A Madman (n.) is precisely someone who adheres to the imaginary, purely and simply.
Madman (n.) is the one witness to the half-outside position every speaker holds toward language — and he testifies energetically.
A Madman (n.) may know more of human thought than the psychologists — Schreber at least knew his knowledge came from semantic analysis, not from the nature of things.
Madman (n.) is not someone who does without recognition: Schreber wrote five hundred pages so that nobody would be unaware of what he had lived.
Madman (n.) does not believe in the reality of his hallucinations: he readily grants that no one else heard it — what he is sure of is that it concerns him.