How is the fragile separation between reality and perception within Cymbeline enacted on and through physical bodies? How do bodies act both as reliable markers of "truth" and sites over/through which one can enact deception?

What function does Philarmonus serve within the play? Especially in the final scene -- wherein everyone seems to have a piece of the narrative puzzle to contribute -- what effect does a soothsayer tying all the strands together have?