The Republic - End of BOOK VI - The Line Analogy
SOCRATES - GLAUCON
And the soul is like the eye: when resting upon that on which
truth and being shine, the soul perceives and understands and is
radiant with intelligence; but when turned towards the twilight of
becoming and perishing, then she has opinion only, and goes blinking
about, and is first of one opinion and then of another, and seems to
have no intelligence?
Just so.
Now, that which imparts truth to the known and the power of
knowing to the knower is what I would have you term the idea of
good, and this you will deem to be the cause of science, and of
truth in so far as the latter becomes the subject of knowledge;
beautiful too, as are both truth and knowledge, you will be right in
esteeming this other nature as more beautiful than either; and, as
in the previous instance, light and sight may be truly said to be like
the sun, and yet not to be the sun, so in this other sphere, science
and truth may be deemed to be like the good, but not the good; the
good has a place of honour yet higher.
What a wonder of beauty that must be, he said, which is the author
of science and truth, and yet surpasses them in beauty; for you surely
cannot mean to say that pleasure is the good?
God forbid, I replied; but may I ask you to consider the image in
another point of view?
In what point of view?
You would say, would you not, that the sun is only the author of
visibility in all visible things, but of generation and nourishment
and growth, though he himself is not generation?
Certainly.
In like manner the good may be said to be not only the author of
knowledge to all things known, but of their being and essence, and yet
the good is not essence, but far exceeds essence in dignity and power.
Glaucon said, with a ludicrous earnestness: By the light of
heaven, how amazing!
Yes, I said, and the exaggeration may be set down to you; for you
made me utter my fancies.
And pray continue to utter them; at any rate let us hear if there is
anything more to be said about the similitude of the sun.
Yes, I said, there is a great deal more.
Then omit nothing, however slight.
I will do my best, I said; but I should think that a great deal will
have to be omitted.
You have to imagine, then, that there are two ruling powers, and
that one of them is set over the intellectual world, the other over
the visible. I do not say heaven, lest you should fancy that I am
playing upon the name ('ourhanoz, orhatoz'). May I suppose that you
have this distinction of the visible and intelligible fixed in your
mind?
I have.
Now take a line which has been cut into two unequal parts, and
divide each of them again in the same proportion, and suppose the
two main divisions to answer, one to the visible and the other to
the intelligible, and then compare the subdivisions in respect of
their clearness and want of clearness, and you will find that the
first section in the sphere of the visible consists of images. And
by images I mean, in the first place, shadows, and in the second
place, reflections in water and in solid, smooth and polished bodies
and the like: Do you understand?
Yes, I understand.
Imagine, now, the other section, of which this is only the
resemblance, to include the animals which we see, and everything
that grows or is made.
Very good.
Would you not admit that both the sections of this division have
different degrees of truth, and that the copy is to the original as
the sphere of opinion is to the sphere of knowledge?
Most undoubtedly.
Next proceed to consider the manner in which the sphere of the
intellectual is to be divided.
In what manner?
Thus: --There are two subdivisions, in the lower or which the soul
uses the figures given by the former division as images; the enquiry
can only be hypothetical, and instead of going upwards to a
principle descends to the other end; in the higher of the two, the
soul passes out of hypotheses, and goes up to a principle which is
above hypotheses, making no use of images as in the former case, but
proceeding only in and through the ideas themselves.
I do not quite understand your meaning, he said.
Then I will try again; you will understand me better when I have
made some preliminary remarks. You are aware that students of
geometry, arithmetic, and the kindred sciences assume the odd and
the even and the figures and three kinds of angles and the like in
their several branches of science; these are their hypotheses, which
they and everybody are supposed to know, and therefore they do not
deign to give any account of them either to themselves or others;
but they begin with them, and go on until they arrive at last, and
in a consistent manner, at their conclusion?
Yes, he said, I know.
And do you not know also that although they make use of the
visible forms and reason about them, they are thinking not of these,
but of the ideals which they resemble; not of the figures which they
draw, but of the absolute square and the absolute diameter, and so
on --the forms which they draw or make, and which have shadows and
reflections in water of their own, are converted by them into
images, but they are really seeking to behold the things themselves,
which can only be seen with the eye of the mind?
That is true.
And of this kind I spoke as the intelligible, although in the search
after it the soul is compelled to use hypotheses; not ascending to a
first principle, because she is unable to rise above the region of
hypothesis, but employing the objects of which the shadows below are
resemblances in their turn as images, they having in relation to the
shadows and reflections of them a greater distinctness, and
therefore a higher value.
I understand, he said, that you are speaking of the province of
geometry and the sister arts.
And when I speak of the other division of the intelligible, you will
understand me to speak of that other sort of knowledge which reason
herself attains by the power of dialectic, using the hypotheses not as
first principles, but only as hypotheses --that is to say, as steps
and points of departure into a world which is above hypotheses, in
order that she may soar beyond them to the first principle of the
whole; and clinging to this and then to that which depends on this, by
successive steps she descends again without the aid of any sensible
object, from ideas, through ideas, and in ideas she ends.
I understand you, he replied; not perfectly, for you seem to me to
be describing a task which is really tremendous; but, at any rate, I
understand you to say that knowledge and being, which the science of
dialectic contemplates, are clearer than the notions of the arts, as
they are termed, which proceed from hypotheses only: these are also
contemplated by the understanding, and not by the senses: yet, because
they start from hypotheses and do not ascend to a principle, those who
contemplate them appear to you not to exercise the higher reason
upon them, although when a first principle is added to them they are
cognizable by the higher reason. And the habit which is concerned with
geometry and the cognate sciences I suppose that you would term
understanding and not reason, as being intermediate between opinion
and reason.
You have quite conceived my meaning, I said; and now,
corresponding to these four divisions, let there be four faculties
in the soul-reason answering to the highest, understanding to the
second, faith (or conviction) to the third, and perception of
shadows to the last-and let there be a scale of them, and let us
suppose that the several faculties have clearness in the same degree
that their objects have truth.
I understand, he replied, and give my assent, and accept your
arrangement.