I think it is in Plato's Phaedo where Socrates considers joy impossible without pain. I always thought that this ancient idea of harmony, dating back to the ear

I think it is in Plato's Phaedo where Socrates considers joy impossible without pain. I always thought that this ancient idea of harmony, dating back to the earliest philosophical records and pertaining also to the philosophy of the East, made sense also as a principle of consciousness. So in this respect, the notion of absolute pain (or joy) is disconcerting. Because, where does it reside? What processes constitute pain? Nerve signals, sure, and chemicals. But what is the essence to that? Can the dynamic be abstracted and generalized? Perhaps these questions are the frontier and the real question of the Cartesian ego. Finally, if we don't have answers to this, who is to say then, really, even that there isn't a Hell and eternal pain after death?