The aim of this article is to think of the place of the witness as a third place that the analyst, in the clinical space of trauma, is able to sustain. According to Ferenczi, in traumatic dreams a third is already being summoned. It is not the witness of the realm of law, nor the place of the father or the symbolic law. This is a third space that can be called potential, interstitial space, indeterminate and formless, where something that at first would be incommunicable circulates and gradually takes shape. This space allows and supports the literalness of a testimonial narrative, its hesitations, paradoxes and silences. More than a trauma theory, the notion of a potential space would be the great contribution of psychoanalysis to the treatment of trauma survivors, establishing the difference between the task of a psychoanalyst and the one of a truth commission.