apply themselves wholly to learning,
but people of mean condition, who in that only seek the means to live;
and by such people, whose souls are, both by nature and by domestic
education and example, of the basest alloy the fruits of knowledge are
immaturely gathered and ill digested, and delivered to their recipients
quite another thing. For it is not for knowledge to enlighten a soul
that is dark of itself, nor to make a blind man see. Her business is not
to find a man's eyes, but to guide, govern, and direct them, provided he
have sound feet and straight legs to go upon. Knowledge is an excellent
drug, but no drug has virtue enough to preserve itself from corruption
and decay, if the vessel be tainted and impure wherein it is put to keep.
Such a one may have a sight clear enough who looks asquint, and
consequently sees what is good, but does not follow it, and sees
knowledge, but makes no use of it. Plato's principal institution in his
Republic is to fit his citizens with employments suitable to their
nature. Nature can do all, and does all. Cripples are very unfit for
exercises of the body, and lame souls for exercises of the mind.
Degenerate and vulgar souls are unworthy of philosophy. If we see a
shoemaker with his shoes out at the toes, we say, 'tis no wonder; for,
commonly, none go worse shod than they. In like manner, experience often
presents us a physician worse physicked, a divine less reformed, and
(constantly) a scholar of less sufficiency, than other people.

Old Aristo of Chios had reason to say that philosophers did their
auditors harm, forasmuch as most of the souls of those that heard them
were not capable of deriving benefit from instruction, which, if not
applied to good, would certainly be applied to ill:

["They proceeded effeminate debauchees from the school of
Aristippus, cynics from that of Zeno."
--Cicero, De Natura Deor., iii., 31.]

In that excellent institution that Xenophon attributes to the Persians,
we find that they taught their children virtue, as other nations do
letters. Plato tells us that the eldest son in their royal succession
was thus brought up; after his birth he was delivered, not to women, but
to eunuchs of the greatest authority about their kings for their virtue,
whose charge it was to keep his body healthful and in good plight; and
after he came to seven years of age, to teach him to ride and to go
a-hunting. When he arrived at fourteen he was tr