_Socr._ The method of the art of rhetoric is, in a manner, the same as
that of medicine.
_Phæ._ How so?
_Socr._ In both it is requisite that nature should be thoroughly
investigated, the nature of the body in the one, and the soul in the
other, if you mean not only by practice and experience, but by art, to
give health and strength to the former by applying medicine and diet,
and to impart such persuasion as you please and virtue to the latter, by
means of speeches and legitimate employments.
_Phæ._ This indeed seems probable, Socrates.
_Socr._ But do you think it possible rightly to understand the nature of
the soul, without understanding the nature of the universe?
_Phæ._ If we are to believe Hippocrates, of the family of Æsculapius, we
cannot understand even the nature of body without this method.
_Socr._ For he says well, my friend. But it is necessary, in addition to
the authority of Hippocrates, to examine our argument, and consider
whether it is consistent.
_Phæ._ I agree.
122. _Socr._ Consider, then, with respect to nature, what Hippocrates
and true reason say. Is it not thus necessary to examine into the nature
of any thing? In the first place, whether that is simple or manifold
about which we are desirous, both ourselves to be skilled, and to be
able to make others so; and, in the next place, if it be simple, to
examine the power it naturally possesses of acting on each particular
thing, or of being acted upon by each particular thing? And if it
possesses several species, having enumerated these, as in the case of
the one, ought we not to consider this in each of them, what active and
passive power they naturally have?
_Phæ._ It seems so, Socrates.
123. _Socr._ The method, then, that neglected these, would resemble the
walk of a blind man. He however who proceeds by art, ought on no account
to be compared either to a blind or a deaf man; but it is clear that
whosoever teaches another speaking by art, should accurately shew the
real nature of the things to which he will have to apply his speeches;
and this surely is the soul.
_Phæ._ How not?
_Socr._ His whole endeavour, therefore, must be directed to this; for in
this he attempts to produce persuasion. Is it not so?
_Phæ._ Yes.
_Socr._ It is clear, therefore, that Thrasymachus, and any one else who
seriously endeavours to teach the art of rhetoric, will in the first
place describe with all possible accuracy, and make it be seen whether
the soul is naturally one and similar, or, like the form of the body,
composed of different elements; for this we say is to make known nature.
_Phæ._ Most assuredly.
_Socr._ And, in the second place, in what respect it naturally acts or
is acted upon by any thing.