The episteme features a contradictory taken from Boolean algebra, and assumes four different forms, depending on whether ambiguity resulting from the contradictory is understood by neither, by both, or by either the sender or the receiver of a message, In the first two instances, a character foreign to the episteme intervenes to resolve confusion in the narreme, or appears as the victim of the sophistical assumption of a contrary-to-fact reality; in the latter instances the sender or the receiver of the message in the episteme triumphs in the narreme. The resulting inventory, including and augmenting the texts admitted by Per Nykrog and discarding numerous stories already challenged for authenticity, is theoretically defensible to a degree not previously achieved.