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.
Obj. 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.
Obj. 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 (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 or 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 Obj. 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 Obj. 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 Obj. 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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