Is truth essential for Defoe? If truth seems to be the condition of existence of an historical text, it is not the case for a literary work whose aim is never to convey cognitions. The question should thus be rephrased as follows: Where is Defoe's writing situated in the discursive system? Defoe paradoxically anchors his texts in reference by negotiating with the truth instead of giving an account of factual truths, and his rhetoric of ambivalence mimics the epistemological uncertainty of his time, when the frontier between history and fiction is blurred. This article ventures to analyse the concept of truth at the heart of the emergence of fiction at the beginning of the eighteenth century through Defoe's in-between writing.