"A reasonable inference is that the wooden slips contain messages passed between yourself and other parties, we do not know when. It remains for you to explain what the messages say and who the other parties were."
A secret policeman presents you with "a reasonable inference" while interrogating you. The inference is a complete misinterpretation of the matter at hand. What do you do?
Colonel Joll of the "Third Bureau" of the "Civil Guard" makes the above statement to the anonymous Magistrate who is the narrator of Coetzee's Waiting for the Barbarians. The "wooden slips" that he refers to were collected by the Magistrate from an archaeological site near the frontier city where the Magistrate works and lives. The Magistrate never makes any progress deciphering the writing on the slips.
Thus, Colonel Joll's "reasonable inference" is completely off base: no messages are being passed, no conspiracy is occurring. The problem for the Magistrate, of course, is that Colonel Joll may well not believe the truth, given that he finds his inference "reasonable" and has actually already concluded that the Magistrate is involved in a conspiracy with the "barbarians" of the book's title.
This situation reads like an allegory of the difficulties of artistic interpretation: the interpreter's "reasonable inferences" of various fragmentary elements of a work (especially those inferences that have to do with the artist's intention) may well be as misguided as Colonel Joll's "reading" of the "wooden slips."
What to do, if you are the one being misread? The Magistrate's response is quite surprising: he begins to translate the slips for Colonel Joll, making up complex stories to give the Colonel what he wants. Give the interrogator what he wants? Is that we should do, confronted by such interrogations? I won't pursue the implications further.