Plotinos: Complete Works, v. 2 In Chronological Order,...

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.