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.