But how can the soul's irascible-part[36] be at one time courageous, and at the other cowardly? When it is cowardly, it does not consider reason, or considers reason as having already become evil; or because the deficiency of its instruments, that is, the lack of weakness of its organs, hinders it from acting, or feeling emotion, or being irritated. In the contrary condition it is courageous. In either case, the soul undergoes no alteration, nor is affected. PSYCHOLOGICAL EXPLANATION OF VIRTUE OR VICE OF APPETITE. Further, the soul's appetite is intemperate when it alone is active; for then, in the absence of the principles that ought to command or direct her, it alone does everything. Besides, the rational part, whose function it is to see (by considering the notions it receives from intelligence), is occupied with something else, for it does not do everything simultaneously, being busy with some other action; it considers other than corporeal things, so far as it can.[37] Perhaps also the virtue or vice of the appetite depend considerably on the good or evil condition of the organs; so that, in either case, nothing is added to the soul. THE SOUL ORIGINATES MOVEMENTS, BUT IS NOT ALTERED (AGAINST STOICS). POLEMIC AGAINST THE STOIC THEORY OF PASSIONS. 3. There are desires and aversions in the soul, which demand consideration. It is impossible to deny that pain, anger, joy, appetite and fear are changes and affections which occur in the soul, and that move her.[38] We must here draw a distinction, for it would be denying the evidence to insist that there are in us no changes or perception of these changes. We cannot attribute them to the soul, which would amount to the admission[39] that she blushes, or grows pale, without reflecting that these "passions," though produced by the soul, occur in a different substance. For the soul, shame consists in the opinion that something is improper; and, as the soul contains the body, or, to speak more exactly, as the body is a dependency of the animating soul, the blood, which is very mobile, rushes to the face. Likewise, the principle of fear is in the soul; paleness occurs in the body because the blood concentrates within the interior parts. In joy, the noticeable dilation belongs to the body also; what the body feels is not a "passion." Likewise with pain and appetite; their principle is in the soul, where it remains in a latent condition; what proceeds therefrom is perceived by sensation. When we call desires, opinions and reasonings "movements of the soul," we do not mean that the soul becomes excited in the production of these movements,[40] but that they originate within her. When we call life a movement, we do not by this word mean an alteration; for to act according to one's nature is the simple and indivisible life of each part of the soul. VIRTUE AND VICE AFFECT THE SOUL DIFFERENTLY FROM ALL THE OTHER PASSIONS.