Abstract
The authors argue that attention to the Freudian and Derridean concepts of Nachtr®aglichkeit and diff¥erance might challenge the implicit assumption of the linear development of traumatic stress from originary event to presenting symptoms. These concepts raise fundamental questions as to the origin of trauma and its ontological status. It is suggested that the psychical reality of retro-causality necessitates a reorientation of current thought about traumatic stress to reflect the paradoxical temporal dynamics of postmodernity.