"Sensations are not imprints nor engravings on the soul. That said, we definitively exclude the persistence of any imprint in the soul by which things learned and felt are retained as memories, when no such print is made in the first place. The notion that a trace is produced in the soul depends on the same thesis as its persistence as memory: to reject one is to reject the other. We who reject both are obliged to discover their true workings, since we dispute that sensation is an imprint produced in or on the soul, and that memory is a matter of the imprint's persistence.
"The conclusions we reach by examining our brightest sense will apply to the other four as a matter of course. In all cases of seeing, it is clear that we focus our gaze on the object of sight in the place where it is directly exposed to us, and that the resulting cognitive event take place there, exterior to the seeing soul. There being no blow produced within the soul, I daresay it takes no mark from any such blow (as wax does from a signet-ring) when it sees. Nor would it be necessary to look out at anything, if the soul already contained the form of the thing beheld, and looked on its stamp as something pressed therein.... Semblances and shadows of the visible would be all that we saw, and the visible and the real would be two distinct orders."
"So how does it work, if not like this? Perception is not the vessel of what it relates, for it is not a passive faculty but a dynamic one which acts on whatever is ordained for it. Thus it is that the soul is capable of discriminating between the visible and the audible, which I do not believe would be possible if both were imprints. Perceptions are not passive impressions, but active engagements of what the senses comprehend. Accustomed as we are to believing that the senses know nothing until they are struck, we mistake sensation for a passive event, and think the senses mastered by what they in fact master."
Ennead IV.6.1-2
"The conclusions we reach by examining our brightest sense will apply to the other four as a matter of course. In all cases of seeing, it is clear that we focus our gaze on the object of sight in the place where it is directly exposed to us, and that the resulting cognitive event take place there, exterior to the seeing soul. There being no blow produced within the soul, I daresay it takes no mark from any such blow (as wax does from a signet-ring) when it sees. Nor would it be necessary to look out at anything, if the soul already contained the form of the thing beheld, and looked on its stamp as something pressed therein.... Semblances and shadows of the visible would be all that we saw, and the visible and the real would be two distinct orders."
"So how does it work, if not like this? Perception is not the vessel of what it relates, for it is not a passive faculty but a dynamic one which acts on whatever is ordained for it. Thus it is that the soul is capable of discriminating between the visible and the audible, which I do not believe would be possible if both were imprints. Perceptions are not passive impressions, but active engagements of what the senses comprehend. Accustomed as we are to believing that the senses know nothing until they are struck, we mistake sensation for a passive event, and think the senses mastered by what they in fact master."
Ennead IV.6.1-2