The normal person, says Adler, takes guiding principles and goals, metaphorically, with the sense of “as if.”
“To him they are a figure of speech,” heuristic, practical constructs. “The neurotic, however, catches at the straw of fiction, hypostasizes it, ascribes to it a real value.” Finally, “in the psychoses, it is elevated to a dogma. The symbol as ‘modus dicendi’ dominates our speech and thought”. What makes madness is literalism.
Now if the progression from sanity toward mental illness is distinguished by degrees of literalism, then the therapeutic road from psychosis back to sanity is one of going back through the same hermeneutic passage – deliteralizing.
To be sane we must recognize our beliefs as fictions, and see through our hypotheses as fantasies. For the difference between madness and sanity depends not on society or politics, upbringing or chemistry, but wholly upon our sense of fiction.
Even more: to take literally any of the hypotheses such as upbringing or chemistry, society or politics, as the real truth and reason for mental illness is simply mental illness itself, now in the form of an explanatory fiction taken literally rather than heuristically.
— What Does The Soul Want, Healing Fiction