Whether the Intelligible Species Are Derived by the Soul from Certain
Separate Forms?
Objection 1: It would seem that the intelligible species are derived
by the soul from some separate forms. For whatever is such by
participation is caused by what is such essentially; for instance,
that which is on fire is reduced to fire as the cause thereof. But
the intellectual soul forasmuch as it is actually understanding,
participates the thing understood: for, in a way, the intellect in
act is the thing understood in act. Therefore what in itself and in
its essence is understood in act, is the cause that the intellectual
soul actually understands. Now that which in its essence is actually
understood is a form existing without matter. Therefore the
intelligible species, by which the soul understands, are caused by
some separate forms.
Obj. 2: Further, the intelligible is to the intellect, as the
sensible is to the sense. But the sensible species which are in the
senses, and by which we sense, are caused by the sensible object
which exists actually outside the soul. Therefore the intelligible
species, by which our intellect understands, are caused by some
things actually intelligible, existing outside the soul. But these
can be nothing else than forms separate from matter. Therefore the
intelligible forms of our intellect are derived from some separate
substances.
Obj. 3: Further, whatever is in potentiality is reduced to act by
something actual. If, therefore, our intellect, previously in
potentiality, afterwards actually understands, this must needs be
caused by some intellect which is always in act. But this is a
separate intellect. Therefore the intelligible species, by which we
actually understand, are caused by some separate substances.
_On the contrary,_ If this were true we should not need the senses in
order to understand. And this is proved to be false especially from
the fact that if a man be wanting in a sense, he cannot have any
knowledge of the sensibles corresponding to that sense.
_I answer that,_ Some have held that the intelligible species of our
intellect are derived from certain separate forms or substances. And
this in two ways. For Plato, as we have said (A. 1), held that the
forms of sensible things subsist by themselves without matter; for
instance, the form of a man which he called _per se_ man, and the
form or idea of a horse which is called _per se_ horse, and so forth.
He said therefore that these forms are participated both by our soul
and by corporeal matter; by our soul, to the effect of knowledge
thereof, and by corporeal matter to the effect of existence: so that,
just as corporeal matter by participating the idea of a stone,
becomes an individuating stone, so our intellect, by participating
the idea of a stone, is made to understand a stone. Now participation
of an idea takes place by some image of the idea in the participator,
just as a model is participated by a copy. So just as he held that
the sensible forms, which are in corporeal matter, are derived from
the ideas as certain images thereof: so he held that the intelligible
species of our intellect are images of the ideas, derived therefrom.
And for this reason, as we have said above (A. 1), he referred
sciences and definitions to those ideas.
But since it is contrary to the nature of sensible things that their
forms should subsist without matter, as Aristotle proves in many ways
(Metaph. vi), Avicenna (De Anima v) setting this opinion aside, held
that the intelligible species of all sensible things, instead of
subsisting in themselves without matter, pre-exist immaterially in the
separate intellects: from the first of which, said he, such species
are derived by a second, and so on to the last separate intellect
which he called the "active intelligence," from which, according to
him, intelligible species flow into our souls, and sensible species
into corporeal matter. And so Avicenna agrees with Plato in this, that
the intelligible species of our intellect are derived from certain
separate forms; but these Plato held to subsist of themselves, while
Avicenna placed them in the "active intelligence." They differ, too,
in this respect, that Avicenna held that the intelligible species do
not remain in our intellect after it has ceased actually to
understand, and that it needs to turn (to the active intellect) in
order to receive them anew. Consequently he does not hold that the
soul has innate knowledge, as Plato, who held that the participated
ideas remain immovably in the soul.
But in this opinion no sufficient reason can be assigned for the soul
being united to the body. For it cannot be said that the intellectual
soul is united to the body for the sake of the body: for neither is
form for the sake of matter, nor is the mover for the sake of the
moved, but rather the reverse. Especially does the body seem necessary
to the intellectual soul, for the latter's proper operation which is
to understand: since as to its being the soul does not depend on the
body. But if the soul by its very nature had an inborn aptitude for
receiving intelligible species through the influence of only certain
separate principles, and were not to receive them from the senses, it
would not need the body in order to understand: wherefore to no
purpose would it be united to the body.
But if it be said that our soul needs the senses in order to
understand, through being in some way awakened by them to the
consideration of those things, the intelligible species of which it
receives from the separate principles: even this seems an insufficient
explanation. For this awakening does not seem necessary to the soul,
except in as far as it is overcome by sluggishness, as the Platonists
expressed it, and by forgetfulness, through its union with the body:
and thus the senses would be of no use to the intellectual soul except
for the purpose of removing the obstacle which the soul encounters
through its union with the body. Consequently the reason of the union
of the soul with the body still remains to be sought.
And if it be said with Avicenna, that the senses are necessary to
the soul, because by them it is aroused to turn to the "active
intelligence" from which it receives the species: neither is this
a sufficient explanation. Because if it is natural for the soul to
understand through species derived from the "active intelligence,"
it follows that at times the soul of an individual wanting in one
of the senses can turn to the active intelligence, either from the
inclination of its very nature, or through being roused by another
sense, to the effect of receiving the intelligible species of which
the corresponding sensible species are wanting. And thus a man born
blind could have knowledge of colors; which is clearly untrue. We
must therefore conclude that the intelligible species, by which our
soul understands, are not derived from separate forms.
Reply Obj. 1: The intelligible species which are participated by our
intellect are reduced, as to their first cause, to a first principle
which is by its essence intelligible--namely, God. But they proceed
from that principle by means of the sensible forms and material
things, from which we gather knowledge, as Dionysius says (Div. Nom.
vii).
Reply Obj. 2: Material things, as to the being which they have
outside the soul, may be actually sensible, but not actually
intelligible. Wherefore there is no comparison between sense and
intellect.
Reply Obj. 3: Our passive intellect is reduced from potentiality to
act by some being in act, that is, by the active intellect, which is
a power of the soul, as we have said (Q. 79, A. 4); and not by a
separate intelligence, as proximate cause, although perchance as
remote cause.
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