2. What occurs in the soul when she contains a vice? We ask this
because it is usual to say, "to snatch a vice from the soul;" "to
introduce virtue into her," "to adorn her," "to replace ugliness by
beauty in her." Let us also premiss, following the opinions of the
ancients,[30] that virtue is a harmony, and wickedness the opposite.
That is the best means to solve the problem at issue. Indeed, when the
parts of the soul (the rational part, the irascible part, and the part
of appetite), harmonize with each other, we shall have virtue;[31] and,
in the contrary case, vice. Still, in both cases, nothing foreign to
the soul enters into her; each of her parts remain what they are, while
contributing to harmony. On the other hand, when there is dissonance,
they could not play the same parts as the personnel of a choric ballet,
who dance and sing in harmony, though not all of them fill the same
functions; though one sings while the remainder are silent; and though
each sings his own part; for it does not suffice that they all sing
in tune, they must each properly sing his own part. In the soul we
therefore have harmony when each part fulfils its functions. Still each
must have its own virtue before the existence of a harmony; or its
vice, before there is disharmony. What then is the thing whose presence
makes each part of the soul good or evil? Evidently the presence of
virtue or vice. The mere statement that, for the rational part (of
the soul) vice consists in ignorance,[32] is no more than a simple
negation, and predicates nothing positive about reason.