Whether One Man Can Teach Another?
Objection 1: It would seem that one man cannot teach another. For the
Lord says (Matt. 22:8): "Be not you called Rabbi": on which the gloss
of Jerome says, "Lest you give to men the honor due to God."
Therefore to be a master is properly an honor due to God. But it
belongs to a master to teach. Therefore man cannot teach, and this is
proper to God.
Obj. 2: Further, if one man teaches another this is only inasmuch as
he acts through his own knowledge, so as to cause knowledge in the
other. But a quality through which anyone acts so as to produce his
like, is an active quality. Therefore it follows that knowledge is an
active quality just as heat is.
Obj. 3: Further, for knowledge we require intellectual light, and the
species of the thing understood. But a man cannot cause either of
these in another man. Therefore a man cannot by teaching cause
knowledge in another man.
Obj. 4: Further, the teacher does nothing in regard to a disciple
save to propose to him certain signs, so as to signify something by
words or gestures. But it is not possible to teach anyone so as to
cause knowledge in him, by putting signs before him. For these are
signs either of things that he knows, or of things he does not know.
If of things that he knows, he to whom these signs are proposed is
already in the possession of knowledge, and does not acquire it from
the master. If they are signs of things that he does not know, he can
learn nothing therefrom: for instance, if one were to speak Greek to
a man who only knows Latin, he would learn nothing thereby. Therefore
in no way can a man cause knowledge in another by teaching him.
_On the contrary,_ The Apostle says (1 Tim. 2:7): "Whereunto I am
appointed a preacher and an apostle . . . a doctor of the Gentiles
in faith and truth."
_I answer that,_ On this question there have been various opinions.
For Averroes, commenting on _De Anima_ iii, maintains that all men
have one passive intellect in common, as stated above (Q. 76, A. 2).
From this it follows that the same intelligible species belong to all
men. Consequently he held that one man does not cause another to have
a knowledge distinct from that which he has himself; but that he
communicates the identical knowledge which he has himself, by moving
him to order rightly the phantasms in his soul, so that they be
rightly disposed for intelligible apprehension. This opinion is true
so far as knowledge is the same in disciple and master, if we
consider the identity of the thing known: for the same objective
truth is known by both of them. But so far as he maintains that all
men have but one passive intellect, and the same intelligible
species, differing only as to various phantasms, his opinion is
false, as stated above (Q. 76, A. 2).
Besides this, there is the opinion of the Platonists, who held that
our souls are possessed of knowledge from the very beginning, through
the participation of separate forms, as stated above (Q. 84, AA. 3,
4); but that the soul is hindered, through its union with the body,
from the free consideration of those things which it knows. According
to this, the disciple does not acquire fresh knowledge from his
master, but is roused by him to consider what he knows; so that to
learn would be nothing else than to remember. In the same way they
held that natural agents only dispose (matter) to receive forms,
which matter acquires by a participation of separate substances. But
against this we have proved above (Q. 79, A. 2; Q. 84, A. 3) that the
passive intellect of the human soul is in pure potentiality to
intelligible (species), as Aristotle says (De Anima iii, 4).
We must therefore decide the question differently, by saying that the
teacher causes knowledge in the learner, by reducing him from
potentiality to act, as the Philosopher says (Phys. viii, 4). In
order to make this clear, we must observe that of effects proceeding
from an exterior principle, some proceed from the exterior principle
alone; as the form of a house is caused to be in matter by art alone:
whereas other effects proceed sometimes from an exterior principle,
sometimes from an interior principle: thus health is caused in a sick
man, sometimes by an exterior principle, namely by the medical art,
sometimes by an interior principle as when a man is healed by the
force of nature. In these latter effects two things must be noticed.
First, that art in its work imitates nature for just as nature heals
a man by alteration, digestion, rejection of the matter that caused
the sickness, so does art. Secondly, we must remark that the exterior
principle, art, acts, not as principal agent, but as helping the
principal agent, but as helping the principal agent, which is the
interior principle, by strengthening it, and by furnishing it with
instruments and assistance, of which the interior principle makes use
in producing the effect. Thus the physician strengthens nature, and
employs food and medicine, of which nature makes use for the intended
end.
Now knowledge is acquired in man, both from an interior principle, as
is clear in one who procures knowledge by his own research; and from
an exterior principle, as is clear in one who learns (by
instruction). For in every man there is a certain principle of
knowledge, namely the light of the active intellect, through which
certain universal principles of all the sciences are naturally
understood as soon as proposed to the intellect. Now when anyone
applies these universal principles to certain particular things, the
memory or experience of which he acquires through the senses; then by
his own research advancing from the known to the unknown, he obtains
knowledge of what he knew not before. Wherefore anyone who teaches,
leads the disciple from things known by the latter, to the knowledge
of things previously unknown to him; according to what the
Philosopher says (Poster. i, 1): "All teaching and all learning
proceed from previous knowledge."
Now the master leads the disciple from things known to knowledge of
the unknown, in a twofold manner. Firstly, by proposing to him
certain helps or means of instruction, which his intellect can use
for the acquisition of science: for instance, he may put before him
certain less universal propositions, of which nevertheless the
disciple is able to judge from previous knowledge: or he may propose
to him some sensible examples, either by way of likeness or of
opposition, or something of the sort, from which the intellect of the
learner is led to the knowledge of truth previously unknown.
Secondly, by strengthening the intellect of the learner; not, indeed,
by some active power as of a higher nature, as explained above (Q.
106, A. 1; Q. 111, A. 1) of the angelic enlightenment, because all
human intellects are of one grade in the natural order; but inasmuch
as he proposes to the disciple the order of principles to
conclusions, by reason of his not having sufficient collating power
to be able to draw the conclusions from the principles. Hence the
Philosopher says (Poster. i, 2) that "a demonstration is a syllogism
that causes knowledge." In this way a demonstrator causes his hearer
to know.
Reply Obj. 1: As stated above, the teacher only brings exterior help
as the physician who heals: but just as the interior nature is the
principal cause of the healing, so the interior light of the
intellect is the principal cause of knowledge. But both of these are
from God. Therefore as of God is it written: "Who healeth all thy
diseases" (Ps. 102:3); so of Him is it written: "He that teacheth man
knowledge" (Ps. 93:10), inasmuch as "the light of His countenance is
signed upon us" (Ps. 4:7), through which light all things are shown
to us.
Reply Obj. 2: As Averroes argues, the teacher does not cause
knowledge in the disciple after the manner of a natural active cause.
Wherefore knowledge need not be an active quality: but is the
principle by which one is directed in teaching, just as art is the
principle by which one is directed in working.
Reply Obj. 3: The master does not cause the intellectual light in the
disciple, nor does he cause the intelligible species directly: but he
moves the disciple by teaching, so that the latter, by the power of
his intellect, forms intelligible concepts, the signs of which are
proposed to him from without.
Reply Obj. 4: The signs proposed by the master to the disciple are of
things known in a general and confused manner; but not known in
detail and distinctly. Therefore when anyone acquires knowledge by
himself, he cannot be called self-taught, or be said to have his own
master because perfect knowledge did not precede in him, such as is
required in a master.
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