The author considers uncertainty in analysis as a process, not as an aim in itself. Based on the analysis of an instance of a countertransference enactment in an analysis, invalidating her listening, she elucidates the two stages of what turned out to be a traumatic countertransference. She shows how affect makes it possible to qualify the transference and the countertransference, and analyses the unconsciously denied traumatic issues. In so doing, she examines the analogy between a traumatic countertransference and Michel de M’Uzan’s notion of a paradoxical system, which heralds the arrival of the concept of the chimera, an analogy she rejects, despite the overlaps. Indeed, while for de M’Uzan, in the paradoxical system, the productions that assail the analyst do not constitute an individual reaction to the patient’s transference, the traumatic countertransference as understood here reveals, on the contrary, a resistance on the part of the analyst due to a repressed traumatic zone.