that touches something hot becomes
hot, while the tongue is moistened by the humidity of the flavored
morsel. But the organs of smelling and hearing are not affected in
their respective operations by any natural immutation unless
indirectly.

Now, the sight, which is without natural immutation either in its organ
or in its object, is the most spiritual, the most perfect, and the most
universal of all the senses. After this comes the hearing and then the
smell, which require a natural immutation on the part of the object;
while local motion is more perfect than, and naturally prior to, the
motion of alteration, as the Philosopher proves (Phys. viii, 7). Touch
and taste are the most material of all: of the distinction of which we
shall speak later on (ad 3,4). Hence it is that the three other senses
are not exercised through a medium united to them, to obviate any
natural immutation in their organ; as happens as regards these two
senses.

Reply to Objection 1: Not every accident has in itself a power of
immutation but only qualities of the third species, which are the
principles of alteration: therefore only suchlike qualities are the
objects of the senses; because "the senses are affected by the same
things whereby inanimate bodies are affected," as stated in Phys. vii,
2.

Reply to Objection 2: Size, shape, and the like, which are called
"common sensibles," are midway between "accidental sensibles" and
"proper sensibles," which are the objects of the senses. For the proper
sensibles first, and of their very nature, affect the senses; since
they are qualities that cause alteration. But the common sensibles are
all reducible to quantity. As to size and number, it is clear that they
are species of quantity. Shape is a quality about quantity. Shape is a
quality about quantity, since the notion of shape consists of fixing
the bounds of magnitude. Movement and rest are sensed according as the
subject is affected in one or more ways in the magnitude of the subject
or of its local distance, as in the movement of growth or of
locomotion, or again, according as it is affected in some sensible
qualities, as in the movement of alteration; and thus to sense movement
and rest is, in a way, to sense one thing and many. Now quantity is the
proximate subject of the qualities that cause alteration, as surface is
of color. Therefore the common sensibles do not move the senses first
and of their own nature, but by reason of the sensible quality; as the
surface by reason of color. Yet they are not accidental sensibles, for
they produce a certain variety in the immutation of the senses. For
sense is immuted differently by a large and by a small surface: since
whiteness itself is said to be great or small, and therefore it is
divided according to its proper subject.

Reply to Objection 3: As the Philosopher seems to say (De Anima ii,
11), the sense of touch is generically one, but is divided into several
specific senses, and for this reason it extends to various
contrarieties; which senses, however, are not separate from one another
in their organ, but are spread throughout the whole body, so that their
distinction is not evident. But taste, which perceives the sweet and
the bitter, accompanies touch in the tongue, but not in the whole body;
so it is easily distinguished from touch. We might also say that all
those contrarieties agree, each in some proximate genus, and all in a
common genus, which is the common and formal object of touch. Such
common genus is, however, unnamed, just as the proximate genus of hot
and cold is unnamed.

Reply to Objection 4: The sense of taste, according to a saying of the
Philosopher (De Anima ii, 9), is a kind of touch existing in the tongue
only. It is not distinct from touch in general, but only from the
species of touch distributed in the body. But if touch is one sense
only, on account of the common formality of its object: we must say
that taste is distinguished from touch by reason of a different
formality of immutation. For touch involves a natural, and not only a
spiritual, immutation in its organ, by reason of the quality which is
its proper object. But the organ of taste is not necessarily immuted by
a natural immutation by reason of the quality which is its proper
object, so that the tongue itself becomes sweet and bitter: but by
reason of a quality which is a preamble to, and on which is based, the
flavor, which quality is moisture, the object of touch.
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Whether the interior senses are suitably distinguished?

Objection 1: It would seem that the interior senses are not suitably
distinguished. For the common is not divided against the proper.
Therefore the common sense should not be numbered among the interior
sensitive powers, in addition to the proper exterior senses.

Objection 2: Further, there is no need to assign an interior power of
apprehension when the proper and exterior sense suffices. But the
proper and exterior senses suffice for us to judge of sensible things;
for each sense judges of its proper object. In like manner they seem to
suffice for the perception of their own actions; for since the action
of the sense is, in a way, between the power and its object, it seems
that sight must be much more able to perceive its own vision, as being
nearer to it, than the color; and in like manner with the other senses.
Therefore for this there is no need to assign an interior power, called
the common sense.

Objection 3: Further, according to the Philosopher (De Memor. et Remin.
i), the imagination and the memory are passions of the "first
sensitive. " But passion is not divided against its subject. Therefore
memory and imagination should not be assigned as powers distinct from
the senses.

Objection 4: Further, the intellect depends on the senses less than any
power of the sensitive part. But the intellect knows nothing but what
it receives from the senses; whence we read (Poster. i, 8), that "those
who lack one sense lack one kind of knowledge. " Therefore much less
should we assign to the sensitive part a power, which they call the
"estimative" power, for the perception of intentions which the sense
does not perceive.

Objection 5: Further, the action of the cogitative power, which
consists in comparing, adding and dividing, and the action of the
reminiscence, which consists in the use of a kind of syllogism for the
sake of inquiry, is not less distant from the actions of the estimative
and memorative powers, than the action of the estimative is from the
action of the imagination. Therefore either we must add the cognitive
and reminiscitive to the estimative and memorative powers, or the
estimative and memorative powers should not be made distinct from the
imagination.

Objection 6: Further, Augustine (Gen. ad lit. xii, 6,7,24) describes
three kinds of vision; namely, corporeal, which is the action of the
sense; spiritual, which is an action of the imagination or phantasy;
and intellectual, which is an action of the intellect. Therefore there
is no interior power between the sense and intellect, besides the
imagination.

On the contrary, Avicenna (De Anima iv, 1) assigns five interior
sensitive powers; namely, "common sense, phantasy, imagination, and the
estimative and memorative powers. "

I answer that, As nature does not fail in necessary things, there must
needs be as many actions of the sensitive soul as may suffice for the
life of a perfect animal. If any of these actions cannot be reduced to
the same one principle, they must be assigned to diverse powers; since
a power of the soul is nothing else than the proximate principle of the
soul's operation.

Now we must observe that for the life of a perfect animal, the animal
should apprehend a thing not only at the actual time of sensation, but
also when it is absent. Otherwise, since animal motion and action
follow apprehension, an animal would not be moved to seek something
absent: the contrary of which we may observe specially in perfect
animals, which are moved by progression, for they are moved towards
something apprehended and absent. Therefore an animal through the
sensitive soul must not only receive the species of sensible things,
when it is actually affected by them, but it must also retain and
preserve them. Now to receive and retain are, in corporeal things,
reduced to diverse principles; for moist things are apt to receive, but
retain with difficulty, while it is the reverse with dry things.
Wherefore, since the sensitive power is the act of a corporeal organ,
it follows that the power which receives the species of sensible things
must be distinct from the power which preserves them.

Again we must observe that if an animal were moved by pleasing and
disagreeable things only as affecting the sense, there would be no need
to suppose that an animal has a power besides the apprehension of those
forms which the senses perceive, and in which the animal takes
pleasure, or from which it shrinks with horror. But the animal needs to
seek or to avoid certain things, not only because they are pleasing or
otherwise to the senses, but also on account of other advantages and
uses, or disadvantages: just as the sheep runs away when it sees a
wolf, not on account of its color or shape, but as a natural enemy: and
again a bird gathers together straws, not because they are pleasant to
the sense, but because they are useful for building its nest. Animals,
therefore, need to perceive such intentions, which the exterior sense
does not perceive. And some distinct principle is necessary for this;
since the perception of sensible forms comes by an immutation caused by
the sensible, which is not the case with the perception of those
intentions.

Thus, therefore, for the reception of sensible forms, the "proper
sense" and the "common sense" are appointed, and of their distinction
we shall speak farther on (ad 1,2). But for the retention and
preservation of these forms, the "phantasy" or "imagination" is
appointed; which are the same, for phantasy or imagination is as it
were a storehouse of forms received through the senses. Furthermore,
for the apprehension of intentions which are not received through the
senses, the "estimative" power is appointed: and for the preservation
thereof, the "memorative" power, which is a storehouse of such-like
intentions. A sign of which we have in the fact that the principle of
memory in animals is found in some such intention, for instance, that
something is harmful or otherwise. And the very formality of the past,
which memory observes, is to be reckoned among these intentions.

Now, we must observe that as to sensible forms there is no difference
between man and other animals; for they are similarly immuted by the
extrinsic sensible. But there is a difference as to the above
intentions: for other animals perceive these intentions only by some
natural instinct, while man perceives them by means of coalition of
ideas. Therefore the power by which in other animals is called the
natural estimative, in man is called the "cogitative," which by some
sort of collation discovers these intentions. Wherefore it is also
called the "particular reason," to which medical men assign a certain
particular organ, namely, the middle part of the head: for it compares
individual intentions, just as the intellectual reason compares
universal intentions. As to the memorative power, man has not only
memory, as other animals have in the sudden recollection of the past;
but also "reminiscence" by syllogistically, as it were, seeking for a
recollection of the past by the application of individual intentions.
Avicenna, however, assigns between the estimative and the imaginative,
a fifth power, which combines and divides imaginary forms: as when from
the imaginary form of gold, and imaginary form of a mountain, we
compose the one form of a golden mountain, which we have never seen.
But this operation is not to be found in animals other than man, in
whom the imaginative power suffices thereto. To man also does Averroes
attribute this action in his book De sensu et sensibilibus (viii). So
there is no need to assign more than four interior powers of the
sensitive part---namely, the common sense, the imagination, and the
estimative and memorative powers.

Reply to Objection 1: The interior sense is called "common" not by
predication, as if it were a genus; but as the common root and
principle of the exterior senses.

Reply to Objection 2: The proper sense judges of the proper sensible by
discerning it from other things which come under the same sense; for
instance, by discerning white from black or green. But neither sight
nor taste can discern white from sweet: because what discerns between
two things must know both. Wherefore the discerning judgment must be
assigned to the common sense; to which, as to a common term, all
apprehensions of the senses must be referred: and by which, again, all
the intentions of the senses are perceived; as when someone sees that
he sees. For this cannot be done by the proper sense, which only knows
the form of the sensible by which it is immuted, in which immutation
the action of sight is completed, and from immutation follows another
in the common sense which perceives the act of vision.

Reply to Objection 3: As one power arises from the soul by means of
another, as we have seen above ([634]Q[77], A[7]), so also the soul is
the subject of one power through another. In this way the imagination
and the memory are called passions of the "first sensitive. "

Reply to Objection 4: Although the operation of the intellect has its
origin in the senses: yet, in the thing apprehended through the senses,
the intellect knows many things which the senses cannot perceive. In
like manner does the estimative power, though in a less perfect manner.

Reply to Objection 5: The cogitative and memorative powers in man owe
their excellence not to that which is proper to the sensitive part; but
to a certain affinity and proximity to the universal reason, which, so
to speak, overflows into them. Therefore they are not distinct powers,
but the same, yet more perfect than in other animals.

Reply to Objection 6: Augustine calls that vision spiritual which is
effected by the images of bodies in the absence of bodies. Whence it is
clear that it is common to all interior apprehensions.
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OF THE INTELLECTUAL POWERS (THIRTEEN ARTICLES)

The next question concerns the intellectual powers, under which head
there are thirteen points of inquiry:

(1) Whether the intellect is a power of the soul, or its essence?

(2) If it be a power, whether it is a passive power?

(3) If it is a passive power, whether there is an active intellect?

(4) Whether it is something in the soul?

(5) Whether the active intellect is one in all?

(6) Whether memory is in the intellect?

(7) Whether the memory be distinct from the intellect?

(8) Whether the reason is a distinct power from the intellect?

(9) Whether the superior and inferior reason are distinct powers?

(10) Whether the intelligence is distinct from the intellect?

(11) Whether the speculative and practical intellect are distinct
powers?

(12) Whether "synderesis" is a power of the intellectual part?

(13) Whether the conscience is a power of the intellectual part?
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Whether the intellect is a power of the soul?

Objection 1: It would seem that the intellect is not a power of the
soul, but the essence of the soul. For the intellect seems to be the
same as the mind. Now the mind is not a power of the soul, but the
essence; for Augustine says (De Trin. ix, 2): "Mind and spirit are not
relative things, but denominate the essence. " Therefore the intellect
is the essence of the soul.

Objection 2: Further, different genera of the soul's powers are not
united in some one power, but only in the essence of the soul. Now the
appetitive and the intellectual are different genera of the soul's
powers as the Philosopher says (De Anima ii, 3), but they are united in
the mind, for Augustine (De Trin. x, 11) places the intelligence and
will in the mind. Therefore the mind and intellect of man is of the
very essence of the soul and not a power thereof.

Objection 3: Further, according to Gregory, in a homily for the
Ascension (xxix in Ev. ), "man understands with the angels. " But angels
are called "minds" and "intellects. " Therefore the mind and intellect
of man are not a power of the soul, but the soul itself.

Objection 4: Further, a substance is intellectual by the fact that it
is immaterial. But the soul is immaterial through its essence.
Therefore it seems that the soul must be intellectual through its
essence.

On the contrary, The Philosopher assigns the intellectual faculty as a
power of the soul (De Anima ii, 3).

I answer that, In accordance with what has been already shown
([635]Q[54], A[3]; [636]Q[77], A[1]) it is necessary to say that the
intellect is a power of the soul, and not the very essence of the soul.
For then alone the essence of that which operates is the immediate
principle of operation, when operation itself is its being: for as
power is to operation as its act, so is the essence to being. But in
God alone His action of understanding is His very Being. Wherefore in
God alone is His intellect His essence: while in other intellectual
creatures, the intellect is power.

Reply to Objection 1: Sense is sometimes taken for the power, and
sometimes for the sensitive soul; for the sensitive soul takes its name
from its chief power, which is sense. And in like manner the
intellectual soul is sometimes called intellect, as from its chief
power; and thus we read (De Anima i, 4), that the "intellect is a
substance. " And in this sense also Augustine says that the mind is
spirit and essence (De Trin. ix, 2; xiv, 16).

Reply to Objection 2: The appetitive and intellectual powers are
different genera of powers in the soul, by reason of the different
formalities of their objects. But the appetitive power agrees partly
with the intellectual power and partly with the sensitive in its mode
of operation either through a corporeal organ or without it: for
appetite follows apprehension. And in this way Augustine puts the will
in the mind; and the Philosopher, in the reason (De Anima iii, 9).

Reply to Objection 3: In the angels there is no other power besides the
intellect, and the will, which follows the intellect. And for this
reason an angel is called a "mind" or an "intellect"; because his whole
power consists in this. But the soul has many other powers, such as the
sensitive and nutritive powers, and therefore the comparison fails.

Reply to Objection 4: The immateriality of the created intelligent
substance is not its intellect; and through its immateriality it has
the power of intelligence. Wherefore it follows not that the intellect
is the substance of the soul, but that it is its virtue and power.
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Whether the intellect is a passive power?

Objection 1: It would seem that the intellect is not a passive power.
For everything is passive by its matter, and acts by its form. But the
intellectual power results from the immateriality of the intelligent
substance. Therefore it seems that the intellect is not a passive
power.

Objection 2: Further, the intellectual power is incorruptible, as we
have said above ([637]Q[79], A[6]). But "if the intellect is passive,
it is corruptible" (De Anima iii, 5). Therefore the intellectual power
is not passive.

Objection 3: Further, the "agent is nobler than the patient," as
Augustine (Gen. ad lit. xii, 16) and Aristotle (De Anima iii, 5) says.
But all the powers of the vegetative part are active; yet they are the
lowest among the powers of the soul. Much more, therefore, all the
intellectual powers, which are the highest, are active.

On the contrary, The Philosopher says (De Anima iii, 4) that "to
understand is in a way to be passive. "

I answer that, To be passive may be taken in three ways. Firstly, in
its most strict sense, when from a thing is taken something which
belongs to it by virtue either of its nature, or of its proper
inclination: as when water loses coolness by heating, and as when a man
becomes ill or sad. Secondly, less strictly, a thing is said to be
passive, when something, whether suitable or unsuitable, is taken away
from it. And in this way not only he who is ill is said to be passive,
but also he who is healed; not only he that is sad, but also he that is
joyful; or whatever way he be altered or moved. Thirdly, in a wide
sense a thing is said to be passive, from the very fact that what is in
potentiality to something receives that to which it was in
potentiality, without being deprived of anything. And accordingly,
whatever passes from potentiality to act, may be said to be passive,
even when it is perfected. And thus with us to understand is to be
passive. This is clear from the following reason. For the intellect, as
we have seen above ([638]Q[78], A[1]), has an operation extending to
universal being. We may therefore see whether the intellect be in act
or potentiality by observing first of all the nature of the relation of
the intellect to universal being. For we find an intellect whose
relation to universal being is that of the act of all being: and such
is the Divine intellect, which is the Essence of God, in which
originally and virtually, all being pre-exists as in its first cause.
And therefore the Divine intellect is not in potentiality, but is pure
act. But no created intellect can be an act in relation to the whole
universal being; otherwise it would needs be an infinite being.
Wherefore every created intellect is not the act of all things
intelligible, by reason of its very existence; but is compared to these
intelligible things as a potentiality to act.

Now, potentiality has a double relation to act. There is a potentiality
which is always perfected by its act: as the matter of the heavenly
bodies ([639]Q[58], A[1]). And there is another potentiality which is
not always in act, but proceeds from potentiality to act; as we observe
in things that are corrupted and generated. Wherefore the angelic
intellect is always in act as regards those things which it can
understand, by reason of its proximity to the first intellect, which is
pure act, as we have said above. But the human intellect, which is the
lowest in the order of intelligence and most remote from the perfection
of the Divine intellect, is in potentiality with regard to things
intelligible, and is at first "like a clean tablet on which nothing is
written," as the Philosopher says (De Anima iii, 4). This is made clear
from the fact, that at first we are only in potentiality to understand,
and afterwards we are made to understand actually. And so it is evident
that with us to understand is "in a way to be passive"; taking passion
in the third sense. And consequently the intellect is a passive power.

Reply to Objection 1: This objection is verified of passion in the
first and second senses, which belong to primary matter. But in the
third sense passion is in anything which is reduced from potentiality
to act.

Reply to Objection 2: "Passive intellect" is the name given by some to
the sensitive appetite, in which are the passions of the soul; which
appetite is also called "rational by participation," because it "obeys
the reason" (Ethic. i, 13). Others give the name of passive intellect
to the cogitative power, which is called the "particular reason. " And
in each case "passive" may be taken in the two first senses; forasmuch
as this so-called intellect is the act of a corporeal organ. But the
intellect which is in potentiality to things intelligible, and which
for this reason Aristotle calls the "possible" intellect (De Anima iii,
4) is not passive except in the third sense: for it is not an act of a
corporeal organ. Hence it is incorruptible.

Reply to Objection 3: The agent is nobler than the patient, if the
action and the passion are referred to the same thing: but not always,
if they refer to different things. Now the intellect is a passive power
in regard to the whole universal being: while the vegetative power is
active in regard to some particular thing, namely, the body as united
to the soul. Wherefore nothing prevents such a passive force being
nobler than such an active one.
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Whether there is an active intellect?

Objection 1: It would seem that there is no active intellect. For as
the senses are to things sensible, so is our intellect to things
intelligible. But because sense is in potentiality to things sensible,
the sense is not said to be active, but only passive. Therefore, since
our intellect is in potentiality to things intelligible, it seems that
we cannot say that the intellect is active, but only that it is
passive.

Objection 2: Further, if we say that also in the senses there is
something active, such as light: on the contrary, light is required for
sight, inasmuch as it makes the medium to be actually luminous; for
color of its own nature moves the luminous medium. But in the operation
of the intellect there is no appointed medium that has to be brought
into act. Therefore there is no necessity for an active intellect.
Objection 3: Further, the likeness of the agent is received into the
patient according to the nature of the patient. But the passive
intellect is an immaterial power. Therefore its immaterial nature
suffices for forms to be received into it immaterially. Now a form is
intelligible in act from the very fact that it is immaterial. Therefore
there is no need for an active intellect to make the species actually
intelligible.

On the contrary, The Philosopher says (De Anima iii, 5), "As in every
nature, so in the soul is there something by which it becomes all
things, and something by which it makes all things. " Therefore we must
admit an active intellect.

I answer that, According to the opinion of Plato, there is no need for
an active intellect in order to make things actually intelligible; but
perhaps in order to provide intellectual light to the intellect, as
will be explained farther on [640](A[4]). For Plato supposed that the
forms of natural things subsisted apart from matter, and consequently
that they are intelligible: since a thing is actually intelligible from
the very fact that it is immaterial. And he called such forms "species
or ideas"; from a participation of which, he said that even corporeal
matter was formed, in order that individuals might be naturally
established in their proper genera and species: and that our intellect
was formed by such participation in order to have knowledge of the
genera and species of things. But since Aristotle did not allow that
forms of natural things exist apart from matter, and as forms existing
in matter are not actually intelligible; it follows that the natures of
forms of the sensible things which we understand are not actually
intelligible. Now nothing is reduced from potentiality to act except by
something in act; as the senses as made actual by what is actually
sensible. We must therefore assign on the part of the intellect some
power to make things actually intelligible, by abstraction of the
species from material conditions. And such is the necessity for an
active intellect.

Reply to Objection 1: Sensible things are found in act outside the
soul; and hence there is no need for an active sense. Wherefore it is
clear that in the nutritive part all the powers are active, whereas in
the sensitive part all are passive: but in the intellectual part, there
is something active and something passive.

Reply to Objection 2: There are two opinions as to the effect of light.
For some say that light is required for sight, in order to make colors
actually visible. And according to this the active intellect is
required for understanding, in like manner and for the same reason as
light is required for seeing. But in the opinion of others, light is
required for sight; not for the colors to become actually visible; but
in order that the medium may become actually luminous, as the
Commentator says on De Anima ii. And according to this, Aristotle's
comparison of the active intellect to light is verified in this, that
as it is required for understanding, so is light required for seeing;
but not for the same reason.

Reply to Objection 3: If the agent pre-exist, it may well happen that
its likeness is received variously into various things, on account of
their dispositions. But if the agent does not pre-exist, the
disposition of the recipient has nothing to do with the matter. Now the
intelligible in act is not something existing in nature; if we consider
the nature of things sensible, which do not subsist apart from matter.
And therefore in order to understand them, the immaterial nature of the
passive intellect would not suffice but for the presence of the active
intellect which makes things actually intelligible by way of
abstraction.
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Whether the active intellect is something in the soul?

Objection 1: It would seem that the active intellect is not something
in the soul. For the effect of the active intellect is to give light
for the purpose of understanding. But this is done by something higher
than the soul: according to Jn. 1:9, "He was the true light that
enlighteneth every man coming into this world. " Therefore the active
intellect is not something in the soul.

Objection 2: Further, the Philosopher (De Anima iii, 5) says of the
active intellect, "that it does not sometimes understand and sometimes
not understand. " But our soul does not always understand: sometimes it
understands, sometimes it does not understand. Therefore the active
intellect is not something in our soul.

Objection 3: Further, agent and patient suffice for action. If,
therefore, the passive intellect, which is a passive power, is
something belonging to the soul; and also the active intellect, which
is an active power: it follows that a man would always be able to
understand when he wished, which is clearly false. Therefore the active
intellect is not something in our soul.

Objection 4: Further, the Philosopher (De Anima iii, 5) says that the
active intellect is a "substance in actual being. " But nothing can be
in potentiality and in act with regard to the same thing. If,
therefore, the passive intellect, which is in potentiality to all
things intelligible, is something in the soul, it seems impossible for
the active intellect to be also something in our soul.

Objection 5: Further, if the active intellect is something in the soul,
it must be a power. For it is neither a passion nor a habit; since
habits and passions are not in the nature of agents in regard to the
passivity of the soul; but rather passion is the very action of the
passive power; while habit is something which results from acts. But
every power flows from the essence of the soul. It would therefore
follow that the active intellect flows from the essence of the soul.
And thus it would not be in the soul by way of participation from some
higher intellect: which is unfitting. Therefore the active intellect is
not something in our soul.

On the contrary, The Philosopher says (De Anima iii, 5), that "it is
necessary for these differences," namely, the passive and active
intellect, "to be in the soul. "

I answer that, The active intellect, of which the Philosopher speaks,
is something in the soul. In order to make this evident, we must
observe that above the intellectual soul of man we must needs suppose a
superior intellect, from which the soul acquires the power of
understanding. For what is such by participation, and what is mobile,
and what is imperfect always requires the pre-existence of something
essentially such, immovable and perfect. Now the human soul is called
intellectual by reason of a participation in intellectual power; a sign
of which is that it is not wholly intellectual but only in part.
Moreover it reaches to the understanding of truth by arguing, with a
certain amount of reasoning and movement. Again it has an imperfect
understanding; both because it does not understand everything, and
because, in those things which it does understand, it passes from
potentiality to act. Therefore there must needs be some higher
intellect, by which the soul is helped to understand.

Wherefore some held that this intellect, substantially separate, is the
active intellect, which by lighting up the phantasms as it were, makes
them to be actually intelligible. But, even supposing the existence of
such a separate active intellect, it would still be necessary to assign
to the human soul some power participating in that superior intellect,
by which power the human soul makes things actually intelligible. Just
as in other perfect natural things, besides the universal active
causes, each one is endowed with its proper powers derived from those
universal causes: for the sun alone does not generate man; but in man
is the power of begetting man: and in like manner with other perfect
animals. Now among these lower things nothing is more perfect than the
human soul. Wherefore we must say that in the soul is some power
derived from a higher intellect, whereby it is able to light up the
phantasms. And we know this by experience, since we perceive that we
abstract universal forms from their particular conditions, which is to
make them actually intelligible. Now no action belongs to anything
except through some principle formally inherent therein; as we have
said above of the passive intellect ([641]Q[76], A[1]). Therefore the
power which is the principle of this action must be something in the
soul. For this reason Aristotle (De Anima iii, 5) compared the active
intellect to light, which is something received into the air: while
Plato compared the separate intellect impressing the soul to the sun,
as Themistius says in his commentary on De Anima iii. But the separate
intellect, according to the teaching of our faith, is God Himself, Who
is the soul's Creator, and only beatitude; as will be shown later on
([642]Q[90], A[3]; FS, [643]Q[3], A[7]). Wherefore the human soul
derives its intellectual light from Him, according to Ps. 4:7, "The
light of Thy countenance, O Lord, is signed upon us. "

Reply to Objection 1: That true light enlightens as a universal cause,
from which the human soul derives a particular power, as we have
explained.

Reply to Objection 2: The Philosopher says those words not of the
active intellect, but of the intellect in act: of which he had already
said: "Knowledge in act is the same as the thing. " Or, if we refer
those words to the active intellect, then they are said because it is
not owing to the active intellect that sometimes we do, and sometimes
we do not understand, but to the intellect which is in potentiality.

Reply to Objection 3: If the relation of the active intellect to the
passive were that of the active object to a power, as, for instance, of
the visible in act to the sight; it would follow that we could
understand all things instantly, since the active intellect is that
which makes all things (in act). But now the active intellect is not an
object, rather is it that whereby the objects are made to be in act:
for which, besides the presence of the active intellect, we require the
presence of phantasms, the good disposition of the sensitive powers,
and practice in this sort of operation; since through one thing
understood, other things come to be understood, as from terms are made
propositions, and from first principles, conclusions. From this point
of view it matters not whether the active intellect is something
belonging to the soul, or something separate from the soul.

Reply to Objection 4: The intellectual soul is indeed actually
immaterial, but it is in potentiality to determinate species. On the
contrary, phantasms are actual images of certain species, but are
immaterial in potentiality. Wherefore nothing prevents one and the same
soul, inasmuch as it is actually immaterial, having one power by which
it makes things actually immaterial, by abstraction from the conditions
of individual matter: which power is called the "active intellect"; and
another power, receptive of such species, which is called the "passive
intellect" by reason of its being in potentiality to such species.

Reply to Objection 5: Since the essence of the soul is immaterial,
created by the supreme intellect, nothing prevents that power which it
derives from the supreme intellect, and whereby it abstracts from
matter, flowing from the essence of the soul, in the same way as its
other powers.
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Whether the active intellect is one in all?

Objection 1: It would seem that there is one active intellect in all.
For what is separate from the body is not multiplied according to the
number of bodies. But the active intellect is "separate," as the
Philosopher says (De Anima iii, 5). Therefore it is not multiplied in
the many human bodies, but is one for all men.

Objection 2: Further, the active intellect is the cause of the
universal, which is one in many. But that which is the cause of unity
is still more itself one. Therefore the active intellect is the same in
all.

Objection 3: Further, all men agree in the first intellectual concepts.
But to these they assent by the active intellect. Therefore all agree
in one active intellect.

On the contrary, The Philosopher says (De Anima iii, 5) that the active
intellect is as a light. But light is not the same in the various
things enlightened. Therefore the same active intellect is not in
various men.

I answer that, The truth about this question depends on what we have
already said [644](A[4]). For if the active intellect were not
something belonging to the soul, but were some separate substance,
there would be one active intellect for all men. And this is what they
mean who hold that there is one active intellect for all. But if the
active intellect is something belonging to the soul, as one of its
powers, we are bound to say that there are as many active intellects as
there are souls, which are multiplied according to the number of men,
as we have said above ([645]Q[76], A[2]). For it is impossible that one
same power belong to various substances.

Reply to Objection 1: The Philosopher proves that the active intellect
is separate, by the fact that the passive intellect is separate:
because, as he says (De Anima iii, 5), "the agent is more noble than
the patient. " Now the passive intellect is said to be separate, because
it is not the act of any corporeal organ. And in the same sense the
active intellect is also called "separate"; but not as a separate
substance.

Reply to Objection 2: The active intellect is the cause of the
universal, by abstracting it from matter. But for this purpose it need
not be the same intellect in all intelligent beings; but it must be one
in its relationship to all those things from which it abstracts the
universal, with respect to which things the universal is one. And this
befits the active intellect inasmuch as it is immaterial.

Reply to Objection 3: All things which are of one species enjoy in
common the action which accompanies the nature of the species, and
consequently the power which is the principle of such action; but not
so as that power be identical in all. Now to know the first
intelligible principles is the action belonging to the human species.
Wherefore all men enjoy in common the power which is the principle of
this action: and this power is the active intellect. But there is no
need for it to be identical in all. Yet it must be derived by all from
one principle. And thus the possession by all men in common of the
first principles proves the unity of the separate intellect, which
Plato compares to the sun; but not the unity of the active intellect,
which Aristotle compares to light.
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Whether memory is in the intellectual part of the soul?

Objection 1: It would seem that memory is not in the intellectual part
of the soul. For Augustine says (De Trin. xii, 2,3,8) that to the
higher part of the soul belongs those things which are not "common to
man and beast. " But memory is common to man and beast, for he says (De
Trin. xii, 2,3,8) that "beasts can sense corporeal things through the
senses of the body, and commit them to memory. " Therefore memory does
not belong to the intellectual part of the soul.

Objection 2: Further, memory is of the past. But the past is said of
something with regard to a fixed time. Memory, therefore, knows a thing
under a condition of a fixed time; which involves knowledge under the
conditions of "here" and "now. " But this is not the province of the
intellect, but of the sense. Therefore memory is not in the
intellectual part, but only in the sensitive.

Objection 3: Further, in the memory are preserved the species of those
things of which we are not actually thinking. But this cannot happen in
the intellect, because the intellect is reduced to act by the fact that
the intelligible species are received into it. Now the intellect in act
implies understanding in act; and therefore the intellect actually
understands all things of which it has the species. Therefore the
memory is not in the intellectual part.

On the contrary, Augustine says (De Trin. x, 11) that "memory,
understanding, and will are one mind. "

I answer that, Since it is of the nature of the memory to preserve the
species of those things which are not actually apprehended, we must
first of all consider whether the intelligible species can thus be
preserved in the intellect: because Avicenna held that this was
impossible. For he admitted that this could happen in the sensitive
part, as to some powers, inasmuch as they are acts of corporeal organs,
in which certain species may be preserved apart from actual
apprehension. But in the intellect, which has no corporeal organ,
nothing but what is intelligible exists. Wherefore every thing of which
the likeness exists in the intellect must be actually understood. Thus,
therefore, according to him, as soon as we cease to understand
something actually, the species of that thing ceases to be in our
intellect, and if we wish to understand that thing anew, we must turn
to the active intellect, which he held to be a separate substance, in
order that the intelligible species may thence flow again into our
passive intellect. And from the practice and habit of turning to the
active intellect there is formed, according to him, a certain aptitude
in the passive intellect for turning to the active intellect; which
aptitude he calls the habit of knowledge. According, therefore, to this
supposition, nothing is preserved in the intellectual part that is not
actually understood: wherefore it would not be possible to admit memory
in the intellectual part.

But this opinion is clearly opposed to the teaching of Aristotle. For
he says (De Anima iii, 4) that, when the passive intellect "is
identified with each thing as knowing it, it is said to be in act," and
that "this happens when it can operate of itself. And, even then, it is
in potentiality, but not in the same way as before learning and
discovering. " Now, the passive intellect is said to be each thing,
inasmuch as it receives the intelligible species of each thing. To the
fact, therefore, that it receives the species of intelligible things it
owes its being able to operate when it wills, but not so that it be
always operating: for even then is it in potentiality in a certain
sense, though otherwise than before the act of understanding---namely,
in the sense that whoever has habitual knowledge is in potentiality to
actual consideration.

The foregoing opinion is also opposed to reason. For what is received
into something is received according to the conditions of the
recipient. But the intellect is of a more stable nature, and is more
immovable than corporeal nature. If, therefore, corporeal matter holds
the forms which it receives, not only while it actually does something
through them, but also after ceasing to act through them, much more
cogent reason is there for the intellect to receive the species
unchangeably and lastingly, whether it receive them from things
sensible, or derive them from some superior intellect. Thus, therefore,
if we take memory only for the power of retaining species, we must say
that it is in the intellectual part. But if in the notion of memory we
include its object as something past, then the memory is not in the
intellectual, but only in the sensitive part, which apprehends
individual things. For past, as past, since it signifies being under a
condition of fixed time, is something individual.

Reply to Objection 1: Memory, if considered as retentive of species, is
not common to us and other animals. For species are not retained in the
sensitive part of the soul only, but rather in the body and soul
united: since the memorative power is the act of some organ. But the
intellect in itself is retentive of species, without the association of
any corporeal organ. Wherefore the Philosopher says (De Anima iii, 4)
that "the soul is the seat of the species, not the whole soul, but the
intellect. "

Reply to Objection 2: The condition of past may be referred to two
things---namely, to the object which is known, and to the act of
knowledge. These two are found together in the sensitive part, which
apprehends something from the fact of its being immuted by a present
sensible: wherefore at the same time an animal remembers to have sensed
before in the past, and to have sensed some past sensible thing. But as
concerns the intellectual part, the past is accidental, and is not in
itself a part of the object of the intellect. For the intellect
understands man, as man: and to man, as man, it is accidental that he
exist in the present, past, or future. But on the part of the act, the
condition of past, even as such, may be understood to be in the
intellect, as well as in the senses. Because our soul's act of
understanding is an individual act, existing in this or that time,
inasmuch as a man is said to understand now, or yesterday, or tomorrow.
And this is not incompatible with the intellectual nature: for such an
act of understanding, though something individual, is yet an immaterial
act, as we have said above of the intellect ([646]Q[76], A[1]); and
therefore, as the intellect understands itself, though it be itself an
individual intellect, so also it understands its act of understanding,
which is an individual act, in the past, present, or future. In this
way, then, the notion of memory, in as far as it regards past events,
is preserved in the intellect, forasmuch as it understands that it
previously understood: but not in the sense that it understands the
past as something "here" and "now. "

Reply to Objection 3: The intelligible species is sometimes in the
intellect only in potentiality, and then the intellect is said to be in
potentiality. Sometimes the intelligible species is in the intellect as
regards the ultimate completion of the act, and then it understands in
act. And sometimes the intelligible species is in a middle state,
between potentiality and act: and then we have habitual knowledge. In
this way the intellect retains the species, even when it does not
understand in act.
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Whether the intellectual memory is a power distinct from the intellect?

Objection 1: It would seem that the intellectual memory is distinct
from the intellect. For Augustine (De Trin. x, 11) assigns to the soul
memory, understanding, and will. But it is clear that the memory is a
distinct power from the will. Therefore it is also distinct from the
intellect.

Objection 2: Further, the reason of distinction among the powers in the
sensitive part is the same as in the intellectual part. But memory in
the sensitive part is distinct from sense, as we have said ([647]Q[78],
A[4]). Therefore memory in the intellectual part is distinct from the
intellect.

Objection 3: Further, according to Augustine (De Trin. x, 11; xi, 7),
memory, understanding, and will are equal to one another, and one flows
from the other. But this could not be if memory and intellect were the
same power. Therefore they are not the same power.

On the contrary, From its nature the memory is the treasury or
storehouse of species. But the Philosopher (De Anima iii) attributes
this to the intellect, as we have said (A[6], ad 1). Therefore the
memory is not another power from the intellect.

I answer that, As has been said above ([648]Q[77], A[3]), the powers of
the soul are distinguished by the different formal aspects of their
objects: since each power is defined in reference to that thing to
which it is directed and which is its object. It has also been said
above ([649]Q[59], A[4]) that if any power by its nature be directed to
an object according to the common ratio of the object, that power will
not be differentiated according to the individual differences of that
object: just as the power of sight, which regards its object under the
common ratio of color, is not differentiated by differences of black
and white. Now, the intellect regards its object under the common ratio
of being: since the passive intellect is that "in which all are in
potentiality. " Wherefore the passive intellect is not differentiated by
any difference of being. Nevertheless there is a distinction between
the power of the active intellect and of the passive intellect: because
as regards the same object, the active power which makes the object to
be in act must be distinct from the passive power, which is moved by
the object existing in act. Thus the active power is compared to its
object as a being in act is to a being in potentiality; whereas the
passive power, on the contrary, is compared to its object as being in
potentiality is to a being in act. Therefore there can be no other
difference of powers in the intellect, but that of passive and active.
Wherefore it is clear that memory is not a distinct power from the
intellect: for it belongs to the nature of a passive power to retain as
well as to receive.

Reply to Objection 1: Although it is said (3 Sent. D, 1) that memory,
intellect, and will are three powers, this is not in accordance with
the meaning of Augustine, who says expressly (De Trin. xiv) that "if we
take memory, intelligence, and will as always present in the soul,
whether we actually attend to them or not, they seem to pertain to the
memory only. And by intelligence I mean that by which we understand
when actually thinking; and by will I mean that love or affection which
unites the child and its parent. " Wherefore it is clear that Augustine
does not take the above three for three powers; but by memory he
understands the soul's habit of retention; by intelligence, the act of
the intellect; and by will, the act of the will.

Reply to Objection 2: Past and present may differentiate the sensitive
powers, but not the intellectual powers, for the reason give above.

Reply to Objection 3: Intelligence arises from memory, as act from
habit; and in this way it is equal to it, but not as a power to a
power.
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Whether the reason is distinct from the intellect?

Objection 1: It would seem that the reason is a distinct power from the
intellect. For it is stated in De Spiritu et Anima that "when we wish
to rise from lower things to higher, first the sense comes to our aid,
then imagination, then reason, then the intellect. " Therefore the
reason is distinct from the intellect, as imagination is from sense.

Objection 2: Further, Boethius says (De Consol. iv, 6), that intellect
is compared to reason, as eternity to time. But it does not belong to
the same power to be in eternity and to be in time. Therefore reason
and intellect are not the same power.

Objection 3: Further, man has intellect in common with the angels, and
sense in common with the brutes. But reason, which is proper to man,
whence he is called a rational animal, is a power distinct from sense.