VIRTUE AND VICE AFFECT THE SOUL DIFFERENTLY FROM ALL THE OTHER PASSIONS.
In short, we insist that action, life and desire are not alterations, that memories are not forms impressed on the soul, and that actualizations of the imagination are not impressions similar to those of a seal on wax.[41] Consequently in all that we call "passions" or "movements," the soul undergoes no change in her substance (substrate) or "being" (nature); virtue and vice in the soul are not similar to what heat, cold, whiteness or blackness are in bodies; and the soul's relation to vice and virtue is entirely different, as has been explained.
PASSIONAL CHANGES OCCUR IN THE BODY, NOT EVEN TO THE PASSIONAL PART OF THE SOUL.
4. Let us now pass to that part of the soul that is called the "passional" (or, affective). We have already mentioned it,[42] when treating of all the "passions" (that is, affections), which were related to the irascible-part and appetitive part of the soul; but we are going to return to a study of this part, and explain its name, the "passional" (or, affective) part. It is so called because it seems to be the part affected by the "passions;"[43] that is, experiences accompanied by pleasure or pain.[44] Amidst these affections, some are born of opinion; thus, we feel fear or joy, according as we expect to die, or as we hope to attain some good; then the "opinion" is in the soul, and the "affection" in the body. On the contrary, other passions, occurring in an unforeseen way, give rise to opinion in that part of the soul to which this function belongs, but do not cause any alteration within her, as we have already explained. Nevertheless, if, on examining unexpected fear, we follow it up higher, we discover that it still contains opinion as its origin, implying some apprehension in that part of the soul that experiences fear, as a result of which occur the trouble and stupor which accompany the expectation of evil. Now it is to the soul that belongs imagination, both the primary imagination that we call opinion, and the (secondary) imagination that proceeds from the former; for the latter is no longer genuine opinion, but an inferior power, an obscure opinion, a confused imagination which resembles the action characteristic of nature, and by which this power produces each thing, as we say, unimaginatively.[45] Its resulting sense-agitation occurs within the body. To it relate trembling, palpitation, paleness, and inability to speak. Such modifications, indeed, could not be referred to any part of the soul; otherwise, such part of the soul would be physical. Further, if such part of the soul underwent such affections these modifications would not reach the body; for that affected part of the soul would no longer be able to exercise its functions, being dominated by passion, and thus incapacitated.
THE SOUL'S AFFECTIVE PART MAY BE THE CAUSE OF AFFECTIONS; BUT IS INCORPOREAL.
The affective part of the soul, therefore, is not corporeal; it is a form indeed, but a form engaged in matter, such as the appetite, the power of growth, both nutritive and generative, a power which is the root and principle of appetite, and the affective part of the soul. Now a form cannot undergo an affection or a passion, but must remain what it is. It is the matter (of a body) which is capable of being affected by a "passion" (an affection), when this affection is produced by the presence of the power which is its principle. Indeed it is neither the power of growth that grows, nor the nutritive power that is fed; in general, the principle that produces a motion is not itself moved by the movement it produces; in case it were moved in any way, its movement and action would be of an entirely different nature.[46] Now the nature of a form is an actualization, by its mere presence producing (something), just as if the harmony alone could cause the vibration of the strings of a lyre. Thus the affective part (of the soul, without itself being affected) is the cause of the affections, whether the movement proceed from it, that is, from sense-imagination, or whether they occur without (distinct) imagination.
THE AFFECTIONS OF THE SOUL COMPARED TO A MUSICIAN PLAYING THE LYRE.
We might further consider whether, inasmuch as opinion originates in a higher principle (of the soul), this principle does not remain immovable because it is the form of harmony, while the cause of the movement plays the role of the musician, and the parts caused to vibrate by the affection, that of the strings; for it is not the harmony, but the string that experiences the affection; and even if the musician desired it, the string would not vibrate unless it were prescribed by the harmony.