This is what I mean, I replied: I will admit that there is a science of
science;--can this do more than determine that of two things one is and
the other is not science or knowledge?
No, just that.
But is knowledge or want of knowledge of health the same as knowledge or
want of knowledge of justice?
Certainly not.
The one is medicine, and the other is politics; whereas that of which we
are speaking is knowledge pure and simple.
Very true.
And if a man knows only, and has only knowledge of knowledge, and has no
further knowledge of health and justice, the probability is that he will
only know that he knows something, and has a certain knowledge, whether
concerning himself or other men.
True.
Then how will this knowledge or science teach him to know what he knows?
Say that he knows health;--not wisdom or temperance, but the art of
medicine has taught it to him;--and he has learned harmony from the art
of music, and building from the art of building,--neither, from wisdom
or temperance: and the same of other things.
That is evident.
How will wisdom, regarded only as a knowledge of knowledge or science of
science, ever teach him that he knows health, or that he knows building?
It is impossible.
Then he who is ignorant of these things will only know that he knows,
but not what he knows?
True.
Then wisdom or being wise appears to be not the knowledge of the things
which we do or do not know, but only the knowledge that we know or do
not know?
That is the inference.
Then he who has this knowledge will not be able to examine whether a
pretender knows or does not know that which he says that he knows: he
will only know that he has a knowledge of some kind; but wisdom will not
show him of what the knowledge is?
Plainly not.
Neither will he be able to distinguish the pretender in medicine from
the true physician, nor between any other true and false professor of
knowledge. Let us consider the matter in this way: If the wise man or
any other man wants to distinguish the true physician from the false,
how will he proceed? He will not talk to him about medicine; and that,
as we were saying, is the only thing which the physician understands.
True.
And, on the other hand, the physician knows nothing of science, for this
has been assumed to be the province of wisdom.
True.
And further, since medicine is science, we must infer that he does not
know anything of medicine.
Exactly.
Then the wise man may indeed know that the physician has some kind of
science or knowledge; but when he wants to discover the nature of this
he will ask, What is the subject-matter? For the several sciences are
distinguished not by the mere fact that they are sciences, but by the
nature of their subjects. Is not that true?
Quite true.
And medicine is distinguished from other sciences as having the
subject-matter of health and disease?
Yes.