If, (on the Stoic hypothesis) the soul were extended, and corporeal, it would be difficult, or rather impossible for her to remain impassible and unalterable when the above-mentioned occurrences take place within her. If, on the contrary, she be a "being" that is unextended, and incorruptible, we must take care not to attribute to her affections that might imply that she is perishable. If, on the contrary, her "being" be a number[28] or a reason,[29] as we usually say, how could an affection occur within a number or a reason? We must therefore attribute to the soul only irrational reasons, passions without passivity; that is, we must consider these terms as no more than metaphors drawn from the nature of bodies, taking them in an opposite sense, seeing in them no more than mere analogies, so that we may say that the soul experiences them without experiencing them, and that she is passive without really being such (as are the bodies). Let us examine how all this occurs. VIRTUE AS A HARMONY; VICE AS A DISHARMONY. 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. THIS DEFINITION SUFFICES TO EXPLAIN THE FACTS OF EVIL IN THE SOUL.