Again, there is a third line, in which a Sophist may be traced. For is he
less a Sophist when, instead of exporting his wares to another country, he
stays at home, and retails goods, which he not only buys of others, but
manufactures himself?

Or he may be descended from the acquisitive art in the combative line,
through the pugnacious, the controversial, the disputatious arts; and he
will be found at last in the eristic section of the latter, and in that
division of it which disputes in private for gain about the general
principles of right and wrong.

And still there is a track of him which has not yet been followed out by
us. Do not our household servants talk of sifting, straining, winnowing?
And they also speak of carding, spinning, and the like. All these are
processes of division; and of division there are two kinds,--one in which
like is divided from like, and another in which the good is separated from
the bad. The latter of the two is termed purification; and again, of
purification, there are two sorts,--of animate bodies (which may be
internal or external), and of inanimate. Medicine and gymnastic are the
internal purifications of the animate, and bathing the external; and of the
inanimate, fulling and cleaning and other humble processes, some of which
have ludicrous names. Not that dialectic is a respecter of names or
persons, or a despiser of humble occupations; nor does she think much of
the greater or less benefits conferred by them. For her aim is knowledge;
she wants to know how the arts are related to one another, and would quite
as soon learn the nature of hunting from the vermin-destroyer as from the
general. And she only desires to have a general name, which shall
distinguish purifications of the soul from purifications of the body.

Now purification is the taking away of evil; and there are two kinds of