In “The Trace of Time and the Death of Life: Bergson, Heidegger, Derrida” Martin Hägglund gives a brilliantly clear exposition of Derrida’s trace as a relationship that undermines both the continuity and punctate discreteness of time and poses an “arche-materiality” of time against a vitalistic/continuist conception of temporality.
The trace-structure is the minimal form of any temporality – an inextricable relation to a past that has never been present. Derrida might, on first reading, appear to endorse something like a vitalist or continuist conception of time. He accepts that temporality requires the displacement of temporal event from itself: a series of absolutely independent nows would not be a temporal series, any more than an unrepeatable sign could signify anything.
However, it is not merely the time of consciousness or life: of memory and habit, say. According to Derrida, this displacement is always “inscribed” in some material-spatial medium. E.g. Freud’s purely neurological trace consists of difference in the conduciveness of neural pathways to stimulation – a primary basis for memory which is always repeated differently (iterated) as a result of the causal action on neural tissue of subsequent stimuli.
The synthesis of time cannot be appropriated without spatial support by an immaterial life or subjectivity, or Dasein, etc.Haggelund concludes that this implies an asymmetric dependence of life on matter. The living depends on the non-living but is contingent product of a physical nature characterized by an arche-material temporality. Life, consciousness etc. depends on the material existence of the trace but not vice versa. The trace is (somehow) built into physical reality but it is equally implicit in inorganic or mechanical existence. The zombie-like repetition of the trace is as implicated in the most vivid conscious experience as it is in the evolution of material inorganic structures.