business of him who philosophizes? To throw away self-conceit ([Greek:
oiaesis]). For it is impossible for a man to begin to learn that which
he thinks that he knows. As to things then which ought to be done and
ought not to be done, and good and bad, and beautiful and ugly, all of
us talking of them at random go to the philosophers; and on these
matters we praise, we censure, we accuse, we blame, we judge and
determine about principles honorable and dishonorable. But why do we go
to the philosophers? Because we wish to learn what we do not think that
we know. And what is this? Theorems. For we wish to learn what
philosophers say as being something elegant and acute; and some wish to
learn that they may get profit from what they learn. It is ridiculous
then to think that a person wishes to learn one thing, and will learn
another; or further, that a man will make proficiency in that which he
does not learn. But the many are deceived by this which deceived also
the rhetorician Theopompus, when he blames even Plato for wishing
everything to be defined. For what does he say? Did none of us before
you use the words good or just, or do we utter the sounds in an
unmeaning and empty way without understanding what they severally
signify? Now who tells you, Theopompus, that we had not natural notions
of each of these things and preconceptions ([Greek: prolaepseis])? But
it is not possible to adapt preconceptions to their correspondent
objects if we have not distinguished (analyzed) them, and inquired what
object must be subjected to each preconception. You may make the same
charge against physicians also. For who among us did not use the words
healthy and unhealthy before Hippocrates lived, or did we utter these
words as empty sounds? For we have also a certain preconception of
health, but we are not able to adapt it. For this reason one says,
Abstain from food; another says, Give food; another says, Bleed; and
another says, Use cupping. What is the reason? is it any other than that
a man cannot properly adapt the preconceptions of health to particulars?