I didn't say a body disappears
What you did say was that your audience here (presumably including myself) is comparable to a person standing in a pipe looking one direction who is too stupid or too unobservant to turn around and notice that the pipe also extends in the other direction. That variety of
ad hominem was kind of adorable when Plato wrote about it, but it hasn't worn well over the ensuing few thousand years.
Specifically, no one has returned from the open daylight that supposedly exists above Plato's Cave carrying some of the three-dimensional wonders that one could presumably find there. (A rock or pine cone would do, for people who have only ever had shadows on the cave wall to look at.) No one has shown how, once unchained, they can go in front of the fire and take control of the shadows or force the mysterious actors casting the shadows to reveal themselves. No one who claims to be unchained seems to be able to move in any way that this benighted chained mind cannot.
Meanwhile, the very people that Plato was mocking with his famous allegory, the empiricists who Plato described as taking pride in being able to predict the appearances of the mere shadows, have studied and characterized and modeled "shadows" that Plato hadn't the slightest trace of a clue about, like oxygen, combustion, metabolism, germs and their role in disease, genetics, galaxies, electricity, the periodic table, the equations of light, digital computing, evolution, gravity, relativity, the deep cosmos, anesthesia, neuroscience, embryogenesis, and quantum mechanics. The same silly **** who thought studying the natural world was like being chained in a cave looking at shadows, also thought the stars were lights mounted on a hollow sphere. Ironic, eh?
Which is why I ask, jumping forward in time from Plato's Cave to return to Nick's Sewer: What is your superior understanding of the metaphorical pipe behind us, the understanding that all the rest of us are too chained up in perceptual illusions to grasp,
actually useful for? What wonders from
outside the cave the other side of the sewer can you show us?