I'm on a roll with this stuff at the moment. Nothing settled, but the questions are pouring out.
Essence seems to me to be tied up with memory. We recall essences. Find words to communicate them. Our capacity to remember would seem to be related to our capacity to perceive the essence of something. If our ability to perceive the essence of something is related to our ability to coordinate the regulating mechanisms of perception then inability to regulate perception effectively will cause forgetting. What this may mean is that memories do not 'exist' in the head, but are the result of a process of controlling perception. Alzheimers (for example) screws up the control mechanisms.
I'm trying to explore this with this improvisation.